Description of Coutieralpheus setirostris, new genus, new species, an infaunal alpheid shrimp (Crustacea: Decapoda) from Florida, U.S.A.

Abstract

The extent of biosphere in its ecological association with the seafloor hydrothermal system was studied based on the distribution and stable isotopic composition of organic matter in sediments, cores, and biological samples. The origins of organic matter were estimated by the following geochemical approach; i.e., primarily by the analysis of lipid compositions and their molecular-level isotopic ratios, as well as by bulk analysis of organic carbon content and isotopic ratios of each sample. We also developed two new sampling devices for the organic matter analyses. One is a sediment and rock scooper, which has a tight cap for preventing exposure to surface seawater. The other is a stand-alone in situ filtering system for concentrating dissolved organic matter in the hydrothermal fluid. We found large variations in isotopic signatures of organic carbon in bulk samples (.DELTA.13C=-12-31.PERMIL.) and at the molecular-level (-22-31.PERMIL.) in the core and seafloor sediment samples. Although the organic carbon content of core samples was very low, a large variation in bulk stable carbon isotopic ratios suggests that a high diversity of microbes inhabits the subvent environment.