Effects of Climate Change on Contaminant Cycling in … of Climate Change on Contaminant Cycling in the Coastal and Marine Ecosystems Project Leader ... peak in methylated mercury,

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ContaminantsG. Stern, R. Macdonald and F. Wang

ArcticNet Annual Research Compendium (2012-13)

Effects of Climate Change on Contaminant Cycling in the Coastal and Marine Ecosystems

Project LeaderGary A. Stern, Robie W. Macdonald, Feiyue Wang (University of Manitoba)

Network InvestigatorsBrendan Hickie, Holger Hintelmann (Trent University); Peter Outridge (University of Manitoba); Terry Bidleman (University of Toronto)

CollaboratorsLiisa Jantunen (Environment Canada - Science and Technology Branch); Hamed Sanei (Natural Resources Canada - Geological Survey of Canada); Louis Fortier, Jean-Eric Tremblay (Université Laval); David G. Barber, Steven Ferguson, Ashley Gaden, Alex Hare, Tim N. Papakyriakou (University of Manitoba)

Postdoctoral FellowsJesse Carrie, Karen Foster, Maija Heikkila, Monika Pucko (University of Manitoba)

PhD StudentsAnabelle Baya (Trent University); Kang Wang (University of Manitoba)

MSc StudentsSarah Beattie, Pamela Godin, Breanne Reinfort, Dan Zhu (University of Manitoba); Anya Gawor (University of Toronto)

Undergraduate StudentsAshley Elliott (University of Manitoba)

Technical StaffGail Boila, Joanne DeLaronde, Sheri Friesen, Allison MacHutchon (Fisheries and Oceans Canada - Freshwater Institute)Debbie Armstrong, Amanda Chaulk, Colin Fuchs (University of Manitoba)

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Abstract

Contaminants pose a potential hazard to Arctic fish and marine mammal health, and ultimately to northerners that consume the tissues of these animals as part of their traditional diets. It is therefore imperative that we strive to understand how climate variability in physical forcing and the biogeochemical response to this primary forcing will affect among others 1) contaminant transport processes and cycling; 2) biomagnification through Arctic marine food webs; 3) foraging behaviour of marine mammals (e.g. in response to changing sea ice regimes); and 4) changes to hunting patterns and diets of northerners to reflect availability of traditional foods (e.g. less ice may lead to reduced reproductive success of ringed seals forcing northerners to consume more beluga tissues which typically have 10-fold higher contaminant concentrations). Overall, results from our research will help assess the vulnerability of coastal Inuit communities to climate change, document and project impacts of climate change on traditional food security and community health and provide the information required by communities, scientists and policy makers to help develop adaptation strategies. Our findings will help to test and shape the policy for the future management of contaminants emissions and long range transport to the Arctic and will support integrated ocean management programs such as Marine Protected areas and Large Ocean Management Areas (MPA and LOMA, respectively) such as zone 1(a) in the Beaufort Sea.

Key Messages

The delivery of contaminants to the Arctic food web: Why sea ice matters: Sea ice is a ‘catalyst’ for the delivery of organic contaminants to the Arctic marine food web through: 1) ‘uniform’ processes independent ofcontaminant physical-chemical properties, and 2) ‘differentiated’ processes depending on contaminant physical-chemical properties.

Mercury uptake within an ice algal community during the spring bloom in first-year Arctic sea ice: Mercury in ice algae originates from a combination of brine

and seawater as finite sources, while atmospheric mercury depletion events (AMDEs) do not appear to significantly contribute as a source in real time.

Importance of Arctic Zooplankton Seasonal Migrations for α-Hexachlorocyclohexane (α-HCH) Bioaccumulation Dynamics: Seasonal migration of zooplankton between contaminant-enriched surface waters and contaminant-depleted deep waters influences α-HCH concentrations and enantiomer fractions (EFs) in C. hyperboreus significantly; tissue concentrations change by a factor of 2-3, and EFs reflect ambient seawater values (~0.300 for deep water period and ~0.450 for surface water period).

Dinoflagellate Cysts as Environmental Indicators in the Hudson Bay System: 1) Production of both autotrophic and heterotrophic dinoflagellate cysts in Hudson Bay is low during the ice-covered season. This contrasts with the general view of the connection of dark-adapted heterotrophic dinoflagellate species to sea-ice cover and provides crucial information for the calibration of sediment core cyst data. 2) Cysts of autotrophic Polarella glacialis, a sea-ice dwelling dinoflagellate, were recovered after the sea-ice melt. This species has not been commonly identified in sediment, but it should be more comprehensively assessed as a potential sediment tracer of past sea-ice cover.

Holocene Primary Productivity and Mercury Dynamics and Trends in the NOW Polynya, Baffin Bay: Contrary to expectations, the sediments of ice-marginal sites south and northwest of the Northwater Polynya (NOW) proper display more evidence of change during the 20th Century than sites in the polynya interior. Absolute fluxes of marine organic matter (OM) increased only in the northwest margin, but fluxes were stable in the interior over the last 500-70 years. Southern margin sites experienced declining terrigenous OM inputs and inorganic sedimentation rates for reasons that are as yet unclear.

Zooplankton as Monitors of Mercury in Hudson Bay: 1) The variability of mercury concentrations in pelagic

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zooplankton in Hudson Bay is best explained by the trophic transfer and biomagnification of mercury from prey to predators up food webs. Variability explained by spatial/temporal factors possibly influencing exposures was found to be insignificant for most taxa. 2) Total mercury was found to biomagnify in all four zooplankton food webs investigated, and monomethylmercury was found to biomagnify in three of the four food webs.

Organic mercury species in the Arctic Ocean: The concentrations of organic mercury species, namely monomethylmercury (MMHg) and dimethylmercury (DMHg) at the air-water interface, was monitored over 2 consecutive summers. The data collected suggests that the atmosphere is potentially a direct source of MMHg to the Arctic Ocean.

Transport and transformation of mercury across the ocean-sea ice-atmosphere (OSA) interface: Different from an acidic sea ice surface implied by the current model for the atmospheric mercury depletion events (AMDEs), our studies at the Sea-ice Environmental Research Facility (SERF) revealed that the sea ice surface could be highly alkaline, suggesting the role of sea ice surface in AMDEs is yet to be identified. The sea ice cover was shown to affect the total mercury profile in the upper layer of the underlying seawater, but not the methylated mercury. Analysis of a multi-year sea ice core also did not show evidence of mercury methylation in the core.

Production of methylated mercury in Arctic seawater: The first high-resolution measurement of the water column in the Beaufort Sea revealed a sub-surface peak in methylated mercury, which occurred at the same depth of nutrient maximum and rapid oxygen decline. This is attributed to the local, short-term remineralization of labile organic matter, and not the larger signal of organic remineralization advected from the Chukchi Sea in the halocline. The finding that methylated mercury is produced locally, reflecting recent strength of organic matter cycling, not only explains wide variance in methylated mercury in seawater and biota over time and space, but also

implies that methylated mercury could be used as an indicator of the recent export flux of labile organic matter.

Linking the carbon and mercury cycles in the Beaufort Sea using a seasonal, one-dimensional water column model: A dynamic model was developed that describes the speciation and fate of mercury in concert with carbon cycling in the water column of the Beaufort Sea. The model was developed to allow us to explore scenarios related to changes in drivers impacted by climate change such as ice cover, light and nutrient loading. Initial model results are in good agreement with mercury (Hg) concentrations in seawater and zooplankton measured previously in the same area, but also highlight the need for more information on the seasonal rates of mercury methylation and demethylation. Results from preliminary modeling scenarios suggest that an earlier breakup of sea ice will not significantly alter Hg concentrations in plankton, while a 50% increase in nutrient availability will only marginally decrease Hg concentrations in plankton.

Air-water-food web exchange dynamics of Persistent Organic Pollutants in Canadian Arctic ecosystems: For the first time organophosphate flame retardants and plasticizers have been identified in Canadian Arctic air. Archived air samples collected on ArcticNet expedtions from 2007-2011 were analyzed generating baseline concentrations in from which future trends can be gauged. These results suggest that pesticides, legacy and most current use are declining in Arctic air. Per-fluorinated compounds (PFAS) in Arctic air may be also declining but further sampling is needed to confirm this. The upper 50-100m of the water column in the Canadian Archipelago is well mixed for PFAS compounds, showing no change in concentrations in the upper 100m.

Standardisation of Rock-Eval pyrolysis for analysis of recent sediments and soils: We show that the Arctic is undergoing vast change in the OM cycle, becoming increasingly fresh and influenced by aquatic primary productivity. We also show that the High Arctic lakes and deep water marine (continental rise) sites have

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undergone much larger degrees of degradation of OM relative to more temperate areas, and that the OM is increasingly comminuted/remineralised at these sites. In sum, we show that Rock-Eval is a very useful, rapid, and inexpensive method for analysing OM cycling across a wide range of matrices.

Preliminary results from the BREA studies of mercury and hydrocarbons in Beaufort sediments and biota: The 2012 field campaign was a great success, with all major sampling objectives having been met, despite challenging weather and logistics. Our initial findings indicate that sediment mercury concentrations increase with distance offshore along all four transects and that zooplankton mercury concentrations are generally highest along the continental slope, with the lowest concentrations generally found on the shelf.

Biogeochemical cycles and organic carbon sources and inputs in Hudson Bay: The organic carbon cycle in the Hudson Bay region is greatly influenced by the inputs of terrigenous materials from Arctic rivers. Samples analyzed from 15 rivers show a latitudinal gradient for the distribution of organic carbon (OC) in the Hudson Bay. There are higher amounts of OC entering from the southern rivers with the highest concentrations occurring in the southwest region of Hudson Bay. Lignin biomarker data for the same rivers further strengthens this gradient and lignin product ratios were also consistent with vegetation ecozones of the Hudson Bay region. Preliminary Δ14C ages when compared to acid aldehyde ratios for the dissolved phase (dissolved organic carbon - DOC) show that modern samples were more degraded than much older samples that were from fresh sources. It is apparent that there is potential for the use of lignin biomarkers and isotopes when understanding the terrigenous inputs of OC into the Hudson Bay from Arctic rivers.

IRIS 1 Western and Central Arctic: Successful consultations were held with Kitikmeot representatives to discuss specific regional concerns about climate change impacts and adaptation strategies, involve participants in writing and reviewing sections of the Regional Impact Assessment, and to seek interest in a

Steering Committee representative. New regional-scale atmospheric and ocean-sea ice climate projections will be completed and sent out to all authors by early spring 2013. Estimated completion and publishing of the IRIS 1 document is December 2013.

Community Perspectives on Communicating Contaminants Research: Experiences and impressions of the processes of communication, such as communication methods (how) and communicators/sources (who), influence an individual’s perceptions of a hazard, (e.g. environmental contaminants); the process is part of the overall message, and the process is a message unto itself. Recommendations to improve communication include: smaller, less formal ‘discussion-style’ gatherings with researchers; suggestions that researchers spend more time in the communities to build relationships that will help foster mutual communication over the long term; and working with community members to create contaminants messages of which locals can take ownership and thus better circulate throughout their community. Building local capacity to contend with issues such as contaminants is viewed as especially important because of the significant trust and retention of information and knowledge when it is shared by a respected person from one’s own culture.

Objectives

The delivery of contaminants to the Arctic food web: Why sea ice matters: For decades sea ice has been perceived almost exclusively as a physical barrier for the airborne delivery of organic contaminants to the Arctic Ocean, and the presence of ice cover has been a determinant of the lack of the flux between the seawater and air [1]. Here we postulate, building on research using α-HCH as a process tracer, that sea ice plays a profound role in the delivery of organic contaminants to Arctic food webs causing a risk of increased exposures to biota through 1) high contaminants concentrations in the brine fraction of sea ice [2], 2) concentration of contaminants in the underlying seawater during early stages of ice

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formation [3], and 3) atmospheric deposition of contaminants to melt ponds and their subsequent drainage [4].

Mercury uptake within an ice algal community during the spring bloom in first-year Arctic sea ice: In-situ processes associated with Hg accumulation by Arctic sea ice algae are virtually unknown even though recent studies suggest that the warming climate in the western Canadian Arctic and the decrease in perennial ice cover may result in an increase in biological Hg exposure due to perturbations to top-down and/or bottom-up processes [1-3]. In this study, we examine Hg accumulation by sea ice algae and its sources under natural conditions in the western Canadian Arctic Ocean during the 2008 spring bloom season.

Importance of Arctic Zooplankton Seasonal Migrations for α-Hexachlorocyclohexane (α-HCH) Bioaccumulation Dynamics: The response of zooplankton tissue contaminant concentrations, EFs and BAFs (Bioaccumulation Factors) to seasonal migration have never been determined, even though a few recent studies propose that zooplankton may provide a mechanism to transfer POPs (persistent organic pollutants) vertically in the water column [1-3]. Here we have cultured C. hyperboreus to determine how their α-HCH tissue concentrations, EFs and BCFs (bioconcentration factors) respond to changes in water concentration that would have been experienced presently otherwise in the Canadian high Arctic. Further, we compare experimental results with C. hyperboreus samples collected directly from the Arctic waters during periods of dormancy at depth and grazing at surface. Finally, we determine the extent to which zooplankton could actively transfer α-HCH between depth and surface during annual vertical migration.

Dinoflagellate Cysts as Environmental Indicators in the Hudson Bay System: We will disentangle seasonal patterns of dinoflagellate cyst production and their potential environmental cues in order to aid interpretation and calibration of sediment cyst data.

Holocene Primary Productivity and Mercury Dynamics and Trends in the NOW Polynya, Baffin Bay: We will determine the history of OM sources, production and benthic flux at different locations around and in the interior of the NOW; to determine the relationship between OM and sedimentary mercury fluxes in the NOW during the late Holocene.

Zooplankton as Monitors of Mercury in Hudson Bay: We will assess the factors contributing to the variability of mercury concentrations in zooplankton taxa, including bioaccumulation, biomagnification, spatial and temporal trends.

Organic mercury species in the Arctic Ocean: The objectives of this project are 1) To measure trace concentrations of organic mercury species (MMHg and DMHg) in the ocean water – air interface and 2) to identify the sources and factors influencing MMHg concentrations in the Arctic Ocean.

Transport and transformation of mercury across the ocean-sea ice-atmosphere (OSA) interface: The presence of sea ice has a profound impact on the magnitude and timing of mercury transport, and potentially transformation, across the OSA interface, and ultimately to the Arctic marine food webs. Our objectives are 1) to uncover the role of sea ice in the occurrence of atmospheric mercury depletion events (AMDEs); 2) to understand and quantify the processes by which mercury is transported from the atmosphere to the ocean via snow packs and sea ice; and 3) to examine sea ice brine as a pathway for mercury and methlylated mercury to Arctic marine ecosystem via sea ice algae.

Methylmercury production in Arctic seawater: Although inorganic mercury is usually the most abundant mercury species in seawater, methymercury is the dominant form (>80%) found in higher trophic levels in the foodweb. Our objective hence is to examine and quantify the sources of methylmercury in Arctic seawater, which is a crucial component of the pathways leading to mercury uptake by biota.

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Linking the carbon and mercury cycles in the Beaufort Sea using a seasonal, one-dimensional water column model: The overall objective of this study is to improve our understanding of factors affecting the fate and bioavailability of mercury species (total mercury (THg) and methylmercury (MeHg)) in Arctic marine ecosystems. This will be accomplished by: (1) Developing and calibrating a comprehensive mercury fate model for the marine ecosystem that links mercury inputs from the atmosphere to uptake in marine foodwebs; (2) Using the model to improve our understanding of how changing climate regimes will affect the fate, cycling and bioavailability of mercury in the Arctic marine ecosystem; and (3) Using the model to identify data gaps that can then be addressed by further field sampling. One such example involves measuring the partitioning of mercury species between water and suspended particles in the water column of the Beaufort Sea.

Air-water-food web exchange dynamics of Persistent Organic Pollutants in Canadian Arctic ecosystems: The objectives of this study are to: (1) Collect a set of baseline seawater concentration data for legacy persistent organic pollutants (POPs) and new chemicals in the Arctic against which future trends, sources and sinks in the ocean may be evaluated; (2) Collect accompanying air, phytoplankton and zooplankton concentration data in a way that will assist transport and environmental fate modeling of Arctic contaminants; (3) Develop a better understanding of the air-water-food web exchange dynamics and framework for assessing climate change impact on Arctic contamination; and (4) To apply the ocean contaminant data to the design of a practical monitoring strategy for Canadian Arctic waters.

Standardisation of Rock-Eval pyrolysis for analysis of recent sediments and soils: In this study our aim was to: (1) Develop Rock-Eval analyses as a reliable, efficient method for analysing the quantity and quality of organic matter in sediments and soils, by comparing sediments and soils across a wide variety of environments (e.g. climatic, geological, terrestrial/marine); (2) Determine what changes are occurring across a suite of Arctic

sediments and soils (peat cores) due to climate change; and (3) Develop new descriptive ratios to help interpret organic matter quality and quantity, which in turn can be used statistically with other variables (e.g. stable isotopes, metals).

Preliminary results from the BREA studies of mercury and hydrocarbons in Beaufort sediments and biota: The objectives of this study are to: (1) Establish the background levels of mercury and composition of sentinel hydrocarbon compounds (HC) in both abiotic and biotic compartments of the Beaufort Sea outer shelf and slope regions (including lease blocks) prior to further oil and gas development; (2) Establish baseline measures of hydrocarbon metabolites in fish (i.e. determine nature and levels affecting key fishes); (3) Measure indicators of fish health and link these to hydrocarbon exposure and internal metabolite concentrations; (4) Generate maps and tables showing spatial distributions and concentrations of mercury and predominant and toxicologically significant hydrocarbon compounds in each of the sample compartments (e.g. selected species of zooplankton, benthic invertebrates, fishes, and surface and suspended sediments); (5) Assess the geographical variability of current mercury and hydrocarbon levels in this region, and determine their natural variability over time prior to the industrial period (i.e. about pre-1850). This will be done using sediment cores collected during the joint Amundsen cruise in 2013; (6) Conduct chemical and physical oceanographic measurements in tandem with the collection of zooplankton and fishes so as to try to determine how, for example, increasing water temperatures and primary productivity may affect HC exposure; and (7) Use hydrocarbon composition biomarkers derived from these data to establish their sources (natural seeps, terrestrial run-off, oil/gas combustion-related) in the marine ecosystem in this part of the Canadian Arctic, prior to any future oil and gas exploration in the region and prior to the likely expansion of shipping traffic through the Northwest Passage.

Biogeochemical cycles and organic carbon sources and Inputs in Hudson Bay: The objectives of this project are: (1) To develop an understanding of the organic carbon

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cycle (sources, sinks, processes) in Hudson Bay and its sensitivity to recent change occurring in the ocean and adjacent terrestrial watersheds; (2) to understand the implications of permafrost degradation, SOC (suspended organic carbon) transport, and hydrological changes to the landscape on the organic carbon cycle of the Hudson Bay; and (3) to understand the role of lignin biomarkers in determining the role of terrigenous sources such as permafrost entering the Hudson Bay organic carbon cycle.

IRIS 1 Western and Central Arctic: The objectives of this project are to 1) consult with Kitikmeot representatives about appointing a suitable volunteer to the Steering Committee; (2) obtain RIA draft 1 review comments and edits from the Steering Committee to forward to lead and contributing authors; (3) circulate regional-scale atmospheric climate projections and GCM (global climate model) marine projections to lead and contributing authors to incorporate into the supporting scientific chapters; (4) have a working second RIA (Regional Impact Assessment) draft by mid-2013 to present to ISR and Kitikmeot stakeholders for consultation; and (5) complete the first RIA edition by December, 2013.

Community Perspectives on Communicating Contaminants Research: The objectives of this project are to (1) explore contaminants issues in the context of their applicability to the daily lives of community members, and in the broader context of risk perception, local and scientific knowledge of climate variability, and overall environmental research throughout the North; (2) investigate the role of relationships in contaminant message construction, reliability and retention; and (3) create a community-driven pamphlet about mercury that incorporates a communications protocol for disseminating contaminants information.

