Archive for March, 2009

EPOCA educational pdf

Ocean Acidification, the other CO2 problem: how far will life resist?

a quest for answers in the **Arctic**

EPOCA, the European Project on Ocean Acidification and CarboSchools, promoting teacher-scientist partnerships about global change research, are happy to release a new 8-page educational leaflet introducing Ocean Acidification research challenges to teachers of all levels and subjects.

The leaflet gives an overview of what we know and do not know about Ocean Acidification and introduces how a major experiment in the Arctic in May 2009 and May 2010 will progress our understanding. The prime goal is to help teachers and scientists to get started with collaborative projects, including through the follow-up of Arctic research through a blog project associated with physical meetings.
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Key Arctic pelagic mollusc (Limacina helicina) threatened by ocean acidification

Thecosome pteropods (shelled pelagic molluscs) can play an important role in the food web of various ecosystems and play a key role in the cycling of carbon and carbonate. Since they harbor an aragonitic shell, they could be very sensitive to ocean acidification driven by the increase of anthropogenic CO2 emissions. The impact of changes in the carbonate chemistry was investigated on Limacina helicina, a key species of Arctic ecosystems. Pteropods were kept in culture under controlled pH conditions corresponding to pCO2 levels of 350 and 760 μatm. Calcification was estimated using a fluorochrome and the radioisotope 45Ca. It exhibits a 28% decrease at the pH value expected for 2100 compared to the present pH value. This result supports the concern for the future of pteropods in a high-CO2 world, as well as of those species dependent upon them as a food resource. A decline of their populations would likely cause dramatic changes to the structure, function and services of polar ecosystems.
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La biologie marine bouleversée par les émissions de CO2

Le CO2 ne menace pas seulement le climat, il dégrade aussi les océans : en absorbant une part du carbone atmosphérique excédentaire, les mers tendent à devenir de plus en plus acides. Un phénomène qui pourrait à l’avenir fragiliser certaines espèces formant la base de la chaîne alimentaire. Des travaux publiés, dimanche 8 mars dans la revue Nature Geoscience, suggèrent que ces bouleversements, prévus par les expérimentations en laboratoire, sont en cours et que leur magnitude est déjà importante.
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The other CO2 problem movie


Clay animation about the potentially disastrous rise in ocean acidity. Created by pupils from Ridgeway School Plymouth, Sundog Media, and Dr Carol Turley of Plymouth Marine Laboratory. Commissioned by EPOCA [European Project on OCean Acidification]; supported by UCP Marjon, and National Marine Aquarium.
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Sale temps pour les coraux (audio; in french)

Depuis le milieu du siècle dernier, la planète a perdu 19% de ses récifs coralliens. Principalement le long des zones du littoral les plus urbanisées. Et le phénomène ne cesse de s’amplifier.
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The Federal Ocean Acidification Research and Monitoring (FOARAM) Act

The Federal Ocean Acidification Research and Monitoring (FOARAM) Act passed in the House of Representatives and Senate respectively on 3rd and 19th March 2009.
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Oceanic acidification affects marine carbon pump and triggers extended marine oxygen holes

Rising atmospheric CO2 levels will not only drive future global mean temperatures toward values unprecedented during the whole Quaternary but will also lead to massive acidification of sea water. This constitutes by itself an anthropogenic planetary-scale perturbation that could significantly modify oceanic biogeochemical fluxes and severely damage marine biota. As a step toward the quantification of such potential impacts, we present here a simulation-model-based assessment of the respective consequences of a business-as-usual fossil-fuel-burning scenario where a total of 4,075 Petagrams of carbon is released into the atmosphere during the current millennium. In our scenario, the atmospheric pCO(2) level peaks at approximate to 1,750 mu atm in the year 2200 while the sea-surface pH value drops by >0.7 units on global average, inhibiting the growth of marine calcifying organisms. The study focuses on quantifying 3 major concomitant effects. The first one is a significant (climate-stabilizing) negative feedback on rising pCO(2) levels as caused by the attenuation of biogenic calcification. The second one is related to the biological carbon pump. Because mineral ballast, notably CaCO3, is found to play a dominant role in carrying organic matter through the water column, a reduction of its export fluxes weakens the strength of the biological carbon pump. There is, however, a third effect with severe consequences: Because organic matter is oxidized in shallow waters when mineral-ballast fluxes weaken, oxygen holes (hypoxic zones) start to expand considerably in the oceans in our model world-with potentially harmful impacts on a variety of marine ecosystems.
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Impact of CO2-driven ocean acidification on invertebrates early life-history – What we know, what we need to know and what we can do

