Researchers led by Nina Baltrau of the Max Plank Institute for Marine Microbiology, have discovered and isolated numerous phages from the North Sea. These bacteriophages, named Flavophages, were of particular interest as they target the Flavobacterium, a gram-negative bacterium of which several species of this genus cause disease in freshwater fish. Flavophages strongly impact the bacterial mortality and carbon cycle of this habitat. Research provides exciting insights focused on spring phytoplankton blooms, which are known to be closely followed by a highly specialized bacterial community.
Flavobacteria are the main responders as consequential blooms are fueled by high amounts of organic matter, which is a result of ephemeral events produced by an increase in temperature and solar radiation inducing the formation of phytoplankton blooms in spring, resulting in high amounts of organic matter. Flavobacteria are the main responders of the subsequent blooms, and their increase is linked to the release of phytoplankton-derived polysaccharides. Microalgae produce these polysaccharides as storage compounds, cell wall building blocks, and exudates.
Bacteria play a role in the breaking down of fine algae debris during the flowering process. This process releases carbon dioxide which is absorbed by the algae from the atmosphere. Nina Bartlau added, “with a virus World carbon cycle, this is certainly very exciting to investigate“. Nina Baltrau and her colleagues have so far collected evidence to show that bacteriophages play a crucial role in bacterial mortality during the spring flowering period.
Christina Moral, the co-author of the Institute for Marine Environmental Chemistry and Biology at the University of Oldenburg, explains “the amount and type of phage changed during spring flowering. For example, only a few phages were found at the beginning of flowering, but the amount increased over time. Only certain phage species are present. We were also able to show that, for a short period of time, only their relatives remained”. It was examined that the phage community has been stable and researchers were able to find and isolate various bacteriophages for the second consecutive year.
In Bremen’s laboratory, the research has succeeded in culturing a variety of previously unknown viruses. “We have identified 10 new genera and 10 new families,” says Nina Bartlau; 9 out of 10 genera, 4 out of 10 families to be exact, which have never previously existed in culture. “These new isolates are now enabling exciting experiments in the lab and deepening our knowledge of the role of viruses in Flavophages and the ocean,” added Nina Bartlau. Such an understanding goes beyond just bacteriophages and marine habitats. Some of the phage families have also been isolated in freshwater, sewage, and soil.
- Max Planck Institute for Marine Microbiology, Bremen
- Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg
- Imaging Core Facility, Biozentrum, University of Würzburg
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven
- Quadram Institute Bioscience, Norwich Research Park, Norwich, UK