While non-photosynthetic sources of organic carbon have been implicated as the primary energy source fueling invertebrate populations at deep-sea hydrothermal vents, details of carbon transfer have not been elucidated for an entire community. Multiple paths for transfer of carbon exist, and dominance by one or another path varies dramatically at geographically disjunct sites. Mid-Atlantic Ridge vent communities are striking in their apparent dependence on free-living primary production associated with sulfide surfaces to support large and metabolically active populations of shrimp. This research will use the TAG site on the Mid- Atlantic Ridge for a case-study of carbon transfer within a vent community. Dr. Van Dover and colleagues will identify the major trophic links, with particular emphasis on 1) testing alternative hypotheses regarding the source of food for shrimp and 2) determination of the spatial isotopic, taxonomic and biomass heterogeneity of basal dietary pools, the degree of specificity of consumers to these pools, and the strength of interactions between consumers. To accomplish these tasks, they will employ molecular and isotopic techniques to define distinctive basal dietary pools and to trace the paths of these pools through the food web. The field program will be designed to relate spatial heterogeneity to microhabitat characteristics as defined by temperature, mineralogical assays and macrofaunal assays and distributions.
