New nitrogen-fixing microorganisms detected in oligotrophic oceans by amplification of Nitrogenase (nifH) genes.

Journal Article (Journal Article)

Oligotrophic oceanic waters of the central ocean gyres typically have extremely low dissolved fixed inorganic nitrogen concentrations, but few nitrogen-fixing microorganisms from the oceanic environment have been cultivated. Nitrogenase gene (nifH) sequences amplified directly from oceanic waters showed that the open ocean contains more diverse diazotrophic microbial populations and more diverse habitats for nitrogen fixers than previously observed by classical microbiological techniques. Nitrogenase genes derived from unicellular and filamentous cyanobacteria, as well as from the alpha and gamma subdivisions of the class Proteobacteria, were found in both the Atlantic and Pacific oceans. nifH sequences that cluster phylogenetically with sequences from sulfate reducers or clostridia were found associated with planktonic crustaceans. Nitrogenase sequence types obtained from invertebrates represented phylotypes distinct from the phylotypes detected in the picoplankton size fraction. The results indicate that there are in the oceanic environment several distinct potentially nitrogen-fixing microbial assemblages that include representatives of diverse phylotypes.

Full Text

Duke Authors

Cited Authors

  • Zehr, JP; Mellon, MT; Zani, S

Published Date

  • September 1998

Published In

Volume / Issue

  • 64 / 9

Start / End Page

  • 3444 - 3450

PubMed ID

  • 9726895

Pubmed Central ID

  • PMC106745

International Standard Serial Number (ISSN)

  • 0099-2240

Digital Object Identifier (DOI)

  • 10.1128/AEM.64.9.3444-3450.1998


  • eng

Conference Location

  • United States