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Fig. 8. Frequency of injury for the three most common species of massive
) 10% Mortsty
natural populations from laboratory-based physiological data or small-scale, short-term press perturbation experiments in the field (2, 3, 48, 52, 53).
Third, sublethal effects are extensive and may be more important in the long term than initial mortality (3, 48). Changes in stomatopod behavior and population structure were more pronounced than might be expected from a simple reduction in numbers. Likewise, injury of corals has allowed colonization of their bare skeleton by algae and other sessile organisms that may overgrow parts of colonies that survived the initial effects of oil (3, 54). Corals stressed by oil are probably also more susceptible to epidemic disease and likely to grow and reproduce more slowly than unaffected colonies (3, 5, 52). Any combination of these effects may further reduce overall abundance of corals as much as the initial spill (54). Such a chain reaction could continue long after any petroleum hydrocarbons are present in the environment or coral tissues, just as staghorn coral continued to decline precipitously following a severe hurricane in Jamaica (55).
The response of organisms to an oil spill, or any other major disturbance, will depend on the conditions in which they normally live (15, 48, 56). Moreover, the suite of organisms able to survive under conditions of chronic pollution, and their resistance to further stress, is typically different from that in similar unpolluted habitats (48, 57). Much of Bahia las Minas has been subjected to human disturbance, beginning with decades of excavation, dredging, and landfilling for the construction of the Panama Canal and the City of Colon, drainage and spraying of mangroves for mosquito control, construction of the refinery and a large cement plant on landfill, a major oil spill in 1968, and unknown amounts of chronic oil pollution from the refinery and ships passing to and from the Canal (4, 5, 17, 58). It is a measure of the severity of the 1986 oil spill that the biological consequences were so detectable despite this history of environmental abuse.
REFERENCES AND NOTES
1. National Research Council, Oil in the Sea: Inputs, Fates, & Effects (National Academy Press, Washington, DC, 1985).
2. R. B. Clark, Philos. Trans. R. Soc. London Ser. B 297, 185 (1982); R. S. Carey, Am. Sa 74, 298 (1986).
3. Y Loys and B. Rinkevich, Mar Ecol. Prog. Ser. 3, 167 (1980).
6 JANUARY 1989
4. K. Rurzier and W. Sterrer, BioScience 20, 222 (1970).
5. C. Birkeland, A. A. Reimer, J. R. Young, Survey of Marine Communities in Panama and Experments with Oil (Publ. EPA-600/3-76-028, Environmental Protection Agency Ecological Research Series, Narragansett, RI, 1976).
6. J. D. Cubit et al., in 1987 Oil Spill Conference (Publ. 4452, American Petroleum Institute, Washington, DC, 1987), pp. 401-406.
7. J. Cubit and S. Williams, Atoll Res. Bull. 269, 1 (1983).
8. J. D. Cubet, R. C. Thompson, H. M. Caffey, D. M. Windsor, Smithsonian Contrib Mar. Sci. 32, 1 (1988); L. G. Macintyre and P. W. Glynn, Am. Assoc. Petrol Geal. Bull. 60, 1054 (1976).
9. G. L. Hendler, in Proceedings of the Third International Coral Reef Symposium, D. L Tavlor, Ed. (University of Miami, Miami, FL, 1977), vol. 1, pp. 217-223, 1. D. Cubit, D. M. Windsor, R. C. Thompson, J. M. Burgett, Estuarine Coastal Shelf Sc 22, 719 (1986).
