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Tag Archive: acidification

  1. Some marine creatures may be more resilient to harsher ocean conditions than expected

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    Posted: 15 Feb 2017 05:41 AM PST full article here

    As the world continually emits carbon dioxide into the atmosphere, the oceans are taking a hit, absorbing some of it and growing more acidic. Among other effects, scientists have found that coral reefs and oyster hatcheries are deteriorating as a result. However, scientists studying a type of sea snail report a bit of bright news: The animal can adapt by rejiggering its shell-making process and other functions

    …While ocean acidification appears to cause damage to many calcifying organisms, recent studies have suggested that some of those organisms may be more resistant to acidification than previously thought. Sean D. Connell and colleagues wanted to find out how this might be possible.

    The researchers exposed sea snails called periwinkles to the ocean conditions predicted for 2100, when some waters at a pH of 8.10 today are expected to reach a pH of 7.85. Although the animals’ metabolism declined, they were able to speed up their shell-making by producing less-dense inner shells. In addition, they developed less-soluble shells, which are more resistant to future, harsher ocean conditions. The researchers say these changes suggest that the periwinkle, and potentially other calcifying organisms, could have the ability to adapt to the acidifying oceans….

    Jonathan Y. S. Leung, Bayden D. Russell, Sean D. Connell. Mineralogical Plasticity Acts as a Compensatory Mechanism to the Impacts of Ocean Acidification. Environmental Science & Technology, 2017; DOI: 10.1021/acs.est.6b04709

  2. Why the ocean has absorbed more carbon over the past decade

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    Posted: 08 Feb 2017 01:46 PM PST  full article here

    With the ocean absorbing more carbon dioxide over the past decade, less of the greenhouse gas is reaching the Earth’s atmosphere. That’s decidedly good news, but it comes with a catch: Rising levels of carbon dioxide in the ocean promote acidification, which breaks down the calcium carbonate shells of some marine organisms….

    new research….demonstrates that a slowdown of the ocean’s overturning circulation is the likely catalyst. Their findings appear in the journal Nature. “Such a slowdown is consistent with the projected effects of anthropogenic climate change, where warming and freshening of the surface ocean from melting ice caps leads to weaker overturning circulation,” DeVries explained….

    ….According to DeVries, this finding may seem counterintuitive. Prevailing scientific wisdom asserts that the deceleration of circulation diminishes the ocean’s ability to absorb anthropogenic CO2 from the atmosphere as surface waters warm and become saturated with CO2.  “While that is true, there is another effect that appears to be more important in the short term,” DeVries said. “The weaker overturning circulation brings less naturally CO2-rich deep waters to the surface, which limits how much of that gas in the deep ocean escapes to the atmosphere. That causes the ocean to absorb more CO2 from the atmosphere.

    Tim DeVries, Mark Holzer, Francois Primeau. Recent increase in oceanic carbon uptake driven by weaker upper-ocean overturning. Nature, 2017; 542 (7640): 215 DOI: 10.1038/nature21068

  3. Maine’s coastal waters unhealthy from carbon, acidity. Are seaweed gardens the answer?

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    Bill Trotter, BDN Staff Feb 7 2017  See full article here

    BOOTHBAY, Maine — Seaweed cultivation has been promoted in recent years in Maine as a way to produce local nutritious food and to boost the coastal economy.

    Now, seaweed harvesters say their industry provides yet another benefit: environmental protection, in the form of improving water quality.

    A new study from Bigelow Laboratory for Marine Sciences in Boothbay indicates growing and harvesting seaweed may be an antidote for increasing carbon and acidity levels in the ocean, which is harming a variety of marine life.

    Since January 2016, the lab has been studying the effect of kelp growth on surrounding carbon levels at the Ocean Approved seaweed farm off Great Chebeague Island in Casco Bay…. According to Price, in the six months that scientists measured carbon dioxide levels in and around the 3-acre kelp farm, they found the kelp was absorbing carbon at the same rate carbon levels are expected to increase in the Gulf of Maine over the next 100 years from global use of fossil fuels….

