Mike Fulton

Effects of the antifouling compound, Irgarol 1051, on a simulated estuarine salt marsh ecosystem.

Toxicity effects of the antifouling compound, Irgarol 1051, were examined using a simulated estuarine salt marsh ecosystem. The 35xa0day mesocosm exposure incorporated tidal flux and contained seawater, sediments, marsh grass, and estuarine biota. Irgarol (10.0xa0μg/l) caused a significant reduction in phytoplankton biomass and primary productivity. HPLC pigment analysis indicated significant effects of irgarol on both phytoplankton and periphyton community composition, with decreased concentrations of pigments representative of diatom species. There was also a significant decrease in dissolved oxygen levels in the 10.0xa0μg/l irgarol treatment. Growth of the hard shell clam was significantly reduced in the 1.0 and 10.0xa0μg/l irgarol treatments. The effects observed occurred at irgarol concentrations greater than those typically measured in the environment. Prolonged exposure, the accumulation of irgarol in sediments, plant, or animal tissues, and the interaction of irgarol with other chemicals in the environment; however, could increase risk.

Assessment of animal impacts on bacterial water quality in a South Carolina, USA tidal creek system.

Fecal pollution may adversely impact water quality in coastal ecosystems. The goal of this study was to determine whether cattle were a source of fecal pollution in a South Carolina watershed. Surface water samples were collected in June 2002 and February through March 2003 in closed shellfish harvesting waters of Toogoodoo Creek in Charleston County, SC. Fecal coliform concentrations in 70xa0% of the water samples taken for this study exceeded shellfish harvesting water standards. Ribotyping was performed in order to identify animal sources contributing to elevated fecal coliform levels. Escherichia coli isolates (nu2009=u2009253) from surface water samples were ribotyped and compared to a ribotype library developed from known sources of fecal material. Ribotypes from water samples that matched library ribotypes with 90xa0% maximum similarity or better were assigned to that source. Less than half of the unknown isolates (38xa0%) matched with library isolates. About half (53xa0%) of the matched ribotypes were assigned to cattle isolates and 43xa0% to raccoon. Ribotyping almost exclusively identified animal sources. While these results indicate that runoff from cattle farms was a likely source of fecal pollution in the watershed, wildlife also contributed. Given the small size of the library, ribotyping was moderately useful for determining the impact of adjacent cattle farms on Toogoodoo Creek. Increasing the number and diversity of the wildlife sources from the area would likely increase the usefulness of the method.

An assessment of benthic condition in several small watersheds of the Chesapeake Bay, USA

We examined benthic condition in three small watersheds in the Chesapeake Bay. Characterization of benthic condition was based on the combined measurements of benthic fauna, sediment toxicity, and sediment contaminant loads. Significant differences between watersheds were detected for sediment contaminant concentrations and water quality. The intensity of benthic impairment was greatest in the river surrounded by the most developed watershed. Spatial patterns of benthic condition were detected within all three watersheds. In contrast to current, intense focus on nutrient pollution in the Chesapeake Bay, qualitative comparison of our findings to land-use patterns supports findings of other studies that suggest benthic condition in tributaries of the Chesapeake Bay may more closely relate to urbanization than agricultural land uses.