Program and Agenda

Abstract

RESPONSE OF BENTHIC FORAMINIFERA FROM COASTAL HABITATS TO OCEAN ACIDIFICATION

Ocean acidification is expected to reduce the calcification of benthic foraminifera. However, coastal eutrophic regions such as the southwestern Baltic Sea are characterized by high CO2 variability during the seasonal cycle. Organic-rich mud prevails in this area, which are populated by large numbers of benthic foraminifera despite high sediment pore water pCO2 ranging from 1244 to 3324 μatm. The impact of elevated pCO2 was investigated in mid- and long-term laboratory experiments, and a one-year monitoring field study was performed. Without their protective sediment, calcification of endobenthic foraminifera was reduced and test dissolution started below Ωcalc<1, a complete decalcification began at Ωcalc<0.5. In contrast, within their natural, sedimentary habitat, foraminifera tolerate elevated pCO2 as long as sediment pore waters remains supersaturated, which is a result of higher alkalinity in the sediment pore water. Thereby the sediment chemistry creates a microhabitat, which supports growth and reproduction of endobenthic foraminifera even at highly elevated pCO2. These results emphasize the importance of understanding the carbonate chemistry in the natural environment of benthic foraminifera when predicting the fade of benthic foraminifera in a changing world.

Authors

Haynert, K., GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany, khaynert@geomar.de

Schönfeld, J., GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany, jschoenfeld@geomar.de

Thomsen, J., GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany, jthomsen@geomar.de

Details

Oral presentation

Session #:100
Date: 2/26/2014
Time: 08:45
Location: 304 AB

Presentation is given by student: No