Gábor Bernát, a scientific senior research fellow at the ELKH Balaton Limnological Research Institute (BLKI), and his co-authors have reported the latest results of their studies on nitrogen uptake by cyanobacteria in the journal Frontiers in Microbiology. The researchers used state-of-the-art methods, including Nano SIMS mass spectrometry, an innovative technique in the field of biology, to monitor the uptake of nitrogen by cyanobacteria and the pattern and diurnal variation of nitrogen binding. They have been able to explore several carbon and nitrogen management mechanisms that contribute to the success of the studied unicellular organisms in a dynamically changing aquatic environment.

Nitrogen-binding microorganisms are extremely important in the production of bioavailable forms of nitrogen. Unicellular nitrogen-fixing cyanobacteria (UCYN) are common members of marine phytoplankton communities, including those with rapidly changing nitrogen concentrations.

“We monitored the nitrogen uptake of cyanobacteria by modern biophysical methods, including Nano SIMS mass spectrometry, which is a new technique in biology. Cells were grown in two ways: with or without nitrogen in the culture medium. In the latter case, the cells are forced to bind nitrogen from the atmosphere in order to survive. The growth of cyanobacteria nurtured under different conditions is characterized by different energy requirements, different biochemical pathways and completely divergent daily cycles. In cyanobacteria grown in a nitrogen-free medium, nitrogen fixation occurs at night because the dioxygen (O2) produced during photosynthesis is toxic to the nitrogen-fixing apparatus. However, the energy needed to fix nitrogen is provided by photosynthesis, so nitrogen-binding cells store some ‘fuel’ in the form of polysaccharides overnight,” explains Gábor Bernát.

Researchers were also curious about when and where key chemical elements grown under different conditions would incorporate key chemical elements in the course of the day. Using the new examination procedures, the experts have gained a much richer and more complex picture of cell activity than before and have also been able to explore several carbon and nitrogen management mechanisms that contribute to the success of the cyanobacteria being studied in a dynamically changing aquatic environment.