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Karen A. Smith

Publications and source records attributed to Karen A. Smith.

4 recordsLinked to original sources
USGS2010

Polycyclic aromatic hydrocarbons in soil of the Canadian River floodplain in Oklahoma

The accumulation of polycyclic aromatic hydrocarbons (PAH) in soil, plants, and water may impart negative effects on ecosystem and human health. We quantified the concentration and distribution of 41 PAH (n = 32), organic C, total N, and S (n = 140) and investigated PAH sources using a chronosequence of floodplain soils under a natural vegetation succession. Soil samples were collected between 0- and 260-cm depth in bare land (the control), wetland, forest, and grassland areas near a closed municipal landfill and an active asphalt plant (the contaminant sources) in the north bank of the Canadian River near Norman, OK. Principal component, cluster, and correlation analyses were used to investigate the spatial distribution of PAH, in combination with diagnostic ratios to distinguish pyrogenic vs. petrogenic PAH suites. Total PAH concentration (SigmaPAH) had a mean of 1300 ng g(-1), minimum of 16 ng g(-1), and maximum of 12,000 ng g(-1). At 0- to 20-cm depth, SigmaPAH was 3500 +/- 1600 ng g(-1) (mean +/- 1 SE) near the contaminant sources. The most common compounds were nonalkylated, high molecular weight PAH of pyrogenic origin, i.e., fluoranthene (17%), pyrene (14%), phenanthrene (9%), benzo(b)fluoranthene (7%), chrysene (6%), and benzo(a)anthracene (5%). SigmaPAH in the control (130 +/- 23 ng g(-1)) was comparable to reported concentrations for the rural Great Plains. Perylene had a unique distribution pattern suggesting biological inputs. The main PAH contamination mechanisms were likely atmospheric deposition due to asphalt production at the 0- to 20-cm depth and past landfill operations at deeper depths.

Journal of Environmental Quality↗
USGS2003

Predator exclusion methods for managing endangered shorebirds: Are two barriers better than one?

Reproductive success of shorebirds can be improved by placement of predator exclosure fences along beaches or wire-mesh exclosure “cages” over nests. We predicted that these two types of exclosures used simultaneously might further improve reproductive success over that when cages alone are used. Field experiments were carried out on Piping Plovers ( Charadrius melodus ) on prairie alkali lakes in North Dakota and Montana. During 1996 and 1997, we compared success of nesting plover pairs provided with: (1) no protection, (2) cages that protected eggs in individual nests from both mammalian and avian predators, and (3) a combination of cages plus a temporary electric fence that excluded mammalian predators from the entire nesting beach where chicks were being reared. In 20 replicated trials, fledgling production rates were: no protection, 0.72 chicks/pair (95% CI: 0.29-1.15, N = 43 pairs); cage only, 1.73 (1.30-2.16, N = 46); fence plus cage, 2.06 (1.63-2.49, N = 50). Production by protected pairs was significantly greater than for unprotected pairs. However, no significant difference in production was detected between the two protection types. Temporary electric fences were relatively expensive to apply and added little to the effectiveness of cages, but may be appropriate in situations where cages cannot be used or where mammalian predation on chicks is a greater threat.

Montana, North Dakota↗