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A controlled experiment was conducted in June 2000 to identify the impacts of an artificial oil spill on an Atlantic coastal salt marsh and to evaluate in situ biological remediation techniques to help restore the environment. Marsh microfossils known as foraminifera, are sensitive to several types of environmental stress, and were used here to monitor the effects of the oil spill and the treatments.

The project, run by the Department of Fisheries and Oceans Canada (DFO) and funded by the United States Environmental Protection Agency (EPA), was situated within Petpeswick Inlet on Conrod's Beach, along the Eastern Shore of Nova Scotia. Plots were laid out and weathered crude oil was applied to the surface of the designated plots in early June at low tide. Six different treatments were used in triplicate for a total 18 plots, including a control plot with nutrients (no oil), a control plot without nutrients (no oil), an oiled plot (natural attenuation), and plots with the added enrichment of nutrients, cut plants and/or agricultural disking.

Results show that the foraminifera responded quickly to the oil and that the oil had a statistically significant negative impact on at least one particular species, Miliammina fusca. This was seen by a dramatic increase in deformities in the shape of the test, in comparison to specimens from the non-oiled control plots, and to previous work conducted in an analogous inlet nearby. Remediation measures appear to have had no significant mitigating effect and in fact may have had a negative impact on foraminiferal assemblages within the treated plots. Percentages of deformities were some of the highest ever observed and took place within three days of the oil application. The results clearly show that foraminifera can be excellent indicators of oil pollution using only the percent of deformed tests. The advantage of foraminifera is the ease of sampling, processing and examination, with the added benefit that because these organisms leave a fossil record, we can detect the effects of previous oil spills in buried sediment from coastal marshes.

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Pages: 164
Supervisor: David Scott