Many processes in the deep sea are not yet well understood, and the role of microbial communities in particular is often a big unknown. This includes, for example, how organic material that sinks from the water surface to the ocean floor is metabolised – an important building block for a better understanding of the global carbon cycle. The team from MARUM – Center for Marine Environmental Sciences and the Departments of Geosciences and Biology/Chemistry at the University of Bremen, led by first author Qing-Zeng Zhu, has now published a study on this topic in the journal Science Advances.