The proposal addresses a fundamental aim of the ocean drilling program, namely to help characterize one of the largest and least studied ecosystems on Earth, the deep biosphere of the igneous crust buried below the ocean floor. The principal scientific objective of IODP expedition 336 is, in particular, to investigate the microbial population in basaltic crust from the North Pond area near the Mid-Atlantic Ridge. The study samples are weathered and porous basalts taken from beneath ~100 m of sediment in the North Pond area. The study proposes to determine both the diversity of the microbe population (using DNA) and its metabolic activity (using RNA). The PI?s will investigate the relationship between microbes in the basement and those in the water column and determine which metabolic pathways are used by the deep basement microbes. The study will also provide baseline data for the long-term biological observatories installed in the sub-seafloor basement during expedition 336. Understanding deep biosphere life is a major thrust of the new IODP science plan and has implications for understanding the limits of life. The NSF-funded C-DEBI (Center for Dark Energy Biosphere Investigations) program and Deep Earth Academy promote K-12 education and communicate the results of deep biosphere studies to broad technical and popular audience. An undergraduate student will be involved in the research.
