Though oil had been carelessly carried and spilled the world over long before the 1989 Exxon Valdez disaster in Alaska's Prince William Sound, images of the region's oil slicked and dying sea offers made the point like never before. The past six years have seen some new regulation, including the U.S. Oil Pollution Act of 1990. But as continuing spills and their wildlife victims make clear, oil still is not moved safely. Both tankers ran aground spilling large quantities of oil, contaminating huge areas of shoreline, and killing large numbers of ocean and shore dwelling organisms. The impact of oil on a marine ecosystem is extensive, but is greater on organisms living at or near H the oceans surface.
Oil spills pose an immediate threat to many types of organisms, particularly birds and mammals.
T T are usually estimated by counting the number of oiled birds washed onto beaches, but these estimates often do not include dead birds not reaching shore. The primary effect of oil on birds has been the fouling of feathers, to which oil clings. Birds may sink and drown or may rapidly lose body heat and succumb to pneumonia. Fouled birds exhibit excessive preening, which may disrupt normal feeding activity or result in ingestion of oil. Ingested oil may poison the birds through inflammation of the digestive track or disturb other physiological processes.