In the two years since the BP oil spill, most scientific research on its effects falls into one of two categories — seafood safety or environmental damage.

Now there are signs science is moving beyond those preliminary assessments to career-defining work that the some researchers don’t want to see misused by others.

That can be difficult in a region known for strong opinions and still divided over whether the Gulf’s message for the rest of the country should be the recovery of its seafood and tourism industries or the possible ecological disaster that may be in its early innings.

Dr. Peter Roopnarine, curator of the California Academy of Sciences (CAS), is one scientist who decided playing offense is the best way to navigate those choppy Gulf waters.

To mark the second anniversary of the Deepwater Horizon explosion, Roopnarine announced his team had detected evidence that pollutants from BP oil have entered the ecosystem’s food chain.

Mother Jones, the activist magazine and website, made its story on Roopnarine’s research its BP oil spill anniversary-day story.

“As if eyeless shrimp, toxic beaches, and dead dolphins weren’t bad enough, a new study suggests Gulf oysters are also in trouble,” MJ reported. The key finding reported was that Roopnarine’s team “measured higher concentrations of vanadium, cobalt, and chromium–three heavy metals present in oil–in the oyster samples after the spill.”

On the first anniversary of the spill, the 150-year-old CAS produced a short movie highlighting the work of three of its researchers, including Roopnarine, where the narrator explained that like tree-rings, heavy metals could be detected and read in oyster shells.

Among the many places where Roopnarine’s work appeared — along with the Mother Jones story, and related reports and comments — was on a rather large email chain shared with many people around the country who are interested in scientific news from the Gulf.

One who took exception to the heavy metals in oysters study was Texas food writer Robb Walsh, who decided both Roopnarine and Mother Jones are hurting the Gulf’s recovery. The author of “Texas Eats” especially took exception to MJ’s headline: “Gulf Oysters Full of Heavy Metals.”

Walsh objected because he thought no oyster shells were included in the study from Gulf areas that were not touched by the oil — like Florida’s Apalachicola Bay. He basically opined that the San Francisco-based CAS should stay home and study SF Bay, “once the greatest oyster reefs in the world,” which he says, “were wiped out a century ago by mining wastes, unfettered pollution and raw sewage.”

“Mother Jones claims to care about the livelihoods of poor oyster fisherman — and then it destroyed the market for their oysters for the sake of a sensational headline,” Walsh said.

In response to Walsh and similar comments, Roopnarine replied to the email exchange,

“We do not claim that GOM (Gulf of Mexico) oysters are unsafe to eat. What we do claim is that the concentration of oil derived heavy metals is greater in oysters collected after May 2010 than they are prior to that, including oysters collected in the 20th century.”

He says oysters from Appalachicola Bay are included in the study and effects of the oil are being found in them. “We also claim that metal concentrations in the post-spill GOM oysters are greater than in oysters collected outside the GOM, specifically controls from North Carolina.”

Roopnarine said people have to make their own decisions about the safety of eating oysters from spill areas, and he asked everyone to “read our work before spewing off.”

But he ends with: “FACT: The metals are there. No amount of ranting, sticking your head in the sand or environmental extremism on the hand, matters. Not in the least.”

Separately from those comments, Roopnarine said: “The bottom line is we don’t know the full impacts of the spill yet, and saying that everything is alright, or that it is a permanent catastrophe, is for you or the folks at Mother Jones.”

He says opinion does not matter in the Gulf. “What matters are the facts that we can uncover.”

A top federal government scientist, not involved in the research, responded by saying there are now “delicate steps” that need to be taken to determine if the heavy metals in oyster shells are “dangerous or harmless” to those who might ingest them.

That scientist says Roopnarine’s research should be put out there for use by others in answering those questions in order to find out whether or not the heavy metals found in the oyster shells move through the food chain.

The April 20 to July 15, 2010 oil spill put about 53,000 barrels of oil per day into the Gulf of Mexico off the coast of Louisiana.

Another prominent recipient of the emails, Oregon First Lady Cylvia Hayes, wrote to all earlier this week to say her thoughts are with the group as it goes through “the emotional challenge of dealing with the oil-related assault on the Gulf Coast.”

It’s a good bet someone will respond to her.