This in today's NYTimes -- "Scientists are finding enormous oil plumes in the deep water of the Gulf of Mexico, including one as large as 10 miles long, 3 miles wide and 300 feet thick in spots ... There's a tremendous amount of oil in multiple layers, three or four or five layers deep in the water column." (note that in the illustration above -- click to enlarge -- the subsurface oil plumes represented are nowhere near as massive as those being detected in the Gulf.)
The initial conservative estimate of oil volume being released from the wellhead following the British Petroleum disaster was roughly 5000 barrels of oil per day. The discovery of subsurface oil plumes raises the calculated rate of flow to between 25,000 to 80,000 barrels of oil per day. BP has consistently stonewalled appeals by independent oceanographers to sample and examine the actual flow at the well site.
In addition to oil contamination of the Gulf, adjacent beaches and wetlands, and both sea and land-dwelling wildlife, the dispersants being used by BP to break up oil into smaller particles are themselves contaminating the Gulf. Another effect has been the depletion of oxygen in the water. Since it takes oxygen a long time to circulate from the surface to the sea botttom (at the well site, a mile deep), we are face with the looming prospect of a dead zone of immense proportions (see sample map below).
The corporate and governmental shining lights, whose neglect and willful malfeasance have created this catastrophe, must be held accountable not only for the cleanup, but also for the restoration of both marine and shore habitat to its former state. Their decisions have been morally bankrupt and environmentally catastrophic. BP has promised to pay for all cleanup costs. I'm skeptical of the promise, since we're only beginning to understand the ongoing ripple effects of offshore drilling gone wrong. Corporate (BP, Transocean and Halliburton) and governmental agency (Minerals Management Service) behavior has been criminal, and fines are insufficient consequence. Prison time is called for, and let them drink crude oil-contaminated water with all their prison meals.