Gasping for Breath: Exploring the consequences of coastal deoxygenation on microbial processes and ecosystem services

Oxygen deficiency (anoxia) is spreading in coastal seas and estuaries as a consequence of anthropogenic eutrophication and global warming.

This has strong implications for ecosystems functioning by reducing suitable zones for nurseries of many fish species and causing shifts in global biogeochemical cycles.

In this project, I will investigate the consequences of deoxygenation on microbial processes occurring in anoxic conditions.

In absence of oxygen, microorganisms are able to do anaerobic respirations using a wide range of nitrogen, sulfur, carbon and trace elements. In illuminated anoxic waters, certain microorganisms are able to perform anoxygenic anaerobic photosynthesis.

Finally, enhanced transformation of mercury into the neurotoxin methylmercury is expected to increase with the expansion of oxygen-deficient water and sediment zones.

I will couple methods of molecular ecology, bioinformatics, biogeochemistry and paleoecology to study the past and current consequences of deoxygenation of coastal systems on these microbial anaerobic processes.

More specifically, DNA and RNA molecules present in water column, surface sediments and sedimentary archives will be used to describe the taxonomic diversity and metabolic activities of microbial communities inhabiting the Baltic Sea, Black Sea and Norwegian fjords.

This project aims to advance knowledge related to deoxygenation consequences on microbial metabolisms to predict near-future changes in coastal systems.