Geomicrobiology of the ocean crust : the phylogenetic diversity, abundance, and distribution of microbial communities inhabiting basalt and implications for rock alteration processes
Geomicrobiology of the ocean crust : the phylogenetic diversity, abundance, and distribution of microbial communities inhabiting basalt and implications for rock alteration processes
Date
2007-06
Authors
Santelli, Cara M.
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As Published
Date Created
Location
9°N
East Pacific Rise
East Pacific Rise
DOI
10.1575/1912/1735
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Keywords
Sediments
Biogeochemical cycles
Microbiology
Atlantis (Ship : 1996-) Cruise AT11-7
Atlantis (Ship : 1996-) Cruise AT11-20
Biogeochemical cycles
Microbiology
Atlantis (Ship : 1996-) Cruise AT11-7
Atlantis (Ship : 1996-) Cruise AT11-20
Abstract
Basaltic ocean crust has the potential to host one of the largest endolithic
communities on Earth. This portion of the biosphere, however, remains largely
unexplored. In this study, we utilize molecular biological, microscopic, and geochemical
tools to gain a better understanding of the geomicrobiology of the ocean crust.
Specifically, we examine the phylogenetic diversity of microorganisms inhabiting
basaltic lavas, the activities and abundances of these microorganisms, the spatial extent of
the biosphere, and the potential effect that microbial activity has on the geochemistry of
the ocean crust and overlying water column.
Our study demonstrates that young, fresh volcanic lavas near mid-ocean ridges
host an incredibly diverse and dense population of microorganisms dominated by
Bacteria, quite distinct from the microbial communities found in surrounding deep
seawater and hydrothermal vents. Furthermore, these communities may contribute to the
elemental cycling of Fe, S, Mn, N, and C in this environment. The inability to definitively
identify microorganisms in drill-cores of old (> 15 Ma) ocean crust, however, implies
that these once prolific communities may become scarce as the crust ages and moves
further away from the ridge axis. Finally, we provide evidence suggesting that these
communities are fueled by oxidative alteration reactions occurring in the basaltic crust.
Description
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy
at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2007
Embargo Date
Citation
Santelli, C. M. (2007). Geomicrobiology of the ocean crust : the phylogenetic diversity, abundance, and distribution of microbial communities inhabiting basalt and implications for rock alteration processes [Doctoral thesis, Massachusetts Institute of Technology and Woods Hole Oceanographic Institution]. Woods Hole Open Access Server. https://doi.org/10.1575/1912/1735