As a consequence of increasing atmospheric CO2, the world’s oceans are becoming more acidic and the rate of change is increasingly fast. This ocean acidification is expected to have significant physiological, ecological and evolutionary consequences at many organizational levels of marine biodiversity. Alarmingly little is known about the long term impact of predicted pH changes (a decrease of −0.3/−0.4 units for the end of this century) on marine invertebrates in general and their early developmental stages in particular, which are believed to be the more sensitive to environmental disturbances, are essential as unit of selection, recruitment and population maintenance. Ocean acidification (OA) research is in its infancy and although the field is moving forward rapidly, good data are still scarce. Available data reveal contradictory results and apparent paradoxes. In this article, we will review available information both from published sources and work in progress, drawing a general picture of what is currently known, with an emphasis on early life-history larval stages. We will also discuss what we need to know in a field with very limited time resources to obtain data and where there is a high expectation that the scientific community should rapidly be able to provide clear answers that help politicians and the public to take action. We will also provide some suggestions about what can be done to protect and rescue future ecosystems.
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Effect of CO2-related acidification on aspects of the larval development of the European lobster, Homarus gammarus (L.)

Oceanic uptake of anthropogenic CO2 results in a reduction in pH termed “Ocean Acidification” (OA). Comparatively little attention has been given to the effect of OA on the early life history stages of marine animals. Consequently, we investigated the effect of culture in CO2-acidified sea water (approx. 1200 ppm, i.e. average values predicted using IPCC 2007 A1F1 emissions scenarios for year 2100) on early larval stages of an economically important crustacean, the European lobster Homarus gammarus. Culture in CO2-acidified sea water did not significantly affect carapace length or development of H. gammarus. However, there was a reduction in carapace mass during the final stage of larval development in CO2-acidified sea water. This co-occurred with a reduction in exoskeletal mineral (calcium and magnesium) content of the carapace. As the control and high CO2 treatments were not undersaturated with respect to any of the calcium carbonate polymorphs measured, the physiological alterations we record are most likely the result of acidosis or hypercapnia interfering with normal homeostatic function, and not a direct impact on the carbonate supply-side of calcification per se. Thus despite there being no observed effect on survival, carapace length, or zoeal progression, OA related (indirect) disruption of calcification and carapace mass might still adversely affect the competitive fitness and recruitment success of larval lobsters with serious consequences for population dynamics and marine ecosystem function.
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Impact of anthropogenic ocean acidification on thermal tolerance of the spider crab Hyas araneus

Future scenarios project combined developments of elevated CO2 concentrations and global warming and their impact on marine ecosystems. The synergistic impact of both factors was addressed by studying the effect of CO2 accumulation on thermal tolerance of the cold-eurythermal spider crab Hyas araneus. Animals were exposed to present day normocapnia (380 ppm CO2), CO2 levels expected towards 2100 (710 ppm) and beyond (3000 ppm). Heart rate and haemolymph PO2 (PeO2) were measured during progressive short term cooling from 10 to 0°C and during warming from 10 to 25°C. An increase of PeO2 occurred during cooling with highest values reached at 0°C under all three CO2 levels. Heart rate increased during warming until a critical temperature (Tc) was reached. The putative Tc under normocapnia was presumably >25°C, from where it fell to 23.5°C under 710 ppm and then 21.1°C under 3000 ppm. At the same time, thermal sensitivity, as seen in the Q10 values of heart rate, rose with increasing CO2 concentration in the warmth. Our results suggest a narrowing of the thermal window of Hyas araneus under moderate increases in CO2 levels by exacerbation of the heat or cold induced oxygen and capacity limitation of thermal tolerance.
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