As oil nears coast, some experts say the Gulf's marshland is particularly vulnerable.
Jessica Marshall, from Discovery News, reports on why oil and marshes don't mix:
In this case, marshes along the coast are most threatened by the oil's arrival. Oil that settles on the surface of sandy beaches and can be bulldozed away. Oil-coated rocks can be removed.
"If the oil gets into the marsh, that's a totally different scenario. That's much more difficult to deal with," Kinner said. "Unfortunately, most of the area where that oil is going is to these marshes."