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Messy legacy of Gulf oil spill
BILL CURTSINGER/National Geographic Creative
This week driven by other factors? Kimberly Reich and her colleagues at Texas A&M University in Galveston presented data at a February meeting in Houston, Texas, showing that the turtles stopped foraging on the seabed in areas contaminated by oil. But there’s no proof that this affected survival and precipitated the collapse of nest numbers. Other possible factors behind the drop include cold weather and the turtle population outgrowing –Life’s not a beach the gulf’s capacity to support it, two explanations favoured by BP, which owned the oil rig. “Nest counts alone are not enough to point the finger at BP, as there are a number of things on average, from a record low of that could affect nest numbers,” 702 in 1985 to 21,000 in 2009. says Heppell. But, we’ve never Then, in 2010, it all started seen such a dramatic drop in to unravel (see chart, below). one year as in 2010, she says. “Suddenly, the number of nests Also, the recovery came to an counted at the primary nesting abrupt halt, and didn’t slow beaches plummeted by nearly gradually as we might expect if 40 per cent,” says Selina Heppell it were coming to some sort of of Oregon State University in environmental carrying capacity. Corvallis. Although nest numbers “Long-term research is critical returned to 2009 levels in 2011 to finding out the real answer,” and 2012, they did not resume the says Benny Gallaway, president increasing trajectory. “Now, the of LGL Ecological Research number of nests is declining, with Associates in Bryan, Texas. 2014 showing the lowest number But with cuts in turtle research since 2006,” says Heppell. funding from the US Fish and Was the 2010 collapse and Wildlife Service, and secrecy over slowdown in recovery caused by ongoing legal cases against BP, the spill, or was it a coincidence this may prove hard to do. n
Messy legacy of Gulf oil spill Andy Coghlan
THERE’S something amiss with iconic marine animals in the Gulf of Mexico. Five years on from the largest oil spill in US history, effects are still lingering. Sea turtle populations are in retreat, dolphins are in poor shape and whales are avoiding their usual hunting grounds. The explosion of the Deepwater Horizon rig on 20 April 2010 killed 11 workers and the subsequent oil spill wreaked havoc on the region’s wildlife. There was an immediate reverse in the recovery of the world’s most endangered sea turtle. Until that
point, the number of nests of the Kemp’s ridley turtle, which neared extinction in the 1980s, had been growing for two decades. To what extent the oil disaster is to blame is still under debate, but the matter is shrouded in mystery, partly because ongoing litigation over compensation means that few scientists are prepared to discuss their data publicly. Most Kemp’s ridleys lay their eggs on beaches in the Tamaulipas region of northeastern Mexico. A joint Mexican and US programme, launched in 1978, had put the turtles on the route to recovery: the number of nests rose by 15 per cent per year
Slickstory story Slick Slick story
Beyond turtles
Therise risein inthe the number ofKemp’s Kemp’s ridley turtle nests theTamaulipas Tamaulipas The number turtle nests ininthe The rise in theof number ofridley Kemp’s ridley turtle nests in the Tamaulipas andVeracruz Veracruz regionsof ofMexico Mexico took hit 2010, the Deepwater and regions aahit inin2010, the Deepwater and Veracruz regions oftook Mexico took a hit when inwhen 2010, when the Deepwater Horizonoil oilspill spilloccured occured Horizon Horizon oil spill occured
TURTLES aren’t the only animals that seem to have been affected by the 2010 Deepwater Horizon oil spill. In February, at the 2015 Gulf of Mexico Oil Spill & Ecosystem Science Conference in Houston, Texas, several teams presented data on large mammals. Bottlenose dolphins caught between 2011 and 2014 in Barataria Bay, Louisiana – close to the spill zone – were more likely to have lung disease and poor body condition than those caught in Sarasota Bay in Florida, which was unaffected by the spill. Those from the spill zone had
Number of nests (thousands)
Number Number of of nests nests (thousands) (thousands)
30 30
20 20
10 10
Gulfof ofMexico Mexico Gulf Gulf of Mexico Deepwater Deepwater Deepwater HorizonHorizon oilspill spill oil spill Horizon oil
30
Afterthe the 2010 dip, nestdip, numbers After 2010 dip, nest numbers After the 2010 nest numbers 20 bouncedbounced backinin2011 2011 and 2012, but bounced back 2012, but backand in 2011 and 2012, but dippedagain again 2013.The The drop looks dipped inin2013. drop looks dipped again in 2013. The drop looks likelyto tohave havecontinued continued 2014 in 2014 likely inin2014 likely to have continued 10
00 0 1980 1980 1980
1990 1990
1990 Year Year
2000 2000 2000 Year
SOURCE: MARINE TURTLE NEWSLETTER 143:1-7, 2014/WWW.NMFS.NOAA.GOV SOURCE: MARINE TURTLE NEWSLETTER 2014/WWW.NMFS.NOAA.GOV SOURCE: MARINE TURTLE143:1-7, NEWSLETTER 143:1-7, 2014/WWW.NMFS.NOAA.GOV
16 | NewScientist | 25 April 2015
2010 2010
2010
changes in their immune system that left them more vulnerable to bacterial infections, especially Brucella, which is linked with newborn dolphin deaths. And six sperm whales, tracked between 2010 and 2013, didn’t forage in a region of the seabed that covered 4000 square kilometres and included the spill site, an area whales had been tracked visiting between 2001 and 2005. This could be because contamination has reduced bottom-dwelling fish and the squid that feed on them, which are in turn prey for whales.
