http://www.mysanantonio.com/
Study: Gulf oil spill might have lasting impact
Updated 08:59 p.m., Tuesday, July 10, 2012
MOBILE, Ala. (AP) – New research by an Auburn University professor and other scientists suggests that the 2010 Gulf of Mexico oil spill may have affected microscopic life in ways that might not become apparent for years. Auburn professor Ken Halanych and scientists from the University of New Hampshire, the University of California Davis Genome Center, and the University of Texas at San Antonio published their work last month in the scientific journal PLoS ONE.
“When the samples were taken, there wasn’t any obvious oil on the beaches, wasn’t anything obvious to indicate that the oil spill had happened,” Halanych said. “When you went outside and looked at it, it looked rather normal. There was clearly (microscopic) community change and hidden effects.”
The Press-Register of Mobile reports (http://bit.ly/PLxU9t) that researchers collected soil samples from five spots around Alabama’s Dauphin Island and Mobile Bay, as well as a persistently oiled beach in Grand Isle, La. What they found, according to their report, was that diverse communities of microscopic animals had given way to fungi, some of which are associated with oil spills.
“Based on this community analysis, our data suggest considerable (hidden) initial impacts across Gulf beaches may be ongoing, despite the disappearance of visible surface oil in the region,” they wrote.
Halanych said the long-term effects could be dramatic because the organisms that lost ground after the spill form the base of the food chain. He noted the collapse of the herring population in Prince William Sound after the Exxon Valdez oil spill in Alaska. It didn’t happen until several years after the 1989 spill, and it has been traced to changes at the microscopic level. “When you change the ecosystem, all these things have a ripple effect,” he told the newspaper. “Some of these effects can take years to develop.”
Patricia Sobecky, who chairs the Biological Sciences Department at the University of Alabama, said the study adds details about a Gulf environment that many scientists say has received too little attention. “What they reported is completely in line with what you would expect,” said Sobecky. “How to interpret that is going to the tricky part.”
Sobecky was not part of the research, but she was part of a team that expects to publish its own paper in PLoS ONE in the coming weeks. She said her work focused on the impact of the oil spill on microscopic life in salt marshes near Bayou La Batre.
Sobecky said the work of Halanych and others is important in helping to establish a baseline to track changes over time.
“I think it will ready us for future events,” she said.
Meanwhile, John Valentine, director of the Dauphin Island Sea Lab, said other research he has reviewed indicates that microbes harmed by the oil spill had rebounded by the end of the year.
“It was pretty clear in the microbial community that there was a pretty dramatic effect immediately after the oil spill,” he said. “It would be interesting to know if (Halanych and his partners) persisted beyond September 2010.” ‘Halanych said he did, in fact, collect samples a full year after the oil spill. But he said he has not yet analyzed the results.
Information from: Press-Register, http://www.al.com/press-register/
Read more: http://www.mysanantonio.com/news/article/Study-Gulf-oil-spill-might-have-lasting-impact-3695961.php#ixzz21HpzEnrr
____________________________
BP Oil Spill May Have Contributed to Dolphin Deaths, Study Finds
By Stephanie Pappas, LiveScience Senior Writer | LiveScience.com – Fri, Jul 20, 2012
The 2010 BP oil spill contributed to an unusually high death rate for dolphins in the Gulf of Mexico, a new study suggests.
Between January and April 2011, 186 dead bottlenose dolphins washed ashore between Louisiana and western Florida. Most alarmingly, nearly half of these casualties were calves, which is more than double the usual proportion of young to old dolphins found dead. Scientists now blame both natural factors and human catastrophe for the unusual die-off.
“Unfortunately, it was a ‘perfect storm’ that led to the dolphin deaths,” study researcher Graham Worthy, a biologist at the University of Central Florida, said in a statement. “The oil spill and cold water of 2010 had already put significant stress on their food resources. Š It appears the high volumes of cold freshwater coming from snowmelt water that pushed through Mobile Bay and Mississippi Sound in 2011 was the final blow.” [Gulf Oil Spill: Animals at Risk]
Cold water and spilled oil
The winter of 2010 was a cold one, the researchers reported July 18 in the open-access journal PLoS ONE. Oil began spilling into the Gulf in April 2011, after the Deepwater Horizon platform exploded following a blowout.
The unusually harsh winter of 2010 already dealt wildlife a disadvantage, Worthy and his colleagues wrote. Finfish, marine birds, sea turtles and manatees had been hit hard, with about 6 percent of the U.S. population of manatees lost to cold weather.
Just before the baby dolphins began washing ashore in January 2011, meltwater from an unusually heavy Mobile Bay watershed snowfall hit the Gulf. A comparison of dolphin stranding sites and water conditions revealed that the discovery of the carcasses followed temperature dips from meltwater by two to three weeks, indicating that the dolphins were stressed, died, washed ashore and were eventually found and recorded.
Normally, the researchers wrote, dolphins are able to withstand fluctuating temperatures. But a National Oceanic and Atmospheric Administration (NOAA) survey of Louisiana dolphins in 2011 found that the animals were overwhelmingly underweight and anemic, suggesting that they were already struggling before the cold water rushed into their habitat.
Stress on wildlife
The findings suggest, but don’t prove, that the BP oil spill may have helped weaken the dolphins before the cold influx of early 2011 began, the researchers report. There is evidence that the oil spill affected the dolphin food chain, making prey scarce in the midst of the breeding season, they wrote. Study leader Ruth Carmichael, a marine scientist at the Dauphin Island Sea Lab, said the combined factors led to distinct patterns in how the dolphins washed ashore.
“When we put the pieces together, it appears that the dolphins were likely weakened by depleted food resources, bacteria or other factors as a result of the 2010 cold winter or oil spill, which made them susceptible to assault by the high volumes of cold freshwater coming from land in 2011,” Carmichael said in a statement.
Follow Stephanie Pappas on Twitter @sipappas or LiveScience @livescience. We’re also on Facebook & Google+.
10 Species You Can Kiss Goodbye
Deepwater Horizon: Images of an Impact
Deep Divers: A Gallery of Dolphins
Special thanks to Richard Charter