10 Marine Oil Ecology

7/30/2019 10 Marine Oil Ecology

1/6

British Columbians have enjoyed a moratorium on the human pursuit of offshore oil for three decades.Calls to rescind the moratorium have recently intensified, coincident with a downturn in local andprovincial economies.To some, offshore oil represents a quick fix. To others, including the Heiltsuk, oil might threaten what'smore important a healthy ecosystem and a way of life. The Heiltsuk believe that the implications of

lifting this moratorium deserve analysis and discussion, which is the purpose of this paper.

What follows here, is a brief examination of the potential consequences of oil spills and blowouts to theHeiltsuk's traditional marine territories. This paper, the second in a series on ecosystem and culturalintegrity, affirms the need to carefully assess the risks that such narrowly-focussed actions might pose toour collective futures.

Proposed Drilling AreaThe quest for oil would focus on Hecate Strait, the shelf area between Haida Gwaii and B.C.'s CentralCoast. Experience suggests that seismic testing (using explosives) for potential well sites conductedalong more than 5,000 km of transects poses a very real risk to benthic (bottom-dwelling) fishes andother organisms. Yet the major concern in the minds of most is the potential for spills (drilling, production,

transportation).Though no one can state what the precise threat is, we do know that Hecate Strait boasts some of thefiercest winds (exceeding 200 kph) and storms anywhere and that it has a history of major seismicactivity, with quakes recorded up to magnitudes of 7.0 (1929 and 1970) and 8.1 (1949). A Spilling HistoryWe also know that marine oil spills occur. The 1989 Exxon Valdez spill released more than 35,000 tonnesof crude. In 1998, there were 176 spills reported world-wide. Britain's 1995 record was 458 tonnes of oilaccidentally or deliberately discharged, an 8.3 percent increase from the previous year. Some expertssuggest much of that oil has been discharged from ships flying "flags of convenience". With major spills, there's little that can be done

exept to track the oil's path and impacts. Scientists tell

us that only the deep-dwelling or "benthic" organisms are likely to escape the coating effects of oil, aparticular threat to intertidal organisms and marine mammals and birds. Prior to drilling off Canada's eastcoast, government and oil companies were required to spend millions assessing such potential ecologicalimpacts.Oil and Salmon: An Aromatic StoryScientists are also telling us that oil may inflict its greatest damage on organisms such as salmon. Therisks appear to come mainly from the polycyclic aromatic hydrocarbons contained in the oil. Polycyclicaromatic hydrocarbons (PAHs) are compounds formed when organic substances coal, oil, wood,gasoline are heated without sufficient air for complete oxidation. Heat causes the oil, composed of

hydrogen and carbon, to shed its hydrogen, a process called aromatization. The resulting carbon atoms,shorn of hydrogen (aromatic), recombine into rings (polycyclic) that can be perilous to life.PAHs were first shown to be carcinogenic in a 1775 study of chimney sweeps (specifically, thebenzo[a]pyrene in soot). PAHs pose a particular threat to bioaccum-ulating organisms, depending on thesize (molecular weight) of the PAH. The smaller PAHs (2 and 3 rings) are acutely toxic to manyorganisms, especially crustaceans and molluscs. PAHs adsorb to sediment and bioaccumulate in theseorganisms, which lack efficient mixed-function oxidase detoxification mechanisms.


2/6

PAHs with four or more rings (heavier molecular weights) have mutagenic (deform-causing) andcarcinogenic effects. Such PAHs such as Benzo[a]pyrene is suspected of causing cancer by covalentbonding to guanine residues on DNA, which is thought to lead to errors in reading the genetic code duringtranscription.National Marine Fisheries Service biologists in Alaska recently reported that PAHs might pose an

extremely grave threat to Pacific salmon

for many years after a spill.

These scientists found that: Buried oil pockets (from 1989) may act like "land mines" loaded with poisons; Contamination by only one part per billion of crude oil caused significant growth and reproductive

failure in pink salmon; Exposure to oil [PAHs] in egg stage is "akin to taking a shotgun to DNA."

A Coming Salmon Apocalypse?Ultimately, the biggest threat oil may pose to salmon comes from burning the oil and from the oil'scontribution to global warming. Many global climate models predict a doubling of CO2, and a 3 Ctemperature increase during next 50 years. For B.C.'s salmon, warmer temperatures are bad news spawning, incubation, and emergence are all influenced by stream temperature.Dr. Kees Groot, a retired salmon scientist, predicts that a 3 C increase would shorten total incubationtime (egg to emergence) in B.C. salmon by 55 to 131 days. Earlier emergence and emigration of salmonmay, in turn, lead to:

Juvenile fish being out of phase with food production; A greater proportion returning as jacks; Smaller fish and lower survival.

In terms of a "life history strategy," it is better to be a bigger salmon than a smaller one. Provincialbiologists have clearly shown that body size in juvenile steelhead is directly correlated with their chancesof surviving to spawn. Size confers an advantage when competing for food, avoiding predators, andmating.Salmon also exhibit well-defined temperatures preferences in the high Pacific.Salmon temperature preferences in North Pacific watersWinter < 7 CSpring < 10 CSummer < 15 C

A 3 C rise will decrease preferred habitat, and increase competition for both food and space. Ultimately,this means fewer salmon in our future. It might thus be time to consider using energy sources that arecleaner and less risky than B.C.'s offshore oil.


