Abstract
A novel hydrothermal field has been discovered at the base of Lihi Seamount, Hawaii, at 5000 mbsl. Geochemical analyses demonstrate that FeMO Deep, while only 0.2 °C above ambient seawater temperature, derives from a distal, ultra-diffuse hydrothermal source. FeMO Deep is expressed as regional seafloor seepage of gelatinous iron-and silica-rich deposits, pooling between and over basalt pillows, in places over a meter thick. The system is capped by mm to cm thick hydrothermally derived iron-oxyhydroxide-and manganese-oxide- layered crusts. We use molecular analyses (16S rDNA-based) of extant communities combined with fluorescent in situ hybridizations to demonstrate that FeMO Deep deposits contain living iron-oxidizing Zetaproteobacteria related to the recently isolated strain Mariprofundus ferroxydans. Bioenergetic calculations, based on in-situ electrochemical measurements and cell counts, indicate that reactions between iron and oxygen are important in supporting chemosynthesis in the mats, which we infer forms a trophic base of the mat ecosystem. We suggest that the biogenic FeMO Deep hydrothermal deposit represents a modern analog for one class of geological iron deposits known as umbers (for example, Troodos ophilolites, Cyprus) because of striking similarities in size, setting and internal structures.
Original language | English (US) |
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Pages (from-to) | 1748-1758 |
Number of pages | 11 |
Journal | ISME Journal |
Volume | 5 |
Issue number | 11 |
DOIs | |
State | Published - Nov 2011 |
Keywords
- deep biosphere
- geomicrobiology
- hydrothermal
- iron bacteria
- iron oxidation
ASJC Scopus subject areas
- Microbiology
- Ecology, Evolution, Behavior and Systematics