Stimulation of Toxic Blooms of the Diatom Pseudo-nitzschia spp. by Urban River Discharge into Southern California Coastal WatersEPA Grant Number: R831705
Title: Stimulation of Toxic Blooms of the Diatom Pseudo-nitzschia spp. by Urban River Discharge into Southern California Coastal Waters
Investigators: Caron, David A. , Miller, Peter E.
Current Investigators: Caron, David A. , Miller, Peter E. , Schnetzer, Astrid
Institution: University of Southern California , University of California - Santa Cruz
EPA Project Officer: Hiscock, Michael
Project Period: September 1, 2004 through August 31, 2007 (Extended to August 31, 2008)
Project Amount: $350,765
RFA: Ecology and Oceanography of Harmful Algal Blooms (2004) RFA Text | Recipients Lists
Research Category: Aquatic Ecosystems , Ecosystems , Water
This is a field-oriented research program to investigate the relationship between freshwater inputs from a highly urbanized region (southern California from the Palos Verdes peninsula to Long Beach) to the growth of Pseudo-nitzschia spp. and the production of domoic acid by members of this diatom genus in the adjacent coastal ocean.
Freshwater discharge into the Southern California Bight is strongly episodic, highly channelized, and restricted primarily to the winter/early spring. These freshwater inputs contribute substantial amounts of inorganic nutrients, labile organic compounds and trace metals to coastal ecosystems. It is hypothesized that these meteorological events greatly influence phytoplankton dynamics and the formation of harmful algal blooms in these waters. This research program will examine the connection between storm events and Pseudo-nitzschia species success and the production of domoic acid in coastal communities.
A sampling grid (up to 45 sites) encompassing three major river discharges will be studied following a major rainfall event in each of two consecutive years. Samples will be collected at 2-4 day intervals for a period of 2-3 weeks following each event. Supplemental samples will be collected bi-weekly throughout the year along a single cross-shelf transect. Remote sensing will be used to guide sampling during the storm events. Plankton abundances will be determined using flow cytometry, FlowCAM and fluorescence microscopy. Pseudo-nitzschia spp. abundance will be determined by microscopy (light, SEM), fluorescent in-situ hybridization, and quantitative real-time PCR. Domoic acid concentrations will be obtained using an immunological method. Physical parameters, nutrient and trace metals will be analyzed.
This project will discern the patterns of environmental and biological factors stimulating population growth and domoic acid production by Pseudo-nitzschia species in coastal waters of southern California. Key factors leading to blooms of these species and toxicity events will be documented.