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Curso de Lagunas CosterasAlice Newton
Universidad de Algarve, Portugal
Universidad EAFIT, Abril 8-23, 2008
22 Abril
~Cambio global y las lagunas costeras.
~Escenarios futuros
Cambio Global y las lagunas costeras
Coastal zones and lagoons play a key role in Earth System functioning
Provide a significant contribution to the life support systems of most societies.
Goods and services derived from coastal systems depend strongly on multiple trans-boundary interactions with the land, atmosphere, open ocean and sea bottom.
Human habitation, food production, growing tourism and transportation accelerate the exploitation of the coastal landscape and resources.
Coastal lagoons and Earth System Science
Global change and coastal lagoons
~ Changes in ecosystem function and biodiversity
~ Changes in biogeochemical cycles~ Changes in sea level and morphological
modifications~ Changes in sediment supply and erosion~ Changes in population, urbanization and
tourism~ Changes in use of lagoons: salt and fisheries,
aquaculture~ Changes in economy and ecosystem services
Coastal lagoons are fragile due to direct water draining form highly inhabited areas, their shallowness and low water volume to surface ratio.
As a consequence there is a high probability that among marine ecosystems coastal lagoons will be the first to react to consequences of changes in climatic trends
(Esenreich, 2005).
Climate Changeand the
European Water Dimension
A Report to the European Water Directors2005
Lagoons are
sentinel systems
Monitoring and data sets
~ Long time-series of data
~ Historical data sets
~ Rare but valuable
~ Useful in hindcast scenarios
~ Heterogeneous meta-data remains problem
~ Accessibility issues
Ringkøbing Fjord,
North Sea, Dk
16361636
Ringkøbing Fjord,
North Sea, Dk
17681768
Nymindegab, Dk
Vulnerability and risk
~sea-level change
~coastal erosion
~storms~tsunamis
Vulnerability maps
Vulnerable and valuable ecosystems
Lagoons are valuable ecosystems, provide valuable ecosystem services and support valuable activities such as tourism, aquaculture and fisheries.
Lagoons throughout the latitudes are subject to multiple pressures
Lagoons are very vulnerable to global, natural and societal changes
In particular:~ Erosion-deposition~ Sea-level change~ Changes in the water and
biogeochemical cycles~ Human settlement and exploitation
of natural resources
Coastal lagoons are vulnerable systems
•High population density (>60/km2) •High cropland use (>10%)
Global typology (polar regions cropped)
Potential Vulnerability Level (PVL)
Units Low Moderate High
Very High
Score 3 2 1 0
Water Residence Time Days <1 1-7 7-15 >15
Net Ecosystem Metabolism mol m-2y-1 >5 5-0 0-(-5) < -5
Granulometry - Sand Sand-silt Silt-clay clay
Sedimentary Organic Matter
% dw < 1 1-5 5-10 >10
Sedimentary C:N ratio - >20 10-20 5-10 <5
Sedimentary Reactive Iron µmol cm-3 >200 100-200 50-100 <50
Sedimentary AVS µmol cm-3 <50 50-100 100-150 >150
Sedimentary carbonates % dw >40 20-40 5-20 <5
Venice lagoon is the best known case study of sea level rise
Flooding of Piazza San Marco
~ Sea level trend at Trieste (open) and Venice (green), 1896-1996. Source: Carbognin L, CNR, Venice, Italy, and Rafael Bras, MIT
Annual distribution of exceptional high water events, 1923-1996.
Source: Centre for tidal forecasting of the Venice Municipality and Rafael Bras, MIT
Flooding in St. Mark’s Piazza
Rising sea level has led to increased flooding of Venice
Acqua Alta
Acqua Alta doesn’t
deter tourists
Brenta CanalBrenta Canal
Brenta RiverBrenta River
VeniceVenice
Water diversion reduced sediment delivery to Venice Lagoon
Venice circa 1500 Source: Consorzio Venezia Nuova
Management responsesSource: Chiozzotto and Drusiani, IWA Conference 2002
A massive engineering
project has been initiated for storm surge
protection
Escenarios futuros
~ Why are coastal lagoons an “issue” for the 21st C?
~ What is the prognosis for coastal lagoons?
~ What have we learned about coastal lagoons?
~ What do we still need to work on?
Types of Scenarios
~ Global change: eg rate of sea-level rise, storm frequency, erosion/deposition rates
~ Futures: business as usual, industrial development, green “eco-scenario”
~ Modeling: increase pig farming, build sewage treatment plant, grant aquaculture concessions
What is the scenario?
Santa Marta:
~ Industrial and port development “full speed ahead”
~ Tourist and golf resorts
~ Aquaculture and mineral extraction
~ Eco-tourism paradise, no development
Scenarios
Cartagena?
“Your” lagoon
Who are the actors?
~ Scientists?
~ Stakeholders?
~ Decision makers and managers?
Stakeholders
Decision makers
Scientists
21stC Prognosis for coastal lagoons?~ Coastal lagoons are ephemeral, dynamic
systems on a geological time-scale Consequences of climate change and sea-level rise? ~ We will loose some coastal lagoons, some very
soon, e.g. Chesil fleet in the UK~ New coastal lagoons will form in flooded coastal
plains~ Furthermore, what are the consequences of
changes in the biogeochemical cycles ?~ Increased urbanization of the coastal zone?
Scenarios (consider main economical activities and DPSIR scheme):• Extension of clam farming areas• Simulation with different initial clam densities• Simulation with different seeding levels• Simulation with and without macroalgae • Natural variability/Climatic changes (wet/normal/dry years)• Human activities in the watershed (variation of nutrient loads: lower/normal/higher )
Scenarios developed together with the regional authorities eg Sacca di Goro, Ferrara Province, Italy
Scenario 1 : Areas of priority - identification of sub-areas of the basin where the highest effect of management intervention is obtained in terms of N-load reduction to coastal waters.
Scenario 2: A targeted 35% reduction in nitrate loads by means of implementing the national program, Environmentally Sound Agricultural Production'( MVJ) (7000 ha), catch crops (5000 ha), reduced discharge from pump drained areas, restored wetlands (4000 ha).
Scenario 3: A targeted 50 % reduction in nitrate loads by means of all scenario 2 elements and an additional reduction in animal stock (29.000 animal units) in selected areas of the basin.
Examples of management scenarios Ringkøbing Fjord, Dk
From science to management and back to science
~ Science, i.e. ecological status, biogeochemical cycles and fluxes, climate change, etc.
~ Science for management, e.g. assessing environmental flows, sustainable yields, etc.
~ Science of management, e.g. modeling human impacts and land uses, resource optimisation
~ Management based on science, e.g. wetland restoration, lagoon sustainability,
~ Managing competing demands of society – policy and politics
Goal: integrating science in management
The sustainability challenge
GEOMORPHIC SUSTAINABILTY(relative sea level rise, sediment deficit)
ECOLOGICAL SUSTAINABILITY(pollution, fragmentation, global warming)
SOCIOECONOMIC SUSTAINABILITY(overexploitation, land uses, policy)
Goal : integrating the three levels of sustainability