MONITORING OIL SPILL BIOREMEDIATION USING MARSH FORAMINIFERA AS INDICATORS

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, which are sensitive to several types of environmental stress, 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 US 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 of 18 plots, including a control plot without nutrients, a control plot with nutrients, an oiled plot (natural attenuation), and oiled 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 it had a statistically significant negative impact on at least one particular species, Miliammina fusca. This was seen by a dramatic increase in the 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. Percentages of deformities were some of the highest ever observed and took place within three days of the oil application. Results clearly show that foraminifera can be excellent indicators of oil pollution using only the percent of deformed tests. The advantage of foraminifera is that because these organisms leave a fossil record, they can be used to detect the effects of previous oil spills in buried sediment from coastal marshes.