Today’s Forecast: Windy and Toxic

Heading out to dig clams at your favorite beach? Someday you may be able to check the red tide forecast in addition to the tide tables. Using local sampling data and satellite measurements, two Oregon researchers are developing a method to predict red tides that can contaminate razor clams, mussels and other filter-feeding shellfish.

Their project could lead to an early warning system for coastal managers, health officials and commercial and recreational fishers. At present, shellfish closures are based on regular testing by the Oregon Department of Agriculture.

Peter Strutton of the OSU College of Oceanic and Atmospheric Sciences and Michelle Wood of the University of Oregon Department of Biology are leading the project with funding from the National Oceanic and Atmospheric Administration’s Oceans and Human Health Initiative.

They believe that certain areas, including Heceta Bank off the central Oregon coast, may act as “incubators” for generating the blooms of Pseudonitzschia, a phytoplankton species that produces toxic domoic acid. Shellfish that feed on the plankton accumulate the toxin in their tissues.

“Every spring there is an algal bloom in the Pacific from San Diego, Calif., to Vancouver, B.C.,” Strutton says. “Often one species of phytoplankton will dominate, and we need to identify when it is Pseudonitzschia so we can create an early warning system.”

Key to the project is understanding Pseudonitzschia’s response to changing ocean conditions and how those conditions can be detected by satellites. The researchers have combed through data over the last 10 years from the Oregon shellfish monitoring program. They are comparing recorded levels of toxicity in razor clams, mussels and other shellfish with archival satellite data showing sea surface temperatures and “ocean color” — chlorophyll levels and rates of fluorescence.

They hope to find a combination of physical and optical signatures for potential blooms. During the next two years they will sample those areas at peak times to measure phytoplankton abundance and toxicity levels.

Wood is also affiliated with the OSU Cooperative Institute for Oceanographic Satellite Studies.


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