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Climate Variability and Paralytic Shellfish Toxins in Puget Sound Shellfish Stephanie K. Moore School of Oceanography University of Washington Box 355351, Seattle, WA 98195 Nathan J. Mantua, Vera L. Trainer and Barbara M. Hickey Alexandrium catenella Photographs: Anthony Odell Paralytic Shellfish Toxins (PSTs) • Suite of toxins produced by species of Alexandrium • Saxitoxin (potent neurotoxin) • Can accumulate in filter-feeding shellfish – Paralytic Shellfish Poisoning • Death in 2 hours Butter Clam Closures only in Northwest basin and Strait First Central and Whidbey basin closures Closures in most of Sound First South basin closures Trainer et al. 2003 Project Goals • To better understand the role of climate forcing on Harmful Algal Blooms in Puget Sound… Climate variability and Puget Sound PSTs Puget Sound PSTs Puget Sound Oceanography “Weather” ENSO PDO Global Warming • Days to Weeks • Years • Decades • Centuries? • < 2 Weeks • 1 Year • 2 Years • Decades? Project Goals • To better understand the role of climate forcing on Harmful Algal Blooms in Puget Sound – Describe space-time patterns of seasonal, interannual, and interdecadal variability in Puget Sound oceanographic properties – Evaluate the nature of local, regional, and large-scale forcings on Puget Sound – Identify environmental conditions conducive to HAB development – Determine the capacity for prediction of HAB risks Oceanographic data • WA DoE Marine Waters Monitoring Program monthly temperature and salinity profiles from 16 stations for 1993-2002 • Biannual (summer/winter) UW PRISM transects from 40 stations from 1998-2003 • DFO monthly average Race Rocks SST and SSS from 1937-2002 • USGS stream gage data, 1950-present • PFEL monthly mean upwelling index at 48N, 1950-2002 • US Climate Division air temperature and precipitation, 1950-2002 • Large scale climate indices: NPI, PDO, Nino3.4, 19502002 Climatological mean temperature profiles Surface intensified warming in Whidbey, Hood Canal and South basins Climatological mean salinity profiles Winter freshening Winter/Spring freshening Summer freshening Monthly mean river discharge 1993-2002 • Total runoff into Puget Sound peaks biannually in Winter and May-June • Fraser River has minimum discharge in Winter, peaks in May-June-July Climatological mean density profiles Year-round stratification Summer stratification PRISM cruise temperature transects: 6 yr means for 1998-2003 PRISM cruise salinity transects: 6 yr means for 1998-2003 Interannual variability • EOF/PCA analysis of DoE MWM profiles • Normalized anomalies of temperature, salinity, density, and the depth and strength of stratification • Leading EOF/PC captures a substantial fraction of the total variance in profiles for all 16 stations • Temperature 42% • Salinity 58% • Density 56% • Coherence not as strong for stratification • Maximum Buoyancy Frequency 22% • PC’s highlight strong interannual variability during the 1993-2002 period of record Profiles during extreme periods Vertical profiles of temperature, salinity and density at station CMB003 for months when PC1T, PC1S and PC1D, respectively, showed extreme positive (top) and negative (bottom) anomalies Loading patterns • The loading vectors for the leading PC of temperature, salinity (shown right) and density generally show strong positive values from surface to depth • Therefore, the leading PC’s represent depth and area averaged variations in oceanographic properties at all 16 station in Puget Sound We use Race Rocks SST and SSS as a proxy for PC1T, PC1S, and PC1D to increase our sample sizes Correlations with PCs for 1993-2002 JFM AMJ JAS OND Race Rocks SST with PC1T .868*** .748*** .456 .748*** Race Rocks SSS with PC1D .733 .832 .804** .817*** Race Rocks SSS with PC1S .733 .823* .886*** .827*** Statistical significance at 90%, 95%, and 99% confidence intervals are indicated by *, **, and ***, respectively. Correlation analysis Race Rocks SST and SSS with local and large scale indices, 1951-2002; degrees of freedom are noted with subscripts • Puget Sound streamflow is significantly correlated with SSS during winter, spring and summer • SST is strongly correlated with regional air temperature during all seasons, but correlations with large-scale climate indices are also significant during winter Lag correlations: large scale indices and Race Rocks SST and SSS 1950-2002 Longer term context 1937 to 2002 Annual mean SST and SSS phase diagram for Race Rocks lighthouse The 1993-2002 MWM data we’ve examined comes from a period that was substantially warmer than prior decades Race Rocks annual mean SST 1921-2005 Figure courtesy of Dr. Phil Mote, UW Climate Impacts Group Summary: Part I • Analysis of monthly T and S profiles reveals basin-wide coherence at seasonal to interannual timescales • We use longer term time series of SST and SSS from Race Rocks to evaluate correlations between Puget