Trichodesmium

Trichodesmium is the dominant N2 fixing organism. BUT Less abundant N2 fixing organisms are found in certain regions. It is a cyanobacterium of the order Oscillatoriales, produces only vegetative cells, Trichodesmium means a bundle of threads, a number of species have been described, surface aggregations can be detected from space. Trichodesmium only fixes N2 during the day! – and in fact N2 -fixation is light dependent (very odd).