One of the largest remaining unknowns about the impact of the oil is what it will do to corals and other life at the bottom of the Gulf of Mexico. The communities under the spill are about 1500 meters deep, but life has been found much deeper elsewhere in the ocean, as this handsome chart  shows.
Even in the ocean's deepest trench, about 11 kilometers down, researchers have discovered abundant life. The so-called Challenger Deep contains many kinds of single-celled shelled organisms called foraminifera . Earlier this year, researchers reported  that these deepwater foraminifera build their shells with materials that sink from overlying water.