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Optical tagging and tracking of water masses for prediction of human health hazards. Pete Strutton College of Oceanic and Atmospheric Sciences Oregon State University Michelle Wood, Brittany Scott and Andy Ohana-Richardson Department of Biology, University of Oregon.
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Optical tagging and tracking of water masses for prediction of human health hazards Pete StruttonCollege of Oceanic and Atmospheric Sciences Oregon State University Michelle Wood, Brittany Scott and Andy Ohana-Richardson Department of Biology, University of Oregon
Background and General Approach Increasing frequency and persistence of HABs Anthropogenic impacts, climatic shifts, ballast water dispersal Monitoring programs exist, but are not pro-active Off Oregon the main toxic species are: Pseudo-nitzschia, diatom, produces Domoic Acid, leads to Amnesic Shellfish Poisoning Alexandrium, dinoflagellate, produces saxitoxin, leads to Paralytic Shellfish Poisoning Some HAB species (notably K. brevis) have unique optical signatures that can be used to detect in situ or from space. Goal: Use (multiple) satellite products to predict and track HABs
Large database of coastal toxin concentrations Both saxitoxin and domoic acid in mussels and razor clams Most comprehensive from 1998 to present Includes two large events (1998 and 2005) Backtrack from coastal observations to offshore conditions Historical data from the Oregon Dept of Agriculture
Large domoic acid event in 1998 Observed along the entire west coast Linked to California Sea Lion deaths, particularly in central CA Relatively well-sampled with documented hot-spots on Heceta Bank and the Juan de Fuca eddy Focussed attention on the JdF eddy as a potential incubator From: Hickey and Banas, 2003
Juan de Fuca eddy: HAB incubator? From: Sackmann & Perry, in press
Spectral signatures as a tracking tool From: Sackman & Perry, in press
Heceta Bank: A Juan de Fuca eddy analog? From: Barth, Pierce and Castelao, 2005
Chl [mg m-3] Domoic acid [nM] HB In situ measurements: May 2005 event
Logistic Regression: Events vs Upwelling Logistic regression: An appropriate tool for analyzing a categorical response to continuous physical forcing Regress toxin > closure level (or not) vs upwelling dynamics (Bakun upwelling index) Performed for saxitoxin (PSP) for 5 sites spanning the OR coast Determined that closure levels of saxitoxin are often associated with downwelling conditions - toxin brought close to the coast By monitoring blooms by satellite and upwelling conditions (local meteorology) we can better target sampling. Analysis works poorly for DA (retention) but same principle
~10s km Upwelling/Downwelling and Coastal Impacts N P Si Fe toxic impact
Education and Outreach Significant public interest in the project because of the connection to recreational shellfish harvesting Press release in 2005 yielded significant coverage At least 3 Oregon newspapers + OSU and UO university papers Local TV and radio Article in NIEHS’ Environmental Health Perspectives Two graduate students currently involved Undergraduate, satellite data processing, summer 2005 High school student and undergraduate involvement for 2006 Short course on HABs at UO’s OIMB, July 2006 Collaboration with CoastWatch: Preliminary products
Accomplishments to date and future work Retrospective analysis of Oregon Dept of Agriculture toxin data Confirms Heceta Bank (and Columbia) as HAB hot spots Have begun coupling these data with SeaWiFS chlorophyll Next step: Go beyond chlorophyll to spectral signatures Include analysis of fronts: both chlorophyll and temperature Large-scale event in 2005, with record Domoic Acid concentrations observed onshore in situ sampling of this bloom coupled with remote sensing Established collaborations with WA and CA colleagues Strengthen these ties in the interest of standardized methods Expanded in situ sampling and collaboration with CoastWatch in 2006
Increasing toxicity of Oregon events Note: 2005 DA concentrations were highest ever observed
La Niña El Niño Increasing PSP toxicity associated with El Niño Also some evidence for increasing toxicity at interannual scales 2005: Highest domoic acid concentrations observed 2000, 2001: Highest saxitoxin years on record
Results from Juan de Fuca work Transport events from the JdF to the WA coast are frequently observed. Delivery of seed populations to the coast by (1) direct advection, (2) switch to downwelling winds, or (3) sinking and upwelling of cells. Despite the absence of a clear optical signal for Pseudonitzschia, radiance spectra can be used to track masses. Satellite data monitoring could enhance shore-based sampling and management.