Publication Date:
2022-05-25
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
Description:
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:
Funding for this project came from: RIDGE 2000 Grant #OCE-0241791 awarded to
Katrina J. Edwards and Wolfgang Bach, the NASA Astrobiology Institute - Cycle 3
CAN-02-OSS-02 awarded to Katrina J. Edwards, USSSP ODP Post-cruise funding Grant
#TX A&M F001724 awarded to Cara M. Santelli and Katrina J. Edwards, and a
Schlanger Ocean Drilling Fellowship awarded to Cara M. Santelli.
Keywords:
Sediments
;
Biogeochemical cycles
;
Microbiology
;
Atlantis (Ship : 1996-) Cruise AT11-7
;
Atlantis (Ship : 1996-) Cruise AT11-20
Repository Name:
Woods Hole Open Access Server
Type:
Thesis
Format:
application/pdf
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