N2 fixation by unicellular bacterioplankton from the Atlantic and Pacific oceans: phylogeny and in situ rates.

ABSTRACT: N2-fixing proteobacteria (alpha and gamma) and unicellular cyanobacteria are common in both the tropical North Atlantic and Pacific oceans. In near-surface waters proteobacterial nifH transcripts were present during both night and day while unicellular cyanobacterial nifH transcripts were present during the nighttime only, suggesting separation of N2 fixation and photosynthesis by unicellular cyanobacteria. Phylogenetic relationships among unicellular cyanobacteria from both oceans were determined after sequencing of a conserved region of 16S ribosomal DNA (rDNA) of cyanobacteria, and results showed that they clustered together, regardless of the ocean of origin. However, sequencing of nifH transcripts of unicellular cyanobacteria from both oceans showed that they clustered separately. Thi

SUBMITTER: Falcon LI 

PROVIDER: S-EPMC348867 | biostudies-literature | 2004 Feb

REPOSITORIES: biostudies-literature