A Seafloor Microbial Biome Hosted within Incipient Ferromanganese Crusts

Journal Article · Sun Nov 15 04:00:00 EST 2009 · Nature Geoscience, 2(12):872-876

DOI:https://doi.org/10.1038/ngeo696· OSTI ID:969614

Templeton, Alexis S; Knowles, A S; Eldridge, D L; Arey, Bruce W; Dohnalkova, Alice; Webb, Samuel M; Bailey, B E; Tebo, Bradley M; Staudigel, Hubert

Unsedimented volcanic rocks exposed on the seafloor at ridge systems and Seamounts host complex, abundant and diverse microbial communities that are relatively cosmopolitan in distribution (Lysnes, Thorseth et al. 2004; Mason, Stingl et al. 2007; Santelli, Orcutt et al. 2008). The most commonly held hypothesis is that the energy released by the hydration, dissolution and oxidative alteration of volcanic glasses in seawater drives the formation of an ocean crust biosphere (Thorseth, Furnes et al. 1992; Fisk, Giovannoni et al. 1998; Furnes and Staudigel 1999). The combined thermodynamically favorable weathering reactions could theoretically support anywhere from 105 to 109 cells/gram of rock depending upon the metabolisms utilized and cellular growth rates and turnover (Bach and Edwards 2003; Santelli, Orcutt et al. 2008). Yet microbially-mediated basalt alteration and energy conservation has not been directly demonstrated on the seafloor. By using synchrotron-based x-ray microprobe mapping, x-ray absorption spectroscopy and high-resolution scanning and transmission electron microscopy observations of young volcanic glasses recovered from the outer flanks of Loihi Seamount, we intended to identify the initial rates and mechanisms of microbial basalt colonization and bioalteration. Instead, here we show that microbial biofilms are intimately associated with ferromanganese crusts precipitating onto basalt surfaces from cold seawater. Thus we hypothesize that microbial communities colonizing seafloor rocks are established and sustained by external inputs of potential energy sources, such as dissolved and particulate Fe(II), Mn(II) and organic matter, rather than rock dissolution.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 969614
• Report Number(s): PNNL-SA-67664; 26704; KP1704020
• Journal Information: Nature Geoscience, 2(12):872-876, Journal Name: Nature Geoscience, 2(12):872-876 Journal Issue: 12 Vol. 2
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
ABSORPTION SPECTROSCOPY
BASALT
BIOSPHERE
COMMUNITIES
DISSOLUTION
DISTRIBUTION
ENERGY CONSERVATION
Environmental Molecular Sciences Laboratory
HYDRATION
HYPOTHESIS
ORGANIC MATTER
PARTICULATES
POTENTIAL ENERGY
SEAWATER
TRANSMISSION ELECTRON MICROSCOPY
VOLCANIC ROCKS
WEATHERING