Prof. Dr Anja Engel
GEOMAR Helmholtz Centre for Ocean Research Kiel
Principal Investigator
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Dr Markus Schartau
GEOMAR Helmholtz Centre for Ocean Research Kiel
Principal investigator
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Dynamic enrichment processes of organic matter in the SML

Organic matter (OM) enrichment in the SML modifies air-sea exchange processes, but which OM components become selectively enriched, why and when is largely unknown. Biopolymers derived from photoautotrophic production are quantitatively important components of the SML and can influence air-sea exchange by acting as biosurfactants and as a source for primary organic aerosols.

SP1.1 will decipher the sources, amount and biochemical composition of OM in the SML, with emphasis on carbohydrates, amino acids and lipids, and thus provide important information for all BASS subprojects. A central aim is to improve the mechanistic relationships between photoautotrophic production as the primary origin of OM in the surface ocean and the organic matrix properties of the SML, with a particular focus on the relevance for air-sea exchange.

A new modelling approach shall consolidate the mechanistic understanding of the linkages between plankton growth conditions, production and release of biochemicals including potential surfactants, and the accumulation of OM within the SML. The model will act as a basis for deriving credible parameterization for simulating and upscaling relevant processes for large-scale and global biogeochemical model applications.

The model development in SP1.1 establishes a linkage between the production of OM to its enrichment within SML and aims at resolving corresponding effects on air-sea gas exchange, by accounting for changes in momentum flux on ocean surface layers as well as in buoyancy. The proposed SML sub-model will be refined based on results from other BASS subprojects. The model will act as a tool for the interpretation and integration of field, mesocosm and laboratory measurements of OM enrichment in the SML. Results from model sensitivity analyses will provide complementary information about surface-active properties of various OM and their impacts on air-sea exchange processes.

(Changed: 19 Jul 2022)