Marine microbe interactions and processes during simultaneous degradation of organic macromolecules

Marine microbes play critical roles in global ocean biogeochemical cycles as primary degraders of organic matter, especially by degrading and recycling abundant macromolecules like polysaccharides, lipids, proteins, and nucleic acids.
Interestingly, various microbial interactions are promoted by the release of degradation products and/or metabolic by-products. These fuel other microbes with carbon, and also essential elements like nitrogen and phosphorus, which are typically limiting in marine systems. While degradation processes and microbial interactions that occur during the degradation of individual macromolecules have been studied before, the processes and interactions that occur when they are degraded simultaneously has not been studied experimentally at all.

This project therefore aims to understand the processes and interactions that occur when different major macromolecules are degraded simultaneously, and how the sharing of key elements like nitrogen and phosphorus drive these processes and interactions.  This project will involve experimental work with seawater microbial communities and/or specific isolates or synthetic communities. Model marine macromolecules will be supplied in parallel and in different combinations, and their degradation rates will be studied by biochemical, imaging and/or isotope-tracing methods. Microbial communities will be analysed by a combination of state-of-the-art molecular methods including 16S rRNA gene sequencing, fluorescence microscopy, metagenomics, and metatranscriptomics. This will also be complemented with nutrient and metabolomic analyses. Overall, this work will provide new insights into the functioning and ecology of marine microbes, to better understand how they facilitate the large-scale recycling of organic matter and the transfer of elements in the global ocean.