Summary:
Ciliates are extremely important in aquatic ecosystems as primary consumers of bacteria. Protists are important consumers in the freshwater food web (Heath et al., 2003; Marxsen, 2006) and the ciliates are key in this web. Ciliates and other protists appear to be important in contaminated marine ecosystems (Andrew and Floodgate, 1974; Parker 1983). Given this role, a survey of marine ciliates in contaminated Gulf waters provides a unique opportunity for the discovery of basic consumers involved in the natural decontamination process.
Petroleum products have been apart of the marine environment long before human began using them as fuel sources. It is reasonable to assume that specialized organisms, including prokaryotes and the ciliates which feed primarily on prokaryotes, have evolved that are capable of exploiting this energy and raw materials source. My proposal is to collect water samples from both contaminated and non-contaminated areas to begin a molecular survey of the ciliates present with the aim of identifying any that have adapted to these specific conditions. These ciliates might be adapted to feeding on petroleum-feeding microbes and might be key members of the petroleum-degradation food web.
We have been able to demonstrate that the proposed methodology of collecting and characterizing ciliates from Gulf of Mexico shallow water sources is valid. Initial sampling sites included Dauphin Island, near Fort Morgan, Bon Secour Wildlife Refuge, and Gulf Shores (all Alabama). These includes site that were both heavily very lightly oiled. Samples were obtained from beach sand at about 1 m depth and from shallow water where water depth is about 1 m. Concentration of organisms from water samples was conducted by on site filtering as well as by centrifugation. Tuna trap were also used to attract ciliates. Amplification of SSU rDNA from DNA isolated by these methodologies revealed ciliate-specific DNA for all sampling methodologies. Cloning of SSU rDNA fragments and sequencing have yielded 11 ciliates to date. More exhaustive sequencing of numerous clones is currently underway in order to obtain an estimate of the diversity of the ciliate communities at these sites.