Tracing the effect of Ocean Acidification and Ocean Warming in the shells of calcifiers and the potential proxy implications

• Applicants: Dr. Nina Keul; Dr. Lester Lembke-Jene
• Subject Area: Geology ; Oceanography
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 522414573

Global climate change is one of the most pressing challenges our society is facing at the moment. In combination with temperature reconstructions, accurate atmospheric paleo-CO2 estimates are necessary to validate models that aim at predicting global temperature rise related to CO2 -forcing mechanisms, while reconstruction of atmospheric pCO2 going further back in time relies on sedimentary archives. Although work to date has led to important advances in the use of proxies for CO2 reconstructions, existing uncertainties in the measurement of these proxies results in the need for the establishment of new CO2-proxies. The research proposed here will remedy this gap by developing new, pteropod based proxies (e.g. via B isotopes) as well as validate/ improve the calibration of foraminiferal based proxies. We will focus on the Indian Ocean Sector of the Southern Ocean, an important region in the climate system, which remains, however, vastly understudied. During the PS 141 EASI-3 cruise we plan a total of 40 stations over a broad range of latitudes where plankton and water samples will be collected using multi-net and CTD casts down to 800 m water depth. The chemical composition of the water in combination of the measurement of the trace elemental and stable isotopic composition of the shells allow a precise proxy-calibration.

• DFG Programme: Infrastructure Priority Programmes
• Subproject of: SPP 1158: Infrastructure area - Antarctic Research with Comparative Investigations in Arctic Sea Ice Areas
• International Connection: Netherlands, Poland
• Cooperation Partners: Dr. Michael Lintner; Dr. Katja Peijnenburg