In a new study, a transdisciplinary research team with the participation of Kiel University and GEOMAR Helmholtz Centre for Ocean Research Kiel was able to gather previously unknown details about the origin and adaptation of certain unicellular organisms to these special environmental conditions and their influence on the marine nutrient cycle: Because their metabolism does not rely on oxygen, numerous species of foraminifera are found in the OMZ. These are unicellular, shell-forming microorganisms that already feature a cell nucleus and thus belong to the so-called eukaryotes.

Their special lifestyle is based on so-called anaerobic respiration or nitrate respiration, in which nitrate available in the water is converted into molecular nitrogen in the absence of oxygen. Nitrogen, as a basic nutrient of all living organisms, is no longer biologically available as a result of this process and is thus lost to the marine habitat. The research team led by Professor Tal Dagan of the Institute of General Microbiology at Kiel University has now been able to prove via genome analyses that the ability of nitrate respiration, still preserved in most foraminifera today, might have originated in a common predecessor around 100 million years ago.