DISTRIBUTIONS AND STABLE ISOTOPIC COMPOSITION OF ROSE BENGAL STAINED BENTHIC FORAMINIFERA INHABITING METHANE SEEPS IN THE CLAMFLATS AREA OF MONTEREY BAY, CALIFORNIA

In a continuing effort to understand the factors that influence the ecology and isotope geochemistry of benthic foraminifera living in methane seep habitats, the remotely operated research vehicle, JASON II, was used to collect samples in clam beds associated with methane seeps in Monterey Bay, California. Isotopic signatures and vertical and spatial distribution patterns of Rose Bengal stained foraminifera were examined in push cores in both seep and non-seep environments from water depths of approximately 1000m. Dominant taxa in the >150 micron fractions of both seep and non-seep habitats included Epistominella pacifica, Buliminella tenuata, and Globobulimina species. Cibicides wuellerstorfi was abundant in clam bed sites, possibly due to the availability of substrate for attachment. Clam beds had greater infaunal abundances (occurring below 1 cm in sediment depth) compared to those of the control site cores. Carbon isotopic signatures of carbonate from stained foraminifera from clam bed sites are similar to those of non-seep environments. Results from this study are consistent with previous seep studies, and provide important clues about the ecology and isotope geochemistry of benthic foraminifera.