Northwest Fisheries Science Center


Staff Directory

Algal Growth

Algal growth and spreading are important factors that determine the magnitude and location of HAB events. These factors drive the production and movement of marine toxins through the marine food web. In order to understand how biotoxins move through the food web, we have several ongoing projects investigating the individual components of HAB events:

Propogation of Algal Blooms

Image of Penn Cove, WA.
Blooms of Pseudo-nitzschia, the organism capable of producing domoic acid, occur sporadically along the West Coast of North America. How and why these blooms occur is not understood. A predictive model explaining these occurrences would provide risk managers with a powerful tool in mitigating domoic acid impact on marine resources. Our current working hypothesis is that Pseudo-nitzschia bloom in waters over the Washington continental shelf in an oceanic structure called the Juan De Fuca eddy, a retentive feature that is thought to be an "initiation site" of these blooms. We suspect that this location may be the "breeding ground" of Pseudo-nitschia and that these diatoms are transported from this area to the beaches where they become responsible for domoic acid accumulation in razor clams. The precise timing of these physical processes (currents, winds, upwelling, and downwelling) determines whether a bloom will be advected into the nearshore region and be sustained there long enough for razor clams to become toxic.

Algal Growth and Nutrition Studies

There are several species of Pseudo-nitschia and not all species produce toxin. Which ones produce the toxins and under what conditions is not completely understood. To address these questions the cells are isolated from a sample and identified using SEM and genetic probes. Once the species has been identified they are grown in culture under differing nutrient conditions. Toxin production is then measured by the receptor binding assay.