By NewsGram Staff Writer
After the 2010 BP oil spill, Dolphins swimming in the oil-contaminated waters of the Gulf of Mexico have suffered from lung lesions and are dying at high rates because of petroleum pollution, as per a recent study.
More than 1,300 bottlenose dolphins have stranded themselves in the northern Gulf of Mexico since early 2010. The recent research links this unusual mortality event to the massive Deepwater Horizon oil spill.
The rise in the death toll of dolphin began shortly before the spill in April 2010, when 4.9 million barrels of oil was spilled into the ocean, and the scientists have struggled to understand whether the two events are related. According to a report of PLOS ONE, all the underwater animals found dead had lung and adrenal-gland lesions that are consistent with exposure to petroleum compounds.
Stephanie Venn-Watson, a veterinary epidemiologist at the National Marine Mammal Foundation said, “Dolphins take big, deep breaths right at the surface of the water, where oil sheens are most concentrated, and where there is a good chance of inhaling oil itself.”
According to the research which compared autopsies of 46 dolphins that were found dead in the spill area had lesions in the lungs and adrenal glands, which regulate hormones and stress response. That’s when researchers came to know that something is wrong with the dolphins.
Kathleen Colegrove, pathologist at the University of Illinois said, “We found that dolphins that died after the oil spill had distinct adrenal gland and lung lesions that were not present in the stranded dolphins from other areas.”
One out of three stranded dolphins in the spill area had a thinned adrenal gland cortex, a rate that was significantly higher than the reference population of stranded dolphins in Sarasota Bay, Florida, in which one in 10 had such a condition.
Colegrove told reporters during a conference call to discuss the findings, “The thinning of the adrenal gland cortex was a very unusual abnormality for us that has not been previously reported in dolphins in the literature. This is something which is latest in a series of research papers on dolphin health in the region after the spill.”
Other differences were also apparent. More than one in five dolphins from the mass-death group had bacterial pneumonia, a serious lung disease that was severe enough to cause or contribute to the animals’ deaths.
Venn-Watson described that inhaling oil can cause adrenal dysfunction, lung disease and bacterial pneumonia, which is one of the most common outcomes of chemical inhalation injury in other animals. Whereas other diseases like brucellosis and morbillivirus are also responsible for increase in the number of deaths.
A 2013 study on cetaceans in Louisiana’s Barataria Bay, found that dolphins were losing their teeth, had lung lesions and high pervasiveness of disease after the worst oil spill in US history.
Venn-Watson added, “Combination of live and dead dolphin analyses, including the latest study, have provided a strong body of evidence. We feel that this study is a critical link in the chain.”
According to figures from the National Oceanic and Atmospheric Administration (NOAA), minimum 1.300 dolphins have washed up in the area of the Gulf of Mexico since the spill. An additional 114 were stranded from February, two months prior to the spill, until April 20.
Geoff Morell, BP senior vice president for US communications and external affairs said, “This new paper fails to show that the illnesses observed in some dolphins were caused by exposure to Macondo oil.” After BP took the issue to the scientific findings.