* More data needed on pre-spill ecosystems, U.S. government scientists say
* Deepwater Horizon case highlights need for preparedness, cooperation
By Environment Correspondent Deborah Zabarenko
WASHINGTON, Dec 3 (Reuters) - One lesson learned from the deadly 2010 Deepwater Horizon spill is the need to gauge how much oil is leaking from a blown-out well, prompting U.S. government scientists to recommend all future drilling permits require mechanisms to assess the flow rate.
Figuring out the flow rate was a key problem during and after the 2010 spill in the Gulf of Mexico, according to Jane Lubchenco, who heads the National Oceanic and Atmospheric Administration and played a key role in the U.S. response to the disaster.
Lubchenco is the lead author of one of 15 scholarly articles published Monday in the Proceedings of the National Academy of Sciences journal as a special feature on how science figured in the response to the Deepwater Horizon spill.
"Because the oil was flowing almost a mile down, it was very, very difficult to get accurate information about the flow rate," Lubchenco told Reuters in a telephone interview.
U.S. officials managing a massive containment operation in 2010 were in the delicate position of relying on well-flow estimates from BP executives who had a vested interest in downplaying the severity of the leak. A New Orleans grand jury has indicted David Rainey, former head of BP's Gulf of Mexico exploration, on charges of falsifying flow data provided to U.S. lawmakers.
BP originally estimated that 5,000 barrels of crude were leaking from the well. Government estimates indicated the flow was greater than 10 times that rate - 53,000 barrels a day when the well was capped in July 2010.
"After the first couple of announcements were made about the flow rate, the government quickly realized we did not have a good handle on the number and needed solid evidence to back it up," Lubchenco said.
Government scientists took the time to get an accurate estimate, despite widespread frustration at how long it took, she said.
"It is reasonable to suggest that future permits be conditional on having mechanisms to rapidly assess flow rate to ameliorate the problem in the future," the scientists wrote in one of the journal reports.
The reports were released five days after the U.S. Environmental Protection Agency suspended BP from obtaining new U.S. contracts due to its "lack of business integrity" after the Deepwater Horizon accident, which killed 11 men and caused the biggest-ever U.S. offshore oil spill.
Determining the flow rate proved difficult, but scientists eventually figured out how to assess it in a variety of ways, including by measuring chemicals in the air hundreds of feet above the water's surface.
Another method of estimating the flow rate was based on proprietary data from BP about pressure in the undersea reservoir of oil and conditions in the pipes in the well, said Marcia McNutt, director of the U.S. Geological Survey, another central player in the government's response effort.
BP's information "could have given us a ballpark number of how much the flow rate would have been, even before the well blew out," McNutt said in a telephone interview. "One of the strong recommendations we had was that before a well is even put into production, that analysis should be done and on hand."
McNutt, lead author of another article in the journal, said one discovery was that dispersant chemicals used to break up the oil in the deep water made a positive difference.
Dispersants spread by underwater robots meant less oil and volatile organic compounds reached the surface, cutting down on chemicals that could affect human health, McNutt said.
The scientists recommended getting baseline information about the ecosystems in all regions at risk of a spill, information they lacked in the Deepwater Horizon case.
"In any spill, you want to understand what's the (environmental) impact, and you aren't going to know that unless you understand what's the condition of the ecosystem before the oil gets there," McNutt said.
They also recommended developing new technologies to spur a fast and robust response; getting more information on how oil, a changing climate and other factors affect wildlife in coastal and aquatic ecosystems; and researching how dispersant chemicals affect a wide range of species at various stages of their lives.
The response to the BP spill showed the benefits of advance preparation and coordination among government, academic and corporate experts, the reports found.