Sound properties and local to large-scale forcing parameters – Local air temperature is highly correlated with SST, while freshwater inflow is highly correlated with SSS – Large-scale influences (indicated by Aleutian Low, ENSO and PDO indices) are most prominent in winter, but winter SST effects persist for the following 2-3 seasons, and this indicates relatively good prospects for predicting Puget Sound temperature variations one to a few seasons into the future • There are strong warming trends in Race Rocks SST in the period since 1970, so the recent period of MWM and PRISM sampling is unique at least for the past ~85 years Alexandrium catenella Photographs: Anthony Odell Shellfish toxicity data ADVANTAGES • Toxin levels in shellfish provide proxy for bloom dynamics • Integrates fine-scale spatial and temporal variability in water column toxicity WDoH Biotoxin Program Other shellfish 20% LIMITATIONS • Sampling concentrated in summer and during high PST episodes • Few long term records at same site • Various shellfish species – e.g. Pacific Oysters, Butter Clams, Blue Mussels Littleneck clams 16% Blue mussels 31% Butter clams 18% Pacific oysters 17% Must match toxin uptake and depuration rates of shellfish with water column dynamics! Shellfish toxicity and bloom dynamics decoupled when: 1. Toxin retention is high and detoxification rates are long e.g. Sequim Bay butter clams 2. Shellfish species sensitive to PSTs e.g. Filucy Bay pacific oysters Selection of blue mussel PST data for trend analysis • Because the more you look the more you see… • Only sites with regular, long term observations – Must have one or more observations per month for at least 70% months – Leaves 23 sites over the time period 1990 to 2002 Puget Sound The more you look the more you see… Climatology of toxicity 1990 to 2002 Spatial and temporal variability in blue mussel PSTs NB: 20,000 µg STXeq 100 g-1 November 2002! PCA blue mussel PSTs “Hot spot” indicator sites Annual indices of bloom behavior No significant trends with time No. of toxic sites 1990 to 2002 Closures only in Northwest basin and Strait First Central and Whidbey basin closures Closures in most of Sound First South basin closures Trainer et al. 2003 Correlations of annual indices with environmental properties Env. properties HOT SPOT SITES (1990 to 2002) Day of First No. Days Day of Max -.0111 -.4911 -.396 -.286 -.036 .5311 -.3611 -.3811 .0211 .2111 .0211 .623 PRCP -.3911 .1911 -.0111 -.4711 -.4311 -.4011 -.243 STRM -.1711 .3911 .1611 .0211 .0211 -.593 TIDE <.011 -.021 .141 -.051 -.141 -.041 -.231 UPWL .014 .324 .474 .114 -.024 .134 -.173 WIND -.034 .204 .254 .034 .024 .084 -.463 NPI -.3511 .0811 .2111 -.2211 -.3111 -.1811 -.303 ENSO .3011 -.1311 -.2111 -.2911 -.2011 -.2111 .483 PDO .036 .146 .036 -.236 .016 .066 .403 SST -.1811 SSS -.056 AIR First to Last .0811 .3211 Log10 (Max+1) Log10 (Mean+1) Log10 (Cum+1) -.0511 -.1111 -.093 -.406 -.436 <.013 No significant trends with environment at p ≤ 0.05 Finer temporal resolution… 6 biggest events identified by “hot spots” Hindcasting of mean toxicity for all of Puget Sound 1990 to 2002 Timescales of El Niño effects ENSO teleconnections to Puget Sound are most apparent from Nov-Apr… Exceptional PST events tend to occur in the fall Capacity for prediction • Low streamflow, weak surface winds and low tidal variability precede toxic events – Typically occurs in early fall following the peak of seasonal warming of surface waters • Forecasting PSP risk is limited to days/weeks • No evidence for increased risk during El Niño years Summary: Part II • Shellfish species selection for trend analysis of PSTs is important • Toxicity in Puget Sound is highly variable in space and time • Annual indices of bloom behavior from 1990 to 2002 show – No significant trends with time – No relationships with environmental properties • A combination of high frequency weather events determine bloom occurrence Acknowledgments • Mitsuhiro Kawase, Jan Newton, Jonathan Kellogg and Mark Warner (UW) • Skip Albertson (DoE) • Sheryl Day (NOAA NWFSC) • Funding provided by NOAA's West Coast Center for Oceans and Human Health Meaningful relationship with environment? Mean annual toxicity versus PC1T, PC1N and PC1S Basin-wide annual mean temperature and maximum buoyancy frequency Basin-wide annual mean temperature and salinity PRISM cruise density transects: 6 yr means for 1998-2003 Climate variability Pacific Decadal Oscillation 20-30 years El Niño/Southern Oscillation 6-18 months Warm phase PDO Warm phase ENSO (El Niño) Source: Climate Impacts Group, University of Washington What does this mean for the PNW? El Niño and warm phase PDO generally affect: – Weather patterns • Warmer and drier winters • ↓ Precipitation/runoff/stream flow – Structure of ocean • ↓ Upwelling • Warmer surface waters in ocean • Less nutrients Decadal variability of butter clam toxicity Butter clam toxicity and no. warm SST days 1957 to 1991