SGER: Microbial Alteration of Basaltic Glass in seawater: Feasibility Study on Loihi Seamount and the Flanks of Hawaii

University Of California-San Diego Scripps Inst Of Oceanography, La Jolla CA

Investigators

Abstract

The PI will carry out exposure experiments of fresh basaltic glass in seawater on the ocean floor, and compare the results to the behavior of natural basalt glass exposed at the same site in terms of the role of microbial communities in the alteration of the glass. Study environments are located on the submarine slopes of Hawaii at water depths ranging from 200-2000m, at water temperatures ranging from near freezing to hydrothermal spring temperatures of approximately 80 degree C. Exposed rock surfaces vary in age from a few years to several 100kyrs and include sites on Loihi Seamount, Puna Ridge and the submarine slopes of Kohala and Hualalai. With other funds from NOAA's NURP program, the PIs will undertake 16 submersible dives in FY's 2002/2003, to carry out the field portion of the study. This award will support cruise participation for the recovery of previously-placed exposure charges, and the chemical, and microbiological laboratory investigations of materials recovered from the dives. The PIs will observe and characterize the microbial populations and physical effects of natural microbial alteration on well defined glass surfaces. They will compare reaction rates in the one-year exposure experiments to the rates of basalt alteration in natural exposure of several years to nearly a million years. Chemical mass balance will allow the PIs to determine the chemical exchange rates between seawater and the basalt exposure experiments.