Nitrogen is essential for all life on Earth. In the global oceans, however, this element is scarce, and nitrogen availability is therefore critical for the growth of marine life.
Nitrogen is essential for all life on Earth. In the global oceans, however, this element is scarce, and nitrogen availability is therefore critical for the growth of marine life. Some bacteria found in marine waters can convert nitrogen gas (N2) to ammonia (known as N2 fixation), and thereby supply the marine food web with nitrogen.
How on Earth?
It has puzzled scientists for years whether and how bacteria, that live from dissolved organic matter in marine waters, can carry out N2 fixation. It was assumed that the high levels of oxygen combined with the low amount of dissolved organic matter in the marine water column would prevent the anaerobic and energy consuming N2 fixation.
Already in the 1980s it was suggested that aggregates, so-called “marine snow particles”, could possibly be suitable sites for N2 fixation, and this was recently confirmed. Still, it has been an open question why the bacteria carrying out this N2fixation can be found worldwide in the ocean. Moreover, the global magnitude and the distribution of the activity have been unknown.
Read more at University of Copenhagen - Faculty of Science
Image: Marine snow consists of debris from diverse organisms in the water column. Picture shows marine snow from the Sargasso Sea (Credit: L. Riemann)
