Ocean acidification could have broader effects on marine ecosystems

December 18th, 2008 - 4:43 pm ICT by ANI  

Washington, Dec 18 (ANI): A new research has determined that ocean acidification could result in broader disruptions of biological processes in the oceans.
The research was conducted by Donald Potts, a professor of ecology and evolutionary biology at the University of California, Santa Cruz, US.
Ocean acidification is one of the side effects of the rising concentration of carbon dioxide (CO2) in Earth’’s atmosphere due to the burning of fossil fuels.
The term “acidification” refers to a slight lowering of the pH of ocean water, pushing it closer to the acidic end of the scale, although it is still slightly alkaline.
A small decrease in pH affects the chemical equilibrium of ocean water, reducing the availability of carbonate ions needed by a wide range of organisms to build and maintain structures of calcium carbonate.
The oceans can absorb enormous amounts of CO2 from the atmosphere, but as the gas dissolves, it makes the water more acidic.
Increasing acidity can make life difficult for corals and other marine organisms that build shells and skeletons out of calcium carbonate.
Scientists fear that acidification will slow the growth of these organisms and cause calcium carbonate structures to dissolve.
Potts agrees that dissolving shells will certainly be a problem for many marine organisms, but he thinks the disruptions will run much deeper.
“It’’s not just a question of coral reefs, and it’’s not just a question of calcification,” he said. “What we are potentially looking at are disruptions of developmental processes and of populations and communities on many scales,” he added.
Many phytoplankton, microscopic algae that form the base of the marine food web, build calcium carbonate shells to protect themselves from microscopic predators called ciliate protozoa.
A disruption of the ability of phytoplankton to build their shells could have ripple effects throughout the marine food web, according to Potts.
“It’’s going to change the dominant organism in the food chain, and there’’s a very real danger that it may short-circuit the food chains,” he said.
In other words, ciliate protozoa gorging on unprotected phytoplankton may flourish at the expense of other organisms higher up the food chain.
But calcification of shells is not the only biological process affected by acidification, Potts said.
“All biochemical physiological reactions are potentially going to change,” he added.
Developing organisms are most likely to be affected, due to their low range of environmental tolerances, but it is unclear what the ecological ramifications will be. (ANI)

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