This article doesn't pass the smell test for a few reasons.
a) Everything i've heard so far about the dissolved methane has been pretty positive. e.g. http://www.upstreamonline.com/incoming/article240856.ece
The current article doesn't make anything but a FUD statement that the methane is "a big deal".
b) Having watched live video feeds (for hundreds of hours (Go CRAW! )) from the well area during the capping process two things don't jive: First of all the area immediately around the well, say within 200m or so didn't have anything living on it. It was just mud. Occasionally (maybe once a day at most ) a fish , squid or shark would swim by, but that's it. No crabs, sea cucumbers, corals or anything else were on the bottom. This is probably because it was all at 5000 ft depth where there's no light and not a whole heck of a lot going on. Second, even around the well there was no actual oil visible.
c) I'm glad they took samples over "2600 square miles". What percentage of the area was impacted ? where ? over such a huge area even if all the oil had sunk straight to the bottom it would be a vanishingly small amount. certainly not enough to "choke off" anything. Also, as noted in point "b" the corals and sea stars etc would have to be some distance away from the well anyway because coral needs sunlight... which doesn't exist 1 mile down.
d) there's no mention of just how many natural oil and gas seeps there are in the GOM. (answer: thousands). Let's wait and see if those samples really show that the oil is from the mc 252 well.
i fully believe that some of the oil ended up on the bottom and that it's caused damage, but on the balance whatever truth there may be in this article is being spun in a misleading and scare-mongering way. The GOM is open for shrimping and the shrimp is testing out fine.