On May 28, 2025, the German Research Foundation (DFG) approved funding for the Collaborative Research Centre / Transregio (TRR) 420 “CONCENTRATE”. Headed by the universities of Greifswald and Bremen, the researchers in the consortium are investigating sugar polymers from marine algae and how they help to protect the climate. The IOW is involved with a partial project on the role of marine fungi in the transformation of these sugar polymers.

Per year, marine algae convert around five times as much carbon dioxide as the burning of fossil fuels releases worldwide into carbon compounds - including so-called glycans. These gel-like sugar structures are a central component of the marine carbon cycle. Although bacteria can break down glycans in principle and thus release the bound carbon, surprisingly large quantities of glycans are still found in the world's oceans. This indicates that unknown factors prevent the complete degradation and that these polysaccharides therefore contribute to the long-term storage of carbon in the sea and thus to climate protection.

This is the starting point for the TRR 420 research project: It aims at unravelling the molecular and microbial processes that lead to the stabilisation of marine glycans, at clarifying how these substances are spatially distributed in the ocean and what overall influence they have on permanent carbon storage in the sea. In an interdisciplinary approach, the research team combines laboratory experiments with measurements in natural habitats. The DFG funding will initially run for four years.

The IOW is involved in TRR 420 with a partial project focussing on the role of marine plankton fungi in the degradation and storage processes related to the algal sugar polymers. Isabell Klawonn, a junior research group leader in the DFG's Emmy Noether Programme, is specialised in the ecology of microbial and fungal plankton. "Although marine fungi are potentially very important for matter cycles and food webs in the ocean, their interactions with phytoplankton are still something of a ‘blank spot’ in plankton research," explains Klawonn. As part of TRR 420, the marine biologist now wants to clarify how bacteria, diatoms and fungi interact and how this affects the glycan cycle. "Do the fungi obstruct the bacterial degradation of glycans? Do fungi infested algae perhaps become stickier, tend to clump together and thus sink to the sea floor more easily as marine snow? Are there any fungi that help to decompose marine snow and thus release bound carbon? There are many compelling questions that will be investigated as part of a four-year doctorate," says Klawonn.

In addition to the universities of Greifswald and Bremen and the IOW, the Max Planck Institute of Colloids and Interfaces Potsdam, the Max Planck Institute for Marine Microbiology Bremen and the Technical University of Berlin are involved in TRR 420.

More Info: Press release of the University of Greifswald