The 2010 Deepwater Horizon oil spill may have had a global impact as its effects are now seen in the unusual travel routes of sea turtles.
A computer simulation suggests that around 300,000 turtles were in the Gulf of Mexico at that time – a region affected by the oil spill. Nathan Putman, a biologist at the University of Miami, said that rehabilitation efforts after the BP oils spill should go beyond the Gold Coast of the United States.
On April 20, 2010, the Deepwater Horizon oil rig was affected by an explosion, which caused oil to pour out from the well. This lasted for almost four months, until July 15.
It is possible that the high mortality rate of bottlenose dolphin calves is due to long-term impact of the oil spill, the researchers said.
Sea turtles can also be affected by oil spill, which coats their bodies causing organ damage and inflammation. Turtles can even be impacted indirectly since the animals they feed on are also affected by oil spills; thus the food resources slowly vanish. The seaweed, which baby turtles use as camouflage, is also killed by oil spills, leaving the turtles exposed to predators.
The National Wildlife Foundation stated that after the Deepwater Horizon spill, sea turtle stranding occurred five times more often than usual. Stranding suggests impacts that take place far from shore.
In the study – published December 22 in the journal Biology Letters – the researchers used computer simulation that was based on ocean currents. Virtual particles (that represented the turtles) were released into the region affected by the BP Oil Spill. To see where the turtles came from, the researchers then backtracked to five year of data on ocean currents.
The results showed that between April 2010 and August 2010, there were 3,693 Kemp’s ridley turtles (Lepidochelys kempii) and 175,064 green turtles (Chelonia mydas) in the affected area. A previous research group found that there were 30,800 loggerhead turtles in the area and 154,000 green turtles. The results were based on in-water estimated.
Real-world estimates suggested a number of about 217,000 Kemp’s ridley turtles, which is significantly different from what the computer simulations found – about 3,693 turtles. Putman adjusted the model, bringing both of the estimates in line.
The computer model was also able to show where the turtles came from, unlike the real-world estimates. In 2010 the turtles likely travelled from Mexico to the affected area. These included: more than 99 percent of Kemp’s ridleys, 60 to 66 percent of loggerheads, and 43 to 63 percent of greens.
About 16 percent of the green turtles came from Suriname in South America, and 33 percent from Costa Rica, the researchers found. Approximately 4 percent of them may have come from Guinea Bissau in West Africa.
Image Source: fineartamerica