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Thesis - NSU Access Only
M.S. Coastal Zone Management
Richard E. Dodge
In 1984, experimental oil and dispersed oil spill sites were established along the Caribbean coast of Panama, in the Province of Bocas del Toro. Baseline biological, chemical, and physical parameters were collected prior to dosing. Over the following 2.6 years, sites were monitored regularly and results presented in a comprehensive report (Ballou et at., 1987). Ten year follow-up surveys were conducted in 1994 (Dodge et al., 1995). Ten years after dosing, sediment core analysis confirmed the presence of degraded hydrocarbons at both the crude oil and dispersed oil treatment sites. At the whole oil treatment, intertidal regions experienced further mortality in mangroves, while subtidal regions experienced few effects. At the dispersed oil treatment, subtidal corals, significantly impacted following initial treatment, appeared to have recovered. The present study is based on site visits during 2001-02', to the original crude oil, dispersed crude oil, and reference sites established in 1984. Despite the degradation of oil over the past 18 years, sheen is still visible leeching from non-dispersed, crude oil treatment sediments. Previously denuded intertidal mangrove regions currently carry a high sapling density, although recent offsite mangrove mortality may be indicative of continued toxicity and mobility of degraded hydrocarbons. Seagrass growth rates, highly variable at all sites over the duration of monitoring, appear to have been little influence by long-term treatment associated effects, while leaf area parameters at the crude oil treatment have significantly increased relative to the reference site. Sea grasses at the crude oil treatment and dispersed oil treatment both exhibit significantly reduced density relative to the reference site. Within coral zone parameters, current data reveal increased coverage of finger coral (Porites furcata) at the crude oil treatment. Since treatment, percent coverage of P. furcata has grown from 25.0%, in November 1984, to 63.5%, in June 2002. Seagrass and coral parameters are investigated for both between-site differences, and long-term within-site trends. Newly established parameters are investigated to help elucidate possible treatment effects.
Greg Allen Ward. 2003. Long Term Effects of Oil and Dispersed Oil on Mixed Seagrass and Coral Beds: The 18th Year of Studies Following Experimental Dosing. Master's thesis. Nova Southeastern University. Retrieved from NSUWorks, Oceanographic Center. (95)