Questions Linger Over Extent of Gulf Spill

Lack of reliable estimates will affect future cleanup plans

27 May 2010

Personnel aboard the NOAA ship, Thomas Jefferson, prepare to launch a glider that belongs to the Naval Oceanographic Office as part of a Gulf of Mexico Loop Current research cruise.

There are no reliable estimates of exactly how much oil has leaked into the Gulf of Mexico since the

April 20 explosion aboard the Deepwater Horizon oil platform.

The fatal disaster sank the rig and left its 1600-meter-deep well gushing plumes of crude oil and natural gas.

So far, the best estimates of how much oil is venting into the Gulf range between 5,000 to 100,000 barrels per day.

Unknown variable

According to BP, the British oil company leasing the ill-fated rig, 5,000 barrels of oil per day are gushing from the broken well.

BP made its calculation - based on observations from ships, airplanes and satellites - of the thickness and extent of the oil slick they saw spreading on the surface and which has now reached Gulf coast shorelines.

University of California earth science professor David Valentine says surface observations, used for tracking oil tanker spills, don't readily apply to the deep ocean.

ASSOCIATED PRESSAn image from a live video feed of the oil plume is seen on BP.com Wednesday, May 26, 2010 before the oil company's planned "top kill" strategy to choke off the gusher. (AP Photo/BP.com)