Nitrogen-fixing cyanobacteria in a marine microbial mat

The nitrogen cycle in nature ia essentially driven by prokaryotic microorganisms. Nitrogen is one of the most important elements for the synthesis of cell material; it accounts for approximately I4%. of. dry weight. All eukaryotes and the majority of the prokaryotic organisms are dependent on a source of combined nitrogen. 0nly a limited number of bacteria are able to grow with molecular nitrogen. ... Zie: Summary