From today's New York Times:
Scientists are finding enormous oil plumes in the deep waters of the Gulf of Mexico, including one as large as 10 miles long, 3 miles wide and 300 feet thick in spots. The discovery is fresh evidence that the leak from the broken undersea well could be substantially worse than estimates that the government and BP have given (emphasis mine).
The article goes on to say...
The plumes are depleting the oxygen dissolved in the gulf, worrying scientists, who fear that the oxygen level could eventually fall so low as to kill off much of the sea life near the plumes (emphasis mine).
How much oil is really flowing into the gulf?
We don't really know.
Previous estimates were based on satellite images of oil on the surface... but observations of these plumes proves that there's a helluva lot more oil flowing than the government thought, and what BP will admit.
Can we find out?
Again, from the article (again, with my emphasis):
BP has resisted entreaties from scientists that they be allowed to use sophisticated instruments at the ocean floor that would give a far more accurate picture of how much oil is really gushing from the well.
“The answer is no to that,” a BP spokesman, Tom Mueller, said on Saturday. “We’re not going to take any extra efforts now to calculate flow there at this point. It’s not relevant to the response effort, and it might even detract from the response effort.”
Well, Mr. Mueller... it might help when we try to figure out just how badly BP has messed up the planet.