Long-Term Monitoring (2.5 Years) of Effects of Short-Term Field Exposure of Stony Corals to Dispersed and Undispersed Crude Oil
Proceedings of the Colloquium on Global Aspects of Coral Reefs: Health, Hazards, and History
Robert N. Ginsburg
A field experiment was conducted to evaluate long-term effects to shallow sub-tidal coral reef species from short-term exposure to dispersed and untreated crude oil. The study location was in the northwestern Laguna de Chiriqui, Caribbean coast of Panama. Experimental sites consisted of 900m2 plots which were enclosed by a boom with .45cm deep skirts. All sites contained shallow subtidal coral reefs. One site was designated as a control. One site received dispersed oil at a target concentration of 50ppm for 24 hours, representing a high exposure. One site received only crude oil at an amount of about 1 l/m2 for a duration of approximately 48 hours, representing moderate exposure.
Prespill chemical and biological parameters were collected in March and mid November, 1984. The experimental spill was conducted in late November, 1984. Monitoring of parameters continued periodically until August, 1986. Biological parameters that were measured included epifaunal and epifloral coverage of the coral reef substrate utilizing plotless line transects. Skeletal growth of four selected coral species was also measured at each site. Chemical sampling involved analysis (not reported here) of large and small-volume water samples for GC and GC/MS together with large-volume water samples by pumping through XAD resin.
Results indicated that the coverage of all organisms, hard corals, all animals, and all plants was significantly depressed in the Dispersed Oil treatment compared to the Control station. Little recovery of most organisms was evident some 20 months after initial treatment. Coverage parameters of the Oil Only treatment were generally lower than, but not usually significantly different from coverage of the Control. Of the four coral species investigated for growth, two (Agaricia tennuifolia and Porites porites) showed significant effects from exposure to dispersed oil (reduced blade and tip extension rate at the dispersed oil site). These results provided useful indications of long-term effects from short-term field exposure of corals and coral reefs to oil and dispersed oil. Information from this and other field and laboratory studies benefits marine management by providing data upon which to base informed decisions regarding dispersant use in tropical areas.
Rosenstiel School of Marine and Atmospheric Science, University of Miami
Life Sciences | Marine Biology
Dodge, Richard and Anthony H. Knap. (1993). Long-Term Monitoring (2.5 Years) of Effects of Short-Term Field Exposure of Stony Corals to Dispersed and Undispersed Crude Oil. In Robert N. Ginsburg (Eds.), Proceedings of the Colloquium on Global Aspects of Coral Reefs: Health, Hazards, and History (87-93).