Monitoring Benthic Conditions as an Early Warning System for Alexandrium Blooms in Puget Sound

Abstract

The production of saxitoxin by the dinoflagellate Alexandrium catenella and the bioaccumulation of neurotoxin in shellfish can result in people contracting paralytic shellfish poisoning (PSP) after consuming contaminated shellfish. The Washington State Department of Health (WDOH) routinely tests commercially farmed shellfish for saxitoxin concentrations, however, recreationally harvested shellfish pose a public health risk because a delay in posting warning signs about contamination or closing beaches increases the risk of exposure to saxitoxin through contaminated shellfish. Many Alexandrium blooms are initiated by cysts, a dormant form of A. catenella that can remain viable in sediments for long periods of time. The purpose of this research is to develop a low cost and easy to build instrument to serve as an early warning system for Alexandrium blooms that monitors benthic conditions as a proxy for the likelihood of a bloom. The in-situ instrument will have multiple nodes of temperature and light sensors along a submerged cable terminating at an above-water data logger. Temperature and light are monitored because benthic temperatures above 12° C and adequate light reaching the cysts can trigger cyst germination making them good predictors of Alexandrium bloom likelihood. Because of the simple design of the instrument, citizen scientists can become engaged in the coastal and public health issue of harmful algal blooms along their local beaches. With citizen involvement in monitoring where and when blooms are likely to occur it allows citizens become more aware of PSP and increase public safety surrounding the issue as well as increase scientific awareness of Alexandrium bloom progression in Puget Sound as a result of increased monitoring.