Exp 331: Okinawa Deep Hot Biosphere Exp 331: Okinawa Deep Hot Biosphere The deep hot biosphere of the oceanic crust is potentially the largest and most poorly understood ecosystem on Earth. We know almost nothing about the type or number of organisms present, and even less about the metabolisms they engage in. Organic carbon is the currency of microbial metabolism in all known ecosystems. Autotrophic organisms produce organic carbon and heterotrophic organisms consume organic carbon. Both types of metabolism imprint a signature on the composition of the organic molecules in the organic pool. The organic carbon cycling through the deep hot biosphere has not yet been characterized at the molecular level. I proposed to characterize the bulk and molecular-level organic composition of sediment extracts and pore fluids (where available) from the Okinawa hydrothermal mound sediment cores. The techniques to be applied are Excitation-Emission Matrix (EEM) fluorescence spectroscopy and Electrospray ionization mass spectrometry (ESI-MS). The molecular-level composition of the dissolved (pore fluids) and extractable (sediments) organic carbon should reflect the presence and the activity of organisms from the deep hot biosphere. I hypothesize that the composition and concentration of polar organic carbon in sediments and fluids from the hydrothermal mounds will vary down-core and between sites; the organic composition and concentration will be related to the abundance and diversity of microorganisms. The proposed work is complementary to the stated objectives for IODP leg 331. The analysis of polar organic compounds gives insight into the bioavailable and refractory components of the organic carbon pool in sediments and fluids. The data will enhance our understanding of sedimentary carbon beyond bulk CHN and 13C compositions. These measures will provide additional context for understanding the abundance and diversity of organisms in the deep hot biosphere. EEM fluorescence and ESI-MS have been to applied to dissolved and extractable organic carbon many ecosystems including: terrestrial hot springs, rivers and lakes, estuaries and marine systems
|Effective start/end date||9/1/10 → 8/2/13|
- Consortium for Ocean Leadership: $39,201.00
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