A critical problem for the study of the biosphere in deep marine sediments is the pervasively low level of microbial metabolic activity that renders conventional techniques relatively ineffective for detecting microbes. Based on the recognition that H2 is a ubiquitous intermediate product of anaerobic microbial processes, this research program will develop a new hydrogenase(H2ase)-based technique to measure the activity of this enzyme in marine sediments and will calibrate the technique for application to measuring microbial metabolic rates in anoxic sediments like those often encountered during deep ocean drilling. If successful, the methods devised by the researchers will find immediate and wide-ranging application in IODP studies of the deep biosphere and in studies of conventional cores from anoxic marine sediments. The goals of the program directly address the biosphere component of the IODP long-range science plan. The research also has the potential for expanding understanding of the minimum energy required to sustain life and the environmental limits of life in the deep biosphere. The program supports education and human resource development through training of a postdoctoral researcher and involvement of undergraduate research fellows.
