Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 7714
Title: Widespread detection of human- and ruminant origin Bacteroidales markers in subtidal waters of the Salish Sea in Washington State
Author: Zack Oyafuso, Anne E. Baxter, Jason E. Hall, Sean M. Naman, Correigh M. Greene, Linda D. Rhodes
Publication Year: 2015
Journal: Journal of Water and Health
Volume: 13
Issue: 3
Pages: 827-837
Keywords: bacteria, Bacteroidales, fecal contamination, anthropogenic impact,

Rising populations around coastal systems are increasing the threats to marine water quality.  To assess anthropogenic fecal influence, subtidal waters were examined monthly for human- and ruminant-sourced Bacteroidales markers at 80 sites across six oceanographic basins of the Salish Sea (Washington State) from April through October, 2011.  In the basin containing cities with individual populations >190,000, >50% of sites were positive for the human marker, while in the basin with high densities of dairy and cattle operations, ~30% of sites were positive for the ruminant marker.  Marker prevalence was elevated in spring (April and May) and fall (October) and reduced during summer (June through September), corresponding with seasonal precipitation.  By logistic regression, the odds of human marker detection increased with percentage of adjacent catchment impervious surface, dissolved nitrate concentration, and abundance of low nucleic acid bacteria, but decreased with salinity and chlorophyll fluorescence.  The odds of ruminant marker detection increased with dissolved ammonium concentration, mean flow rate for the nearest river, and adjacent shoreline length.  These relationships are consistent with terrestrial to marine water flow as a transport mechanism.  Thus, Bacteroidales markers traditionally used for identifying nearby sources can be used for assessing anthropogenic fecal inputs to regional marine ecosystems.

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Theme: Habitats to Support Sustainable Fisheries and Recovered Populations
Foci: Characterize the interaction of human use and habitat distribution, quantity and quality.
Assess the impacts of toxic chemicals and other pollutants across biological scales, and identify pollution reduction strategies that improve habitat quality.