Introduction

The delivery of contaminants to the Arctic food web: Why sea ice matters: Legacy organochlorine pesticides (OCPs) are a group of hydrocarbon

compounds containing multiple chlorine substitutions. Although no longer used, these pesticides are now ubiquitous in the Arctic environment due to their semi-volatility and chemical persistence [5]. Examples of such compounds include heptachlor epoxide, α-hexachlorocyclohexane (α-HCH), chlordanes, nonachlor and dieldrin. Widespread bans on OCP production and application led to the introduction of a group of large-scale application agro-chemicals often referred to as current-use pesticides (CUPs). Increasing levels of CUPs have been found in regions isolated from their use and production including the Arctic [6], even though most of them were designed to have reduced environmental persistence and low potential to undergo long-range transport (LRT) [7]. CUPs of concern in the Arctic have high production volumes, widespread current or past use, relatively low air-water partitioning, and potential to bioaccumulate and biomagnify (e.g. chlorpyrifos, chlorothalonil, dacthal, and endosulfans) [6,8].

Mercury uptake within an ice algal community during the spring bloom in first-year Arctic sea ice: Sea ice physical structure comprises ice crystals, between which the brine and air inclusions are sandwiched [4]. The ice-water interface is an important habitat for Arctic organisms [5,6]; however, the highest abundance of ice algae resides within the bottom few centimeters of first-year sea ice (FYI), constituting a readily available food source to herbivorous zooplankton species [7-9]. Brine pockets in the bottom few centimeters of Arctic ice provide a unique habitat of near freezing temperatures, high salinity, and high concentrations of contaminants including mercury (Hg) [10-13]. Under-ice seawater may act as an additional source of mercury to the ice algal community in a manner closely resembling the replenishment of nutrients due to the convective mixing at the bottom of ice in the spring and summer. Another plausible source of mercury to the ice algal community could emanate from atmospheric mercury depletion events (AMDEs) [14]. AMDEs, which begin at polar sunrise and end at snow melt onset, are unique to the Arctic marine environment and involve the oxidation of gaseous elemental mercury (GEM,

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Hg0) to reactive gaseous mercury (RGM, Hg2+) by

sunlight-induced reactions in the presence of bromine oxide (BrO) [1]. The RGM is then scavenged from the atmosphere during precipitation events and is deposited on snow, ice or open water surfaces.

Importance of Arctic Zooplankton Seasonal Migrations for α-Hexachlorocyclohexane (α-HCH) Bioaccumulation Dynamics: α-HCH is the most abundant POP in Arctic seawater and lower trophic levels of marine biota [4,5]. α-HCH concentration and EF in the surface water of the Beaufort Sea/Amundsen Gulf were reported to be 1.29 ± 0.38 ng/L and 0.442 ± 0.023, respectively (n = 48, October 2007-May 2008) [6], and decrease with depth reaching ~0.30 ng/L and 0.150-0.300, respectively, in the near bottom water [7,8]. In general, organic contaminants bioaccumulate in zooplankton passively through exposure to surrounding seawater (bioconcentration) and actively through feeding, although the relative importance of these routes is not yet clearly understood [1,9]. Organic contaminant uptake by biota is usually described by a ratio of lipid-based concentration in tissue (kg/kg lipid wet weight) divided by concentration in ambient seawater (kg/L), termed the Bioconcentration Factor (BCF (L/kg lipid wet weight)) where only phase partitioning is involved, or Bioaccumulation Factor (BAF) if all routes of entry are taken into account. The concentration of α-HCH in zooplankton is apparently controlled by equilibration between lipid and ambient seawater given the significant log-linear relationship between BAF or BCF and the octanol-water partitioning coefficient (Kow) for contaminants with logKow < 6 [5,10], the lack of any substantial increase of α-HCH concentration in zooplankton as feeding season progresses [4], and the lack of α-HCH biomagnification within zooplankton [11].

Dinoflagellate Cysts as Environmental Indicators in the Hudson Bay System: In cold-water seas, planktic organisms battle seasonal harshness by producing quiescent, environmentally resistant life stages that enable them to reduce respiration rates to a minimum and sink to the seafloor. Sedimentary archives of

dinoflagellate resting forms (cysts) can be used to reconstruct past environmental conditions [1]. In the Hudson Bay system, dinoflagellate cyst assemblages are primarily organized following nutrient and prey availability and freshwater dynamics [2]. However, marine sedimentation rates are inherently slow and surface mixing is typically pronounced. Due to low temporal resolution, causal relationships between sedimentary cyst assemblages and environmental forcing remain deficiently understood. We use bi-weekly to bi-monthly data from two particle-intercepting traps deployed close to the seafloor in eastern and western Hudson Bay, respectively, to shed light on the seasonal succession of dinoflagellate cyst production in this particular system.

Holocene Primary Productivity and Mercury Dynamics and Trends in the NOW Polynya, Baffin Bay: The Arctic is undergoing rapid change in ice climate [1] that will lead to as yet poorly understood change in the biogeochemical cycling of contaminants as well as carbon, nitrogen, phosphorus and other biologically essential elements [2]. Polynyas, which are defined as polar ocean regions having predictably light ice and open water, form special biological habitats which are likely to be especially vulnerable to change in ice climate and, perhaps, will be the first regions in Arctic seas to express such change. The retreat and advance of sea-ice directly influences biotic and abiotic sedimentation in polar marine environments by altering irradiance levels, stratification and the habitat for primary producers [3-5]. However there is sparse evidence from which to infer exactly how change in ice cover might affect Arctic marine ecosystems, or how this change may have been expressed over the last century [6]. Here we present evidence of recent change in the organic carbon system associated with the NOW polynya in Baffin Bay, using a variety of organic markers in six dated marine sediment cores collected from sites ranging from the shallow northern portion of the polynya to the slope at its southern boundary.

Zooplankton as Monitors of Mercury in Hudson Bay: Little is known about mercury accumulation and transfer to predators within lower trophic levels

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(e.g. zooplankton) of northern marine food webs. Contaminant biomagnification assessments typically treat zooplankton as one homogenous trophic category. Yet, zooplankton themselves form a complex subset of animals, and mercury accumulation and transfer at these lower trophic levels governs the exposure of predators further up the food web, including humans. Existing knowledge gaps on the bioaccumulation and biomagnification of mercury in zooplankton food webs need to be addressed if we are to progress towards understanding the variability of mercury in top predators, and the possible impacts of climate change on mercury in coastal and marine food webs.

Organic mercury species in the Arctic Ocean: Gaseous mercury (Hg) is a persistent pollutant and can be transported over long distances to remote areas as far as the Arctic. The organic form monomethylmercury (MMHg) is a potent neurotoxin and readily available for uptake by biota. The concentrations of Hg in Artic marine mammals and fish are among the highest in the world and often above the consumption guideline of 0.5ug/g. Hg contamination of the Arctic ecosystem has direct repercussions for local communities who rely on the wildlife for their traditional diet and raises serious health concerns. The key factor determining the concentration of Hg in biota is the concentration of MMHg in water. MMHg and dimethylmercury (DMHg), another important organic Hg species, are formed mainly at the sediment-water interface and in anoxic pockets in the water column. However, the sources, behavior and fate of methylated Hg species in ocean waters, particularly at the air-water interface, are still unclear and not completely understood. The direct and indirect contribution of the atmosphere as a source of MMHg to the Arctic ecosystem is still subject to debate. For this study, we hypothesize that DMHg in surface ocean water volatilizes to the atmosphere where it is converted to either reactive Hg (Hg2

+) or MMHg which are rapidly deposited in the ocean contributing to the MMHg pool. Recent analytical techniques based on the use of enriched stable isotopes with subsequent detection by ICP-MS [1] was used for the determination of trace amounts of Hg in air and water. Furthermore, enriched isotopes were used as

tracers in experiments to monitor Hg transformation processes such as methylation and demethylation which are primordial for us to identify the sources and factors affecting the fate of MMHg in the marine ecosystem.

Transport and transformation of mercury across the ocean-sea ice-atmosphere (OSA) interface: Mercury is a global contaminant, and its persistently high concentrations in Arctic marine mammals have raised concerns over the health of these animals and the Northerners who consume these animals’ tissues as part of their traditional diet [1, 2]. As a result, major research initiatives have been undertaken to understand the sources and pathways for Hg bioaccumulation in the Arctic marine ecosystems. Evidence is now mounting that the highly variable Hg concentrations in Arctic marine mammals in recent decades are no longer a simple function of external, anthropogenic Hg emissions; instead, they are increasingly driven by changes in postdepositional processes that control the transport, transformation, and biological uptake of stored Hg in the Arctic Ocean [2, 3]. As part of the ongoing ArcticNet-funded research, we have recently shown that the sea ice environment plays a major role in controlling the magnitude and timing of atmospheric Hg flux to the underlying aquatic system and potentially in affecting the biological Hg uptake via sea ice algae [4, 5]. We have also shown that the local sea ice environment and frost flowers could play a major place in the occurrence and severity of the AMDEs [6, 7]. However, major uncertainties exist with respect to the mechanism by which sea ice affects AMDEs and whether mercury methylation occurs within sea ice.

Methylmercury production in Arctic seawater: Although inorganic Hg(II) is usually the most abundant Hg species in seawater, methylmercury is the dominant form (>80%) found in higher trophic levels in the foodweb. Recent discovery of a subsurface maximum of methylated mercury (MeHg) in seawater and its apparent association with nutrient maxima in the Pacific Ocean [1], Southern Ocean [2], and Mediterranean Sea [3] suggests that Hg methylation

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occurs within oxic ocean domains where organic matter (OM) is undergoing remineralization. Relatively MeHg concentrations have also been reported in deep waters in Hudson Bay and the Canadian Arctic Archipelago (CAA) [4, 5]. However, low vertical resolution in these studies precludes a determination of the role OM remineralization may have played.

Linking the carbon and mercury cycles in the Beaufort Sea using a seasonal, one-dimensional water column model: While efforts to reduce mercury emissions in recent decades have generally lead to gradual declines in global atmospheric concentrations, including in the Arctic [1], concentrations in some Arctic biota and in sediments have either not declined or have increased [2, 3]. This disconnect between trends in air and those in sediments and biota has led to the hypothesis that climate change is altering the cycling of the existing mercury inventory already in the Arctic, and that these changes outweigh the changes in mercury inputs to the system [2-5]. Potential climate-related mechanisms that could alter mercury cycling in the Arctic marine ecosystem include: changes in sea ice cover affecting air-water exchange of mercury; changes in ice cover and light regime altering food web structure, primary production and the vertical flux of organic carbon and particle-bound mercury. In turn, these may affect the rates of mercury methylation and demethylation that determine the quantity of mono-methylmercury that is available to biomagnify through the foodweb. Recent studies have demonstrated a clear link between Hg methylation rates, primary productivity and organic carbon remineralization in mid-depth seawaters near the oxygen minimum [6]. Algal particulate organic matter scavenges inorganic Hg from the euphotic zone, providing a physical focal point and the carbon substrate for subsequent microbial methylation activity as the particles settle. Thus any changes in primary production and the vertical flux of organic matter may affect the supply and bioavailability of methylmercury entering the foodweb.

The primary objective of this project is to develop a comprehensive mechanistic model of the mercury cycle in the Arctic Ocean with a strong emphasis on

linking it to a carbon budget/production model [7, 8] that is sensitive to changes in climate related drivers such as extent of ice cover, light regime and nutrient supply. In addition to providing a cohesive framework for devising a more detailed mercury budget, the model is being developed as a predictive tool to explore the implications of potential future climate change scenarios on mercury cycling.

Air-water-food web exchange dynamics of Persistent Organic Pollutants in Canadian Arctic ecosystems: Contaminants are transported to the Arctic by air and ocean currents. Air in the Arctic is a relatively well-mixed system but Arctic oceanography is very complex, thus levels of contaminants in Arctic water vary; this is demonstrated with hexachlorocylochexanes (HCHs) in surface waters in the Canadian archipelago [1] and the Beaufort Sea [2]. Arctic monitoring programs have observed declines in organochlorine pesticides (OCPs) over the past two decades in air and biota [3, 4], but there has never been a coordinated Arctic water monitoring program. Water is a secondary medium for the Stockholm Convention’s Global Monitoring Plan for Persistent Organic Pollutants (POPs).

Organophosphates (OPs; e.g. flame retardants and plasticizers) are potentially toxic compounds that are high production volume chemicals and the Global Monitoring Plan risk assessment has identified several of these compounds as high priority compounds. Since the banning of the penta- and octa-mixtures of polybrominated diphenyl ethers (PBDEs), the production of OPs has increased and this growth is expected to continue. In this study, we have determined baseline concentrations of OPs in air against which future trends can be gauged. Such information is vital in determining whether a new chemical is a candidate for national and international regulations.

Stain-repellent-related per- and polyfluoroalkyl substances (PFAS) have gained global attention for their bioaccumulative, persistent, long range transport potential and toxicity, particularly perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). Recently, PFOS and its salts were added

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to Annex B of the Stockholm Convention on POPs. Accordingly, industries have changed from producing the more persistent PFAS (including perfluoroalkyl carboxylates (PFCAs) and polyfluoroalkyl sulfonates (PFSAs)) towards more volatile substances, including fluorotelomer alcohols (FTOHs), fluorotelomer acrylates (FTAs)) and shorter chained perfluoroalkyl substances. With the addition of potentially more water soluble compounds to the Stockholm Convention, such as PFAS, it is essential to determine whether air or ocean currents are more efficient carriers of these pollutants to the Arctic aquatic system and lower foodweb.

The intent of this project was to better understand whether air or ocean currents are more important in delivering specific contaminants to the Arctic, what happens to them once they are there and how they enter the aquatic foodweb. To achieve this, we coordinated air-water-phytoplankton-zooplankton sampling in the Canadian Archipelago in collaboration with the ArcticNet program onboard the CCGS Amundsen (October 2011). This study builds on past air and water sampling conducted in the Canadian Archipelago by the same team between 1992-2010. Results of this research will allow us to assess any changes of the aquatic contamination in the Canadian Archipelago over time. This is particularly important in understanding the effect of climate change on Arctic pollution.

Standardisation of Rock-Eval pyrolysis for analysis of recent sediments and soils: Contaminant cycling in the Arctic is increasingly being observed as affected by the changing carbon cycle (e.g. [1]. As such, understanding the carbon cycle is integral to understanding how contaminants interact with their environment. Biogeochemically, carbon is often measured as the total organic carbon (TOC), yet the highly dynamic and diverse nature of organic carbon is often missed using this bulk analytical method. Complementary to biomarker and stable isotope studies, our group has been pioneering the use of Rock-Eval analyses to understand how organic matter (OM) cycles in a wide variety of environments (lake

and marine sediments, peat bogs, soils). Rock-Eval is well-established to describe fossil fuel source rocks [2], but has not been properly standardised for more geologically recent environments. The low-cost, rapid and sample-lean requirements of the method make it ideal for studying organic matter cycling in the environment.

Preliminary results from the BREA studies of mercury and hydrocarbons in Beaufort sediments and biota: The Arctic sea-ice environment is rapidly changing [1-3]. Based on the annual recession of sea-ice observed during the past decade, an increase of marine traffic is expected within the Northwest Passage. This traffic, along with increasing urban and industrial activities associated with offshore oil and gas exploration and production and the transport of crude oil and its refined products, has amplified the probability of accidental oil spillages. The Arctic natural reserves in oil are estimated to be as high as 400 billion barrels, but more realistic estimates place suggest closer to 90 billion barrels [4]. Increased hydrocarbon and mercury exposure may translate into a greater health risk for indigenous people and endanger the endemic wildlife. Petrogenic parental and alkylated polycyclic aromatic hydrocarbons (PAHs) are priority pollutants in the Arctic [5], and are of particular concern. Public concern over the development of offshore oil and gas in the Arctic has increased following the recent Deepwater Horizon oil spill in the Gulf of Mexico.

There is an urgent need to establish the background levels and composition of mercury and hydrocarbons in both abiotic and biotic compartments of the Beaufort Sea outer shelf and slope regions (including lease blocks) prior to further oil and gas development, and develop our understanding of the factors controlling the transport, fate and biological effects of petroleum hydrocarbons spilled in the marine environment. In the Arctic, the presence of sea-ice will play an important role in entrapping oil and transporting it to locations that could be some distance from the source areas. Understanding the fate of oil in ice and in the surrounding seawaters are essential for the conduct of environmental risk assessments,

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the development of oil spill countermeasures, and the monitoring of habitat recovery in the event of a spill. A lack of scientific knowledge for the development of sound policies and regulations may temper the development of Canada’s Arctic oil and gas industry. There is a further need to establish baseline measures of metabolite formation and fish health parameters related to mercury and PAH exposure. PAH exposure can also negatively affect the nutritional status of exposed fishes and their ability to effectively reproduce.

Biogeochemical cycles and organic carbon sources and inputs in Hudson Bay: Rivers drive the freshwater budget of the Arctic Ocean by carrying large amounts of particulate and dissolved materials and depositing them on panarctic shelves to be redistributed by ocean circulation and climate. The Hudson Bay region and its latitudinal location is an important area due to its temperature gradients which influence vegetation, freeze/thaw cycles and ultimately the hydrology and inputs of organic carbon into the Hudson Bay organic carbon cycle. We hypothesize that by analyzing both the Δ14C ages of the DOC and particulate organic carbon (POC) and lignin biomarkers, we may determine source terrigenous inputs of carbon with a particular focus on permafrost.

IRIS 1 Western and Central Arctic: An Integrated Regional Impact Study (IRIS) is a framework that combines and summarizes all available knowledge of a region affected by change, and facilitates better knowledge accessibility. This knowledge is used to produce a climate change Regional Impact Assessment (RIA) for the Western and Central Arctic IRIS, which is a prognosis of magnitude and socio-economic impacts and benefits of change. The IRIS 1 Process includes: a) Consultation – to ensure the RIA is relevant and meets regional needs, and policy recommendations are politically and culturally appropriate; b) Research and Writing – documenting traditional knowledge and scientific observation enable the identification of linkages between environmental change and impacts to health and society; c) Model Future Scenarios – regional-scale climate change scenarios help predict impacts on environments; d) Develop and Analyze Prognoses – observations and models provide insight into future

environmental, health and societal vulnerabilities, and science-to-policy recommendations identify appropriate adaptation strategies. Breanne Reinfort stepped in to temporarily fill Ashley Gaden’s position as IRIS 1 Coordinator when Ashley went on maternity leave (July 2012-March 2013).

Community Perspectives on Communicating Contaminants Research: Northerners continue to receive information about contaminants and the potential impacts on wildlife and human health, and despite improved message sensitivity, years of considerable effort disseminating this complex information has resulted in only general awareness of contaminants issues [1]. This project investigates the overlooked importance of perceptions of environmental risk communication in the assessment of message reception, comprehension, and compliance. Past communication efforts have focused only on message content (what) and target audience perceptions of the hazard itself, while disregarding how audiences perceive communication processes, such as communication methods (how) and communicators/sources (who), that are the primary source of information about a hazard. Therefore, the ways in which risk communication is approached and carried out may be of significant importance to how an environmental hazard is perceived. To address this knowledge gap, this project explores the value of understanding the role of communication processes and sources among target audience members in the construction of messages and communication strategies about environmental health risks, such as long-range atmospheric and oceanic contaminants in Arctic communities. Specifically, it considers risk perceptions of contaminants and contaminants communication in the Inuvialuit community of Sachs Harbour, NT, using contaminants research, specifically mercury, conducted through the International Polar Year’s Circumpolar Flaw Lead System Study, Environmental Monitoring Projects from the Northern Contaminants Program, and Phase II of ArcticNet. We consider participants’ knowledge and perceptions of contaminants research and how research is communicated to communities, and examine current communication methods used. From a community

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perspective, we discuss how contaminants research, using mercury as an example, can be communicated to communities in accessible, understandable, and relevant ways, and uncover the crucial role that relationships play in message construction, reliability, and retention.

