Nitrogen fixation by marine cyanobacteria |
| |
Authors: | Zehr Jonathan P |
| |
Affiliation: | Department of Ocean Sciences, University of California, Santa Cruz, CA 95064, USA |
| |
Abstract: | Discrepancies between estimates of oceanic N(2) fixation and nitrogen (N) losses through denitrification have focused research on identifying N(2)-fixing cyanobacteria and quantifying cyanobacterial N(2) fixation. Previously unrecognized cultivated and uncultivated unicellular cyanobacteria have been discovered that are widely distributed, and some have very unusual properties. Uncultivated unicellular N(2)-fixing cyanobacteria (UCYN-A) lack major metabolic pathways including the tricarboxylic acid cycle and oxygen-evolving photosystem II. Genomes of the oceanic N(2)-fixing cyanobacteria are highly conserved at the DNA level, and genetic diversity is maintained by genome rearrangements. The major cyanobacterial groups have different physiological and ecological constraints that result in highly variable geographic distributions, with implications for the marine N-cycle budget. |
| |
Keywords: | |
本文献已被 ScienceDirect PubMed 等数据库收录! |
|