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Double Trouble: Consequences of Ocean Acidification - Past, Present and Future - Evolutionary changes in calcification mechanisms
Project leader: Dr. G. J. Reichart
Researcher(s): Msc. I. van Dijk, MSc A. Funcke
Starting date:

Abstract
Past extinction events due to rapidly increasing pCO2 and ocean acidification, together with variations in marine chemistry have shaped evolution and diversification of marine calcifying organisms. These processes may also have helped selecting calcification mechanisms. In this individual project, we will test the robustness of different calcification mechanisms among different species of foraminifera with respect ocean acidification. We will compare the resilience of miliolid species and rotalid species. Miliolids, also referred to as porcelaneous foraminifera, form high-Mg calcite tests and originally evolved in a ‘calcite’ sea. Rotalid species, on the other hand, form low-Mg calcite tests and evolved more recently in an ‘aragonite’ sea. The hypothesis we will test is: miliolids will show stronger resilience towards ocean acidification compared to rotalid species. We will follow an experimental laboratory approach where cultures of miliolid and rotalid foraminifera will be exposed to increasing pCO2 levels while calcification rates, test weight, and test composition will be monitored. The results are expected to contribute to predictions of critical pCO2 levels for species survival, biodiversity changes, and validation of paleoenvironmental proxies based on trace metal signatures of foraminifera tests.

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