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Royal Netherlands Institute for Sea Research
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Climate Change Impacts onMarine Biodiversity and
Ecosystem Services
Carlo HeipRoyal Netherlands Institute of Sea Research
European Institute for the Study of Marine Biodiversity and EcosystemFunctioning MarBEF+
Green Week, Brussels 2 June 2010
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§ to present the state of the art knowledge on
climate change impacts on marine biodiversity and
ecosystem services and potential consequences on
human societies and economy.
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Sea SurfaceTemperature
Thermal expansion
Storm frequency andintensity
Ocean currents
Stratification
Ocean acidification
Atmospherictemperature
Melting of Ice
Sea Level Rise
CO2
Deep circulation
Ice biota disappear
Distribution changes, mortality
Distribution changes
Distribution changes
Destruction of coastalhabitats
Reduction of calcification
Productivity changes
The chain of eventsEffects on Marine Biodiversity
Low oxygenDistribution changes, mortality
Destruction of coastalhabitats
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Sea SurfaceTemperature
Thermal expansion
Storm frequency andintensity
Ocean currents
Stratification
Ocean acidification
Atmospherictemperature
Melting of Ice
Sea Level Rise
CO2
Deep circulation
The chain of events
Low oxygen
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Effects on Biodiversity and Ecosystem Services
§ Indirect effect of increasing CO2: Sea surface
temperature
• Changing distributions and food webs: example of the
Arctic
• Increasing stratification, lower productivity and hypoxia
§ Direct effect of increasing CO2
• Ocean acidification
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Increasing SST: what is the evidence?
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Effect: changing distributions
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Sp
eci
es
rich
ne
ss
Fish Species Richness in the North Sea has strongly
increased over time
o Small southern species increase
o Large northern species decrease their range
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Fig. 1. Water temperatures in the Arctic are increasing (Walczowski et al. 2007)
4
3
2
1
-2 0 2 4 6temperature
years
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Climate Change and Overexploitation
lead to decreasing
numbers of top predators.
Example: Bluefin Tuna caught
in the North Sea UK 1933 (upper two)
Denmark (lower) 1946. The species
has now disappeared completely.
(MacKenzie and Myers, 2007)
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Warm and light surface waters
Cold and heavy deep waters
Result = stratificationStable situation
Temperature and Stratification
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Temperature and Stratification
§ Models with rising CO2 indicate that upper ocean
stratification and stability will increase and mixing
will decrease in the next 50 years with rising SST.
§ These conditions increase the dominance of
picoplankton (= very small plankton) relative to
diatoms and other microplankton.
§ It is reasonable to assume that NPP (Net Primary
Production) by picoplankton will increase and NPP
by larger microplankton will decrease, especially at
low and mid-latitudes.
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1999-2004
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Primary production is correlatedwith stratification
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SST, stratification and oxygen
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Eastern Tropical Atlantic
Central Equatorial Atlantic
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Acidification: the other CO2
problem
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Surface pH will decrease with increased CO2
Wallace in SOLAS programme plan 2001
+Calcifying Organisms
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Climate: coccolithophorids, albedo and acidification
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Example: coccolithophorids
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Coccoliths and albedo
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Cloud albedo
§Coccolithophorids produce DMS (dimethylsulfide)
(over 100 times more than diatoms).
§After the cells die, some of this DMS eventually
ends up as cloud condensation nuclei (CCN) in the
atmosphere.
§These CCN help to stimulate cloud formation. In
this way, coccolithophore productivity helps to
increase the reflectiveness (albedo) of the planet
by allowing more clouds to form.
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Acidification effects in corals
Fig. 18: Scleractiniancoral Oculinapatagonica after being maintained for 12 months in (A) normal seawater (pH=8.2) and (B) acidified seawater (pH=7.4). (C) Solitary polyps reforming a colony and calcifying after being transferred back to normal seawater. (D) Percent change in biomass and total buoyant weight over 12 months (pH = 7.4) and control (pH = 8.2) seawater (N = 20). Scale bars indicate 2 mm. From Fine & Tchernov(2007).
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Ecosystem services, humansocieties and the economy
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§Coastal waters account for just 7% of the total
area of the ocean. However the productivity of
ecosystems such as the continental shelves, coral
reefs, seagrass beds and mangroves means that
this small area forms the basis of the world’s
primary fishing grounds, supplying an estimated
50% of the world’s fisheries.
§They provide vital nutrition for close to 3 billion
people, as well as 50% of animal protein and
minerals to 400 million people of the least
developed countries in the world.
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§Each day, more than a hundred million tons of
carbon in the form of CO2 are fixed into organic
material by the microscopic plants of the upper
ocean, and each day a similar amount of organic
carbon is transferred into marine ecosystems by
sinking and grazing.
§The entire phytoplankton biomass of the global
oceans is consumed every two to six days
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§The ocean’s vegetated habitats, in particular
mangroves, salt marshes and seagrasses, cover
<0.5% of the sea bed. These form earth’s blue
carbon sinks and account for more than 50% of all
carbon storage in ocean sediments.
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Conclusions
§ Impacts of climate change on marine biodiversity are
complex and often specific for the oceans
§ Marine biodiversity is changing due to climate change and
increasing overexploitation of higher trophic levels, or both
§ Effects on biodiversity of increasing temperature through
stratification and oxygen content, and of decreasing pH
through impaired calcification, are becoming visible at global
scales
§ This may impair the capacity of the oceans to sequester
carbon, to protect coastal environments against storms and
floods, and to provide food for human populations.
§ Biodiversity can be used for our benefit in mitigating the
effects of climate change
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Thank you for your attention
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