New Nitrogen-Fixing Microorganisms Detected in Oligotrophic Oceans by Amplification of Nitrogenase ( nifH ) Genes
Year: 1998
Type: article
Abstract: ABSTRACT 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 α and γ 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.
Authors: Jonathan P. Zehr, Mark T. Mellon, Sabino Zani
Institution: Rensselaer Polytechnic Institute
Language: English
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
SDG: Life below water
Open Access status: bronze
OpenAlex ID: W4243683031