HR: 15:45h
AN: OS23G-08    [Abstracts]
TI: Spatio-Temporal Variability in Fecal Indicator Bacteria Concentrations at Huntington Beach: Connections to Physical Forcing
AU: * Rippy, M A
EM: mrippy@ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Dr., La Jolla, CA 92093-0208, United States
AU: Feddersen, F
EM: falk@coast.ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Dr., La Jolla, CA 92093-0208, United States
AU: Leichter, J
EM: jleichter@ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Dr., La Jolla, CA 92093-0208, United States
AU: Omand, M
EM: momand@ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Dr., La Jolla, CA 92093-0208, United States
AU: Moore, D F
EM: dmoore@ochca.com
AF: Orange County Public Health Laboratory, 1729 West 17th St., Santa Ana, CA 92706, United States
AU: McGee, C
EM: CMCGEE@OCSD.COM
AF: Orange County Sanitation District, 10844 Ellis Ave., Fountain Valley, CA 92708, United States
AU: Franks, P J
EM: pfranks@ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Dr., La Jolla, CA 92093-0208, United States
AB: Two major factors determine the spatial and temporal distributions of fecal indicator bacteria (FIB) at a given beach: local circulation & mixing patterns, and bacterial inactivation rates. High frequency and spatial resolution bacterial sampling combined with measurements of physical processes can be used to infer inactivation rates, enabling differentiation between dilution & mortality as factors driving variability in nearshore FIB abundance. A FIB sampling experiment (HB06) took place on 16 October 2006, at Huntington State Beach, a site selected due to its persistent problems with FIB pollution. Water samples were taken at 20-minute intervals (from 6:50am to 11:50am) at ten locations; four in an alongshore transect spanning 1 km at the shoreline, and the remainder in a 300-m long cross-shore transect. All samples were analyzed for FIB concentration (Total Coliforms, E. coli & Enterococci) and, for a subset, species level Enterococcus composition was determined. As part of the HB06 experiment, currents, temperature, waves, and chlorophyll fluorescence were measured simultaneously in the cross-shore direction with rapid CTD casts 300 m offshore. Results indicate that E. coli and Enterococcus concentrations exhibit exponential decreases with time, with smaller decay rates associated with depth and with sites in the Talbert Marsh and Santa Ana River. FIB concentrations are also noticeably lower farther offshore (300 m). Spatio-temporal patterns in FIB concentration will be presented in conjunction with the nearshore physical data allowing the relationship between physical dynamics and biological variability to be addressed.
DE: 0496 Water quality
DE: 1871 Surface water quality
DE: 4217 Coastal processes
DE: 4813 Ecological prediction
SC: Ocean Sciences [OS]
MN: 2007 Joint Assembly