bers on how much oil is still out there, it's also hard to get a firm fix on the risks &#151; if any &#151; the remaining crude presents to the Gulf environment. These plumes aren't underwater rivers of oil &#151; they're likely invisible and represent mere parts per billion of oil in the water. "No one is saying it's all doom or gloom, but no one here is saying the oil is all gone either," says Joye, who will be part of a new UGA expedition to the Gulf leaving later this week. "We're trying to point out th