This research will investigate the feeding rates, trophic relationships, and impact of the benthic boundary layer (BBL) zooplankton in deep-sea near-bottom communities. In the collaborative investigations, Drs. Wishner and Gowing will obtain indicators of zooplankton activity in the deep sea and estimate of their impact as particle modifiers and energy consumers. The new methods for measuring in situ zooplankton ingestion rates, with the use of fluorescent particles as unambiguous tracers of ingestion, will allow documentation of gut passage time and the ability of these zooplankters to respond to the presence of food. Examination of the gut contents of the zooplankton, along with similar analyses of water column particulates, will enable them to determine specific trophic pathways in the deep-sea BBL. Electron microscopy will make it possible to resolve material often labeled amorphous, determine the ultrastructural condition living or detrital) of the gut contents, and recognize organisms such as metal-precipitating bacteria. Since zooplankton ingest particulate material and repackage it as fecal pellets, they alter the size, density, and composition of the near-bottom particulates, and thus may affect benthic and pelagic community dynamics and BBL chemical and particulate fluxes.
