to depths of 1,800 feet. into an underwater geography known to few, like the terrorists and the sticky grounds. here deep in the gulf of mexico where more eels and lionback turtles the size of small cars live there is cautiouses optimism. so far the marine biologists on this mission have found no visible signs of oil. you haven't seen a large underwater plume of oil yet. >> no, thankfully. >> what about the microscopic pieces of oil floating in the gulf? >> we have not seen them yet. they have spread this far, the submersible and another unmanned collection container are gathering water samples at various depth and they're harvesting sponges because living spusks are filter