Friday, May 26, 2006
According to a follow-up study by Short published in Environmental Science and Technology, oil from the spill remains throughout the tidal zone of Prince William Sound, which may explain why sea otters and ducks in that area have recovered more slowly than other nearby populations. Thousands of sea otters, seals, birds and other marine species died immediately after 11 million gallons of oil were spilled from the Exxon Valdez. Oil continued to be found in the area over the next decade, but most researchers believed it was confined mainly to the high tidal regions, where the shore is only covered with water at high tide -- which should not have affected sea otters and marine ducks that frequent lower tidal regions. Over the past few years, studies by Short and his colleagues determined that a significant percentage of areas (about 10%) have subsurface oil in lower, middle, and higher tidal zones. Short's new study estimates that sea otters dig three pits a day and encounter oil about once every two months. These encounters likely explain why sea otters and sea ducks have not been reproducing successfully in the area.