Activities

The delivery of contaminants to the Arctic food web: Why sea ice matters: Seawater and air samples collected as part of the IPY-CFL project in 2008 were analyzed for OCP and CUP concentrations at the Environment Canada, Burlington. A manuscript is in preparation for submission to the Proceedings of the National Academy of Sciences: “The delivery of contaminants to the Arctic food web: Why sea ice matters”.

Mercury uptake within an ice algal community during the spring bloom in first-year Arctic sea ice: Ice algae samples collected as part of the IPY-CFL project in 2008 were analyzed for mercury concentrations at the Department of Fisheries and Oceans, Freshwater Institute, Winnipeg. A manuscript was prepared and submitted to the JGR Oceans: “Mercury uptake within an ice algal community during the spring bloom in first-year Arctic sea ice. Environmental Science and Technology”.

Importance of Arctic Zooplankton Seasonal Migrations for α-Hexachlorocyclohexane (α-HCH) Bioaccumulation Dynamics: Seawater and Calanus hyperboreus samples collected as part of the IPY-CFL project in 2007/2008 were analyzed for α-HCH concentrations and EFs. A manuscript was prepared and submitted to Environmental Science and Technology: “importance of Arctic Zooplankton Seasonal Migrations for α-Hexachlorocyclohexane (α-HCH) Bioaccumulation Dynamics”.

Dinoflagellate Cysts as Environmental Indicators in the Hudson Bay System: Dinoflagellate cysts accumulated during one year were isolated from two sediment traps (AN01, AN03) and identified under a light microscope at the Freshwater Institute, DFO, in Winnipeg. Furthermore, microscope identification

of cysts from three sediment core sequences from Hudson Bay progressed with the completion of the analysis of one sediment core and initiation of the analysis of two other cores. Dinoflagellate cysts from a sediment core collected from Foxe Basin were isolated in the Paleoenvironmental Laboratory, University of Victoria, BC in October 2012. A manuscript discussing the environmental drivers of dinoflagellate cyst assemblages in the Hudson Bay system was submitted to Marine Micropaleontology in August 2012.

Holocene Primary Productivity and Mercury Dynamics and Trends in the NOW Polynya, Baffin Bay: Geochemical and radiometric dating work was completed on the six sediment cores which form the basis of this study. A manuscript has been written and submitted to Marine Geology and is still in review at this date.

Zooplankton as Monitors of Mercury in Hudson Bay: A large database of total mercury (THg), monomethylmercury (MMHg), and stable isotopes (δ15N and δ13C) in zooplankton taxa collected from across Hudson Bay over eight years (2003-2010) was compiled and variability in the database owing to trophic transfers of mercury and regional and temporal factors was assessed. One manuscript was just published in Environmental Science and Technology on mercury biomagnification in zooplankton food webs from Hudson Bay. A second manuscript pertaining to spatial/temporal variability in zooplankton taxa is in preparation.

Organic mercury species in the Arctic Ocean: Air and sea water samples were collected during ArcticNet expeditions (July-August 2010 and 2011) on board the CCGS Amundsen in Hudson Bay and the Candian Arctic Archipelago (CAA) for MMHg and DMHg determination. Incubations experiments were also conducted on board to investigate the transformation processes (methylation and demethylation) of organic Hg and reactive Hg (Hg2

+) species in ocean water. Sea water samples were spiked with isotopically enriched Hg species (MM199Hg, DM198Hg and 200Hg2

+) at ambient levels. The analysis of the water samples

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collected in 2010 and 2011 were completed in summer 2012 and two manuscripts are in preparation for submission in peer reviewed journals by spring 2013.

Transport and transformation of mercury across the ocean-sea ice-atmosphere (OSA) interface: Over the periods from December 2011 – April 2012 and December 2012 – April 2013, mesocosm-scale experiment at the Sea-ice Environmental Research Facility (SERF) at the Unversity of Manitoba were conducted to study 1) the role of sea ice in the occurrence and severity of AMDEs; and 2) the partitioning of Hg across the OSA interface during the growth of frost flowers and other first-year sea ice. The chemical anaylysis of the multiyear ice core collected in 2012 from the Beaufort Sea was completed and a manuscript is in preparation.

Methylmercury production in Arctic seawater: A manuscript titled “Total and Methylated Mercury in the Beaufort Sea: The Role of Local and Recent Organic Remineralization” was publshed in the journal Environmental Science and Technology in October, 2012.

Linking the carbon and mercury cycles in the Beaufort Sea using a seasonal, one-dimensional water column model: The mercury/carbon model from the previous year was improved by adding the methylation of Hg(II) in seawater to mono- and di-methylmercury (MMHg and DMHg, respectively) and updating the subsequent uptake of MeHg by the organic component. The instantaneous concentration of total methylmercury in a given cubic meter of seawater is based on an empirical relationship with the organic carbon remineralization rate [6]. The ratio of MMHg to DMHg concentration in seawater is fixed at 2:3 and based on measurements [9].

Air-water-food web exchange dynamics of Persistent Organic Pollutants in Canadian Arctic ecosystems: Thirty-four air samples were collected between Kuglugtuk and Quebec City via Baffin Bay in October 2011, and these were analysed for OCPs, CUPs, PFAS and OPs. Eighteen 100-200L samples were

collected for OCPs, CUPs and OPs, including three depth profiles. Thirty 1L water samples were collected for PFAS, including eight depth profiles. Thirty-two surface water samples were taken for particulate matter. Zooplankton samples were taken at seven locations. A manuscript is in preparation.

Standardisation of Rock-Eval pyrolysis for analysis of recent sediments and soils: We compiled a series of sediment cores from lakes, marine sites, and peat cores, and coupled these with a few literature sources that had the Rock-Eval data in a tabulated form. Cores from some of the Arctic lakes (near Fort Good Hope) were obtained via funding from ArcticNet, as were those from the marine sites (North Water Polynya in Baffin Bay). Collaborations with the Geological Survey of Canada (Peter Outridge in Ottawa and Hamed Sanei in Calgary) provided a variety of cores from Alberta near Edmonton and the oilsands, Flin Flon in Manitoba, two lakes in the High Arctic (DV-09 and Amituk), as well as others in and near the Mackenzie Delta. These cores were collected from 2000 to 2008.

The compiled data were integrated into a large spreadsheet, and each site was plotted for a wide variety of parameters. We also compared regional sites (e.g. all sites near the power plant near Edmonton), as well as types of sites (i.e. marine, lacustrine, peat bogs, and soils). Comparisons of each parameter were made in combination with other data (e.g. microscopic analysis of sediment, radiometric dating, description of environment and geology), yielding a few descriptive ratios of significant power.

Preliminary results from the BREA studies of mercury and hydrocarbons in Beaufort sediments and biota: DFO chartered the F/V Frosti for the 2012 and 2013 field programs. The F/V Frosti is a commercial stern trawler that operates out of Richmond, B.C. The F/V Frosti began its transit to the Canadian Beaufort Sea on July 12th and encountered heavy ice at Point Barrow, Alaska, which delayed its progress by two days. The F/V Frosti reached Tuktoyaktuk, NT, on July 31st where embarkation was delayed three additional

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days while waiting for fuel. Science crew boarded an NTCL fuel barge in Tuktoyaktuk on August 4th, and transferred to the F/V Frosti which was waiting approximately 12 nautical miles offshore. Science activities began the following day with lab setup and trawl calibrations. Station work began on August 6th. Overall the 2012 field campaign was a success, with

all major sampling objectives having been met, despite challenging weather and logistics.

Four primary transects were sampled, each with stations at 40m, 75m, 200m, 350m, 500m, 750m and 1000 m depth (Figure 1). Transects were selected to provide adequate geographic coverage of the Canadian Beaufort and Yukon-Alaskan Shelves, while focusing sampling effort on previously unstudied slope and deep basin fish habitats. Fishing included benthic trawling and mid-water trawling combined with hydroacoustics. Fish habitats were assessed at each station using a conductivity, temperature and depth probe (CTD) that also carried sensors for oxygen and fluorescence (refer to Section 3, Physical Oceanography). The probe was mounted to a 24-bottle rosette which collected water for chemistry and examination of marine productivity. Substrate habitats were assessed using a box-core and trawl mounted video. Additional marine foodweb components were also examined, including zooplankton and benthic invertebrates.

Total mercury, hydrocarbon, trace metal, particle size, Rock-Eval and biomarker analysis on all surface sediment samples have been completed and a manuscript is in preparation. Total and methyl mercury analysis has been completed for all zooplankton and benthic samples. We are still waiting on hydrocarbon and stable isotope results. Analysis of fishes is expected to begin in February 2013.

Biogeochemical cycles and organic carbon Sources and inputs in Hudson Bay: Dissolved and particulate water samples, permafrost and soil samples collected from 15 rivers in the Hudson Bay region (Figure 2) have now been analyzed at the Centre for Oceanic and Atmospheric Sciences (COAS) at Oregon State University for carbon and nitrogen, stable isotopes, organic carbon and lignin biomarkers under the direction of Miguel Goni. Selective samples were also sent to the NOSAMS lab at Woods Hole Oceanographic Institute in order to analyze for Δ14C and δ13C. All the data has now been processed and several manuscripts are in preparation.

• PAVR• KOGR• POLR• INNR• NASR• PWR• GWR• JOSR• WILR• FERG• THAR• THER• CHUR• SEVR• WINR

Figure 19. Map showing the rivers sampled for water, permafrost and soil during the 2010 Amundsen expedition.Figure 2. Map showing the rivers sampled for water,

permafrost and soil during the 2010 Amundsenexpedition.

Figure 1. Location of BREA sampling transects (Tbs12, Gry12, Kug12, Dal12) and the additional hydroacoustic transects (Mackenzie Valley, West-to-East, and Hct12) during the 2012 field program.

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IRIS 1 Western and Central Arctic: Ashley Gaden organized an IRIS 1 Steering Committee and lead author meeting on April 22, 2012, in Montreal, QC, during the International Polar Year From Knowledge to Action Conference, and discussed assessment updates, writing timelines, climate trends and modeling climate indicators.

With assistance from Gayle Kabloona and Kiah Hachey of Nunavut Tunngavik Inc., Breanne Reinfort organized a series of Kitikmeot Regional Consultations, Cambridge Bay, NU, September 19-20, 2012. Attendants represented the following organizations: Kitikmeot Inuit Association; Kitikmeot Corporation; Nunavut Tunngavik Inc.; Hamlet of Cambridge Bay; CHARS Steering Committee; Nunavut Impact Review Board; Nunavut Water Board; Government of Nunavut Department of Environment, and Department of Community and Government Services.

On behalf of Gary Stern, Breanne Reinfort attended the BREA Workshop for the Climate Change and its Potential Effects on Offshore Oil and Gas Activities Working Group, Inuvik, NT, November 19-21 2012, and presented the IRIS framework and the IRIS 1 RIA.

Breanne Reinfort organized an IRIS 1 meeting for the Steering Committee, lead and contributing authors at ArcticNet’s Annual Scientific Meeting, Vancouver, BC, December 11, 2012. Topics of discussion were current progress, gaps in the RIA, changes to the models being used for projections, and a re-examination of the timeline to completion. Work on the Regional Impact Assessment: received submissions for two chapters which were previously missing; confirmed authors for several outstanding sections; received preliminary atmospheric projections to the year 2050, which were sent to lead and contributing authors for consideration and inclusion in their chapters.

Community Perspectives on Communicating Contaminants Research: A follow-up trip to Sachs Harbour in February-March 2012 enabled four focus groups to occur; discussion centred around knowledge and perceptions of mercury, what and how participants

wanted to know about mercury, and their impressions of previous communication efforts. Interview verifications were completed with participants who were in town. Discussions, ideas and suggestions from the focus groups were presented at a community forum on March 6, 2012, where further dialogue on contaminant messages and ways to deliver the message occurred. With the assistance of Chris Furgal at Trent University (May 13-19, 2012), coding structure was re-analyzed and improved to better reflect the information gathered; coding structure is complete and descriptive re-coding of all materials is in progress. Project analysis was delayed as of July 2012 when the project lead temporarily assumed the duties of the IRIS Coordinator; this term position will end in March 2013, at which point further in-depth project analysis will continue.

Results

The delivery of contaminants to the Arctic food web: Why sea ice matters: As the ice forms, organic contaminants present in surface seawater are being re-distributed between the ice crystal lattice, mobile liquid portion of ice (brine), and under-ice seawater in a conservative manner, which means they follow salts’ re-distribution rather closely [2]. As a result, concentrations of organic contaminants in the brine will be 3-4 times higher than those in the under-ice seawater [2], and there will be a temporal increase of about 0.5 times in contaminant concentrations in the under-ice interface seawater compared to water at 5 m [3]. As the ice life cycle progresses to reach melt season, melt pond covered sea ice provides a platform for the exchange of organic contaminants between air and melt-pond water [4]. Melt ponds on Arctic sea ice are relatively shallow and isolated, which facilitates gas exchange allowing ponds to reach near equilibrium concentrations (80% saturation) probably within a couple of weeks from the melt onset [4]. The extent to which different contaminants will load into melt ponds over the course of summer depends on their Henry’s law constants (‘differentiated’ process), as well as on their atmospheric concentrations.

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We have calculated meltwater concentrations (at 80% saturation) and melt pond enrichment factors (MEFs; a ratio of contaminant concentration in melt pond water at near gas exchange equilibrium to surface seawater concentration) for selected legacy OCPs and CUPs in the Beaufort Sea and Amundsen Gulf in May-July 2008 (Figure 3). Predicted concentrations in melt pond water are relatively high for all of the CUPs compared to legacy OCPs. All OCPs have MEFs of about 1 except heptachlor epoxide with MEF of 0.4. For all CUPs analyzed in this study (dacthal, chlorpyrifos, endosulfan I and chlorothalonil), melt pond drainage would increase under-ice exposure with MEFs ranging between 2 for dacthal and 17 for chlorothalonil due to their relatively low HLCs and relatively high air concentrations (Figure 3).

Mercury uptake within an ice algal community during the spring bloom in first-year Arctic sea ice: Ice algae

biomass (chl a concentration) began to increase in mid-March (day 79), and reached a maximum in early May (day 130). Total mercury concentrations in particulate, [PHg]T (μg/g), in bottom 10 cm sections of ice cores ranged from 0.004 to 0.022 μg/g dw, and showed no trend with chl a. MeHg concentrations were below detection limit (n = 2). Prior to mid-April, when both chl a concentrations and the number of algal cells were still relatively low, [PHg] values were quite variable. Once the algal counts started increasing and contributing significantly to the particulate matter biomass in the bottom 10 cm of ice cores, [PHg]T became less variable with a decreasing trend as a function of bloom progression, suggesting that mercury was undergoing biodilution within the ice algal population.

We calculated the concentration of particulate mercury per algal cell, [THg]cell, as a function of bloom progression. From April 4 (day 94), [THg]cell decreased significantly over time, even though the taxonomic cell composition and cell size of major taxonomic groups remained relatively consistent. As the spring in the Arctic progresses, the brine pockets grow in size, which can lead to dilution of contaminant concentrations in the brine fraction of sea ice resulting in decreased exposures [10]. We calculated the concentrations of Hg in the brine, [THg]BR, as a function of bloom progression. There was no trend of [THg]BR with time, and no significant relationships with [PHg]T or [THg]cell (p > 0.05; t-test). Thus, the strong and significant decreasing trend of [THg]cell with time is most likely attributed to biomass dilution [15,16]. This suggests that there is a finite amount of Hg available to the algal population within the ice core sections curtailing the uptake by algal cells.

Importance of Arctic Zooplankton Seasonal Migrations for α-Hexachlorocyclohexane (α-HCH) Bioaccumulation Dynamics: Concentration of α-HCH in C. hyperboreus was 2-3 times higher in summer than in winter; that is 27.1 ± 8.0 ng/g lipid (wet wight (ww) versus 14.3 ± 6.8 ng/g lipid ww, or 3.3 ± 1.2 ng/g ww versus 1.2 ± 0.5 ng/g ww on ww basis and lipid ww basis, respectively. α-HCH concentration in C.

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Figure 1. MEFs (A), HLCs (B), and average air concentrations (C) for selected CUPs and OCPs in the Beaufort Sea and the Amundsen Gulf in the spring and summer of 2008.

Figure 3. MEFs (A), HLCs (B), and average air concentrations (C) for selected CUPs and OCPs in the Beaufort Sea and the Amundsen Gulf in the spring and summer of 2008.

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hyperboreus increased linearly or exponentially during the culturing experiment when based on the lipid ww or ww, respectively. LogBAF in C. hyperboreus was slightly above the equilibrium partitioning value of 4.5 [10] in environmental samples from winter (4.6) and slightly below equilibrium in samples from summer (4.4). Ascent of C. hyperboreus from depths to the surface layer of the ocean would significantly decrease apparent logBCF (~3.9) due to migration to the relatively HCH-rich surface waters. During culturing, logBCF increased gradually and eventually exceeded the equilibrium partitioning value after 5 weeks.

C. hyperboreus samples from the summer had higher α-HCH EF than those from the winter (0.458 ± 0.024 compared to 0.310 ± 0.029). The α-HCH chiral signature in zooplankton reflects surface-water versus deep-water dwelling as seawater α-HCH EFs were measured at ~0.45 in the top 50 m of the water column and at ~0.15-0.30 below 150 m in the study region

in 2007/2008 [8]. During the culturing experiment, C. hyperboreus approached ambient seawater EF (defined as 90% of seawater EF) after 1 to 4 weeks depending on the difference between the initial tissue EF and ambient seawater EF. For line 2, which most closely simulated the natural conditions in the region, equilibration took 3 weeks, which is in accord with the time required to reach equilibrium partitioning concentration.

Dinoflagellate Cysts as Environmental Indicators in the Hudson Bay System: Total particulate matter fluxes peak in late fall in eastern Hudson Bay, whereas low, constant mass fluxes are experienced in western Hudson Bay even under the ice cover (Figure 4). Downward dinoflagellate cyst fluxes are greatest during the ice-free summer season and lowest during the ice-covered season, respectively. Cyst taxa identified in the trap samples are equivalent to the taxa found in surface sediment

Figure 5. Simplified diagram of dinoflagellate cyst species fluxes in the two locations with respect

to sea-ice cover.

Figure 4. Simplified diagram of dinoflagellatecyst species fluxes in the western and eastern Hudson Bay (HB) with respect to sea-ice cover Heikkila et al., in prep.).

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from corresponding locations [2]. Cyst production demonstrates clear taxon-specific seasonality: while the magnitude of taxon-specific cyst fluxes differs between the two locations, the timing of the production is consistent. Whereas most autotrophic cysts (e.g. Pentapharsodinium dalei, Operculodinium centrocarpum) are produced in the summer and fall, ice-dwelling Polarella glacialis is released to the water column during the spring melt. Heterotrophic cysts are produced in the spring and summer, with a clear taxon-specific succession. For instance, Islandinium minutum, I. cezare and Brigantedinium spp. are produced in July-August, whereas Echinidinium karaense seems to have two seasonal production peaks: in July and in October-November.

Holocene Primary Productivity and Mercury Dynamics and Trends in the NOW Polynya, Baffin Bay: Sediment OM bulk concentrations (TOC and total organic nitrogen (TON)), volatile organic compounds (“S1” carbon) and kerogens (“S2” carbon) displayed exponential decreases with water depth reflecting

water-column remineralization processes (Figure 6). OM composition parameters (e.g. C/N, S1/S2, δ13C and δ15N) showed no such relationship. C/N and isotopic composition data have been used to allocate total OM to either marine or terrestrial plant sources. Significant surface sediment mixed layers meant that assigning chronological dates to specific sediment layers was not possible. Modeling of 210Pb data, however, allowed the 1900 year to be defined such that 90% of the sediment above a certain depth in each core was more recent than 1900, and 90% below that depth was older than 1900.