10. J. C. Ogden and E. H. Gladfelter, UNESCO Tech. Pap. Mar. Sci. 23, 1 (1983). Important species in common throughout the tropical western Atlantic are red mangrove R. magle, seagrass T. testudinum, most reef corals and algae, and commercially important lobsters (Paralinus spp.) and oysters (C. rhizophorae). 11. Ongoing drilling and refining off Yucatan and possible production along the west coast of Flonda
12. The oil type was 70% Venezuelan crude, 30% Mexican Isthmus crude, specific gravity 27 (American Petroleum Institute). Percent composition determined at the Bermuda Biological Station by column chromatography with the use of alumina and silica gels: 47.4% saturates (fraction 1, hexane); 6.4% light aromatics (fraction 2, 10% ether/90% hexane); 4.8% heavy aromatics (fraction 3, 20% methylene chloride/80% hexane), 18.9% polar fraction (fraction 4, methylene chlonde); and 22.5% unrecovered.
13. C. D. Getter, G. I. Scott, J. Michel, in 1981 Oil Spill Conference (Publ. 75-4161. American Petroleum Institute, Washington, DC. 1981), pp. 535-540.
14. Refinery officials estimated that <21,000 liters of Coreur 9527 (Exxons Chemicals Amenca) were spraved from aircraft (6). STRI personnel observed this spraving between Asana Chiquita and Punta Galeta
15. J. D. Woodley et al., Sciener 214, 749 (1981), J. H. Connell, ibid. 199, 1302 (1978).
16. Surveys beyond Punta Galeta began the first week of June 1986 and lasted 1 month. Videotapes were made of the coast between Rio Chagres and Islas Naranjos, and still photographs were made all along the coast. Visual assessments were made of degree of oiling (heavy, moderate, light, or absent) and the habitats and types of organisms obvioush affected.
17. J. D. Cubet, G. Batista de Yec, A. Roman, V. Batista, in Agonia de la Naturaleza, S. Heckadon Moreno and J. Espinosa Gonzalez, Eds. (Impretex, Panama, 1985), pp. 183-199, Revista Medica Panama 9, 56 (1984).
18. Oil was observed commonly until the ame of manuscript revision (July 1988) around Isla Pavardi, where it emerged directly from the coral landfill on which the refinery is built, and Punta Muerto, Bahia Cativa, eastern Isla Largo Remo, and Punta Galeta
19. Within this area odd commonly escaped from sediments when we walked among mangroves or cored into shallow subtidal seagrass beds. Intertidal surfaces were heavily coated with oil.
20. Most of the oil that escaped from Bahia Cativa was driven west. Coasts facing north
to northeast were heavily oiled, whereas adjacent areas facing west or south received little oil. The best studied example is at the northwestern side of Isla Largo Remo (Table 2).
21. These low tides occur annually at this time of year (8, 9). Sea levels during most of this time were as much as 10 cm below the 9-year average for this period of normally low sea level.
22. Corals were collected by divers on days when on surface slicks were visible, placed in solvent-rinsed aluminum foil, and frozen. Tissues were removed from skeletons with an air pick and homogenized with a ussue grinder. To minimize variations due to water or carbonate inclusions, standard Lowrey protein determinations were used as one measure of tissue mass. After solvent extraction, total lipid weights were determined microgravimetrically. Extracts were fractionated by adsorption chromatography Hydrocarbons were analyzed with a capillary gas chromatograph equipped with a flame ionization detector and 25-m SE 52 fused silica columns.
23. R. H. Green, Sampling Design and Statistical Methods for Environmental Biologists (Wiley, New York, 1979)
24. J. B. C. Jackson, Bull Mar Sa. 23, (1973); K. L. Heck, Mar. Biol. 41, 335 (1977); R. Vasquez-Montoya, An. Inst. Ciens. Mar Limnol Univ. Nat. Auton Mex. 10, 1 (1983).
This estimate was extrapolated from aerial photographs of 36 km of the 82-km shoreline, of which 76 km contains mangroves Of the photographed shoreline. 36% conrained a band of dead mangroves.
26. Sprouting success was measured for seedlings collected from an unoiled site, and planted in one unoiled and two oiled sites. Of 25 seedlings transplanted into each site, 16 (64%) sprouted at the unouled site and 1 (2%) sprouted at the oiled sites. 27. J. P. Sutherland, Mar. Biol 58, 75 (1980), W. E. Odum, C. C. Mclvor, T. J. Smith III, The Ecology of the Mangroves of South Florida A Community Profile (Publ. 81/24, U.S. Fish Wildlife Service, Washington, DC, 1982).
