Federally-funded scientists predicted a "larger than average" dead zone in the Gulf of Mexico this year, but said it's unclear what the oil spill's effects on the dead zone will be.

Dead zones are underwater areas where oxygen levels are so depleted that they're inhospitable to most marine life. According to the National Oceanic and Atmospheric Administration, these hypoxic (or low-oxygen) areas develop in the Gulf every summer. (Quick science lesson: Typically, nutrient runoff stimulates growth of algae that gets decomposed by oxygen-consuming bacteria, leading to dead zones.)

Here's NOAA, quoting one of the scientists:

"The oil spill could enhance the size of the hypoxic zone through the microbial breakdown of oil, which consumes oxygen, but the oil could also limit the growth of the hypoxia-fueling algae," said R. Eugene Turner, Ph.D., professor of oceanography at Louisiana State University. "It is clear, however, that the combination of the hypoxic zone and the oil spill is not good for local fisheries."

These scientists, however, made no mention of the "astonishingly high" levels of methane gas found by another crew of scientists-levels that were as much as 1 million times normal levels in some areas of the Gulf.

Methane, a primary component of natural gas, accounts for anywhere from 40 to 70 percent of the flow from BP's well.

According to John Kessler, a Texas A&M University oceanography professor, all this extra methane could spur the growth of bacteria that consume oxygen, exacerbating the oxygen problem.

BP spokesman Mark Proegler disputed the suggestion that the Gulf's deep waters harbor large amounts of methane. He told the Associated Press that the company is burning off gas at the surface, and that "the gas that escapes, what we don't flare, goes up to the surface and is gone."