"This was an event that none of us were prepared for or had ever experienced in the past, including many of the federal administrators who had to deal with it," said Lohrenz. Academic researchers, who were among the first on the site, played "a critical role" from the beginning, he said. They complement the federal science teams, which are often more "mission oriented," while the academics are more "hypothesis driven" and may be more flexible regarding the hypotheses they formulate.

Early on, there were some "contentious interactions" between government and academic scientists. "That climate has now changed," added Lohrenz, saying that the two groups are now working cooperatively.

The latest estimate of the extent of the spill is around 200 million gallons of oil, plus or minus 10%, over 86 days, according to Lohrenz. He compared it to the Ixtoc I spill in the southern Gulf of around 140 million gallons over nine months, the Exxon Valdez spill of 10 million gallons in a relatively confined area in Alaska, and the normal seepage in the Gulf of 23 to 58 million gallons each year.

A published assessment by the US National Oceanic and Atmospheric Administration (NOAA) on the fate of the spilled oil "upset a lot of people", Lohrenz said, because it was released without having been properly vetted in the scientific community and was based on many questionable assumptions. He said that the assessment was intended to allay public fears about "a catastrophic death of the ecosystem", which fortunately did not happen.

Recent research establishes that some marshy areas off the Louisiana coast still have substantial amounts of oil. In one test area, Dry Bread Island, oil has seeped deep into the grasslands, but not uniformly, Lohrenz said. Scientists are comparing the fate of marine life in both affected and unaffected areas. Plants are expected to cope better than animal life, explained Lohrenz. Oil rides in with the tides but stays on the surface of the water, so although it may kill grasses, their root systems can survive and regenerate.

Scientists modeled the movement of oil by using dye to simulate the hydrocarbon. When applied to an ocean circulation model, a result emerged in which oil covered much of the Gulf's surface and extended up the east coast of the US. Unfortunately, said Lohrenz, much of the public understood this to be a prediction, but it was actually a worst-case, and unlikely, scenario.

So what's next? Future research will probably focus on the effect of the oil spill on sediments, said Lohrenz. The US National Science Foundation and other government agencies are investing substantial new sums in on-going research, along with $500 m to be provided by BP for independent researchers to study long-term effects of the oil spill.

Huge quantities of samples and massive amounts of data have been collected and await analysis, a process that will continue for years, said Lohrenz. "If anything good comes out of [the oil spill], people are going to have a much better understanding of the ocean and its importance and some of the dynamics that occur in that system."

Deepwater Horizon Oil Spill: ERL Call for Papers. Environmental Research Letters (ERL) – environmentalresearchweb's sister product – would like to invite you to submit your research into the effects of the Deepwater Gulf oil spill to a dedicated focus issue. This issue will build a collection of research on the initial impacts of the disaster and it is the perfect forum to present your work to a massive global audience.