3/6

Impact SummaryWhile inustry and others suggest that the risk is low, the Heiltsuk are concerned that oil exploration mightstill pose a threat to B.C.'s costal ecysystems from:

Physical impacts (coating) of oil Mutagenic, carcinogenic, and toxic impacts of even minute amounts of Polycyclic Aromatic

Hydrocarbons Condoning and continuing the contribution of fossil fuels to global warming, and the anticipated

warming impacts on salmon and humans.Marine Oil Spill Pollution:

Natural breakdown of pollutionThe seas and oceans of the world do an excellent job of storing and in many cases destroying thepollutants that the industrialized world want to get rid off. Some seas are better at this job than others andsome pollutants are more easily destroyed than others. A vegetable oil spill in the middle of the NorthAtlantic in January will generally have a short life expectancy as the actions of wind, wave, and bacteriaattack the slick. The same cannot be said for other types of pollution such as plastics which in manyenvironments can persist for centuries. Similarly, some areas of the world are not as well suited to the jobof waste repository as others. In particular the Mediterranean, a semi-enclosed basin with little flushin, isone of the seas least able to break down oil, sewerage, and chemical pollutants pumped daily into itswaters. Yet it is one of the most actively polluted.

Intentional, accidental, and natural oil spillThe main sources of marine oil pollution are (intentional and accidental) releases from ships, naturalslicks and pollution from land. The first source is the most important. Hydrocarbons are vital to theeconomies of all the nations of the world and for the vast majority, these fuels must be transported across

great distances by sea before they can be used. Inevitably not all of the estimated 100.000.000 tonnes ofoil loaded into tankers every day in the North Sea, the Middle East or any of the other oil production areasends up being delivered to the consumer at the other end. Some is lost in large dramatic spills such asthat from Sea Empress on the South Wales coastline which has the immediate effect of killing waterfowl,mammals and other sea life while also inflicting more insidious harm in the form of long term disruptionand pollution of the food chain long after the clean-up operations needed to remove the cosmeticdamage. These dramatic and news-worthy accidents are a disaster for the local environment but mayrepresent just a quarter of the total input of oil from ships into the oceans each year. For example, of the200.000 tonnes that a tanker might carry, 700 tonnes will remain stuck to the sides of the storage tanksafter delivery of the oil. This oil must be disposed of before the next load can be taken on board and oneof the easiest and cheapest ways of doing this is simply to dump it at sea on the return journey.

Marine oil pollution: a threat to the environmentOil is an extremely toxic substance, containing between 100 and 200 known carcinogens in every 5tonnes released into the oceans. A significant proportion of all oil dumped in the sea is to be found in theMediterranean despite the fact that since 1983 it has been illegal to dump oil in the Mediterranean. It isevident, that such dumping is still widespread, inflicting a heavy cost on a delicate environment as well asdamaging the tourist and fishing industries.In fact, oil spills can cause substantial damage to the environment. In general, spills belong to two maincategories: oil spills due to accidents, and illegal oil releases from platforms or ships, for instance from


4/6

flushing of the ships tanks. Although the amount of oil involved in each spill usually is small, a large totalnumber of spills occurs. The amount of oil spill from rinsing of tankers and "natural" losses in theMediterranean alone is estimated to 600.00 tonnes yearly (three times the Amoco-Cadiz pollution). Earlywarning of oil spills can help reduce the damages to the environment by identifying the amount of clean-up possibly needed.

Environmental status of the MediterraneanThe Mediterranean Sea is a well frequented sea route allowing access to Southern Europe, North Africa,The Middle East and The Black Sea. The result of this extensive marine traffic is a high risk of oilpollution, both intentional and accidental. In addition to the obvious ecological risks associated with suchpollution in a closed sea area, it is in the interest of all nations bordering the Mediterranean to protect theircoastal zones on which they depend for tourism and other human activities. There are two important economical activities that can be affected by oil pollution and which would benefitfrom any measure taken in the direction of oil spill monitoring and detection: tourism and fishing. Thequantification of a benefit analysis is rather difficult, therefore only a qualitative analysis is given below:

TourismTourism can be considered as the most important Mediterranean industry, and the majority of the tourismactivities are based on coastal resources. The negative effects that oil spills can have on tourism areobvious. In this case, the main concern is focused onto the arrival of the pollution to the vicinity of theseaside.

FishingFishing is a traditional economic activity in the Mediterranean. Although most of the captures are donefrom the coast, coastal fishing is not to be forgotten. Furthermore, the importance of fish farming is

steadily increasing. These two latter activites can be sereously affected by the presence of oil pollution.

The deliberate dumping of oil in the Mediterranean is illegal. It is estimated that around 330.000 tonnes ofoil are deliberately and illegally dumped in the Mediterranean Coastal zone each year. Other figuresindicate that there may be as much as 1.000.000 tonnes dumped each year, perhaps demonstrating thattoo little is known about the full extent of the pollution problem in the Mediterranean, a problem that EarthObservation may be in a position to solve.

