A springtime source of toxic Pseudo-nitzschia cells on razor clam beaches in the Pacific Northwest Public Deposited

Downloadable Content

Download PDF


Attribute NameValues
  • Concentrations of domoic acid (DA) above the regulatory limit in Washington coast razor clams are usually higher on northern beaches from summer to fall. Recent field studies have confirmed that the primary source of toxic Pseudo-nitzschia (PN) cells in those seasons is a semi-retentive topographically trapped seasonal eddy located offshore and north of the clamming beaches. Another semi-retentive coastal feature, Heceta Bank, that has been shown to support toxic PN cells in summer, is located south of Washington's clamming beaches. In this paper we present evidence to demonstrate that Heceta Bank, although not a likely source of toxic cells to Washington in summer due to the prevailing southward seasonal currents, may be a source of cells in springtime before the southward currents develop. In contrast to summer and fall seasons, concentrations of DA in razor clams are typically higher at southern beaches in spring. The likelihood of a southern source is explored using biological and transport data surrounding a period of toxic razor clams in April 2005. In particular, satellite-derived chlorophyll data confirm that a bloom occurred over Heceta Bank in March of that year, just prior to a period of strong storm-driven northward transport. PN cells of the same species observed in the April bloom on Washington beaches and in offshore waters were documented in Oregon offshore waters on the northern edge of Heceta Bank. That species, P. australis, has been shown to be highly toxic in this region; shore-based data show that razor clams on Oregon beaches were also toxic at the time when P. australis was observed offshore. Both measured and modeled currents show that transport was more than sufficient to move cells from the vicinity of Heceta Bank, Oregon to southern Washington beaches by the time the toxic cells were observed on those beaches. The rapid transport was due in part to the presence of the buoyant plume from the Columbia River, a common feature in winter and spring in nearshore waters of the U.S. Pacific Northwest. (c) 2013 Elsevier B.V. All rights reserved.
Resource Type
Date Available
Date Issued
  • Hickey, B., Trainer, V., Kosro, P., Adams, N., Connolly, T., Kachel, N., & Geier, S. (2013). A springtime source of toxic pseudo-nitzschia cells on razor clam beaches in the pacific northwest. Harmful Algae, 25, 1-14. doi:10.1016/j.hal.2013.01.006
Journal Title
Journal Volume
  • 25
Academic Affiliation
Rights Statement
Funding Statement (additional comments about funding)
  • Model results provided by the MoSSeamodeling framework were funded primarily by the UW PRISMprogram and the PNWTOX program. This research was supportedby grants to B. Hickey from the U.S. National Science Foundation(NSF) (OCE-0234587) and from the Center for Sponsored CoastalOcean Research (CSCOR) of the National Ocean and AtmosphericAdministration (NOAA) through the ORHAB and ECOHAB PNWprograms (NA07OA0310 and NA17OP2789), the PNWTOX program(OCE-0942675 and NA09NOS4780180), and the GLOBECprogram (OCE-0001034 and NA17RJ1232). Dr. Trainer and Mr.Adams were supported by NOAA CSCOR through ORHAB andECOHAB PNW. Moored current data was obtained with grant OCE-0000733 to M. Kosro under the GLOBEC program. Surface current mapping and analysis were supported by grant OCE-0000734 to M.Kosro under the GLOBEC program, OCE-0237710 under the RiverInfluences on Shelf Ecosystems (RISE) study, and NOAA NANOOSNA11NOS0120036.
Peer Reviewed
Additional Information
  • description.provenance : Made available in DSpace on 2013-06-17T17:33:25Z (GMT). No. of bitstreams: 1 KosroPMichaelCEOASSpringtimeSourceToxic.pdf: 4814216 bytes, checksum: 0ab875e2e1fe5d995fac7f137eef8e92 (MD5) Previous issue date: 2013-05
  • description.provenance : Submitted by Deborah Campbell ( on 2013-06-17T17:33:25Z No. of bitstreams: 1 KosroPMichaelCEOASSpringtimeSourceToxic.pdf: 4814216 bytes, checksum: 0ab875e2e1fe5d995fac7f137eef8e92 (MD5)



This work has no parents.