28. Roots were sampled three times before the spill in rivers and channels (September to October 1981, January 1982, and June 1982) and twice in open habitats (September to October 1981 and January 1982). Several areas of shore within each habitat were chosen haphazardly Fifteen to 25 intertidal roots ≥20 cm long that had not become firmly attached to the mud were lifted from the water, and cover of attached organisms was measured for each root by 100 random point counts after the oil spill or was estimated visually before the spill. Afte the spill, previously sampled riverine and channel habitats included both oiled and unoiled sites but all open sites were oiled. Thus it was necessary to choose sites near Portobelo (Fig. 2).
the nearest equivalent unoiled shoreline, for unoiled open habitat similar to oiled open habitat. One hundred roots were sampled in each oiled and unoiled habitar after the spill.
29. A. K. O'Gower and J. W. Wacasey, Bull. Mar. Sci. 17, 175 (1967); J. B. C Jackson, Mar. Biol: 14, 304 (1972); D. K. Young and M. W. Young, in Ecology of Manne Benthos, B. C. Coull, Ed. (University of South Carolina Press, Columbia, 1977), pp. 359-382; 1. C. Ogden, in Handbook of Seagrass Biology An Ecosystem Perspective, R. C. Phillips and C. P. McRoy, Eds. (Garland, New York, 1980), pp. 173-198, A. W. Stoner, Bull. Mar. Sci. 30, 537 (1980).
30. All seagrass beds sampled lie adjacent to mangrove shoreline and are ≥1 m deep, unoiled beds meeting these criteria occur near Portobelo and Isla Grande (Fig. 2). Infauna were collected with 10.2-cm inside diameter polyvinyl chloride (PVC) tubes pushed into the sediment to a depth of at least 10 cm. Each sample consists of three pooled cores (240 m2). At each census eight samples were collected haphazardly at each site. Samples were sieved over 500-μm mesh and preserved in 10% formalin with rose bengal. Animals were sorted to major taxa and counted or weighed wet.
31. M. B. Bertness; Ecology 62, 751 (1981).
32. J. D. Cubit, in Proceedings of the Fifth International Coral Reef Congress, C. Gabrie, J. L
33. Percent cover of sessile species attached to the substratum was estimated by point
35. R. L. Caldwell and H. Dingle, Sci. Am 234, 80 (January 1976); R. Steger, Ecology
36. M. L. Reaka, in Proceedings of the Fifth International Coral Reef Congress, M. Harmelin Vivien and B. Salvat, Eds (Antenne Museum-Ephe, Moorea, French Polynesia, 1985), vol. 5, pp. 439-444, R. L. Caldwell, G. Rodenck, S. Shuster, lal Zool. Union Mone, in press; R. L. Caldwell, Bull Mar Sa. 41, 135 (1987).
37. The four collection sites ranged from 100 to 125 m x 25 to 40 m (all larger than
39. We estimated growth by comparing the length of the carapace of animals newly
40. Almost every piece of rubble in the heavily ouled plots was covered by hundreds of hermit crabs. Such densites were not observed in unoued plots or in any years previoush
41. See P. W. Glynn (Bull Biol. Soc Wash 2, 13 (1972)] and J. W. Porter (ibid., p. 89) for general descriptions of Panamanian reets. We selected fringing reefs that extended at least 100 m along the shoreline and to a depth of at least 12 m. At each reef four or five line transects were extended from haphazardly chosen points at the shoreward edge of the reet to the deepest point of the reef. Along each line, 1-m2 quadrats were placed contiguously or up to 3 m apart. depending on transect length (8 to 81 quadrats per transect). Quadrats were divided into 100-cm2 cells,
and total cover was estimated by eve within each cell.