Cores from the interior of the NOW (sites 108, 111, 115) showed no significant change in OM quantity or composition between pre-1900 and post-1900 sediments, and little variance among cores (see Figure 5). In contrast, a core from the shallow northwest boundary (site 101) showed significantly higher marine OM flux during the 20th Century compared to the pre-20th century period, whereas two cores

Figure 5. Post-1900 (open black circles) and pre-1900 (closed red squares) bulk sediment concentration and composition plotted as a function of ocean depth (metres). S1, S2, TOC, and TON all presented significant (p<0.05) exponentially decreasing trends with water depth, indicated by dashed lines and accompanied by r2 values.

Figure 6. Post-1900 (open black circles) and pre-1900 (closed red squares) bulk sediment concentration and composition plotted as a function of ocean depth (metres). S1, S2, TOC, and TON, all presented significant (p<0.05) exponentially decreasing trends with water depth, indicated by dashed lines and accompanied by r2

values.

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from the southeast slope boundary (sites 136 and 138) showed evidence of decreased terrigenous carbon input since 1900. Site 136 also displayed a decline in marine carbon input since 1900. In addition, both southeast boundary cores witnessed a significant decline in sedimentation rate during the same time interval whereas the interior and NW margin sites did not.

Zooplankton as Monitors of Mercury in Hudson Bay: Zooplankton taxa had δ15N values ranging from 3.4 to 14.0 ‰, implying trophic levels from 1 to 4, and corresponding to a range in THg from 5 to 242 ng g-1 dw. Four short, but distinct, food webs were identified within the dataset using published feeding ecology studies and confirmed with measured stable isotope data (see Figure 6): 1) Calanus sp..-Limacina helicina-Clione limacina, 2) Calanus sp...-Sagitta sp., 3) Calanus sp..-Paraeuchaeta sp., and 4) Calanus sp.-Euphausiacea-Themisto sp. Total mercury was found to biomagnify in all four food webs with

positive regression slopes of concentration on δ15N (Figure 7a), and MMHg was found to biomagnify in three of the four food webs (Figure 7b), with the exception being food web #1. Computed trophic magnification factors (TMFs, not shown) were in agreement with these observations. Across the range of δ15N values for all data concentrations of THg and inferred inorganic Hg (THg-MMHg) decreased (p=0.019 and p <0.001, respectively), while %MMHg

Figure 8 Concentrations of A) total (THg) and B) monomethyl(MMHg) mercury versus δ15N for zooplankton taxa collected from Hudson Bay. See Figure 1 for taxa codes and food web linkages. Symbols indicate herbivores (○), omnivores (■), and predators (♦). Values shown are multiyear means ± SE.

Figure 7 Concentrations of A) total (THg) and B) monomethyl (MMHg) mercury versus δ15N for zooplankton taxa collected from Hudson Bay. See Figure 1 for taxa codes and food web linkages. Symbols indicate herbivores (○), omnivores (■), and predators (♦). Values shown are multiyear means ± SE.

Figure 7. Isotopic carbon and nitrogen signatures of Hudson Bay zooplankton taxa: Calanus sp. (C), Limacina helicina (LH), Euphausiacea(E), Clione limacina (CL), Themisto sp. (T), Paraeuchaeta sp. (P), Hyperoche sp. (H), and Sagitta sp. (S). Symbols indicate herbivores (○), omnivores (■), and predators (♦). Four food web linkages are indicated by numbered regression lines. Values shown are multiyear means ± SE.

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Figure 6. Isotopic carbon and nitrogen signatures of Hudson Bay zooplankton taxa: Calanu ssp.(C), Limacina helicina(LH), Euphausiacea(E),Clione limacina(CL), Themisto sp.(T), Paraeuchaeta sp.(P), Hyperoche sp. (H), and Sagitta sp.(S). Symbols indicate herbivores (○), omnivores (■), and predators (♦). Four food web linkages are indicated by numbered regression lines. Values shown are multiyear means ± SE.

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increased (p<0.001). Food web #1 was identified as an anomaly where C. Limacina despite feeding exclusively on L. helicina does not have significantly higher concentrations of THg, MMHg or δ15N levels. Yet, together these taxa have significantly higher concentrations of THg than the other taxa and depleted δ13C signatures.

Organic mercury species in the Arctic Ocean: Results obtained during the 2011 and 2012 cruises showed MMHg and DMHg concentrations in air of 2.9 ± 2.6 (mean ± SD, range <0.5 to 8.1) and 3.9 ± 2.8 (range <0.5 to 9.6) pgm-3, respectively. The Hudson Bay air shed was dominated by DMHg while in the CAA, MMHg was the dominant organic Hg species in air Figure 8. MMHg and DMHg concentrations in surface water were on average 23.4 ± 19.07 and 7.7 ± 8.51 pgL-1 in the CAA while lower values were obtained in Hudson Bay (17.7 ± 18.71 and 6.2 ± 5.0 for MMHg and DMHg respectively). An increase in organic Hg species concentrations with depth in the water column, with maximum concentrations at the bottom, was also observed confirming the findings of previous studies. MMHg and DMHg concentrations in water exhibited a strong spatial distribution as indicated by the high standard deviation values of the mean concentrations. MMHg concentrations ranged from <0.5 to 150.9 pgL-1 while DMHg concentrations varied from 31.6 to1.2 pgL-1. The spatial variation of organic Hg species in the Arctic Ocean is presented in Figure 9 (a) and (b). MMHg and DMHg concentrations in water and air showed a strong relationship (r2 = 0.59 and r2 = 0.48 respectively) as shown in Figure 10. Radiation was the environmental parameter that showed the strongest

Figure 9. MMHg and DMHg (average concentrations in Hudson Bay and the Canadian Arctic Archipelago

MMHg

DMHg

Hudson Bay Canadian Archipelago

Con

cent

ratio

n (p

gm-3

)

8

7

6

5

4

3

2

1

0

Figure 8. MMHg and DMHg(average concentrations in Hudson Bay and the Canadian Arctic Archipelago.

Figure 10 (a) Monomethylmercury and (b) dimethylmercury concentrations (pgL-1) in surface water in Hudson Bay and the Canadian Arctic Archipelago.

(a) (b)

Figure 9 (a) Monomethylmercury and (b) dimethylmercury concentrations (pgL-1) in surface water in Hudson Bay and the Canadian Arctic Archipelago.

22



significant relationship with MMHg and DMHg in water (r2 = 0.61 for DMHg and r2 = 0.58 for MMHg). However, only MMHg exhibited a significant relationship with radiation in air (r2 = 0.82).

Transport and transformation of mercury across the ocean-sea ice-atmosphere (OSA) interface: 1) First attempt of creating AMDEs at the mesocosm scale at SERF was not successful in February 2012. A new experiment is being planned for January 2013 to fine tune the experimental setup. 2) Higher Hg levels (10x the seawater value) were found in frost flowers at SERF, but not nearly as high as those observed in the Arctic Ocean during AMDEs. 3) The pH of sea ice and brine was determined potentiometrically and spectroscopically at near-freezing temperatures during initial ice growth and melt at SERF.

Vertical pH profiles from bulk ice cores revealed a consistent C-shaped pattern during columnar ice growth, with highest pH values (>9) in both exterior (top and bottom) ice sections and in frost flowers, and lowest pH (~7) in interior ice sections. Brine pH typically remained below that of the source seawater pH (~8.4). 4) MeHg levels in the multi-year ice core taken from the Beaufort Sea were found to be very low, at or slightly above the instrumental detection limit.

Methylmercury production in Arctic seawater: Seawater total mercury concentrations ([HgT]) in the Beaufort Sea ranged from 0.40 to 2.9 pM (mean ± standard deviation = 1.1 ± 0.45 pM). Total methylated mercury concentrations ([MeHgT], including both monomethylmercury and dimethylmercury) ranged from <0.04 to 0.59 pM (0.20 ± 0.15 pM). Profiles of HgT and MeHgT (Figure 11) show vertical and spatial variations indicating that these two parameters behave at least partially independently of one another. For HgT, all stations show enrichment in the surface seawater (1.0−2.9 pM), with the exception of Stns D29 and D33, which were ice covered at the time of sampling, with the highest enrichment observed at the open-water Stn 421 (2.9 pM) located on the Mackenzie Shelf. HgT tends to decline with depth at most stations to values approaching 0.5 pM at the greatest depths sampled. In contrast, MeHgT shows lower concentrations near the surface and higher concentrations at depth (Figure 12). At most stations, the MeHgT exhibits a peak between 50 and 160 m in apparent association with the nutrient maximum (only phosphate and DIC are shown in Figure 12, nitrate and silica showed similar profiles) and lower DO, which identifies the Pacific halocline water. This association of a subsurface MeHgT peak with the nutrient maximum is similar to observations in the Pacific Ocean [1, 6], Southern Ocean [3], and Mediterranean Sea [2]. We also find a positive correlation between MeHgT and nutrients (R = 0.51, p < 0.01 for phosphate; Figure 13; R = 0.67, p < 0.001

Figure 11. Relationship between DMHg in surface water and air in the Arctic Ocean

[MM

Hg]

in w

ater

(pgL

-1)

[DM

Hg]

in w

ater

(pgL

-1)

[MMHg] in air (pgm-3) [DMHg] in water (pgm-3)

(a) (b)

R2 = 0.5917

R2 = 0.4774

Figure 10. Relationship between DMHgin surface water and air in the Arctic Ocean.

23



for nitrate, and R = 0.48, p = 0.004 for silicate), though the relationship with phosphate is weaker than that reported for the Mediterranean Sea [2].

Linking the carbon and mercury cycles in the Beaufort Sea using a seasonal, one-dimensional water column model: The model was seeded with a total Hg water column profile derived from data collected in the Beaufort Sea during the Circumpolar Flaw Lead Study (Stern, 2008. unpublished data) and then run for 2 years to allow for some Hg concentration stabilization.

Results from this simulation using the base set of model parameters are summarized in Figure 13.

Winter

Overall, the concentrations of all modelled Hg species in seawater change little over the winter months (December–March). Concentrations of HgT in the upper 20m of the water column are lower than those below 20m because of atmospheric evasion of Hg(0) during the previous open water season. Concentrations of Hg(II)

Figure 12. Depth profiles of total mercury (HgT) and methylated mercury (MeHgT), along with salinity, temperature, δ18O, dissolved oxygen (DO), dissolved phosphate (PO4

3-T), nitrate (NO3-) and silicate (Si(OH)4) dissolved

oxygen (DO), and dissolved inorganic carbon (DIC), in the Eastern Beaufort Sea.

Figure 11. Depth profiles of total mercury (HgT) and methylatedmercury (MeHgT), along with salinity, temperature, δ18O, dissolved oxygen (DO), dissolved phosphate (PO4

3-T), nitrate (NO3-), silicate (Si(OH)4) dissolved oxygen (DO), and dissolved

inorganic carbon (DIC), in the Eastern Beaufort Sea.

24



and Hg(0) in seawater in the upper 20m of the simulation increase slowly from January 1st until mid-April due to bulk water movements from lower depths of higher Hg concentration. There is little change in the amount of Hg bound to detritus over this same period since there is insufficient light for primary production and most of the detritus produced in the previous year has been remineralized. Additionally, the rate of organic carbon remineralization is continuing to decline since its peak in summer, causing a shift from MeHg species to inorganic Hg(II) in seawater. The demethylation of MeHg explains the increase in modelled seawater Hg(II) concentrations at mid to deep depths over the winter months. Modelled MeHg in seawater reaches a yearly minimum of 5 ng Hg/m3 over most depths in early April, which corresponds to the simulated organic carbon minimum.

Spring and summer

As the sea-ice thins in spring, solar radiation penetrates deeper into the water column and photolytically induced chemical reactions shift the Hg(0)-Hg(II) equilibrium towards the production of Hg(0). This conversion begins at the surface in late-May where solar radiation is highest and extends down the water column as the season progresses, tapering off at 70m in early-July. It is important to consider HgT when

Figure 13. Relationship between total methylated mercury (MeHgT)and A) total mercury (HgT) and B) dissolved phosphate (PO4

3-T) in

seawater. Data for the Mediterranean Sea are from [2] (MeHgT =0.046 + 0.72 PO4

3-T, R2 = 0.69), and the data for the Eastern

Beaufort Sea are from this study (MeHgT = -0.12 + 0.26 PO43-

T, R2

= 0.23).

Figure 12. Relationship between total methylatedmercury (MeHgT) and A) total mercury (HgT) and B) dissolved phosphate (PO4

3-T) in seawater. Data for the Mediterranean Sea are from [2] (MeHgT= 0.046 + 0.72 PO4

3-T, r2 = 0.69), and the data for the Eastern Beaufort Sea are from this study (MeHgT= -0.12 + 0.26 PO4

3-T, r2 = 0.23).

Figure 14. Modelled Hg concentrations for total mercury (Hg(0) + Hg(II) + MeHg + biological Hg), dissolved gaseous mercury (Hg(0)), Hg(II) in seawater, methylatedmercury MeHg (mono and dimethylmercury), mercury associated with slow sinking detritus (individual dead phytoplankton cells), and mercury associated with fast sinking detritus (zooplankton fecal pellets, clustered dead phytoplankton cells) for the second model year. Hg concentration in detritus is the quantity of Hg bound to detritus per m3

of seawater.

Figure 13. Modelled Hg concentrations for total mercury (Hg(0) + Hg(II) + MeHg+ biological Hg), dissolved gaseous mercury (Hg(0)), Hg(II) in seawater, methylated mercury MeHg (mono and dimethylmercury), mercury associated with slow sinking detritus (individual dead phytoplankton cells), and mercury associated with fast sinking detritus (zooplankton fecal pellets, clustered dead phytoplankton cells) for the second model year. Hg concentration in detritus is the quantity of Hg bound to detritus per m3 of seawater.

25



examining the modelled spike in seawater Hg(0) since concentrations of HgT are lower in the top ten meters compared to deeper in the water column, which gives the incorrect impression that the rapid conversion of Hg(II) to Hg(0) is not beginning at the surface. Furthermore, HgT is relatively high at 80m compared to HgT at mid-depth, giving the impression that the equilibrium shift between Hg(II) to Hg(0) is occurring deeper than sunlight penetration would predict.

After ice breakup (Julian day ~185 in the base scenario) there is a short pulse of Hg(II) and Hg(0) at the surface corresponding snow and AMDE Hg(II) inputs. The resulting spike in HgT at the surface migrates and diffuses down the water column and is noticeable at ~20m in early September. Modelled Hg(0) concentrations in the upper 30m of the water column decrease rapidly in the weeks following the Hg spike due to evasion, and reach equilibrium with the atmosphere at a surface concentration of ~9 ng Hg(0)/m3 in mid July. Evasion of Hg(0) and its removal from the modelled system pushes the Hg(II)-Hg(0) equilibrium towards the formation of Hg(0), resulting in a marked decrease in Hg(II) seawater concentrations at the surface. Modelled Hg(II), and Hg(0) concentrations in the surface reach a minimum concentration of 45 ng Hg(II)/m3 in the third week of July.

Hg(II) and MMHg are sorbed onto detritus, transported down the water column as the detritus sinks, and released back into the water column when the detritus is remineralized. The distribution of MeHg and Hg(II) in the water column is strongly dependant on the mass of detritus remineralized. Melting sea-ice in May forms a layer of relatively fresh water under the ice surface, preventing nutrients from reaching the ice algae and causing the release of this biomass in the form of fast-sinking detritus. A small portion of this detritus (<10%) is remineralized before reaching the 120m model horizon, which can be seen as a faint increase in MeHg concentration in the upper 40m of the water column between late May and early July. The breakup of sea ice near the end of June initiates the phytoplankton bloom, where phytoplankton (diatoms in this simulation) growth rapidly consumes surface nutrients and shades

lower depths. Once the nutrients in a given layer of the model are depleted, the phytoplankton will die off and sink as detritus, subsequently reducing shading and allowing the bloom to continue at lower depths in relatively nutrient rich waters. Aggregations of dead phytoplankton will form fast-sinking detritus, which occurs at the start of the bloom when primary productivity is peaking in mid-July. Similar to ice algae detritus, <10% of fast sinking phytoplankton will be remineralized before reaching the 120m horizon, contributing to the high MeHg concentration below 80m between mid-July and mid-August. All of the slow-sinking detritus is derived from phytoplankton and most of it will be remineralized above 60m, creating a large mass of MeHg and depletion of Hg(II) between 15m and 70m by mid-August. This MeHg signal gradually extends down to 100m by early November, following the pattern of primary productivity.

Autumn

Evasion of Hg(0) ends after freeze-up (Julian day ~290) and the Hg(II)-Hg(0) equilibrium shifts to Hg(II) production in seawater because of decreased solar radiation in the surface layers of the model. Additionally, modelled Hg concentrations in the upper 70m begin to increase in mid October as Hg(0), Hg(II), and MeHg are transported from lower layers via bulk water mixing and will continue to increase until ice break-up in the following year.

Virtually all modelled fast sinking detritus has been remineralized by mid-September, while slow sinking detritus remains in the water column until the end of January. MeHg concentrations reach a maximum concentration of 95 ng Hg/m3 between 5m and 60m in early September due to the large amount of slow-sinking detritus being remineralized over this period. The upper and lower depth limits of the MeHg maximum deepen though the fall as the detritus sinks, and continues until mid-November when MeHg production becomes limited by detritus availability. MeHg concentration in seawater then decreases proportionally with detritus concentration until primary production resumes again in the spring.

26



Air-water-food web exchange dynamics of Persistent Organic Pollutants in Canadian Arctic ecosystems: Air: Organochlorine pesticides (OCPs) including hexachlorocyclohexanes and chlordanes continue to decline as seen with Arctic monitoring stations [3]. The declines between 2010 and 2011 are probably a combination of the declining concentrations and seasonality. Samples were taken in October 2011 while other samples from previous campaigns were taken in the late spring and summer. Current Use Pesticides (CUPs) have been analyzed in air samples from the Canadian Archipelago by our group since 1999. Generally concentrations in 2011 were lower than previous years. This may be due to sampling time differences as mentioned above. Endosulfan concentrations have been steadily decreasing over time where recent declines are probably due to restrictions on usage in Europe and North America [5, 6]. Organophosphates (OPs) identified in Arctic air were: tris-chloro ethyl phosphate (TCEP), tris-chloropropyl phosphate (TCPP) and triphenyl phosphate (TPP). Since the banning of penta-BDE and octa-BDE, the usage of OPs have increased and probably will continue to do so. TCEP had the highest concentration found, followed by TCPP and TPP. The levels of OPs are much higher than the sum of PBDEs (Figure 14). Similar levels of OPs have been seen in the North Sea [7] and the Bering and Chukchi Seas [8]. Levels found in the Arctic are lower than those over lakes Superior and Erie [9] and much lower than in urban Toronto and at a sewage treatment plant in southern-Ontario [10]. The order of gas phase PFAS concentrations found is FTOH>> perfluorooctane sulfonamidoethanol (FOSE)>

perfluorinated sulfonamides (>FOSA). For FTOHs, generally the order was 8:2>10:2>6:2. FTOH ratios (6:2/8:2/10:2) for 2010 and 2011 were 1.0/1.6/0.7 and 1.0/5.0/1.2, respectively. The ratios for 2011 closely match with previously reported Arctic ratios [11, 12]. Ratios in 2010, however, were closer to the ratios found in lower latitudes, although another study found a different order of concentrations with FTOH ratios in the north Atlantic of 6:2>8:2>10:2 [13]. The FOSA/FOSEs found were methyl perfluorooctane sulfonamido ethanol (MeFOSE), ethyl perfluorooctane sulfonamido ethanol (EtFOSE), methyl perfluorooctane sulfonamide (MeFOSA) and ethyl perfluorooctane sulfonamide (EtFOSA). The higher levels of FTOHs over FOSA/FOSEs was also found in other studies, additionally, usage of electrochemical fluorination based fluorosurfactants have been reduced or eliminated over the last decade [14] which has been reflected in the lower levels of FOSEs and FOSAs in Arctic air. PFAS in the particle phase are much lower than the gaseous phase and are different in order of their concentrations.

