Dinitrogen (N2) fixation by diazotrophs is an important source of new bioavailable nitrogen (N) in oligotrophic marine systems (Falkowski, 1997; Gruber, 2008).
More...Dinitrogen (N2) fixation by diazotrophs is an important source of new bioavailable nitrogen (N) in oligotrophic marine systems (Falkowski, 1997; Gruber, 2008). Due to the high energetic requirements of N2 fixation (Howarth et al.,1988; Postgate, 1998; Karl et al., 2002), most studies focused on photoautotrophic diazotrophs such as Trichodesmium spp. (Capone et al. 1997; 2005) or unicellular cyanobacteria (Zehr et al. 2001, Montoya et al. 2004; Langlois et al., 2005) that uses light as energy source. Recently it was found that heterotrophic proteobacteria diazotrophs are also important contributors to N2 fixation (Zehr et al., 2003; Halm et al., 2012; Rahav et al., 2013 frontiers) and are widely distributed throughout many marine environments (Riemann et al., 2010, Hamersley et al., 2011; Rahav et al., 2013 Meteor, 2014).
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