GLOBEC: Microzooplankton in the Northern California Current System

Oregon State University, Corvallis OR

Investigators

Abstract

Microzooplankton, grazing organisms < 200 gm in size, have a central role in marine pelagic food webs and are significant consumers of phytoplankton and a major food resource for larger zooplankton. The PI's will provide detailed information on microzooplankton stocks in the GLOBEC California Current System (CCS), in the context of physical, chemical, and biological data collected in the CCS Long Term Observation Program (LTOP). They will document temporal (seasonal and interannual) and spatial (along-shore and from coast to offshore) variability in distribution of microzooplanktonic protists in the CCS. The specific objectives of the research are: 1) Retrospective analysis of microzooplankton stocks in the CCS from samples collected along the Newport (NH) line off Oregon in September 1997 during a strong El Nino, and in September 1998 after relaxation of the El Nino event, 2) Seasonal/regional sampling of microzooplankton stocks in the CCS as part of the LTOP program through September 2003, 3) Analysis of spatial and interannual variability in microzoo-plankton stocks with respect to environmental parameters collected as part of the LTOP cruises, and 4) Estimating potential rates of herbivory by microzooplankton, and significance of microzooplankton as a food resource for mesozooplankton, for use in CCS food web models. Data will include abundance and carbon biomass of general taxonomic groups of microzooplankton, and observations of ingested prey in protist food vacuoles and of the abundance of mixotrophic ciliates. Results from the retrospective analysis of microzooplankton standing stocks, and from our sampling program during the LTOP cruises in 2000-2003 will be processed, archived and disseminated to other GLOBEC investigators as the data become available. The results of this study will provide important data for CCS ecosystem modelers, and will also be valuable in comparisons of CCS and Coastal Gulf of Alaska (CGOA) ecosystem dynamics.