Water: 1L water samples were collected for PFAS, including eight depth profiles. Concentrations did not significantly vary with depth indicating the upper 50-100 m is well mixed for the PFAS. PFCAs had the highest concentrations, particularly PFBA, PFPeA and PFNA. Additionally, there also is not a spatial distribution of PFAS, except lower concentrations were observed in Baffin Bay compared to the Archipelago. Analysis of other water samples is ongoing.

Phytoplankton: During ArcticNet 2011, PFOS average concentration based on liters of water is 39 fgL-1 or 17 pgg-1 based on estimates of particles in the surface water with no significant spatial trend. OPs were also sought in these samples but are not reportable due to blank problems, where OCPs and CUPs were below detection limits.

Standardisation of Rock-Eval pyrolysis for analysis of recent sediments and soils: Several plots were generated from the Rock-Eval data. Figure 15 shows the novel “freshness” biplot, which measures two independent ratios indicative of organic matter (OM)

0

50

100

150

200

250

300

350

400

TCEP TCPP TPP ΣPBDE

pg/m

3

nd *

ArcticNet 2010ArcticNet 2011Alert 2008/09

ArcticNet 2010ArcticNet 2011Alert 2008/09

nd *Figure 15: Average concentrations of OPs during ArcticNet 2010 and 2011 and Alert 2008/09 [16].

Figure 14: Average concentrations of OPs during ArcticNet 2010 and 2011 and Alert 2008/09 [16].

27



degradation. Most samples plot within a window showing increasing freshness, while there are two other major zones which indicate either the presence of substantial fossil carbon (left-most portion) or microbial mats (right-most portion).

Other ratios that can be used to describe OM are the residual carbon to TOC (RC:TOC). In general, RC:TOC values increase with increasing degree of degradation, as the more labile compounds will be preferentially degraded before less labile (or more refractory) compounds. This ratio can also be used downcore to show how changes are occurring over time. Fresh OM typically has RC:TOC of ~0.40 to 0.50, while highly degraded OM falls closer to 0.70 to 0.80. Results are presented in Figure 16.

Figure 17: Plots of RC:TOC in lake, peat and marine cores. Lake cores are the first three rows except the right-most plot in the third row (the peat core) and the marine cores are on the bottom row. Several of the Arctic lake cores (top row) and marine cores (bottom row) show large increase in more labile compounds due to increasing primary productivity.

Figure 16. Plots of RC:TOC in lake, peat and marine cores. Lake cores are the first three rows except the right-most plot in the third row (the peat core) and the marine cores are on the bottom row. Several of the Arctic lake cores (top row) and marine cores (bottom row) show large increases in more labile compounds due to increasing primary productivity.

Figure 16. “Freshness” biplot showing all lake sediments (circles), soils (diamonds) and marine sediments (triangles).Figure 15. “Freshness” biplot showing all lake sediments

(circles), soils (diamonds) and marine sediments (triangles).

28



Preliminary results from the BREA studies of mercury and hydrocarbons in Beaufort sediments and biota: Mercury (Hg) in sediment generally increased with water depth across all transects (Figure 17). Concentrations ranged from 0.051 to 0.096 ug/g, with a median of 0.082 ug/g. Mercury in zooplankton ranged over two orders of magnitude (0.006 to 0.458 ug/g), with concentrations generally higher in the easternmost transects (KUG and DAL) for a given water depth.

Biogeochemical cycles and organic carbon sources and inputs in Hudson Bay: Initial examination of results shows that there is a latitudinal gradient for the distribution of organic carbon in the Hudson Bay. There are higher amounts of OC entering from the southern rivers with the highest concentrations occurring in the southwest region of Hudson Bay. The Churchill River, at the time sampled, was transporting 13.09 mg/L of OC into the Hudson Bay compared to the average of 4.3 mg/L. For all rivers sampled, 87.5 percent of the OC entering the Hudson Bay is coming from the dissolved phase. This is further strengthened by the lignin biomarker data, which also shows the same latitudinal gradient and same percent of DOC contributions. Lignin biomarker product ratios when

applied to the river samples were also consistent with latitudinal vegetation zones of the Hudson Bay region (Figure 18). Preliminary Δ14C ages when compared to acid aldehyde ratios for the dissolved phase show that more modern dates were more degraded than older samples that were from fresher materials entering the rivers (Figure 19).

IRIS 1 Western and Central Arctic: IRIS 1 meeting at International Polar Year Conference (Montreal, QC, April 22, 2012): The assessment update was as follows: two chapters were still in progress, the writing timeline was slightly modified, and there has still been little consultation with Kitikmeot representatives. Climate data and figures were presented, but regional climate projections were not yet available; the idea of also using the marine model NEMO was discussed.

Figure 20: Lignin product ratios for dissolved and particulate phase of river samplesFigure 18: Lignin product ratios for dissolved and particulate

phase of river samples.

Figure 17. Location of BREA sampling transects (Tbs12, Gry12, Kug12, Dal12) and the additional hydroacoustic transects (Mackenzie Valley, West-to-East, and Hct12) during the 2012 field program.

29



Lead authors or affiliates gave short presentations on their chapters, enabling those present to inquire about results or content; lead authors and Steering Committee members received a physical copy of the first draft of the assessment.

Kitikmeot Regional Consultations (Cambridge Bay, NU, September 19-20, 2012): Here we presented an overview of ArcticNet, the IRIS process, and the current status of IRIS 1 and the RIA (Figure 20). Discussions focused on including more examples of research in the Kitikmeot that showcase regional concerns due to climate change impacts, and representatives approved the overall scientific chapter topics. Participants suggested that a regional sub-committee be formed to represent the diversity of the Kitikmeot Region, of which the Chairperson would sit on the IRIS 1 Steering Committee.

BREAWorkshop for the Climate Change and its Potential Effects on Offshore Oil and Gas Activities (Inuvik, NT, November 19-21, 2012): Here we presented on the ArcticNet IRIS framework, specifically discussing developments within IRIS 1. This included a description of the models being used, how the modeled projections will work with current knowledge to predict various environmental changes to the years 2030 and 2050 and associated policy recommendations and mitigation strategies, and a brief overview of the working scientific chapters. It

was beneficial for the BREA WG to see the regional focus and breadth of topics the IRIS RIA will cover to prevent duplication and enable appropriate cross-referencing with the document being assembled by this WG.

IRIS 1 Meeting at ArcticNet Annual Scientific Meeting (Vancouver, BC, December 11, 2012): We presented the status of each part and chapter to all Steering Committee members and authors present and discussed the knowledge gaps that need to be filled, inquiring into the commitment of some authors who had promised contributions but had not yet come through. Since the NEMO model needs to be forced with atmospheric variables from Ouranos modeled projections, it was determined that a General Circulation Model will be used to predict changes to the marine environment for the first iteration of the RIA instead of waiting for NEMO, which will be incorporated into the second edition of the RIA. The first IRIS 1 RIA is anticipated for publication by December 2013 (Figure 21). Jeannie Ehaloak (NTI, Cambridge Bay), who attended the consultation meetings held in September, was nominated for the ITK Northern Travel Fund. Receiving it enabled her to attend

Figure 22. Kitikmeot Regional Consultations held in Cambridge Bay, NU, September 19-20, 2012. Attendants represented the following organizations: Kitikmeot Inuit Association; KitikmeotCorporation; Nunavut Tunngavik Inc.; Hamlet of Cambridge Bay; CHARS Steering Committee; Nunavut Impact Review Board; Nunavut Water Board; Government of Nunavut Department of Environment, and Department of Community and Government Services.

Figure 20. Kitikmeot Regional Consultations held in Cambridge Bay, NU, September 19-20, 2012. Attendants represented the following organizations: Kitikmeot Inuit Association; Kitikmeot Corporation; Nunavut Tunngavik Inc.; Hamlet of Cambridge Bay; CHARS Steering Committee; Nunavut Impact Review Board; Nunavut Water Board; Government of Nunavut Department of Environment, and Department of Community and Government Services.

Fresh Plant Tissues DOMDOM

715215

2840

MODMOD

MOD

MOD

More Degraded

Figure 21: Acid aldehyde ratios and Δ14C ages for DOC samples of Hudson Bay rivers

Fresh Plant Tissues

Figure 19. Acid aldehyde ratios and Δ14C ages for DOC samples of Hudson Bay rivers.

30



ArcticNet’s ASM and the IRIS 1 meeting, which she said was very beneficial and she will be reporting on the meeting’s activities back in Cambridge Bay. She is also a potential Steering Committee representative.

Community Perspectives on Communicating Contaminants Research: Four focus groups were conducted: females aged 18-30 (n=3); females aged 30+ (n=3); males aged 18-30 (n=4); males aged 30+ (n=2). Two of the 12 focus group participants had previously been interviewed, to give a total of n=29 project participants (interviews: n=19; focus group: n=10). This represents 41% of the Sachs Harbour population over the age of 18. Focus group discussions revealed participants’ lack of basic background information about mercury, which impeded their ability to interact with constantly updating research results, and there was some confusion as to why mercury and contaminants were being studied. Drawing out and talking through such processes as ‘the grasshopper effect’ and biomagnification were very beneficial. Participants emphasized the importance of receiving contaminants information, and a two-page pamphlet about mercury with background facts, diagrams, and more photos than text was agreed on by all. These diagrams were deemed essential to include in the pamphlet, especially because participants would then be able to explain them to other community members who were not present at the meetings. Re-development of the coding structure enabled the importance of participant attributes (potential response modifiers) to be determined, providing insight into the influences of communication processes on contaminant knowledge and risk perception. Attributes reinforce the importance of examining the perceptions of the processes (methods and sources) of communication, instead of just considering perceptions of message content, as significant influences on contaminant information dissemination, understanding, and retention. Project completion is expected by August 2013.

Discussion

The delivery of contaminants to the Arctic food web: Why sea ice matters: The process of atmospheric loading of contaminants to surface meltwater and subsequent

drainage to the Arctic Ocean can be described as a ‘pump’ that transfers contaminants from the atmosphere to an ice-covered ocean via pond meltwater. To determine the significance of this contaminant input route to the Arctic Ocean, we calculated the total amount of various CUPs that would be delivered to the surface seawater of the Beaufort Sea in 2008 due to melt pond leakage into the ocean compared to the standing stock of CUPs held in the top 40 m of the Beaufort Sea. The total amount of CUPs discharged to the Beaufort Sea with surface meltwater drainage in 2008 was 6 kg for dacthal, 16 kg for chlorpyrifos, 5 kg for endosulfan I, and 289 kg for chlorothalonil. The contaminant ‘pump’ could, therefore, deliver annually about 2% of dacthal, 4% of chlorpyrifos, 8% of endosulfan I, and 21% of chlorothalonil relative to the standing stock in the top 40 m of the Beaufort Sea (Polar Mixed Layer). Surface meltwater drainage is an important input route to Arctic Ocean surface water for chemicals like the CUPs, which are presently in high/increasing global use. This finding calls into question the assumption that ice cover provides an effective barrier to atmospherically-deposited contaminants by limiting air-water gas exchange.

Mercury uptake within an ice algal community during the spring bloom in first-year Arctic sea ice: Sea ice algal habitat is located at the interface of ice and the ocean and can thus be exposed to mercury both from brine and

Figure 23. Flow chart showing estimated time lines. Estimated completion date is December, 2013Figure 21. Flow chart showing estimated time lines. Estimated completion date is June, 2015.

31



surface seawater. THgBI (total Hg dissolved in bulk ice) ranged from 0.02 – 0.45 ng and no significant trends were observed over the algal growth season (r2 = 0.057, p > 0.05). However, a significant negative correlation was observed to occur between PHgT(PB/B) (total mercury in particulate pre-bloom) and THgBI (r2 = 0.36, p < 0.05) and between PHgT(PB/B) (total mercury in particulate pre-bloom and bloom) and THgBI + THgSW (total mercury in 10 cm of sea water under the core) (r2 = 0.70, p< 0.05). Conversely, no significant correlation was observed between PHgT(PB/B) and THgSW (r2 = 0.01, p>0.05). These results suggest, therefore, that brine and seawater are both sources of Hg to the ice algal community, and external sources of Hg to these ice cores (e.g. AMDEs) are minimal and can be neglected. Even though levels of Hg in seawater are relatively low compared to PHgT(B) and PHgT(PB), it probably acts as a more continuous source where mixing would allow for the supply to remain relatively constant over time as opposed to brine. The brine volume fraction of the bottom 10 cm of sea ice cores ranged from 5.9 to 22.3%, and so was always above the critical threshold of 5% when brine can migrate vertically within the ice allowing convective mixing with seawater below [17].

Importance of Arctic Zooplankton Seasonal Migrations for α-Hexachlorocyclohexane (α-HCH) Bioaccumulation Dynamics: LogBAF in environmental samples from the summer (4.4;

intense feeding) did not exceed the logBCF estimated at the end of culture (4.5-4.6), confirming that C. hyperboreus accumulate α-HCH primarily through diffusion via body membranes, and BCF and BAF can be used interchangeably. LogBAFs/logBCFs exceeded the equilibrium partitioning value when C. hyperboreus were using fat reserves most intensely as reflected by relatively low lipid content; that is during the winter (8.5 ± 1.6%) and the last week of culturing (9.8 ± 2.6%), suggesting that diminishing the lipid sac volume is, in fact, a solvent-depleting process leading to concentrations temporally exceeding the equilibrium partitioning [12]. In contrast, in the summer when C. hyperboreus undergo the most intense lipid accumulation (12.0 ± 1.9%), logBAF was below the equilibrium partitioning value suggesting that there is a lag between the lipid accumulation and saturation with α-HCH. Thus, ww based concentration is a more reliable measure to determine the time needed for C. hyperboreus to approach equilibrium partitioning with seawater; that is 3-4 weeks with about 60% of bioconcentration taking place in the first week after migration. Based on the zooplankton biomass in our study region, we calculated that migrating zooplankters could actively transfer a net amount (total flux associated with descent minus total flux associated with ascent) of ~82 ng of α-HCH under an area of 1 m2. Compared to the standing stock of α-HCH in the surface and bottom 50 m present under an area of 1 m2 in the region (45000 and 15000 ng, respectively), the α-HCH amount zooplankton could transfer annually would account for 0.2 and 0.5% of the stock, respectively (Figure 22).

Dinoflagellate Cysts as Environmental Indicators in the Hudson Bay System: Taxonomical similarity of trap and surface sediment cyst assemblages lends support to the interpretation of sediment data as an outcome of downward flux of cysts produced in surface water. It should be taken into consideration, however, that site location with respect to general water mass circulation as well as occasional storm events, can cause sediment resuspension. This was likely the case in late fall 2005 in eastern Hudson Bay following an episode of

Figure 22.Conceptual schematic of the influence of C. hyperboreus seasonal migration on α-HCH tissue concentration and cycling in the water along with α-HCH concentration vertical profile in the water [7]; boxes indicate α-HCH inventories.

Figure 4. Conceptual schematic of the influence of C. hyperboreus seasonal migration on α-HCH tissue concentration and cycling in the water along with α-HCH concentration vertical profile in the water [7]; boxes indicate α-HCH inventories.

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very strong winds. Nevertheless, the clear succession of different cyst types throughout the open-water season point to taxon-specific environmental cues, or alternatively internal clocks, which induce cyst production at specific times. Since cyst production is typically assumed to peak during or immediately after the motile population maximum [3, 4], the lack of cysts found in sediment traps during the ice-covered season likely indicate negligible under-ice dinoflagellate populations in winter. In general, it thus seems that Hudson Bay dinoflagellates, both light-dependent autotrophs and dark-adapted heterotrophs, tend to evade dark under-ice environments. This is a key indication that should be considered before attempting to apply sediment dinoflagellate cysts as a proxy for seasonal sea-ice cover. The cysts of ice-dwelling dinoflagellate Polarella glacialis may provide an alternative, straightforward sea-ice proxy, but the preservation of this cyst type in sedimentary environments has yet to be uncovered. Furthermore, the search for the key cues of taxon-specific cyst production should comprise an important focus in the following research schemes.

Holocene Primary Productivity and Mercury Dynamics and Trends in the NOW Polynya, Baffin Bay: An important implication of this study is that the interior portions of the NOW have been relatively stable in the amounts and sources of sedimentary OM inputs, at least over the 500 – 760 years represented by the cores. This long-term stability prevails despite a recent significant decline in sea-ice coverage and extension of the ice-free period by 4-6 weeks in the area [7]. Sedimentary OM continues to be almost exclusively from marine (autochthonous) primary production. In contrast, the cores at the margins (Cores 101, 136 and 138) have experienced significant recent change which is strikingly different on the north and south sides of the polynya. The northwest margin continues to be dominated by marine primary production, like the NOW interior, but with a significantly higher OM flux during the 20th Century than previously. By contrast, the southern sites have seen declining sedimentation rates, and declining inputs of terrestrial (allochthonous) OM. The most

likely explanation for the OM patterns is spatially variable reductions in the sea ice season across the region, with consequent impacts on light and possibly nutrient regimes in different locations. The changes in sedimentation rates are harder to interpret, but may be due to sea-ice related changes in the amounts of ice-rafted terrigenous material brought northwards into the Baffin Bay by the west Greenland current either from continental Greenland or in North Atlantic water.

Zooplankton as Monitors of Mercury in Hudson Bay: Biomagnification assessments typically treat zooplankton as a single, homogenous trophic level; inferring trophic linkages from δ15N or size fractionation of organisms (where larger zooplankton are assumed to eat the smaller ones). However, this approach violates an underlying assumption of biomagnification assessments (and trophic level magnification factor computations), that all organisms included in the assessment must be members of the same food web [1]. For comparison purposes we computed TMFs for zooplankton using all zooplankton data. For both THg and MMHg the TMFs indicated that biomagnification did not occur, despite our cumulative evidence to the contrary using multiple approaches. Thus, using feeding ecology knowledge to establish trophic linkages between zooplankton taxa is imperative, and failing to do so increases the risk of Type II error.

Organic mercury species in the Arctic Ocean: The strong relationship between MMHg concentrations in air and water may suggest that MMHg in the ocean could be of atmospheric origin since MMHg in air is expected to be rapidly deposited. Since aqueous MMHg species have very low vapor pressures, the alternative hypothesis that oceanic MMHg evades into the air is less likely. DMHg concentrations in water reported here are lower than those presented in a previous study [2] where water samples were collected in early fall rather than summer as in this study. Lower DMHg values in surface water are probably caused by photo-degradation as a result of higher radiation since a strong relationship was observed between DMHg in water and radiation. Furthermore, since

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DMHg concentrations in water and air are inversely correlated, lower concentrations of DMHg in water can also be explained by increased gas exchange with the atmosphere in summer. The exchange of mercury (Hg) species at the ocean water - air interface may thus be an important factor influencing organic Hg species concentrations in surface water. Finally, the spatial variation in the concentrations and proportions of MMHg and DMHg suggests that production and degree of bioaccumulation might vary across different regions of the Arctic Ocean. Other environmental and geochemical parameters influencing organic Hg concentrations in air and surface water still need to be identified. The results of the incubation experiments (data analysis still pending) will help to identify the main MMHg production pathways and shed some light of the mechanisms affecting MMHg formation.

Transport and transformation of mercury across the ocean-sea ice-atmosphere (OSA) interface: 1) The observation that frost flowers from SERF contained a mercury level higher than the underlying seawater, but much lower than those reported in the Arctic Ocean during AMDEs, agrees with our earlier finding that mercury in young sea ice primarily originates from seawater instead of from the atmosphere [4, 5]. 2) The high pH of frost flowers and the upper layer of sea ice at SERF is likely derived from a CO2-depeleted brine skim on the sea ice surface. If the same applies to the field conditions in polar oceans, this would imply that the current assumption of an acidic sea ice surface in the AMDE reaction schemes [8, 9] is incorrect and needs to be revisited. 3) The low MeHg levels in the multi-year ice cores suggest multi-year ice is a negligible source of MeHg to the seawater and Arctic marine ecosystem.