42. We determined differences in coral cover before and after the spill (Julv to October
1985 and July to August 1986) by c
(0 to 3, 3 to 6, and 6 to 12 m; prespill «»
43. Dead areas were bare or colonised by thin growth of filaments
colonies of S. siders were sealed in plastic bags underwater, brought laboratory, and placed in clean tanks and seawater. A film of all appeared on thr surface of each tank when the filamentous algae growing over the recently dead areas were squeezed by hand.
44. A. Antonius, in Proceedings of the Fourth International Coral Reef Symp. ED Gomez et al., Eds. (Marine Sciences Center, University of the Philippecs, Quezo City, Philippines, 1981), vol. 2, pp. 3-14, ibid., vol. 2, 7-14.
45. Recent injuries were counted on 12 reefs for all corals in 2 x 50 m haphazardly located at 0 to 1 m and 1 to 2 m depth. Injuries were counted only when the cxposed skeleton was bare or only lightly overgrown by Slamentous algae. Size of injury was visually estimated as percent of the terral surface area of each coral.
46. Significance was tested with hierarchical log-linear models (SPSS/PC-
not distributed equally as a function of amount of oiling for any of the thest coral
47. A. J. Southward and E. C. Southward, J. Fish. Res. Board Can 35, 682 (1978)
49. R. J. Nadeau and E. T. Bergquist, in 1977 Od Spall Conference (Pabc €28€. American Petroleum Institute, Washington, DC, 1977), pp. 535–538. E 1 Chan, bid., pp. 539-542; I. E. G. Cintron and Y. Schaeffer Novelli, UNESCO Tea Pa Mar Sci. 23, 87 (1982).
50. J. H. Vandermeulen, Philos. Trans. R. Soc. London Ser B 297, 335 (1987).
3, 191 (1984), A. H. Knap, Mar. Pollut. Bull. 18, 119 (1987).
54. S. R. Palumbi and J. B. C. Jackson, J. Exp. Mar. Biol. Ecol. 66, 103 (1982), T_P Hughes and J. C. Jackson, Ecol. Monogr. 55, 141 (1985).
55. N. Knowlton, J. C. Lang, M. C. Rooney, P. Clifford, Nator 294, 251 (1981), N Knowlton, J. C. Lang, B. D. Keller, Smithsonian Comer Mar Sc., in press.
56. J. H. Connell, in Population Dynama, R. M. Anderson, B. D. Tumer, L. &... Tark, Eds. (Blackwell Scientific, Oxford, 1979), pp. 141-163, R. T. Pane and 5 A. Levin, Ecol. Monogr. 51, 145 (1981); S. T. A. Pickett and P. S. Whone, The Eunny of Natural Disturbance and Patch Dynamos (Academic Press, Orlando, FL., 1985; 57. R. P. M. Bak, Mar. Polls. Bull. 18, 534 (1987)
58. H. H. Rousseau, in The Panama Canal International Engineeroy Compues (Nical. San Francisco, 1915), pp. 374-432; W. G. Comber, in The Pan Com Engineering Treatise, G. W. Goethals, Ed. (McGraw-Hill, New York, 1916, pp 459-493, D. P. Curry, Am J. Trop. Med. 5, 1 (1925), 1. G. Claybourn, Degung in the Panama Canal (A. Kroch, Chicago, 1931), E. C. Weber, La Defensa de Premie (Editonal Universitaria Panama, Panama, 1973)
59. J. Brawn and R. Green helped with statistics, and G. Jacome, D. Marian, anxi 3. Moss provided technical assistance. B. Carney, D Dodge, R. Grom, 1 Kar. N Knowlton, Y. Loya, and A. Smith reviewed the manascript and helped me other ways. This work was supported by the US. Manerals Management Serve under contract 14-12-0001-30393 and by the Smuchaceae Tropical arch Institute and the Smithsonian Institution Environmental Sciences Program
SCIENCE, VOL. 241