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Person

David Walters

Research Ecologist
Columbia Environmental Research Center

Email: waltersd@usgs.gov
Office Phone: 573-876-1815
Fax: 573-876-1863
ORCID: 0000-0002-4237-2158

Location
CERC - Tech Center
4200 New Haven Road
Columbia , MO 65201
US

Supervisor: Amy M Beussink
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Salt Marsh Turbidity at Mockhorn Island, VA; Plum Island, MA; York River, VA; and Altamaha River, GA
We measured turbidity along transects from channel to marsh interior for 4 sites along the east coast of the United States at: Mockhorn Island, on the Eastern Shore of VA, USA; Plum Island in MA, USA; Goodwin Islands on the York River, VA USA; and the Altamaha River estuary, in GA, USA.
Survival and size of mayflies at each life stage, as well as MeHg concentrations in diatoms and mayflies exposed to low and high MeHg concentrations and a range of selenomethione (SeMet) concentrations.
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The data contain yearly modeled estimates of Pacific salmon escapement (in annual metric tons of wet mass) from 1976 to 2015 across four regions of western North America. A second data file contains modeled estimates of contaminant or nutrient concentrations in Pacific Salmon. The modeled estimates were derived from Bayesian generalized linear models (contaminant or nutrient concentrations) or from Bayesian generalized additive models (Salmon Escapement).
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Polychlorinated biphenyl (PCB) concentrations were measured in the lower Ottawa River in 2009 before dredging and after dredging in 2011, 2012, 2013, and 2015. Media collected for analysis included sediment, water, macroinvertebrates, and tetragnathid spiders at 18 stations. At each station 16 surface sediment core samples (top 15 cm) were collected and composited together with a mechanical mixer to achieve a homogeneous composite sample. Mid-depth water column samples were collected using a Van Dorn, Niskin or similar type sampler. Artificial substrate samplers (Hester Dendys) were used to collect aquatic macroinvertebrates. Riparian spiders (family Tetragnathidae) were collected from their webs by gloved hand...
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Description of Work This work will investigate linkages between sediment PCB concentrations and subsequent exposure in riparian organisms living on land next to the river and harbor. This is an extension of prior work at the site that has been used by the Manistique River and Harbor Remediation Team (comprised of managers and scientists from USEPA GLNPO, USEPA ORD, NOAA, USACOE, USGS and the state of Michigan) to guide plans for delisting activities. Riparian spiders are important mediators of contaminant flux from aquatic systems to nearby terrestrial habitats. Aquatic insects accumulate contaminants in their larval form, and transport these contaminants to terrestrial ecosystems in their adult bodies. Spiders...
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