Archive for August, 2009

Take a few simple steps to reduce ocean acidification

We’ve all seen the headlines about melting sea ice in the Arctic. It is tangible harbinger EVIDENCE of the enormous quantities of carbon dioxide, or CO2, our industrial world has pumped into the atmosphere.

But there is another equally insidious peril below sea level. Alaskans are at the forefront of “the other carbon dioxide problem” — ocean acidification. Some of the CO2 pollution dissolves into the ocean, creating carbonic acid and making the ocean more acidic.

No one fully knows what this change will do to the oceans. But we do know that if we don’t reverse this soon, we’ll end up with a drastically different ocean, to the detriment of nearly everyone who depends on it. Think jellyfish instead of salmon.

Acidification makes it harder for organisms to make shells or other protective structures — they essentially dissolve in the more acidic water. This change poses new risks for a vast range of ocean life, from clams and coral reefs, to crabs, shrimp, lobsters, krill, sea urchins, sea snails, and some kinds of plankton, to name a few.
Continue reading ‘Take a few simple steps to reduce ocean acidification’

Net Loss of CaCO3 from a subtropical calcifying community due to seawater acidification: mesocosm-scale experimental evidence

Acidification of seawater owing to oceanic uptake of atmospheric CO2 originating from human activities such as burning of fossil fuels and land-use changes has raised serious concerns regarding its adverse effects on corals and calcifying communities. Here we demonstrate a net loss of calcium carbonate (CaCO3) material as a result of decreased calcification and increased carbonate dissolution from replicated subtropical coral reef communities (n=3) incubated in continuous-flow mesocosms subject to future seawater conditions. The calcifying community was dominated by the coral Montipora capitata. Daily average community calcification or Net Ecosystem Calcification (NEC=CaCO3 production – dissolution) was positive at 3.3 mmol CaCO3 m−2 h−1 under ambient seawater pCO2 conditions as opposed to negative at −0.04 mmol CaCO3 m−2 h−1 under seawater conditions of double the ambient pCO2. These experimental results provide support for the conclusion that some net calcifying communities could become subject to net dissolution in response to anthropogenic ocean acidification within this century. Nevertheless, individual corals remained healthy, actively calcified (albeit slower than at present rates), and deposited significant amounts of CaCO3 under the prevailing experimental seawater conditions of elevated pCO2.
Continue reading ‘Net Loss of CaCO3 from a subtropical calcifying community due to seawater acidification: mesocosm-scale experimental evidence’

2010 Ocean Sciences Meeting: Session on Biological consequences of ocean acidification

We would like to bring to your attention Session B027, “Biological consequences of ocean acidification” at the upcoming Ocean Sciences Meeting (February 22-26, 2010, in Portland, Oregon, USA).  Abstract submissions are due October 15, 2009.  Please note that there are multiple complementary sessions on this general topic; our session targets biological/ecological impacts, accompanying others that place more emphasis on geochemistry and paleoceanography.
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Apply to participate in OCB Ocean Acidification Short Course by September 1, 2009!

The original announcement of the OCB Ocean Acidification Short Course (November 2-13, 2009 in Woods Hole, MA USA) you may find here. We would like to remind you that the application deadline for the course is SEPTEMBER 1, 2009.
Continue reading ‘Apply to participate in OCB Ocean Acidification Short Course by September 1, 2009!’

Research finds higher acidity in Alaska waters

Erosion threatens to topple coastal Alaskan villages. Melting ice threatens polar bears. Now, a marine scientist says the state’s marine waters are turning acidic from absorbing greenhouse gases faster than tropical waters, potentially endangering Alaska’s $4.6 billion fishing industry.

The same things that make Alaska’s marine waters among the most productive in the world — cold, shallow depths and abundant marine life — make them the most vulnerable to acidification, said Jeremy Mathis, a chemical oceanographer at the University of Alaska Fairbanks.

“Ecosystems in Alaska are going to take a hit from ocean acidification,” he said. “Right now, we don’t know how they are going to respond.”
Continue reading ‘Research finds higher acidity in Alaska waters’

Ecological theory and continental margins: where shallow meets deep

Continental margins, where land becomes ocean and plunges to the deep sea, provide valuable food and energy resources, and perform essential functions such as carbon burial and nutrient cycling. They exhibit remarkably high species and habitat diversity, but this is threatened by our increasing reliance on the resources that margins provide, and by warming, expanding hypoxia and acidification associated with climate change. Continental margin ecosystems, with environments, constituents and processes that differ from those in shallow water, demand a new focus, in which ecological theory and experimental methods are brought to bear on management and conservation practices. Concepts of disturbance, diversity–function relationships, top-down versus bottom-up control, facilitation and meta-dynamics offer a framework for studying fundamental processes and understanding future change.
Continue reading ‘Ecological theory and continental margins: where shallow meets deep’

Effect of CO2-related acidification on aspects of the larval development of the European lobster, Homarus gammarus (L.) (update)

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 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.
Continue reading ‘Effect of CO2-related acidification on aspects of the larval development of the European lobster, Homarus gammarus (L.) (update)’

A biogeochemist sees the value of diversity in a changing ocean

Ocean acidification in response to excess carbon dioxide in the atmosphere could become a problem for marine organisms, especially those that make skeletons or shells out of calcium carbonate. Corals and clams are at risk, as are the coccolithophorids — microscopic algae that are, by volume, the most important shell producers.

These algae have been the guinea pigs in a series of lab studies measuring their response to acidified seawater. But I worry about whether these studies give us an accurate picture of the future. They typically start with clones — descendants of a single cell — grown in acidified conditions for only a few weeks. This set-up precludes the kind of natural selection and adaptation that might occur over decades and centuries in the ocean.

To cloud the waters further, different labs often obtain conflicting results on the same species, a situation some attribute to subtle differences in methods. Fortunately, a recent study by Gerald Langer of the Autonomous University of Barcelona in Spain and his colleagues provides a more satisfying and ultimately more optimistic explanation (G. Langer et al. Biogeosci. Discuss. 6, 4361–4383; 2009). These reserachers grew four different strains of a calcifying algae, Emiliania huxleyi, at different seawater pH levels, and showed that the response to acidification varies significantly among the strains. They argue convincingly that these diverse responses have a genetic basis.
Continue reading ‘A biogeochemist sees the value of diversity in a changing ocean’

Community review of Guide to Best Practices in Ocean Acidification Research and Data Reporting

The community review of the Guide to Best Practices in Ocean Acidification Research and Data Reporting is extended by one month. The deadline for sending comments is extended until 15 September 2009. The two chapters that are still missing will be available on 24 August at the latest.
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Alaska waters facing troubles (audio)

Alaska’s oceans are acidifying at a troubling rate. Water samples collected this spring from the Bering Sea and the Gulf of Alaska show the problem is happening more quickly and is more severe than in warmer parts of the planet. And that could have big implications for Alaska’s fisheries in the years ahead.
Continue reading ‘Alaska waters facing troubles (audio)’

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Ocean acidification in the IPCC AR5 WG II

OUP book