Methylmercury production in Arctic seawater: Our finding of a sub-surface peak in MeHg concentration, occurring at the same depth as the nutrient maximum, in the Beaufort Sea is consistent with the recent findings in the Pacific Ocean, Southern Ocean, and Mediterranean Sea. However, unlike the interior ocean regions, the nutrient maximum in the Beaufort Sea is predominantly an advective feature produced over

the Chukchi Shelf. Based on calculations on the short lifetime of monomethylmercury in seawater [6], we propose that the MeHg profile in the Beaufort Sea reflects the local, short-term remineralization of labile organic matter, and not the larger signal of organic remineralization advected from the Chukchi Sea in the halocline.

Linking the carbon and mercury cycles in the Beaufort Sea using a seasonal, one-dimensional water column model: Results from the model for total- and methyl mercury in seawater are generally in good agreement with measured values collected in previous years [10]. The model suggests that MeHg concentrations and formation kinetics in seawater are tightly linked to processes in the carbon cycle throughout the year and thus indirectly associated with sea-ice and light regimes. Climate change scenarios suggest an earlier breakup of sea ice, longer open water season, and increased frequency of upwelling may increase the amount of nutrients available to primary producers [11]. The model suggests that Hg(II) supply limits the formation of MeHg during the peak of the summer algal bloom, thus suggesting that if the intensity of primary productivity increased, it would have a minor effect on MeHg concentrations in our study area. However, if the duration of the summer phytoplankton bloom were extended because of increased nutrient availability, the duration of peak MeHg present in seawater would also be extended, thus increasing the availability of MeHg to the food web.

The most important next step in developing the model would be to improve the MeHg component by moving from an instantaneous empirical calculation of concentration with fixed MMHg:DMHg ratios to a more mechanistic rate constant/kinetics approach. A recent study [8] shows that these rates can be measured in situ, and provides some estimates of these rates outside of the period of high algal production and carbon mineralization. Measuring methylation/demethylation rates during the upcoming field campaigns should be a priority, with special focus aimed during the spring/summer phytoplankton bloom and subsequent period of elevated organic carbon

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remineralization. Other aspects to improve the model likely include mercury speciation and exchange processes at the air/ice/water interface.

Air-water-food web exchange dynamics of Persistent Organic Pollutants in Canadian Arctic ecosystems: Gas exchange estimates of OCPs indicate they are near equilibrium or volatilizing from the water into the air, hence Arctic water has become a secondary source to the air. Air-water exchange of some CUPs, namely chlorpyrifos and dacthal indicate that Arctic air and water are approaching equilibrium where endosulfan is still being deposited into the Arctic Ocean.

Comparing field campaigns between 2005-2011, air concentrations of FTOHs, FOSAs, and FOSEs (both gaseous and particulate) appear to be decreasing. This is in contrast to FTOHs at Alert, where between 2006-2010 concentrations appear to be increasing [15]. It is uncertain whether the decreasing concentrations found here are a temperature or temporal trend since sampling was done in different seasons. More studies need to be conducted in order to confirm if this is a temporal or seasonal/temperature variability and to determine the effect of sea ice coverage.

Standardisation of Rock-Eval pyrolysis for analysis of recent sediments and soils: The freshness biplot (Figure 15) is very useful to describe a series of systems, and can be used for comparative purposes for any future study that uses Rock-Eval to describe the OM present in a system. Virtually all highly degraded systems (B soil horizons, deep water marine sites, very unproductive lakes such as those found in the Arctic) plot similarly (very low HI:OIRE6, fairly low (S1+S2a):S2b). Of great importance is that these two measures permit a confirmation of a system’s “freshness”. One site in Alberta has an HI:OIRE6 comparable to all others, yet the (S1+S2a):S2b is remarkably low. This site is near some coal outcrops, which are likely eroding into the lake, thereby depressing the (S1+S2a):S2b. Other sites show the importance of microbial mats [3] where the (S1+S2a):S2b is much higher than others in that region, although the HI:OIRE6 is similar. Finally, these

plots show limitations where very high (S1+S2a):S2b are likely due to errors associated with very low concentrations of the components from which the ratio is derived (continental margin marine site).

The RC:TOC data (see Figure 16) are interesting in that similar patterns must be interpreted partly by their trends, and partly by their values. Decreasing trends upcore indicate to a certain extent that fresher material is deposited at the surface, and degrades over time by benthic biological degradation. However, they also signify changes to ecosystems. The Arctic sites (both freshwater and marine) in particular stand out as showing significant decreases in RC:TOC, which is brought on by increasing primary productivity, due to longer ice-free seasons. Interestingly, one site in the Mackenzie Delta actually shows increasing RC:TOC over time, suggesting that either more refractory material is being delivered over time, and/or that primary productivity is decreasing over time. Respective reasons for these possibilities are increased flux of refractory terrigenous OM (including coal) to the lake and decreased photosynthesis due to highly turbid waters from the Mackenzie blocking out light for primary producers.

Preliminary results from the BREA studies of mercury and hydrocarbons in Beaufort sediments and biota: There is a general trend toward higher Hg concentrations in sediments with increasing distance offshore. Further analyses (e.g. grain size, organic matter) will be able to discern the causes of these increasing concentrations. There are no significant east-west differences. Mercury concentrations in zooplankton range from 0.006 to 0.458 ug/g. In general, there is a tendency for Hg concentrations for a given species to be higher farther east (TBS < GRY < KUG < DAL). The reasons for these spatial increases are currently unclear. The trends are most apparent for C. hyperboreus, paraucheata and t. abyssorum.

Biogeochemical cycles and organic carbon sources and inputs in Hudson Bay: In order to understand the impacts of permafrost degradation on the Hudson Bay

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carbon cycle, it is imperative that the river dissolved and particulate phases be compared to permafrost soils, and ocean sediments using bulk measurements on OC, lignin biomarkers, δ13C and Δ14C. The method of isotope-ratio-monitoring gas chromatography/ mass spectrometry (irm-GC/MS) has enhanced the source specificity of biomarkers when coupled with stable carbon isotope analysis [1]. Concentrations of OC and lignin biomarker data are well correlated and suggest a latitudinal gradient regarding OC sources. The Δ14C data suggests there are fresher, preserved older materials now being released with increased permafrost melt and being transported by Arctic rivers to the Hudson Bay. By monitoring changes to permafrost and river hydrology and Δ14C ages of soil OC biomarkers in rivers and ocean sediments we may ascertain a better understanding of permafrost thaw dynamics and the alterations occurring to OC pools of the terrestrial environment and Hudson Bay [2].

IRIS 1 Western and Central Arctic: It was mutually beneficial to connect with representatives from the Kitikmeot Region of Nunavut, as their absence at the IRIS 1 Workshop in Inuvik, April 2011, had prevented meaningful consultations to ensure that the RIA would be relevant, meet regional needs, and that policy recommendations would be politically and culturally appropriate. Participants expressed interest in contributing written portions (e.g. local impacts to infrastructure) and providing review comments to ensure Kitikmeot representation and regional relevance. Since Cambridge Bay and Kugluktuk are not representative of the entire Kitikmeot Region, it was suggested that a regional sub-committee be formed, of which the Chairperson would sit on the IRIS 1 Steering Committee. Several people expressed interest, and we are currently determining the best way to proceed with these committees, and the roles and duties expected of members.

Since the first draft of the Regional Impact Assessment was released to lead authors and Steering Committee members during the IRIS 1 meeting at IPY Montreal, submissions for the two missing chapters have been received. Regional climate projection draft figures

were provided to authors in August 2012, but a new agreement established with Ouranos will enable the model to have more and new references. These new projections are expected to be complete in February 2013. Since the regional climate model only provides atmospheric climate-related output for terrestrial regions, the suggestion was made at the April 2012 IPY meeting to collaborate with people at DFO in Bedford, ON, using the high resolution coupled ocean-sea-ice marine model, NEMO. As of October 2012, the NEMO model is up and running on the WestGrid supercomputing facility at the University of Manitoba. However, NEMO needs to be forced with the atmospheric variables from Ouranos to obtain the ocean and sea-ice projections required for IRIS 1.

Since NEMO will not be ready with projections until at least September 2013, and Ouranos modeled projections are anticipated for February 2013, it was decided, at the December 2012 IRIS 1 meeting during ArcticNet’s ASM, not to wait for the NEMO projections; instead, two editions of the IRIS 1 RIA would be done. A General Circulation Model will be used to predict changes to the marine environment for the first iteration of the RIA. As most chapters are fairly advanced and can incorporate atmospheric projections where necessary, it was determined that the best course of action would be to complete a first edition of the RIA so stakeholders and decision-makers have something to work with now, and incorporate the NEMO modeled projections into a second RIA follow-up edition.

Community Perspectives on Communicating Contaminants Research: With climate change, Inuvialuit have their own knowledges, history, and observations, and are thus able to engage in dialogue with research because their own background enables them to better understand, trust, and communicate with science. However, this extensive historical background knowledge does not exist as such for contaminants issues, and compounded with the fact that contaminants are invisible, local engagement with this new information is more difficult and thus influences the trust of contaminants messages and communication methods.

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Interviews and focus groups indicate the variability of perceptions that Sachs Harbour locals have with regard to contaminants, consistent with previous findings [2, 3, 4, 5], where no consensus exists with respect to the sources or effects of contaminants. This may be due in part to the lack of traditional knowledge about contaminants and/or an individual’s involvement with research activities. Past research efforts that have largely focused on perceptions of message content, creation, and assessing the outcomes of communication (e.g. retention and effectiveness) have missed the crucial roles played by communication processes (e.g. methods, sources). While a given environmental hazard such as contaminants must be understood content-wise, how the information is presented and by who also influence a person’s perception of the hazard and its risk.

Meetings and more formal presentations are not familiar, traditional ways of communicating among Inuvialuit, hence the emphasis on less formal, smaller groups to share knowledge. One-on-one conversations were also advocated, especially for Elders. Communicating research results using such methods also incorporates a significant time contribution, however the importance of time cannot be overlooked nor dismissed. While recognizing the funding constraints placed on researchers, participants emphasized the value of researchers spending more than a few days directly in the community interacting with locals. The formation of relationships and a sincere commitment to the community may influence the trust and credibility of the researcher, and by extension, the trust and credibility of the information he or she imparts.

Smaller group discussions also enabled important questions to be answered, which is how it was discovered that focus group participants had no background information about mercury – this contributed to their confusion as to why mercury was ‘such a big deal.’ Working through mercury information and drawing out diagrams were immensely beneficial, as participants indicated they now had a better understanding about the context in

which current research results were being presented. The inclusion of basic mercury facts on a pamphlet is thus for the benefit of everyone in the community, but also plays an important capacity building and communication role. When people receive pamphlets from outside sources, they often have no context as to what it is about, and often no one in the community is able (or available) to explain the content. Examining mercury information in-depth with participants will enable them, in turn, to clarify questions that others may have about the information and diagrams in the community-developed pamphlet, thereby empowering individuals and reinforcing information retention because it is being shared by a familiar, trusted source from within one’s own community.

Conclusion

The delivery of contaminants to the Arctic food web: Why sea ice matters:

• ‘Uniform’ processes include a 2-3-fold increase in exposures to brine-associated biota as compared to the surface seawater, and ~0.5 times increase in surface seawater concentrations.

• An example of ‘differentiated’ processes is atmospheric loading of contaminants to melt ponds over the summer, and their subsequent leakage to the ocean.

• CUPs are currently at the highest risk of increased exposures through melt pond loading and drainage as the ratio of CMW to CSW (Melt pond enrichment factor, MEF) ranges from 2 for dacthal to 17 for chlorothalonil.

• Melt pond contaminant enrichment can be perceived as a ‘pump’ delivering contaminants from the atmosphere to the ocean under ice-covered conditions, and between 2 and 21% of CUPs could enter the Beaufort Sea via this input route annually compared to the standing stock in the top 40 m of the ocean.

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Mercury uptake within an ice algal community during the spring bloom in first-year Arctic sea ice:

• During the peak of the spring bloom, [PHg]T showed a decreasing trend with time.

• PHg concentration per cell, [THg]cell, decreased as a function of bloom progression, even though taxonomical and cell size composition of algae remained relatively unvarying; a circumstance suggesting biomass dilution.

• Mercury in ice algae originates from a combination of brine and seawater as finite sources, while atmospheric mercury depletion events (AMDEs) do not appear to significantly contribute as a source.

Importance of Arctic Zooplankton Seasonal Migrations for α-Hexachlorocyclohexane (α-HCH) Bioaccumulation Dynamics:

• Concentration of α-HCH was 2-3 times higher in C. hyperboreus from the summer than from the winter.

• After the spring ascent from deep waters, C. hyperboreus approach equilibrium partitioning with the higher surface-water concentrations of α-HCH within 3-4 weeks with about 60% of bioconcentration taking place in the first week.

• LogBAF (Bioaccumulation Factor) from the summer (feeding period) does not exceed logBCF (Bioconcentration Factor) from the culturing experiment (no feeding), suggesting that α-HCH concentration in C. hyperboreus is maintained through equilibration rather than feeding.

• Even though the annual migration does not result in a significant redistribution of α-HCH in the water column, this process could be locally important where the zooplankton biomass is high and ocean depth great enough to provide substantial vertical concentration gradients.

Dinoflagellate Cysts as Environmental Indicators in the Hudson Bay System:

• Dinoflagellate cyst production in the Hudson Bay system takes place during the open-water season, with specific time-windows for different species from ice-melt to freeze-up. Importantly, also dark-adapted heterotrophs, like light-dependent autotrophs, produce cysts when sea-ice is absent. The clearest cyst indicator for sea-ice is found to be sea-ice dwelling species Polarella glacialis, but its application in sediment core studies requires further assessment.

Holocene Primary Productivity and Mercury Dynamics and Trends in the NOW Polynya, Baffin Bay:

• The diversity of settings and responses within NOW indicates that one needs to consider the physical and biological oceanography of each setting to assess what processes may have been affected by change at that particular location. No single sampling location will inform us completely and accurately about change in a region as large and diverse as the North Water Polynya.

Zooplankton as Monitors of Mercury in Hudson Bay:

• The variability of THg and MMHg concentrations in marine zooplankton from Hudson Bay was best explained for most taxa by biomagnification and not significantly by regional/temporal differences in exposure.

• Zooplankton taxa were found to represent a broad range of trophic levels, with δ15N values ranging from 3.4 to 14.0‰, implying trophic levels from 1 to 4.

• THg was found to biomagnify in all four of the identified zooplankton food webs, MMHg was found to biomagnify in three of the four food webs.

• The feeding ecology of zooplankton (from published studies based on stomach content, fatty acid signatures), while typically overlooked, is vital to any assessment of biomagnification

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in zooplankton food webs to: 1) Establish trophic linkages (the use of δ15N and δ13C alone is not sufficient and can lead to violations of underlying assumptions of biomagnification assessments) and 2) Identify prey-predator linkages that are anomalies.

• An anomaly food web was identified: Calanus sp..-Clione limacine-Limacine helicina, where C. Limacina despite feeding exclusively on L. helicina did not have significantly higher concentrations of THg, MMHg or δ15N levels. Yet, together these taxa had significantly higher concentrations of THg than the other taxa as well as depleted δ13C signatures.

Organic mercury species in the Arctic Ocean:

• The results suggest that the concentrations of organic Hg species in the Arctic Ocean and atmosphere exhibit not only a spatial variation but also temporal trend as a result of changing environmental conditions as the season progresses.

• Radiation has been identified as an important parameter influencing the presence of organic Hg species in both air and water.

• These findings demonstrate the need for additional measurements of organic Hg species at the ocean - air interface and over longer periods to better understand the mechanisms influencing the production of bio-available Hg in a rapidly changing Arctic climate.

Transport and transformation of mercury across the ocean-sea ice-atmosphere (OSA) interface:

• Multi-year sea ice is not an important source of MeHg to the Arctic marine ecosystem.

• The alkaline nature of the sea ice surface and frost flower challenges the current model for AMDEs.

Methylmercury production in Arctic seawater:

• Within the Arctic Ocean, the haloclines might be particularly suitable for MeHg production, as the relatively higher level of dissolved OC, low level of DO, and associated microbial

communities could facilitate the formation of MeHg when new labile OM is supplied. The high sensitivity of seawater MeHg production to the remineralization of local and labile OM could explain, at least in part, the exceptional spatial and temporal variability in biotic MMHg concentrations observed in the Arctic marine ecosystems. Furthermore, measurement of MeHg could be potentially used as an indicator of the recent export flux of labile organic matter in the Arctic Ocean.

Linking the carbon and mercury cycles in the Beaufort Sea using a seasonal, one-dimensional water column model:

• Results from the model for total- and methyl mercury in seawater are in good agreement with measured values collected in previous years.

• The model suggests that MeHg concentrations in seawater throughout the year are highly dependent on the carbon cycle and thus indirectly associated with sea-ice regimes.

• Earlier break-up of sea ice may increase the frequency frequency of upwelling may increase the amount of nutrients available to primary produces.

• We determined that Hg(II) is limiting during the peak of the bloom suggesting that if the intensity of primary productivity increased, it would have a minor effect on MeHg concentrations in our study area. However, if the length of the phytoplankton bloom were extended because of increased nutrient availability later in the year, the duration of peak MeHg present in seawater would also be extended increasing the exposure of MeHg to the food web.

• An important refinement to the model would be to improve the MeHg component by moving from an instantaneous calculation of concentration with fixed MMHg:DMHg ratios to a rate constant/kinetics approach, undoubtedly improving the simulation’s fit with measured Hg profiles from the Beaufort.

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• Acquiring sufficient MeHg data during the upcoming field campaigns should be a priority, with special focus during the spring/summer phytoplankton bloom and subsequent period of elevated organic carbon remineralization.

Air-water-food web exchange dynamics of Persistent Organic Pollutants in Canadian Arctic ecosystems:

• The banning of persistent, bioaccumuative, toxic chemicals has impacted the Arctic in declining air and water concentrations which will ultimately lead to declining biota concentrations.

• Organophosphate flame retardants are present in Arctic air at concentrations that are higher than brominated flame retardants. Since production and usage of OPs is increasing, levels in Arctic air is expected to also increase.

• A better understanding of the toxicity and bioaccumulative potential is needed to know whether these compounds have the potential to be added to international regulations.

Standardisation of Rock-Eval pyrolysis for analysis of recent sediments and soils:

• Rock-Eval can be used reliably to qualify and quantify OM across a wide range of environments.

• We have developed a few novel ratios to qualify the OM, which prove to be excellent for distinguishing different environments. While the method is reasonably robust, it must be coupled with other methods (e.g. biomarkers, stable isotopes of C and N, microscopy) to corroborate the observed trends, and to help explain any discrepancies that may arise.

Preliminary results from the BREA studies of mercury and hydrocarbons in Beaufort sediments and biota:

• Our initial data show that mercury concentrations in zooplankton increase from west to east across the Beaufort Sea.

• Sediment mercury concentrations vary with water depth, but not longitude.

Biogeochemical cycles and organic carbon sources and inputs in Hudson Bay:

• It is apparent that there is potential for the use of lignin biomarkers and isotopes when understanding the terrigenous inputs of OC into the Hudson Bay from Arctic rivers.

• Cryosolic soils contain as much as 1672 Pg of carbon (1 Pg is 1015g) accounting for around 50 percent of the below ground global organic carbon pool [3].

• Projected increases in river runoff, coastal erosion and permafrost thaw will all influence OC budgets with an increase in terrigenous inputs and alterations to biogeochemical cycling influencing both the Hudson Bay and global carbon cycle and including regional sea-ice formation [4]. The freshwater system therefore provides a linkage between the Arctic and terrestrial climate and by understanding composition and pathways we may further understand the influence of permafrost degradation on these systems and the feedbacks.

IRIS 1 Western and Central Arctic:

• Kitikmeot representatives are interested in providing written contributions and review comments for the assessment, and the coordinator will continue to consult with them to ensure their input is included in the next RIA edition.

• New regional atmospheric projections, in addition to General Circulation Model predictions for the marine system, are being generated for the first edition of the assessment, which is scheduled for completion by December 2013.

Community Perspectives on Communicating Contaminants Research:

• Community understandings of contaminants are complex and varied; explanations from

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science, personal experiences of changes seen in the environment, and interactions with researchers contribute to perceptions of contaminants, causes for concern, and recommendations for the kinds of information the community needs and how it would be best received.

