Six years on, scientists are continuing to tally the ecological harms caused by the deadly 2010 Deepwater Horizon oil spill in the Gulf of Mexico.
The latest glimpse at the ongoing environmental impacts of the disaster came in a new report by the conservation and advocacy group Oceana, which compiled the findings of a broad range of studies — primarily from the past two years — examining the aftermath of the spill. The report makes clear that the reach of the disaster, which ranks as one of the costliest environmental catastrophes ever, continues to grow.
Among the effects highlighted in the recent report:
▪ Years after the spill, scientists detected hydrocarbons from the Deepwater Horizon spill in 90 percent of pelican eggs tested in Minnesota — more than 1,000 miles away — where many birds that winter in the Gulf of Mexico spend their summers. In addition, the chemical dispersant used to break up oil in the wake of the spill was found in about 80 percent of the eggs. Researchers say that exposing bird eggs to oil can cause birth defects and premature deaths in offspring. Scientists are continuing to study the problem.
▪ Endangered sea turtles that had migrated to the Gulf from West Africa, South America and elsewhere died as a result of the spill, underscoring the global ripple effects of the disaster. Roughly 75 percent of the sea turtles that died following the Deepwater Horizon spill were Kemp’s ridley turtles — among the smallest and most endangered species in the world. Scientists have estimated that four times as many Kemp’s ridley sea turtles died in 2010, about 65,000, than in the year prior to the oil spill.
▪ Bottlenose dolphins living in Barataria Bay, La. — an area heavily affected by the oil spill — had mortality rates 8 percent higher than dolphin populations elsewhere. But their “reproductive success” dropped a startling 63 percent, according to a team of researchers. “Several years after the spill, pregnant bottlenose dolphins only gave birth to healthy calves 20 percent of the time, compared to 83 percent prior to the oil spill,” the report found.
▪ A long list of fish, from bluefin tuna to sharks to shellfish, were exposed to oil from the spill, with potentially devastating consequences. The Oceana report details varied scientific research that has documented heart failure in juvenile bluefin and yellowfin tuna, as well as hindered swimming ability in juvenile mahi-mahi fish caused by gill tissue damage. “The consistency of serious negative effects in embryonic heart development in tuna species indicates that many other large fish species spawning at the same time in the oiled areas also faced high rates of juvenile mortality, including swordfish and billfish,” the report states.
▪ A separate report released this month by Florida International University’s Southeast Environmental Research Center found while crude oil alone didn’t cause significant harm to moon jellyfish — a species commonly found in the Gulf of Mexico where the spill occurred — the chemical used to disperse oil following the 2010 Deepwater Horizon oil spill caused changes in color of jellyfish, irregularities in their bell shape and even death. “The use of dispersant in response to an oil spill is generally regarded as the best option to reduce biological impact and protect shoreline habitats, but it comes with tradeoffs,” Gary Rand, co-author of that study, said in a statement.
The Oceana report, which also details the ongoing human, economic and environmental fallout from the 2010 oil spill, comes amid additional findings that said far more coastline was affected by the catastrophe than experts initially thought. Scientists from the National Oceanic and Atmospheric Administration, along with several private research companies, recently reported finding oil along more than 1,300 miles of shoreline (out of 5,930 miles surveyed) after the spill. The area spanned numerous states, from Texas to Florida.
The recent findings also seem largely in line with a massive damage assessment published by the federal government earlier this year.
“Unprecedented in both scope and nature, the Deepwater Horizon oil spill was the largest offshore oil spill in U.S. history. The spill dealt a heavy blow to the Gulf Coast region natural resources and its natural resource-dependent economy,” the assessment found. “The oil came into contact with and injured natural resources as diverse as deep-sea coral, fish and shellfish, productive wetland habitats, sandy beaches, birds, endangered sea turtles and protected marine life. The oil spill prevented people from fishing, going to the beach and enjoying their typical recreational activities along the Gulf of Mexico. Extensive response actions, including cleanup activities and actions to try to prevent the oil from reaching sensitive resources, were undertaken to try to reduce harm to people and the environment. However, many of these response actions had collateral impacts on the environment.”