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Trichodesmium, a Globally Significant Marine Cyanobacterium
N2 fixation by Trichodesmium is likely a major input to the marine and global nitrogen cycle.
Nitrogenase gene diversity and microbial community structure: a cross-system comparison.
Analysis of the distribution of nifH phylotypes among habitats indicates that there are characteristic patterns of nitrogen fixing microorganisms in termite guts, sediment and soil environments, estuaries and salt marshes, and oligotrophic oceans.
Effects of Growth Irradiance and Nitrogen Limitation on Photosynthetic Energy Conversion in Photosystem II.
The results suggest that nitrogen limitation leads to substantial decreases in photosynthetic energy conversion efficiency, consistent with a loss of functional photosystem II reaction centers.
High rates of N2 fixation by unicellular diazotrophs in the oligotrophic Pacific Ocean
Direct measurements of 15N2 fixation by small diazotrophs in various parts of the Pacific Ocean, including the waters off Hawaii where the unicellular diazOTrophs were first characterized, show that N1 fixation by unicells can support a significant fraction of total new production in oligotrophic waters.
Unicellular cyanobacteria fix N2 in the subtropical North Pacific Ocean
It is shown that there are unicellular cyanobacteria in the open ocean that are expressing nitrogenase, and are abundant enough to potentially have a significant role in N dynamics.
Vertical distributions of nitrogen-fixing phylotypes at Stn ALOHA in the oligotrophic North Pacific Ocean
Differences in the depth distributions of N 2 -fixing plankton at Stn ALOHA are revealed, and it is suggested that unicellular diazotrophs comprise a significant component of plankton biomass in this oligotrophic marine ecosystem.
Nitrogen Cycling in the Ocean: New Perspectives on Processes and Paradigms
  • J. Zehr, B. Ward
  • Environmental Science
    Applied and Environmental Microbiology
  • 1 March 2002
The nitrogen (N) cycle is composed of multiple transformations of nitrogenous compounds, catalyzed primarily by microbes, and is linked to the fixation of atmospheric carbon.
Influence of the Amazon River plume on distributions of free‐living and symbiotic cyanobacteria in the western tropical north Atlantic Ocean
The QPCR study showed the dominance of H. hauckii-Richelia symbioses in the Amazon plume waters, implying that these associations had an ecological advantage over the other diazotrophic communities along gradients of salinity and nutrients in the WTNA.
Use of degenerate oligonucleotides for amplification of the nifH gene from the marine cyanobacterium Trichodesmium thiebautii
  • J. Zehr, L. McReynolds
  • Biology, Environmental Science
    Applied and environmental microbiology
  • 1 October 1989
Examination of the DNA and presumed amino acid sequence shows that the gene is most closely related to that of Anabaena spp.
Unicellular Cyanobacterial Distributions Broaden the Oceanic N2 Fixation Domain
It is found that two major groups of unicellular N2-fixing cyanobacteria (UCYN) have distinct spatial distributions that differ from those of Trichodesmium, the N2+ cyanobacterium previously considered to be the most important contributor to open-ocean N2 fixation.