Marine prokaryotes, keystone populations in the changing ocean

The objective of this project is to comprehend and quantify the link between microbial functioning and the turnover of marine dissolved organic matter (DOM). The majority of molecules released by phytoplankton are respired by heterotrophic prokaryotes. However, a small proportion evades respiration and accumulates in the deep ocean.

This marine DOM pool accumulates to approximately the size of the pre-industrial pool of carbon dioxide in the atmosphere.

A small rise in heterotrophic respiration rates, caused by increasing water temperatures, could have a considerable negative impact on DOC sequestration.

Currently, our understanding of how climate change affects microbes, particularly heterotrophic prokaryotes, is limited, as they are seldom the focus of climate change research.

There are still uncertainties regarding the extent to which increasing surface ocean temperatures will affect heterotrophic species and their cell-specific respiration rates, and how this will impact DOM turnover and carbon export.

In this project, we will employ the latest methods to gain an in-depth understanding of how and which biogeochemically active keystone populations contribute to DOM turnover and respiration at different temperatures and in different representative ocean regions.

This will help to address the challenge of providing direct evidence for causal relationships between DOM and specific prokaryoplankton dynamics.