ENVISYS - a solution to the problem of marine oil spillsIt is a challenge to combine all the information required. It may be necessary to add ancillary data, likemeteorological data, to do a proper assessment of the situation. The technology for this is present

through the application of Internet and Internet-accessible databases. There are still bureaucraticobstacles, like data policy and data pricing that may slow the development within this area. Data must becombined and presented in an optimal way to make the user able to make the right decisions. A wrongdecision may be fatal, so this is crucial. A combination of Geographical Information System (GIS) tools,ordinary database tools and an efficient Graphical User Interface (GUI) makes this possible. TheENVISYS project demonstrates a solution for emergency detection, monitoring and management utilisingthe above mentioned technologies. The system automatically transfers satellite data as they are availablefrom the ground station to the monitoring centre. The data are analysed automatically and immediately,and the attention of the operator is called if a suspicious situation is detected in the satellite data. Satelliteimages, map data, wind data and sea current data are merged together using GIS, RDBMS and GUI


5/6

technology in order to support the operator and users to make the right decisions. One is also supportedwith oil spill development simulators and a database of cleanup equipment to make appropriatedecisions.

Relationship between Liquid Macro-seepage and light hydrocarbon micro-seepage

Seeps play an important role in the exploration of new basins or areas (Hunt, 1996). Only one

basin in three is petroliferous enough to contain producible oil or gas, and only one in six

contains even one large oil field (North, 1985). The importance of seeps has been minimized in

this era of increased use of sophisticated instrumentation and decreased use of ground surveys.

Nevertheless, nearly all the important oil-producing regions of the world were first discovered by

surface oil and gas seeps (Hunt, 1981).

Less than 15% of the hydrocarbons generated by source rocks becomes recoverable oil and

gas in reservoirs. Seeps occur wherever a permeable pathway leads to the surface from mature

source strata or leaking petroleum reservoirs. These pathways include the outcrops of

petroleum carrier beds, source rocks and unconformities, breached reservoirs and the surface

expression of intrusions such as mud volcanoes and salt domes (Link, 1952). As oil migrates

towards the surface, a number of weathering mechanisms begin to alter its composition. These

include the evaporation of the more volatile hydrocarbons and consumption by microbes

(biodegradation). The viscous liquids and asphalt found in surface seeps bear little chemical

resemblance to their source, and a seep-reservoir oil correlation study requires very

sophisticated analytical techniques. Except for indicating that an area has sourced liquid

hydrocarbons, the presence of observable surface seeps reveals little about the source type or

thermal maturity within a basin.

Hydrocarbons generated in petroliferous basins are composed of a large range of components,

from the simplest, lightest methane molecule to very large and complex molecular structures.The light hydrocarbons (C1-C4), methane, ethane, propane and butane, migrate in the

subsurface in gaseous form. Heavier hydrocarbons (C5+) migrate in the liquid phase. This

difference is important with respect to seep detection. Oil seeps can only form where there is an

uninterrupted path with adequate permeability to transport liquids to the surface. Consequently,

observable macroseeps are rare and have often followed tortuous pathways to the surface. The

light gaseous hydrocarbons, however, are more mobile in the subsurface and require a much

less open pathway to be focused at the surface. They are also more likely to be located closer

to their subsurface sources. These microseeps are much more widespread and, although

generally invisible to the naked eye, are present in small concentrations that can now be

sampled in soils, measured and mapped. The pattern and intensity of this microseepage can be

combined with geologic information to predict areas having the greatest probability of containing

subsurface reservoirs.

The relative concentrations of these light hydrocarbons (methane, ethane, propane, and butane)

are directly related to production type and thermal maturity of hydrocarbons in the basin (Jones

and Drozd, 1983). In other words, oil productive basins will contain greater proportions of

ethane, propane and butane relative to methane, and gas prone areas will contain greater

proportions of methane. Thus, light hydrocarbon surveys can be considered as a source rock
http://www.eti-geochemistry.com/j&d/index.htmlhttp://www.eti-geochemistry.com/j&d/index.htmlhttp://www.eti-geochemistry.com/j&d/index.htmlhttp://www.eti-geochemistry.com/j&d/index.htmlhttp://www.eti-geochemistry.com/j&d/index.htmlhttp://www.eti-geochemistry.com/j&d/index.html


6/6

tool applied at the surface. Although the presence of an oil seep proves the existence of oil

generating sources, it does not provide adequate information on the level of thermal maturity

and the potential gas (GOR) available to charge the subsurface reservoirs. This type of

information is not generally present in liquid seeps because of weathering effects. The thermal

maturity of the subsurface hydrocarbons that source the surface seeps can be determined by

sampling the light hydrocarbons in the vicinity of observable seeps. Once established, thissignature can be compared with compositions of light hydrocarbon seeps measured throughout

the basin, with the goal of highlighting those areas that could be sourced from subsurface

reservoirs.

Documents

10 Marine Oil Ecology