Date: 9 November 2021
Time: 4:00 pm – 5:00 pm CET
Location: virtual
Title: Decoupled carbonate chemistry experimental work involving deep-sea benthic foraminifera and new generation environmental simulators
Presenter: Dr. Meryem Mojtahid, Associate Professor, University of Angers, France
Abstract:
Due to ongoing anthropogenic CO2 emissions and the parallel active ocean physical CO2 pumping causing acidification of waters, studying past changes in seawater carbonate chemistry has become a major focus in paleoclimate research. Insight into past marine carbon cycling and perturbations therein critically depends on robust reconstructions of the seawater carbonate system (C-system) through well-controlled experimental setups and accurate C-system manipulations. In the ocean, small calcifying micro-organisms (i.e. foraminifera) incorporate various elements into biogenic calcium carbonate in equilibrium with specific environmental parameters. Here we explore the use of deep-sea foraminiferal Sr/Ca ratio as a new C-system proxy for paleoclimate research studies. We use decoupled carbonate chemistry controls, i.e. changing pH at constant Dissolved Inorganic Carbon (DIC) and changing DIC at constant pH. This experiment was performed for the first time with a new generation of environmental simulator designed for experimentation in ecology (Ecolab system – CEREEP-ECOTRON). Four controlled and regulated climatic chambers were used with four different concentrations of atmospheric pCO2 (180 ppm, 410 ppm, 1000 ppm, 1500 ppm) simulating the last glacial maximum, the current and future projection pCO2 values. Preliminary results describe a positive correlation between Sr/Ca and the carbonate system, namely bicarbonate ion concentration.
21 October 2021. More information.
