NEW ORLEANS — There is oil from the Deepwater Horizon/BP spill buried off the coast of Louisiana, but how much and where it is won’t likely be known until legal cases involving the oil leak are settled, said Edward Overton, Department of Environmental Science professor emeritus at LSU.

Although marsh soil samples taken at the mouth of the Mississippi River and in Barataria Bay in 2011 showed little significant oil, samples taken by other researchers after Hurricane Isaac turned up something different, Overton told scientists attending a Gulf oil leak conference Tuesday.

“There’s this same amount of unweathered oil that came ashore,” Overton said about the chemical signature of what appeared to be fresh oil in the post-Isaac samples. “How much oil was buried (under sediment) is a hot topic and we won’t know that until the case is settled.”

Teams with the Natural Resource Damage Assessment have collected samples as part of the work to determine how much BP will need to pay for damages to natural resources in the wake of the 2010 spill, he said, but that research is part of the legal case and not being made public.

“NRDA has collected those samples but you can’t get folks to talk about it,” Overton said.

The three-day “Gulf of Mexico Oil Spill and Ecosystem Science Conference” brings together scientists across a large spectrum of interests to talk about the work being done and any results about effects of the Deepwater Horizon explosion and subsequent oil leak.

The conference concludes Wednesday.

Other researchers presented their work dealing with the possible effects of dispersants used at the oil leak site and on the water surface as a way to break up the oil particles.

One of those studies examined how different wave action on a beach might affect the ability of an oil or an oil and dispersant mix to penetrate into a sand beach.

Markus Huettel, a Florida State University professor of oceanography, found that the oil and dispersant mix got pushed deeper into the sand with simulated wave action, which could account for layers of oil and sand that were found on some beaches, he said.

Research on the use of dispersants and their impacts is still a mixed bag as far as whether they were positive or negative, said Rita Colwell, research board chairwoman for the Gulf of Mexico Research Initiative.

The initiative was set up to administer $500 million in research funding over 10 years allocated by BP after the oil spill to go directly toward researching the spill’s impacts.

Between 1,400 and 1,500 scientists are currently using a portion of the money to do the research work, Colwell said. The conference is the first in what will be a series of annual meetings to allow researchers to talk about their work and to explore where gaps in the research still exist, Colwell said.

Colwell said about 75 to 100 research papers have been published based on the initiative-funded research.

This year, a couple issues have emerged, including the need to look into questions raised in previous research about dispersant use.

“Now the question is: dispersants good or bad,” Colwell said.

Other issues recognized as in need of future research include the health and socio-economic impacts of the oil spill, Colwell said. Colwell said she wanted to make it clear that the initiative is an independent organization and that although BP provided the money, “BP doesn’t call the shots.”

“The only review of manuscripts are peer review,” she said.