How does rising atmospheric CO2 affect marine organisms?

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Effects of Ocean Acidification on Foraminifera in Seabed Sediments
Haynert, K., Schonfeld, J., Schiebel, R., Wilson, B. and Thomsen, J. 2014. Response of benthic foraminifera to ocean acidification in their natural sediment environment: a long-term culturing experiment. Biogeosciences 11: 1581-1597.

The authors write that "calcifying foraminifera are expected to be endangered by ocean acidification," but they say that up to the time of their writing, there had not yet been a study of "the response of a complete community kept in natural sediment and over multiple generations under controlled laboratory conditions."

What was done
To begin filling this experimental void, Haynert et al. cultured benthic foraminifera that were dominated by Ammonia aomoriensis, but that also included various Elphidium species, in their natural sediments - which they retrieved from the southwestern Baltic Sea's Kiel Fjord - over a period of several generations, during which six-month period they indicate that the foraminiferal assemblages were maintained in natural seawater of either 430, 907, 1865 or 3247 ľatm pCO2.

What was learned
The five researchers report that the chemistry of the sediments employed in their study "created a microhabitat that supported the growth and development of a benthic foraminiferal community even at highly elevated pCO2," such that the "growth and mortality of living A. aomoriensis were unaffected."

What it means
In light of their experimental findings, Haynert et al. conclude that foraminiferal communities are fully able to "withstand present-day, seasonally high pCO2 levels and might also tolerate moderate future pCO2 increases," and maybe even some that are not so "moderate."

Reviewed 2 July 2014