• While a given environmental hazard such as contaminants must be understood content-wise, how (methods) the information is presented and by who (sources) also influence a person’s perception of the hazard and its risk.

• The formation of relationships and a sincere commitment to the community may influence the trust and credibility of a researcher, and by extension, the trust and credibility of the information.

Acknowledgements and References

The delivery of contaminants to the Arctic food web: Why sea ice matters:

Acknowledgements

We thank the crew of the CCGS Amundsen for the field work assistance. We acknowledge the Canadian program office of the International Polar Year, the Natural Sciences and Engineering Research Council (NSERC), Canada Foundation for Innovation (CFI), Canada Research Chairs (CRC), Canada Excellence Research Chairs (CERC), the Department of Fisheries and Oceans Canada, Environment Canada, ArcticNet, Centre for Earth Observation Science, and the University of Manitoba for funding.

References

[1] Hargrave, B.T.; Barrie, L.A.; Bidleman, T.F.; Welch, H.E. Seasonality of exchange of organochlorines between Arctic air and seawater. Environ. Sci. Technol. 1997, 31, 3258-3266.

[2] Pućko, M.; Stern, G.A.; Macdonald, R.W.; Barber, D.G. α- and γ-Hexachlorocyclohexane Measurements in the Brine Fraction of Sea Ice in the Canadian High

Arctic Using a Sump-Hole Technique. Environ. Sci. Technol. 2010, 44, 9258-9264.

[3] Pućko, M.; Stern, G.A.; Macdonald, R.W.; Barber, D.G.; Rosenberg, B.; Walkusz, W. When will α-HCH disappear from the western Arctic Ocean? J. Mar. Syst. In press, doi:10.1016/j.jmarsys.2011.09.007.

[4] Pućko, M.; Stern, G.A.; Barber, D.G.; Macdonald, R.W.; Warner, K.-A.; Fuchs, C. Mechanisms and implications of α-HCH enrichment in melt pond water on Arctic sea ice. Environ. Sci. Technol. 2012, 46, 11862-11869.

[5] Macdonald, R.W.; Barrie, L.A.; Bidleman, T.F. et al. Contaminants in the Canadian Arctic: 5 years of progress in understanding sources, occurrence and pathways. Sci. Total Environ. 2000, 254, 93-234.

[6] Hoferkamp, L.; Hermanson, M.H.; Muir, D.C.G. Current use pesticides in Arctic media; 2000-2007. Sci. Total Environ. 2010, 408, 2985-2994.

[7] Hermanson, M.H.; Isaksson, E.; Teixeira, C.; Li, Y.-F.; Compher, K.M.; Muir, D.C.G.; Igarashi, M.; Kamiyama, K. Current use and legacy pesticide history in the Ausfonna ice cap, Svalbard, Norway. Environ. Sci. Technol. 2005, 39, 8163-8169.

[8] Weber, J.; Halsall, C.J.; Muir, D.; Teixeira, C.; Small, J.; Solomon, K.; Hermanson, M.; Hung, H.; Bidleman, T. Endosulfan, a global pesticide: A review of its fate in the environment and occurrence in the Arctic. Sci. Total Environ. 2010, 408, 2966-2984.

Mercury uptake within an ice algal community during the spring bloom in first-year Arctic sea ice:

Acknowledgements

We thank the crew of CCGS Amundsen for the field work assistance without which this study could never have been accomplished. Also, we express our gratitude to CFL participants Jeff Latonas, Amanda Chaulk, Debbie Armstrong, Joanne Delaronde, Marjolaine Blais, Simon Pineault, Jonathan Gagnon, Guisheng Song and Huixiang Xie without whom the

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sample collection and analysis for this study would have been possible. Special thanks to Bob Flett for the timely analysis of methyl mercury. Funding for this project was provided by the Canadian program office of the International Polar Year (IPY), the Natural Sciences and Engineering Research Council (NSERC), ArcticNet, a Network Centre of Excellence, the Canada Foundation for Innovation (CFI), Northern Science Training Program (NSTP), the University of Manitoba, Centre for Earth Observation Science, and Fisheries and Oceans Canada.

References

[1] Outridge, P. M.; Macdonald, R. W.; Wang, F.; Stern, G. A.; Dastoor, A. P. A mass balance inventory of mercury in the Arctic Ocean. Environ. Chem. 2008, 5, 89-111.

[2] Maslanik, J. A.; Fowler, C.; Stroeve, J.; Drobot, S.; Zwally, J.; Yi, D.; Emery, W. A younger, thinner Arctic ice cover: increased potential for rapid, extensive sea-ice loss. Geophys. Res. Lett. 2007, 34, L24501.

[3] Stern, G. A.; Macdonald, R. W.; Outridge, P. M.; Wilson, S.; Chételat, J.; Cole, A.; Hintelmann, H.; Loseto, L.; Steffen, A.; Wang, F.; Zdanowicz, C. How does climate influence Arctic mercury? Sci. Total Environ. 2012, 414, 22-42.

[4] Weeks, W. F.; Ackley, S. F. The growth, structure and properties of sea ice. In: Untersteiner, N. (ed) The geophysics of sea ice. 1986, Matrinus Nijhoff, Dordrecht (NATO ASI B146), 9-164.

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[16] Chen, C. Y.; Folt, C. L. High plankton densities reduce mercury biomagnification. Environ. Sci. Technol. 2005, 39, 115-121.

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Importance of Arctic Zooplankton Seasonal Migrations for α-Hexachlorocyclohexane (α-HCH) Bioaccumulation Dynamics:

Acknowlegements

We thank the crew of the CCGS Amundsen for the field work assistance, Bruno Rosenberg and Sherri Friesen for help and advice regarding laboratory analysis, and Dr. Louis Fortier and his team for help with C. hyperboreus collection and culturing experiment. We express gratitude to Alexis Burt, Joanne DeLaronde, and Allison MacHutchon for zooplankton collection and sorting. Finally, we thank the Canadian program office of the International Polar Year, the Natural Sciences and Engineering Research Council (NSERC), Canada Foundation for Innovation (CFI), Canada Research Chairs (CRC), Canada Excellence Research Chairs (CERC), the Department of Fisheries and Oceans Canada, ArcticNet, Centre for Earth Observation Science, and the University of Manitoba for funding.

References

[1] Berrojalbiz, N.; Lacorte, S.; Calbet, A.; Saiz, E.; Barata, C.; Dachs, J. Accumulation and cycling of Polycyclic Aromatic Hydrocarbons in Zooplankton. Environ. Sci. Technol. 2009, 43, 2295-2301.

[2] Jaward, F. M.; Barber, J. L.; Booij, K.; Dachs, J.; Lohmann, R.; Jones, K. C. Evidence for dynamic air-water coupling and cycling of Persistent Organic Pollutants over the open Atlantic Ocean. Environ. Sci. Technol. 2004, 38, 2617-2625.

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[4] Hargrave, B. T.; Phillips, G. A.; Vass, W. P.; Bruecker, P.; Welch, H. E.; Siferd, T. D. Seasonality of bioaccumulation of organochlorines in lower trophic level Arctic marine biota. Environ. Sci. Technol. 2000, 34, 980-987.

[5] Hoekstra, P. F.; O’Hara, T. M.; Teixeira, C.; Backus, S.; Fisk, A. T.; Muir, D. C. G. Spatial trends and bioaccumulation of organochlorine pollutants in marine zooplankton from the Alaskan and Canadian Arctic. Environ. Toxicol. Chem. 2002, 21, 575-583.

[6] Pućko, M.; Stern, G. A.; Barber, D. G.; Macdonald, R. W.; Rosenberg, B. The International Polar Year (IPY) Circumpolar Flaw Lead (CFL) System Study: The Importance of Brine Processes for α- and γ-Hexachlorocyclohexane (HCH) Accumulation or Rejection in Sea Ice. Atmos. Ocean. 2010, 48, 244-262.

[7] Pućko, M.; Stern, G. A.; Macdonald, R. W.; Barber, D. G.; Rosenberg, B.; Walkusz, W. When will α-HCH disappear from the western Arctic Ocean? J. Mar. Syst. In press; doi:10.1016/j.jmarsys.2011.09.007.

[8] Pućko, M.; Macdonald, R. W.; Barber, D. G.; Rosenberg, B.; Gratton, Y.; Stern, G. A. α-HCH enantiomer fraction (EF): A novel approach to calculate the ventilation age of water in the Arctic Ocean? J. Geophys. Res. 2012, 117, C08038, doi:10.1029/2012JC008130.

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Dinoflagellate Cysts as Environmental Indicators in the Hudson Bay System:

Acknowledgements

Funding from ArcticNet, DFO, NSERC, Academy of Finland. Laboratory assistance by Joanne Delaronde.

References

[1] de Vernal, A. and Marret, F. (2007) Organic-walled dinoflagellate cysts: tracers of sea-surface conditions. Proxies in Late Cenozoic Paleoceanography (ed. by C. Hillaire-Marcel and A. De Vernal), pp. 371-408. Elsevier, Amsterdam, Oxford.

[2] Heikkilä, M., Pospelova, V., Hochheim, K.P., Kuzyk, Z.A., Stern, G.A., Barber, D. and Macdonald, R.W. (2012) Sediment dinoflagellate cysts from the Hudson Bay system and their relation to freshwater and nutrient cycling. Marine Micropaleontology, submitted.

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Holocene Primary Productivity and Mercury Dynamics and Trends in the NOW Polynya, Baffin Bay:

Acknowledgements

We thank ArcticNet and NRCan for funding, Sophia Johannessen, Klaus Hochheim, and Dave Barber for assistance with this project and the crew of the CCGS Amundsen.

References

[1] Serreze, M.C. 2011. Rethinking the sea-ice tipping point. Nature, 471(3 March): 47-48.

[2] Bates, N.R. and Mathis, J.T. 2009. The Arctic Ocean marine carbon cycle: evaluation of air-sea CO2 exchanges, ocean acidification impacts and potential feedbacks. Biogeosciences, 6: 2433-2459.

[3] Klein, B. et al., 2002. Phytoplankton biomass, production and potential export in the North Water. Deep-Sea Research II, 49: 4983-5002.

[4] Eicken, H. et al., 2005. Sediment transport by sea ice in the Chukchi and Beaufort Seas: Increasing importance due to changing ice conditions? Deep-Sea Research II, 52: 3281-3302.

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[7] Comiso, J. 1999, Updated 2012. Bootstrap Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I [1979-2007]. Boulder, Colorado USA: National Snow and Ice Data Center. Digital media.

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Zooplankton as Monitors of Mercury in Hudson Bay:

Acknowledgements

We are grateful to ArcticNet, a Canadian Network of Centres of Excellence, Fisheries and Oceans Canada, and the Natural Sciences and Engineering Research Council of Canada (NSERC) for supporting this research. A special thanks to the officers and crew of the CCGS ships the Amundsen and Pierre Radisson, and to the Fortier group (Laval University) for their help with sample collections.

References

[1] Borgå, K.; Kidd, K.A.; Muir, D.C.G.; Berglund, O.; Conder, J.M.; Gobas, F.A.P.C.; Kucklick, J.; Malm, O.; Powell, D.E. Trophic magnification factors: Considerations of ecology, ecosystems, and study design. Integrated Environ. Assess. Manag. 2011, 8, 64-84.

Organic mercury species in the Arctic Ocean:

Acknowledgements

We thank the crew of the CCGS Amundsen for the field work assistance. We are grateful to Brent Else and Tim Papakyriakou for the meteorological data.

References

[1] H. Hintelmann, R.D. Evans, Fresenius. Application of stable isotopes in environmental tracer studies-measurement of monomethylmercury (CH3Hg+) by isotope dilution ICP-MS and detection of species transformation. Journal of Analytical Chemistry, 358 (1997) 378-385.

[2] J.L. Kirk, V.L.S. Louis, H. Hintelmann, I. Lehnherr, B. Else, L. Poissant, Methylated mercury species in marine waters of the Canadian high and sub Arctic. Environ Sci Technol, 42 (2008) 8367-8373.

Transport and transformation of mercury across the ocean-sea ice-atmosphere (OSA) interface:

Acknowledgements

This project was supported by funding from ArcticNet, the International Polar Year Circumpolar Flaw Lead System Study, Natural Sciences and Engineering Research Council of Canada, Canada Foundation for Innovation. We are indebted to the entire crew of CCGS Amundsen and the staff at SERF for their logistical support of all the sampling endeavours.

References

[1] AMAP Assessment 2009: Human Health in the Arctic. Arctic Monitoring and Assessment Program.

[2] AMAP Assessment 2011: Mercury in the Arctic. Arctic Monitoring and Assessment Program.

[3] Wang, F., Macdonald, R.W., Stern, G.A., and Outridge, P.M. 2010. When noise becomes the signal: Chemical contamination of aquatic ecosystems under a changing climate. Mar. Pollut. Bull. 60:1633-1635.

[4] Chaulk, A.H. 2011. Distribution and partitioning of mercury in the Arctic cryosphere: Transport across snow-sea ice-water interface in the Western Arctic Ocean. M.Sc. thesis, Department of Environment and Geography, University of Manitoba.

[5] Chaulk, A.H., Stern, G.A., Armstrong, D., Barber, D., and Wang, F. 2011. Mercury distribution and transport in the first- and multi-year sea ice in the Western Arctic Ocean. Environ. Sci. Technol. 45:1866-1872.

[6] Latonas, J. 2010. Measurements of Atmospheric Mercury, Dissolved Gaseous Mercury, and Evasional Fluxes in the Amundsen Gulf: The Role of the Sea-Ice Environment. M.Sc. Thesis, Department of Environment and Geography, University of Manitoba.

[7] Nghiem S.V., Rigor, I.G., Richter, A., Burrows, J.P., Shepson, P.B., Bottenheim, J., Barber, D.G., Steffen, A., Latonas, J., Wang, F., Stern, G., Clemente-Colón, P., Martin, S., Hall, D.K., Kaleschke, L., Tackett, P., Neumann, G., and Asplin, M.G. 2012. Field and satellite observations of the formation and

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distribution of Arctic atmospheric bromine above a rejuvenated sea ice cover. Journal of Geophysical Research-Atmospheres 117.

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[9] Sander, R., and Morin, S. 2009. Introducing the bromide/alkalinity ratio for a follow-up discussion on “Precipitation of salts in freezing seawater and ozone depletion events: a status report”, by Morin et al., published in Atmos. Chem. Phys. Discuss. 8 (3): 9035-9060.

Methylmercury production in Arctic seawater:

Acknowledgements

This project was supported by funding from ArcticNet, the International Polar Year Circumpolar Flaw Lead System Study, Natural Sciences and Engineering Research Council of Canada, Canada Foundation for Innovation, and the Northern Contaminants Program of the Aboriginal Affairs and Northern Development Canada. The nutrients profile data were generously provided by Johannie Martin and Jean-Eric Trembley of Université Laval, and dissolved inorganic carbon by Elizabeth Shadwick and Helmuth Thomas of Dalhousie University. We are indebted to the entire crew of CCGS Amundsen for their logistical support of all the sampling endeavours.

References

[1] Sunderland, E.M., Krabbenhoft, D.P., Moreau, J.W., Strode, S.A., and Landing, W.M. 2009. Mercury sources, distribution, and bioavailability in the North Pacific Ocean: Insights from data and models. Global Biogeochem. Cycles 23:GB2010, doi:10.1029/2008GB003425.

[2] Cossa, D., B. Averty, N. Pirrone. 2009. The origin of methylmercury in open Mediterranean waters. Limnol. Oceanogr. 54:837-844.

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[4] Kirk, J.L., St. Louis, V.L., Hintelmann, H., Lehnherr, I., Else, B., and Poissant, L. 2008. Methylated mercury species in marine waters of the Canadian high and sub Arctic. Environ. Sci. Technol. 42:8367-8373.

[5] St Louis, V.L., Hintelmann, H., Graydon, J.A., Kirk, J.L., Barker, J., Dimock, B., Sharp, M.J., and Lehnherr, I. 2007. Methylated mercury species in Canadian high Arctic marine surface waters and snowpacks. Environ. Sci. Technol. 41:6433-6441.

[6] Lehnherr, I., St Louis, V.L., Hintelmann, H., and Kirk, J.L. 2011. Methylation of inorganic mercury in polar marine waters. Nature Geosci. 4:298-302.

Linking the carbon and mercury cycles in the Beaufort Sea using a seasonal, one-dimensional water column model:

Acknowledgements

This project was supported by funding from ArcticNet, the International Polar Year Circumpolar Flaw Lead System Study and the Northern Contaminants Program of the Aboriginal Affairs and Northern Development Canada. We are indebted to the entire crew of CCGS Amundsen for their logistical and those who graciously allowed us to use their raw data to develop the model.

References

[1] Li, C.; Cornett, J.; Willie, S.; Lam, J. Mercury in Arctic air: The long-term trend. Sci. Total Environ. 2008, 407, 2756-2759.

[2] Carrie, J.; Wang, F.; Sanei, H.; Macdonald, R.W.; Outridge, P.M.; Stern, G.A. 2010. Increasing contaminant burdens in an Arctic fish, Burbot (Lota lota), in a warming climate. Environ. Sci. Technol. 2010, 44, 316-322.

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[3] Outridge, P.M.; Macdonald, R.W.; Wang, F.; Stern, G.; Dastoor, A.P. 2008. A mass balance inventory of mercury in the Arctic Ocean. Environ. Chem. 2008, 5, 89-111.

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[5] Macdonald, R.W.; Harner, T.; Fyfe, J. Recent climate change in the Arctic and it impact on contaminant pathways and interpretation of temporal trend data. Sci. Total Environ. 2005, 342, 5-86.

[6] Sunderland, E.M.; Krabbenhoft, D.P.; Moreau, J.W.; Strode, S.A.; Landing, W.M. Mercury sources, distribution, and bioavailability in the North Pacific Ocean: insights from data and models. Global Biogeochem. Cycles. 2009, 23, GB2010.

[7] Lavoie, D.; Macdonald, R.W.; Denman, K.L. Primary productivity and export fluxes on the Canadian shelf of the Beaufort Sea: A modelling study. J. Mar. Systems. 2009, 75, 17-32.

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[9] Lehnherr, I.; St Louis, V.L.; Hintelmann, H.; Kirk, J. 2011. Methylation of inorganic mercury in polar marine waters. Nature Geosci. 2011, 4, 298-302.

[10] Wang, F.; Macdonald, R.W.; Armstrong, D.A.; Stern, G.A. Total and methylated mercury in the Beaufort Sea: The role of local and recent organic remineralization. Environ. Sci. Technol. 2012, 46, 11821-11828.

[11] Macdonald, R.W.; Harner, T.; Fyfe, J.; Loeng, H.; Weingartner, T. AMAP Assessment 2002: The Influence of Global Change on Contaminant Pathways to, within, and from the Arctic. Arctic Monitoring and Assessment Programme (AMAP), Oslo, Norway. 2003, xii+65 pp.

Air-water-food web exchange dynamics of Persistent Organic Pollutants in Canadian Arctic ecosystems:

Acknowledgements

We thank ArcticNet for providing ship time and the student stipend for Anya Gawor. We also thank the Northern Contaminants Program of providing funding (M-31) and Environment Canada. We also thank the crew and fellow scientist of the CCGS Amundsen and Martina Koblizkova for help during sampling.

References

[1] Bidleman, T.F., H. Kylin, L.M. Jantunen, P.A. Helm and R.W. Macdonald. 2007. Hexachlorocyclohexanes (HCHs) in the Canadian archipelago. Spatial distribution and pathways of alpha, beta, gamma-HCHs in surface waters. Environ Sci Technol. 41: 2688-2695.

[2] Pućko, M., G. Stern, R. Macdonald, D. G. Barber, B. Rosenberg and W. Walkusz. 2012. When will α-HCH disappear from the western Arctic Ocean? J Mar Sci. in press.

