Nitrogen fixation in distinct microbial niches within a chemoautotrophy-driven cave ecosystem.

ABSTRACT: Microbial sulfur and carbon cycles in ecosystems driven by chemoautotrophy-present at deep-sea hydrothermal vents, cold seeps and sulfidic caves-have been studied to some extent, yet little is known about nitrogen fixation in these systems. Using a comprehensive approach comprising of (15)N2 isotope labeling, acetylene reduction assay and nitrogenase gene expression analyses, we investigated nitrogen fixation in the sulfide-rich, chemoautotrophy-based Frasassi cave ecosystem (Italy). Nitrogen fixation was examined in three different microbial niches within the cave waters: (1) symbiotic bacterial community of Niphargus amphipods, (2) Beggiatoa-dominated biofilms, which occur at the sulfide-oxygen interface, and (3) sulfidic sediment. We found evidence for nitrogen fixation in all the three

SUBMITTER: Desai MS 

PROVIDER: S-EPMC3834856 | biostudies-literature | 2013 Dec

REPOSITORIES: biostudies-literature