ELICA - Elucidating lipid-carbon flux dynamics in the Southern Ocean

• Applicant: Dr. Nora-Charlotte Pauli
• Subject Area: Oceanography
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 502024352

The aim of this project is to investigate the lipid-carbon flux of zooplankton faecal pellets and marine snow aggregates between the surface and the deep sea in the Southern Ocean. Our aim is to shed light on the role of lipids and carbohydrates in the biological carbon pump (BCP) and to assess the impact of climate change-induced shifts in plankton communities in the Southern Ocean. The biological carbon pump mediates the transfer of carbon through the water column and thus the ability of the oceans to absorb and sequester atmospheric carbon on long time scales, regulating atmospheric carbon dioxide levels. In particular, the Southern Ocean is a significant sink for atmospheric carbon dioxide and provides a sink for about 40% of the anthropogenically produced carbon dioxide. Sinking particles including faecal pellets of zooplankton and marine snow aggregates are the main drivers of the BCP, but the fate of the various components of particulate organic matter, such as lipids and carbohydrates, is not fully understood. Lipids are an important form of carbon- and energy storage in phytoplankton and form a significant part of the sinking organic matter, but the fate of various lipid compounds and their degradation in the water column are still largely unknown. However, this knowledge is crucial to understand how changes in plankton communities, that have been observed in the Southern Ocean in response to climate change, could alter the efficiency of the carbon pump. Recent advances in mass spectrometry have enabled the analysis of the entire lipid fraction within a cell (lipidomics), allowing thousands of lipid molecules to be identified. In this project, state-of-the-art lipidomics methods will be combined with measurements of particulate organic carbon from sinking particles to study lipid flux dynamics, shedding light on the role of lipids and carbohydrates in the carbon pump and help reveal parts of the "black box" of organic carbon in the ocean.

• DFG Programme: Infrastructure Priority Programmes
• Subproject of: SPP 1158: Infrastructure area - Antarctic Research with Comparative Investigations in Arctic Sea Ice Areas
• International Connection: USA
• Co-Investigator: Professor Dr. Morten Iversen
• Cooperation Partner: Benjamin van Mooy, Ph.D.