[3] Hung, H., R. Kallenborn, K. Breivik, Y. Su, E. Brorstrøm-Lunden, K. Olafsdottir, J.M. Thorlacius, S. Leppanen, R. Bossi, H. Skov, S. Manø, G. Stern, E. Sverko and P. Fellin. 2010. Atmospheric monitoring of organic pollutants in the Arctic under the Arctic Monitoring and Assessment Programme (AMAP): 1993-2006. Sci Tot Environ. 408: 2854–2873.

[4] Riget, F., A. Bignert, B Braune, J. Stow and S Wilson. 2010. Temporal trends of legacy POPs in Arctic biota, an update. Sci Total Environ. 408:2874-2884.

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[8] Möller, A., Z. Xie, A. Caba, R. Sturm and R. Ebinghaus. 2011. Organophosphorus flame retardants and plasticizers in the atmosphere of the North Sea. Environ Pollut. 159: 3660−3665.

[9] Jantunen, L., Gawor, A., Shoeib, M., Ahrens, L., Koblizkova, M., Wong, F., Stern, G., Hung, H., 2012. Organophosphate Flame Retardants and Plasticizers in Great Lakes and Canadian Arctic Air, presented at the Brominated and other Flame Retardants Workshop, Winnipeg, Canada, June 2012.

[10] Shoeib, M., L.M. Jantunen, L. Ahrens and T. Harner. 2012. Polybrominated Diphenyl Ethers and Alternative Flame Retardants in Air at a Waste Water Treatment Plan, Brominated and Other Flame Retardants Workshop, Canada, June 2012.

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[15] Personal communication with Hung, H. 2012. Environment Canada Research Scientist. Toronto, ON.

Standardisation of Rock-Eval pyrolysis for analysis of recent sediments and soils:

Acknowledgements

We would like to thank ArcticNet for providing funding for J. Carrie to compile the data, conduct

analyses, and write the results. We would also like to thank the Geological Survey of Canada for sharing data which was used in this study.

References

[1] Carrie, J., Wang, F., Sanei, H., Macdonald, R.W., Outridge, P.M., Stern, G.A. 2011. Increasing contaminant burdens in an Arctic fish, burbot (lota lota) in a warming climate. Environmental Science and Technology 2010, 44, 316-322.

[2] Peters, K.E., Walters, C.C., Moldowan, J.M. 2005. The Biomarker Guide (2nd ed.), Volume 1: Biomarkers and Isotopes in the Environment and Human History, Cambridge University Press, New York, 471p.

[3] Sanei, H. 2013, Personal communication, Geological Survey of Canada, Calgary.

Preliminary results from the BREA studies of mercury and hydrocarbons in Beaufort sediments and biota:

Acknowledgements

Funding for this study was provide by BREA, ESRF (Environmental Studies Researh Fund), PERD (Petroleum Energy Research Development fund), IGS (International Governance Strategy), DFO and ArcticNet. We would like to thank the entire crew of the F/V Frosti for their dedication and professionalism during this first field season. The crew worked tirelessly to adapt to the challenges faced on deck, and to keep our equipment operational in challenging conditions.

References

[1] Serreze, M.C., Walsh, J.E., Chapin, F.S.I., Osterkamp, T., Dyurgerov, M., Romanovskyet al. (2000) Observational evidence of recent change in the northern high-latitude environment, Climatic Change (46: 159-207).

[2] Stroeve, J., Holland, M.M., Meier, W., Scambos, T. and Serreze, M.. 2007, Arctic sea ice decline:

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faster than forecast, Geophysical Research Letters (34(L09501): doi:10.1029/2007GL029703).

[3] Stroeve, J., Serreze, M., Drobot, S., Gearheard, S., Holland, M., et al., 2008, Arctic sea ice extent plummets in 2007, Eos, Transactions, American Geophysical Union (89(2): 13-14).

[4] Bird, K.J., Charpentier, R.R., Gautier, D.L., Houseknecht, D.W., Klett, T., Pitman, J.K., Moore, T.E., Schenk, C.J., Tennyson, M.E. and Wandrey, C.J., 2008, Circum-Arctic Resource Appraisal: Estimates of Undiscovered Oil and Gas North of the Arctic Circle, US Geological Survey. http://pubs.usgs.gov/fs/2008/3049/.

[5] AMAP, 2004, AMAP Assessment 2002: Persistent Organic Pollutants, Arctic Monitoring and Assessment Program (Chapter 2: 5- 20) Oslo, Norway.

Biogeochemical cycles and organic carbon sources and inputs in Hudson Bay:

Acknowledgements

This project was supported by funding from ArcticNet. We are indebted to the entire crew of CCGS Amundsen for their logistical support of all the sampling endeavours and to Miguel Goni’s laboratory at the Centre for Oceanic and Atmospheric Sciences (COAS) at Oregon State University for the analysis of carbon and nitrogen, stable isotopes, organic carbon and lignin biomarkers.

References

[1] Hedges, J.I. and Oades, J.M., 1997. Comparative organic geochemistries of soils and marine sediments. Organic Geochemistry 27 (7/8): 319-361.

[2] Gustafsson, O., van Dongen, B.E., Vonk, J.E., Dudarev, O.V. and Semiletov, I.P., 2011. Widespread release of old carbon across the Siberian Arctic echoed by its large rivers. Biogeosciences 8: 1737–1743, doi:10.5194/bg-8-1737-2011.

[3] Tarnocai, C., Canadell, J.G., Schuur, E.A.G., Kuhry, P., Mazhitova, G. and Simov, S., 2009. Soil organic carbon pools in the northern circumpolar permafrost region. Global Biogeochemical Cycles 23: GB2023, doi:10.1029/2008GB003327.

[4] Guo, L. and Macdonald, R.W., 2006. Source and transport of terrigenous organic matter in the upper Yukon River: Evidence from isotope (Δ13C, Δ14C, and δ15N) composition of dissolved, colloidal, and particulate phases. Global Biogeochemical Cycles 20: GB2011, doi:10.1029/2005GB002593.

IRIS 1 Western and Central Arctic:

Acknowledgements

Thank you to the IRIS 1 Steering Committee for their commitment and efforts to developing the IRIS 1 RIA; to all authors for their ongoing written contributions and workshop/meeting participation; and to all community representatives from the Inuvialuit Settlement Region and Kitikmeot for sharing their knowledge and providing feedback.

Community Perspectives on Communicating Contaminants Research:

Acknowledgements

Quyanainni to my collaborators in Sachs Harbour, without whom this project would not be possible. This project has received funding from ArcticNet, The Social Sciences and Humanities Research Council of Canada (SSHRC), the Northern Contaminants Program (AANDC), the Northern Scientific Training Program (AANDC), the University of Manitoba, International Polar Year-Circumpolar Flaw Lead (CFL) System Study, and Fisheries and Oceans Canada.

References

[1] Myers, H., and Furgal, C. 2006. Long-range transport of information: Are Arctic residents getting the message about contaminants? Arctic, 59: 47-60.

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[2] Oakes, J. 2008. Human Perceptions, comprehension and awareness of contaminants in Sanikiluaq. In: Synopsis of Research Conducted under the 2007/08 Northern Contaminants Program. Ottawa: Indian and Northern Affairs Canada, pp. 285-289.

[3] Tyrrell, M. 2006. Making sense of contaminants: A case study of Arviat, Nunavut. Arctic, 59: 370-380.

[4] Myers, H., and Furgal, C. 2006. Long-range transport of information: Are Arctic residents getting the message about contaminants? Arctic, 59: 47-60.

[5] Furgal, C. M., Powell, S., and Myers, H. 2005. Digesting the message about contaminants and country foods in the Canadian North: A review and recommendations for future research and action. Arctic, 58: 103-114.

Publications

(All ArcticNet refereed publications are available on the ASTIS website (http://www.aina.ucalgary.ca/arcticnet/).

Bailey, J.N-L.; Macdonald, R.W.; Sanei, H.; Outridge, P.M.; Johannessenc, S.C.; Hochheima, K.; Barber, D.; Stern, G.A., 2012, Change at the margin of the North Water Polynya, Baffin Bay, inferred from organic matter records in dated sediment cores., Marine Geology, submitted.

Barber, D., Asplin, M., Papakyriakou, T., Miller, L., Else, B., Iacozza, J., Mundy, C., Gosslin, M., Asselin, N., Ferguson, S., Lukovich, J., Stern, G., Gaden, A., Pucko, M., Geilfus, N.X. and Wang, F., 2012, Consequences of Change and Variability in Sea Ice on Marine Ecosystem and Biogeochemical Processes During the 2007–2008 Canadian International Polar Year program, Climatic Change, v.115, 135-159.

Baya, A.P., Hintelmann, H., 2012, Organic mercury in the Arctic lower atmosphere, ArcticNet Scientific Meeting 2012; Vancouver, Bristish Columbia, Canada (poster).

Baya, P.A., Hintelmann, H., 2012, The Presence

of Organic Mercury Species in the Arctic Ocean lower atmosphere, International Polar Year (IPY) Conference, Montreal, Québec (oral presentation).

Beattie, S., Armstrong, D., Wang, F., 2012, Mercury Distribution in Arctic Multiyear Sea Ice, International Polar Conference 2012; Montreal, Quebec, Canada (oral presentation).

Beattie, S., Chaulk, A., Armstrong, D., Wang, F., 2012, The Role of Multiyear Sea Ice in the Biogeochemical Cycling of Multiyear Sea ice, ArcticNet Scientific Meeting 2012; Vancouver, Bristish Columbia, Canada (oral presentation).

Burt, A.; Wang, F.; Pucko, M.; Mundy, C-J.; Gosselin, M.; Philippe, B.; Poulin, M.; Tremblay, J-E.; Stern, G.A., 2013, Mercury uptake within an ice algal community during the spring bloom in first-year Arctic sea ice, Journal of Geophysical Research–Oceans, submitted.

Cadieux, M.A., Stern, G.A., Hickie, B.R., Macdonald, R.W., Lavoie, D., Wang, F., 2012, Linking the carbon and mercury cycles in the Beaufort Sea using a seasonal one-dimentional water column model., ASM, Vancouver, BC, December 12-14, 2012 (poster).

Carrie, J., Sanei, H., Outridge, P.M., Stern, G, 2012, Organic matter sources and cycling in soils, sediment, peats and coal: A comparative review using Rock-Eval analyses, ArcticNet Annual Scientific Meeting, Vancouver (oral presentation).

Carrie, J., Sanei, H., Stern, G, 2012, Standardisation of Rock-Eval pyrolysis for the analysis of recent sediments and soils, Joint ICCP-TSOP conference, Beijing, China (oral presentation).

Carrie, J., Stern, G.A., Sanei, H., Macdonald, R.W., Wang, F., 2012, Determination of mercury biogeochemical fluxes in the remote Mackenzie River Basin, northwest Canada, using speciation of sulfur and organic carbon, Applied Geochemistry, 27, 815-824.

Carrie, J.; Sanei, H.; Stern, G.A., 2012, Standardisation of Rock–Eval pyrolysis for the analysis of recent sediments and soils, Organic Geochemistry, 46, 38-53.

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Dietz, R. etal., 2013, What are the toxicological effects of mercury in Arctic biota?, Science of the Total Environment, 443, 775–790.

Douglas, T.A., Loseto, L., Macdonald, R.W., Outridge, P., Dommergue, A., Poulain, A., Amyot, M., Barkay, T., Berg, T., Chételat, J. Constant, P., Evans, M., Ferrari, C., Gantner, N, Johnson, M.S., Kirk, J., Kroer, N., Larose, C., Lean, D., Muir, D., Nielsen, T.G., Poissant, L., Rognerud, S., Skov, H., Sørensen, S., Wang, F., and Zdanowicz, C.M., 2012, The Fate of Mercury in Arctic Terrestrial and Aquatic Ecosystems. A Review, Environmental Chemistry, v. 9, 321-355.

Foster, K.L., Pazerniuk, M.A., Hickie, B., Wang, F., Macdonald, R.W., Stern, G.A., 2012, Zooplankton biomonitors of mercury in Arctic marine ecosystems., International Polar Year (IPY) 2012, Montreal, QC, Canada (poster).

Foster, K.L., Stern, G.A., Pazerniuk, M.A., Hickie, B., Walkusz, W., Wang, F., Macdonald, R.W, 2012, Mercury Biomagnification in Marine Zooplankton Food Webs in Hudson Bay, ASM, Vancouver, BC, December 12-14, 2012 (oral presentation)..

Foster, K.L., Stern, G.A., Pazerniuk, M.A., Hickie, B., Walkusz, W., Wang, F., Macdonald, R.W., 2012, Mercury uptake into northern marine food webs: Bioaccumulation into zooplankton, and transfer to predators, SETAC Laurentian, Peterborough, ON (oral presentation).

Foster, K.L.; Stern, G.A.; Pazerniuk, M.A.; Hickie, B.; Walkusz, W.; Wang, F.; Macdonald, R.W., 2012, Mercury Biomagnification in Marine Zooplankton Food Webs in Hudson Bay, Environmental Science and Technology, 46, 12952-12959.

Gaden, A., Stern, G.A., 2012, The Integrated Regional Impact Study in the Western and Central Canadian Arctic: ArcticNet’s approach for translating knowledge to enable action, International Polar Year (IPY) 2012, Montréal, QC, Canada (poster).

Gaden, A., Stern, G.A., 2012, The ArcticNet IRIS 1 Regional Impact Assessment: A Tool to Bridge Science

and Policy in the Western and Central Canadian Arctic, International Polar Year (IPY) 2012, Montréal, QC, Canada (oral presentation).

Gaden, A.; Ferguson, S.; Harwood, L.; Melling, H.; Alikamik, A.; Stern, G.A., 2012, Western Canadian Arctic ringed seal organochlorine contaminant trends in relation to sea ice break-up, Environ. Science and Technology, 46, 4427-4433.

Godin, P., Stern, G.A., Macdonald, R.W., Goni, M.A., Delaronde, J., Bailey, J., MacHutchon, A., 2012, Tracing the terrignous sources of POC and DOC in the Arctic rivers of the Hudson Bay using lignin biomarkers,d13C and d14C, ASM, Vancouver, BC (oral presentation).

Godin, P., Stern, G.A., Macdonald, R.W., Goni, M.A., Delaronde, J., Bailey, J., MacHutchon, A., 2012, Quantifying the Impacts of Arctic Warming and Permafrost Degradation on the Organic Carbon (OC) Budget of the Hudson Bay using River and Ocean Sediment DOC, POC and Lignin Biomarkers, International Polar Year (IPY) 2012, Montreal, QC, Canada (poster).

Hare, A.A., Wang, F., Barber, D., Geilfus, N.-X., Galley, R., and Rysgaard, S., 2012, pH Evolution in Sea Ice Grown at an Outdoor Experimental Facility, Marine Chemistry, submitted.

Heikkilä M.; Pospelova V.; Hochheim K.P.; Kuzyk Z.A.; Stern, G.A.; Barber, D.G.; Macdonald, R.W., 2012, Sediment dinoflagellate cysts from the Hudson Bay system and their relation to freshwater and nutrient cycling, Marine Micropaleontology.

Heikkilä, M, Pospelova, V., A. Forest, A., Stern, G.A., Fortier, L., Macdonald, R.W., 2012, Seasonal signatures of dinoflagellate cyst production in Hudson Bay based on monthy sediment trap data MONTHLY SEDIMENT TRAP DATA, ArcticNet Scientific Meeting 2012; Vancouver, Bristish Columbia, Canada (poster).

Hintelmann, H., 2012, New (old) challenges in mercury speciation., International Symposium on Environmental Analytical Chemistry (ISEAC-37),

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Antwerp, Belgium (oral presentation).

Nghiem, S.V.; Rigor, I.G.; Richter, A.; Burrows, J.P.; Shepson, P.B.; Bottenheim, B.; Barber, D.G.; Steffen, A,; Latonas, J.; Wang, F.; Stern, G., 2012, Field and satellite observations of the formation and distribution of Arctic atmospheric bromine above a rejuvenated sea ice cover., Journal of Geophysical Research-Atmospheres, 117, D00S05, 15 PP., 2012 doi:10.1029/2011JD016268.

Pucko M., Stern G.A., Barber D.G., Macdonald R.W., Jantunen, L.M., Bidleman T.F, 2012, a-HCH and CUPs enrichment in melt ponds on Arctic sea ice, 1st Annual Arctic Science Partnership meeting, Gimli, Manitoba (poster).

Pucko M., Stern G.A., Macdonald R.W., Rosenberg B., Barber D.G., Walkusz W, 2012, a-hexachlorocyclohexane (a-HCH) degradation – major route of removal from the western Arctic Ocean?, International Polar Year (IPY) Conference, Montreal, Québec (oral presentation).

Pucko, M.; Stern, G.A.; Barber, D.G.; Macdonald, R.W.; Warner, K.A.; Fuchs, C., 2012, Mechanisms and Implications of a-HCH Enrichment in Melt Pond Water on Arctic Sea Ice, Environmental Science and Technology, 46, 11862–11869.

Pucko, M.; Stern, G.A.; Macdonald, R.W.; Barber, D.G.; Rosenberg. B.; Wakusz, W., 2012, When will a–HCH disappear from the Arctic Ocean. J. Mar. Sys., Journal of Marine Systems.

Pucko, M.; Walkusz, W.; Macdonald, R.W.; Barber, D.G.; Fuchs, C.; Stern, G.A., 2012, Importance of Arctic Zooplankton Seasonal Migrations for a-Hexachlorocyclohexane (a-HCH) Bioaccumulation Dynamics, Environmental Science and Technology, 47: 4155-4163.

Reinfort, B., Stern, G.A., 2012, Facing Environmental and Socio-Economic Change in the Western and Central Arctic: Addressing Climate Change Implications and Adaptations in the IRIS 1 RIA, ArcticNet Scientific Meeting 2012; Vancouver, BC,

Canada (poster).

Reinfort, B., Stern, G.A., Wang, F., Furgal, C., 2012, The overlooked importance of communication processes in disseminating contaminants research to Inuvialuit, ArcticNet Scientific Meeting 2012; Vancouver, BC, Canada (oral presentation).

Reinfort, B., Stern, G.A., Wang, F., Furgal, C., 2012, It’s not just what you say, it’s how you say it. How relationships and trust influence perception and communication about Arctic contaminants in Sachs, Harbour, NT, ArcticNet Scientific Meeting 2012; Vancouver, BC, Canada (poster).

Stern, G.A.; Macdonald, R.W.; Outridge, P.M.; Wilson, S.; Chételat , J.; Cole, A.; Hintelmann, H.; Loseto, L.L.; Alexandra, S.; Wang, F.; Zdanowicz, C., 2012, How does climate change influence Arctic mercury?, Science of the Total Enviornment, 414, 22-42.

Walkusz W., Pucko M., Stern G.A., Macdonald R.W., Barber D.G., Fuchs C., 2012, Zooplankton seasonal migrations – a mechanism of a-hexachlorocyclohexane (a-HCH) vertical transfer in the Arctic Ocean?, International Polar Year (IPY) Conference, Montreal, Québec (poster).

Wang, F., Macdonald, R.W., Armstrong, D.A., Stern, G.A., 2012, Total and methylated mercury in the Beaufort Sea: The role of local and recent organic remineralization, ArcticNet Scientific Meeting 2012; Vancouver, Bristish Columbia, Canada (oral presentation).

Wang, F.; Macdonald, R.W.; Armstrong, D.A.; Stern, G.A., 2012, Total and Methylated Mercury in the Beaufort Sea: The Role of Local and Recent Organic Remineralization, Environmental Science and Technology, 46, 11821–11828.

Wong, F., Jantunen, L.M., Papakyriakou, T., Staebler, R., Stern, G.A., Bidleman, T, 2012, Comparison of micrometeorological and two-film estimates of air-water gas exchange for alpha-hexachlorocyclohexane in the Canadian archipelago, Environmental Science and Pollution Research, 19, 1908-1914.

Documents

Effects of Climate Change on Contaminant Cycling in … of Climate Change on Contaminant Cycling in the Coastal and Marine Ecosystems Project Leader ... peak in methylated mercury,