Ubiquity of Heterotrophic Diazotrophs in Marine Microbial Mats
Olson JB, Litaker RW, Paerl HW. 1999. Ubiquity of Heterotrophic Diazotrophs in Marine Microbial Mats. Aquatic Microbial Ecology. 19(1):29-36
Cyanobacteria are a dominant structural component of N sub(2)-fixing microbial mats in diverse marine ecosystems. As a result, much of the measured N sub(2) fixation activity has been attributed to the cyanobacterial component. Until recently, the contribution of heterotrophic N sub(2) fixers has received much less attention. In this study, the presence, diversity, and ubiquity of heterotrophic N sub(2) fixers were investigated in 3 cyanobacteria (Microcoleus)-dominated, intertidal microbial mats obtained from Tomales Bay, California, Sippewissett Salt Marsh, Massachusetts, and Bird Shoal, North Carolina. Using PCR techniques, a diverse array of heretofore uncharacterized heterotrophic nifH (gene encoding the Fe-protein subunit of nitrogenase) sequences were found in these geographically disparate microbial mats, suggesting that heterotrophic diazotrophs may play a larger role in N sub(2) fixation dynamics than previously thought. Phylogenetically similar heterotrophic diazotrophic sequences were obtained from the 3 sites, potentially indicating that similar heterotrophic N sub(2)-fixing communities are responsible for this process at diverse locations.
- Type
- Journal Article
- Authors
- Olson, J; Litaker, R; Paerl, H
- Units
- PORE
- Keywords
- algal mats, Aquatic, DNA, enzymes, Heterotrophic bacteria, heterotrophic diazotrophs, heterotrophic organisms, intertidal environment, Microbial Mats, Microorganisms, Nitrogen Fixation, nitrogenase Polymerase chain reaction, Nucleotide Sequence, Phylogeny