Long-Term Changes in the Species Composition of Calanoid Copepods off Southern CaliforniaEPA Grant Number: U915139
Title: Long-Term Changes in the Species Composition of Calanoid Copepods off Southern California
Investigators: Rebstock, Ginger A.
Institution: University of California - San Diego
EPA Project Officer: Lee, Sonja
Project Period: December 1, 1997 through December 1, 2001
Project Amount: $85,390
RFA: STAR Graduate Fellowships (1997) RFA Text | Recipients Lists
Research Category: Fellowship - Oceanography , Academic Fellowships , Aquatic Ecosystems
The goal of this research project is to investigate the population responses of planktonic species to environmental variability in the California Current System. Four questions will be addressed:
(1) Are there long-term trends in the abundances of any of the selected species?
(2) Are there periodic cycles in the abundances of any of the selected species?
(3) Are there groups of species that vary coherently in their abundances?
(4) Do species abundances correlate with environmental variables?
This research project will utilize zooplankton samples and hydrographic data collected since 1951 by the ongoing California Cooperative Oceanic Fisheries Investigations (CalCOFI) program. Selected species of calanoid copepods will be enumerated to develop a 48-year time series from which interannual to interdecadal scale variability can be analyzed. This studyresearch project will includecover southern California waters, sincebecause only this region has been sampled regularly since the mid-1980s. Only samples collected at night will be used, to avoid problems related to diel vertical migration of plankton. Copepod species have been selected representing different families, biogeographic affinities, and trophic modes.
To obtain estimates of species abundances in the southern California study region, samples from all selected stations for a given cruise will be pooled prior to counting. This will average out small-scale patchiness, and will result in an average abundance for the entire region. A quantitative aliquot representing a standard volume filtered will be removed from each sample using a Stempel pipette. The resulting pooled sample will be subsampled for enumeration.
Time series also will also be developed from environmental data for comparison with the copepod time series. The CalCOFI data set includes hydrographic measurements taken concurrently with the zooplankton samples. Other atmospheric and oceanographic variables that may indicate events such as El Niño and regime shifts are available in other data sets.