Net Environmental Benefit Analysis (NEBA) of Dispersed Oil on Nearshore Tropical Ecosystems: Tropics – the 25th Year Research Visit

ABSTRACT The TROPICS (Tropical Investigations in Coastal Systems) field study began in 1983/84 near Bocas del Toro, Panama. The study was designed to examine the relative short and long-term effects of dispersed crude oil versus non-dispersed crude oil on tropical marine ecosystems. After baseline studies (1983), two 900m2 sites composed of intertidal mangrove and subtidal seagrass-coral zones were dosed (1984) with untreated Prudhoe Bay crude oil and Prudhoe Bay crude oil dispersed with Corexit® 9527. At periodic intervals over 25 years, the sites were monitored and effects were compared to a nearby reference site. A number of papers were published during the study period. In the short term, mortality to invertebrate fauna, seagrass, and corals was observed at both the dispersed oil and non-dispersed oil sites. In the long-term (10–25 years), as compared to the reference site, there was little to no oil detected and the ecosystem appeared to have returned to pre-dosing condition at the dispersed oil site...