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Haynert, K. ., IFM-GEOMAR, Kiel, Germany, khaynert@ifm-geomar.de
Schönfeld, J. ., IFM-GEOMAR, Kiel, Germany, jschönfeld@ifm-geomar.de
Thomsen, J. ., IFM-GEOMAR, Kiel, Germany, jthomsen@ifm-geomar.de
Polovodova, I. ., University of Gothenburg, Gothenburg, Sweden, irina.polovodova@gvc.gu.se

RESPONSE OF BENTHIC FORAMINIFERA TO A NATURALLY CO2-RICH COASTAL HABITAT IN FLENSBURG FJORD (SW BALTIC SEA)

It is expected that the calcification of unicellular foraminifera is negatively affected by the ongoing acidification of the oceans. Nevertheless, compared to the open ocean, already today these organisms are subjected to much more adverse carbonate system conditions in coastal and estuarine environments such as the Baltic Sea. Although foraminifera are abundant in the brackish Flensburg Fjord, test dissolution of living benthic foraminiferal assemblages was observed during the seasonal cycle. Similar levels of test dissolution were observed, when living Ammonia aomoriensis were exposed to elevated pCO2 levels from 929 to 3130 µatm in a culturing experiment. These data indicated drastic effects of the prevailing abiotic conditions on benthic foraminifera. In this study, we compared the seasonal changes of the carbonate chemistry (pCO2, pH) and the response of the foraminiferal community in more detail on bi-monthly cruises to Flensburg Fjord. We observed large seasonal fluctuation of bottom water pCO2 and permanent low Ω. Further, foraminiferal assemblages were characterized by seasonal community shifts. Despite adverse pCO2 and Ω conditions, most tests were intact which indicates the ability of foraminifera to cope with fluctuating pCO2. These results emphasize the need to understand the biological control of the calcification process in foraminifera.

Poster presentation

Session #:056
Date: 2/23/2012
Time: 17:00 - 18:00
Location: Poster/Exhibit Hall

Presentation is given by student: Yes

PosterID: A0223