  4. Unexpected result: Ocean acidification can also promote shell formation

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    Posted: 27 Jan 2017 08:29 AM PST  see full article here

    More carbon dioxide in the air also acidifies the oceans. It seemed to be the logical conclusion that shellfish and corals will suffer, because chalk formation becomes more difficult in more acidic seawater. But now a group of scientists discovered to their own surprise that some tiny unicellular shellfish (foraminifera) make better shells in an acidic environment. This is a completely new insight….

    …”If the classic hypothesis holds and more carbon dioxide leads to less lime production, the oceans can continue to take up CO2 from the atmosphere. But what if the majority of the organisms can regulate the chemical form of their inorganic carbon by biochemical processes like our foraminifers did, and continue to form lime structures in a more acidic ocean? Over time, the concentration of dissolved carbon dioxide in the oceans may start to increase. Consequently, the ability of the oceans to take up a large part of the carbon dioxide in the air may start to decrease. This would mean that more carbon dioxide would remain in the air, leading to a more rapid warming of our planet.”

    Takashi Toyofuku, Miki Y. Matsuo, Lennart Jan de Nooijer, Yukiko Nagai, Sachiko Kawada, Kazuhiko Fujita, Gert-Jan Reichart, Hidetaka Nomaki, Masashi Tsuchiya, Hide Sakaguchi, Hiroshi Kitazato. Proton pumping accompanies calcification in foraminifera. Nature Communications, 2017; 8: 14145 DOI: 10.1038/ncomms14145

  5. How community interactions amplify response of calcifying phytoplankton species to ocean acidification

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    Science Daily Posted: 14 Dec 2016 08:51 AM PST  See full article here

    Coccolithophores, single-celled calcifying phytoplankton that play a key role in the Earth’s climate system, might lose their competitive fitness in a future ocean. In a field experiment investigating the effects of ocean acidification on the coccolithophore Emiliania huxleyi in its natural environment, the species failed to bloom. A team of researchers concludes, that a small response to ocean acidification was amplified through ecological interactions and causes a massive impact on the ecosystem.

    Image result for coccolithophore Emiliania huxleyiPhoto:Dr. Jeremy R. Young Palaeontology Dept. The Natural History Museum LONDON, SW7 5BD, UK

    …The uptake of fossil fuel carbon dioxide (CO2) by the ocean increases seawater acidity and causes a decline in carbonate ion concentrations. This process, termed ocean acidification, makes it energetically more costly for calcifying organisms to form their calcareous shells and skeletons. Several studies have shown that this also holds true for Emiliania huxleyi, the world’s most abundant and most productive calcifying organism….

    …”In view of Emiliania‘s rather small changes in metabolic performance observed in previous laboratory experiments, we predicted that it would still be able to maintain its ecological niche in an acidifying ocean. What we observed came as a big surprise”…A small reduction in cellular growth due to ocean acidification caused the population size to gradually decline during the pre-bloom phase. “When it was time for Emiliania to start bloom formation, there were so few cells left in the plankton community that it couldn’t outgrow its competitors anymore,” reflects Ulf Riebesell….

    The results of this study demonstrate the importance of investigating the effects of ocean acidification in natural communities….”If Emiliania huxleyi fails to maintain its important role, other, possibly non-calcifying, organisms take over. This might initiate a regime shift with far-reaching ecological and biogeochemical consequences,” Prof. Riebesell concludes.

    Ulf Riebesell, Lennart T. Bach, Richard G. J. Bellerby, J. Rafael Bermúdez Monsalve, Tim Boxhammer, Jan Czerny, Aud Larsen, Andrea Ludwig, Kai G. Schulz. Competitive fitness of a predominant pelagic calcifier impaired by ocean acidification. Nature Geoscience, 2016; DOI: 10.1038/ngeo2854