What if polysaccharide fibers also caused food to sink faster and be digested less in the ocean? This is the type of question that Jan-Hendrik Hehemann from MARUM – Center for Marine Environmental Sciences at the University of Bremen is looking into with his Marine Glycobiology working group, which is a joint group and is located both at MARUM and the Max Planck Institute for Marine Microbiology in Bremen. The team will now also be a part of Faculty 2: Biology / Chemistry at the University of Bremen and expand on their research.
In the ocean, food in the surface area is especially produced by microscopic algae. These algae synthesize great quantities of polysaccharides from the greenhouse gas carbon dioxide. Due to these complex carbohydrates, materials such as cells, minerals, and dust stick together and form heavy particles that quickly sink down the water column. Thus – according to Hehemann’s hypothesis – polysaccharides could also be responsible for a more rapid movement of carbon-rich material in the ocean, much like the movement of food in humans. Therefore, they could help with the storage of carbon in the depths of the ocean and in the marine sediment.
Bacteria as teachers
“In order to be able to answer such questions, we need to be able to exactly measure polysaccharides and this poses a problem for us. Polysaccharides are particularly complicated molecules that are hard to collect. However, bacteria have found ways of finding polysaccharides and using them as food. They implement proteins to capture polysaccharides and enzymes to digest them. We are investigating how bacteria recognize polysaccharides and how their enzymes work,” explains Jan-Hendrik Hehemann. “Every bacterium, every microorganism has its very own enzymes – its own tools – in order to cut polysaccharides. We can use such enzymes to measures sugar molecules in the sea and thus test the fiber hypothesis.”
The bacterial enzymes are responsible for the breaking down of sugar compounds – they break the large, complex polysaccharides into small, simple monosaccharide units. These simple sugars are, according to Hehemann, easier to measure than polysaccharides. “By measuring simple sugars, much like in a diabetes blood sugar test, we are able to quantify polysaccharides. Bacteria are teaching us how it is done. This way, polysaccharides can be quantified accurately for the first time ever. Accepting bacteria, the smallest organisms on Earth, as a teacher, in order to analytically record the global carbon cycle, is a new approach in marine research that has been developed and implemented by our working group.”
Thanks to this approach, it is now possible to measure which sugars are most common, which sink into the depths and thus act as a fiber in the ocean. This, in turn, allows conclusions to be drawn about the role of polysaccharides in the carbon cycle. The analytics and research of the new Glycobiochemistry working group make a significant contribution to the understanding of the ocean as a carbon store.
About the person
After his degree in biochemistry in Hamburg, Jan-Hendrik Hehemann completed his doctoral studies at the Université Pierre et Marie Curie in Paris and Station Biologique de Roscoff (France). He subsequently worked as a postdoctoral researcher at the University of Victoria, British Columbia (Canada) and Massachusetts Institute of Technology (USA) prior to joining the University of Bremen and MPI Bremen. In parallel with his time at school, Hehemann completed an apprenticeship as a chemical-technical assistant.
“The Heisenberg Professorship in glycobiochemistry for Jan-Hendrik Hehemann was received with excitement at Faculty 2,” states Thorsten Gesing, Dean of Faculty 2: Biology / Chemistry, happily. “The function of complex sugar molecules is a blank spot on the map of bio sciences in general – not only in the ocean. The innovative, analytical approaches of Dr. Hehemann are an important focal point for joint projects at Faculty 2 and additionally for collaboration between Faculty 2 and MARUM, as well as the Max Planck Institute for Marine Microbiology within the Marine Sciences high-profile area.”
Prof. Rudolf Amann, Managing Director of the Max Planck Institute adds: “Glycobiology investigates the breaking down of sugars by microorganisms and will provide us with many new findings on substance cycles in the ocean. We would like to congratulate Jan-Hendrik Hehemann on the Heisenberg Professorship. We are looking forward to our continuing work with him as head of a Max Planck joint working group. The close collaboration between the university and MPI in the state of Bremen has been successful for nearly three decades.” Prof. Michael Schulz, MARUM Director, agrees: “We are very pleased about this new professorship. The working group is an important connection between the University of Bremen and the Max Planck Institute for Marine Microbiology in Bremen under the umbrella of the MARUM.”
“With the new Heisenberg Professorship for Jan-Hendrik Hehemann, we are strategically strengthening the position of the University of Bremen as a climate university in research and teaching once again. We are pleased about the recognition of this strategy, shown by the funding of the professorship by the German Research Foundation,” explains Prof. Bernd Scholz-Reiter, President of the University of Bremen.
With the Heisenberg Professorship, the German Research Foundation (DFG) supports researchers who stand out for their excellent research and achievements and enables them to pursue their research interests and set up their own working groups.
The research group Marine Glycobiology
Prof. Dr. Jan-Hendrik Hehemann investigates the relevance of algae polysaccharides in marine cycles. His Marine Glycobiology working group is a joint group at both MARUM and MPI Bremen.
Alongside Jan-Hendrik Hehemann, the following persons are also a part of the working group: Alek Bolte, Hagen Buck-Wiese, Guoyin Huang, Joris Krull, Nguyen P. Nguyen, Jaagni Parnami, Dr. Mikkel Schultz-Johansen, Dr. Vipul Solanki, Dr. Nicola Steinke, Astrid Stierle, Tina Trautmann, and Dr. Silvia Vidal Melgosa. The close collaboration between MARUM and MPI Bremen is being continued.