An estimated 42,000 gallons of oil have been gushing into Gulf waters daily since the Deepwater Horizon exploded and sank to the sea floor last week. Eleven crew members were killed in the blast, and several others were injured, and experts fear the spill threatens marine life across the region, particularly on the Chandeleur and Breton barrier islands in Louisiana. In this image, taken by NASA's Aqua satellite, the swirling sheen of oil is seen in the lower right corner, about 40 miles from the Delta National Wildlife Refuge.