Resolving the annual pattern of algal toxins in coastal waters off Los Angeles Website
Period: 2/1/2012 -
|Federal Funds:||State Funds:|
The primary goal of this project is to gain a predictive understanding of HAB occurrence, population dynamics, and toxin production for the 2 most potent toxic algae within the Los Angeles coastal region. The project encompasses 3 main components: 1) identify and quantify Pseudo-nitzschia and Alexandrium together with their associated toxins on a weekly basis to learn about spatial differences and similarities in timing and duration of toxic events among the Los Angeles harbor, Newport Pier, Redondo Beach Harbor and the Wrigley Pier at Catalina Island; 2) employ a recently developed method called Solid Phase Adsorption Toxin Tracking (SPATT) at all sampling sites that will provide information on in situ levels of domoic acid and/or saxitoxin. SPATT tracking is a highly efficient method that has been shown to provide exceptionally sensitive detection of toxins in the field; and 3) conduct a retrospective analysis of a 5-year set of samples that were collected inside and outside the Los Angeles Harbor to determine whether the LA harbor environment serves as a potential hotspot for Pseudo-nitzschia and/or Alexandrium. Our research is aimed at providing insight into the occurrence and timing of toxic algal events at several highly frequented coastal sites within the wider Los Angeles area and will provide information on in situ toxin dynamics and the potential continued exposure of marine life to DA and/or STX.
We will determine abundance changes for Pseudo-nitzschia and Alexandrium and changes in concentrations of domoic acid (DA) and saxitoxin (STX) on a weekly basis inside the Los Angeles harbor, at Newport Pier, inside Redondo Beach harbor and at the Wrigley Pier at Catalina Island. Concurrently we will deploy SPATT sampling units for periods of one week to measure for continued presence of DA and STX at each location. During DA or STX events we plan on increased sampling frequency to better document different phases of each bloom.
Identification and quantification of Pseudo-nitzschia and Alexandrium: Quantitative PCR approaches (qPCR) that have been developed in our laboratory will be employed to identify and quantify Pseudo-nitzschia spp. and Alexandrium catenella. The sensitivity of these molecular approaches will allow us to follow abundance changes even at very low cell concentrations. Cultures of Pseudo-nitzschia and Alexandrium are available in our laboratory for the preparation of standard dilution curves which are run vis à vis natural samples during qPCR analyses. Subsets of formalin-preserved samples will be analyzed via microscopy to validate our qPCR estimates.
Toxin analyses: DA and STX concentrations will be determined on a weekly basis together with cell abundances using an enzyme-linked immmunosorbent assay (ELISA). Algal phycotoxins in the field will be tracked using the Solid Phase Adsorption Toxin Tracking (SPATT) method. This technique allows for the absorption to and subsequent extraction of algal toxins from a small resin-containing bag that will be deployed for a week at a time. DA and STX extracted from SPATT sampling units are subsequently measured via the ELISA method.
Retrospective analyses: In addition to our described 2-year long field sampling efforts we will also determine Pseudo-nitzschia and Alexandrium abundances and DA and STX levels retrospectively for samples collected inside the Los Angeles harbor and from south of the harbor within the adjacent San Pedro Channel. These samples were originally obtained to guide the timing of boat deployments during a previous HAB project (expired). New cost- and time-efficient techniques in hand we believe this is an opportune time to examine the 5-year sample set to complement our Sea Grant project.
This study will provide information on abundance trends and toxin levels for the 2 most potent Southern California algal species at highly frequented pier and harbor sites within the Los Angeles area. Currently, only very little information exists on the frequency, intensity and duration of these toxic events at our proposed study locations which include the Los Angeles and Redondo Beach harbor, the Newport Pier in Orange County and the Wrigley Pier on Catalina Island. Our research project will gather invaluable information to guide future HAB research efforts and will test the potential of SPATT techniques to serve as sentinels for algal toxin detection in the field at multiple locations within the Los Angeles area. As soon as sampling protocols have been optimized it is planned to increase spatial resolution, and during bloom events temporal coverage, for toxin detection by having the community (i.e. local aquaria and marinas) involved in the deployment and retrieval of SPATT units (final analyzes to measure domoic acid (DA) or saxitoxin (STX) will take place in our lab since it requires the use of a extraction column/filtering apparatus and a plate reader for the ELISA format). We believe that this study will be highly complementary to ongoing research projects that focus on the role that toxin production plays for algal species composition within the Redondo Beach Harbor (USC Sea Grant) and a program that monitors for the presence of HAB specimens at several pier locations north and south of LA harbor including Newport Pier (multi-institutional SCOOS project). The latter project does gather information on phytoplankton community composition via microscopy and the data will be available to validate our abundance estimates based on quantitative PCR. None of the described project assesses in situ toxin levels for DA and STX.
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