This week driven by other factors? Kimberly Reich and her colleagues at Texas A&M University in Galveston presented data at a February meeting in Houston, Texas, showing that the turtles stopped foraging on the seabed in areas contaminated by oil. But there’s no proof that this affected survival and precipitated the collapse of nest numbers. Other possible factors behind the drop include cold weather and the turtle population outgrowing –Life’s not a beach the gulf’s capacity to support it, two explanations favoured by BP, which owned the oil rig. “Nest counts alone are not enough to point the finger at BP, as there are a number of things on average, from a record low of that could affect nest numbers,” 702 in 1985 to 21,000 in 2009. says Heppell. But, we’ve never Then, in 2010, it all started seen such a dramatic drop in to unravel (see chart, below). one year as in 2010, she says. “Suddenly, the number of nests Also, the recovery came to an counted at the primary nesting abrupt halt, and didn’t slow beaches plummeted by nearly gradually as we might expect if 40 per cent,” says Selina Heppell it were coming to some sort of of Oregon State University in environmental carrying capacity. Corvallis. Although nest numbers “Long-term research is critical returned to 2009 levels in 2011 to finding out the real answer,” and 2012, they did not resume the says Benny Gallaway, president increasing trajectory. “Now, the of LGL Ecological Research number of nests is declining, with Associates in Bryan, Texas. 2014 showing the lowest number But with cuts in turtle research since 2006,” says Heppell. funding from the US Fish and Was the 2010 collapse and Wildlife Service, and secrecy over slowdown in recovery caused by ongoing legal cases against BP, the spill, or was it a coincidence this may prove hard to do. n
Messy legacy of Gulf oil spill Andy Coghlan
THERE’S something amiss with iconic marine animals in the Gulf of Mexico. Five years on from the largest oil spill in US history, effects are still lingering. Sea turtle populations are in retreat, dolphins are in poor shape and whales are avoiding their usual hunting grounds. The explosion of the Deepwater Horizon rig on 20 April 2010 killed 11 workers and the subsequent oil spill wreaked havoc on the region’s wildlife. There was an immediate reverse in the recovery of the world’s most endangered sea turtle. Until that
point, the number of nests of the Kemp’s ridley turtle, which neared extinction in the 1980s, had been growing for two decades. To what extent the oil disaster is to blame is still under debate, but the matter is shrouded in mystery, partly because ongoing litigation over compensation means that few scientists are prepared to discuss their data publicly. Most Kemp’s ridleys lay their eggs on beaches in the Tamaulipas region of northeastern Mexico. A joint Mexican and US programme, launched in 1978, had put the turtles on the route to recovery: the number of nests rose by 15 per cent per year
Slickstory story Slick Slick story
Beyond turtles
Therise risein inthe the number ofKemp’s Kemp’s ridley turtle nests theTamaulipas Tamaulipas The number turtle nests ininthe The rise in theof number ofridley Kemp’s ridley turtle nests in the Tamaulipas andVeracruz Veracruz regionsof ofMexico Mexico took hit 2010, the Deepwater and regions aahit inin2010, the Deepwater and Veracruz regions oftook Mexico took a hit when inwhen 2010, when the Deepwater Horizonoil oilspill spilloccured occured Horizon Horizon oil spill occured
TURTLES aren’t the only animals that seem to have been affected by the 2010 Deepwater Horizon oil spill. In February, at the 2015 Gulf of Mexico Oil Spill & Ecosystem Science Conference in Houston, Texas, several teams presented data on large mammals. Bottlenose dolphins caught between 2011 and 2014 in Barataria Bay, Louisiana – close to the spill zone – were more likely to have lung disease and poor body condition than those caught in Sarasota Bay in Florida, which was unaffected by the spill. Those from the spill zone had
Number of nests (thousands)
Number Number of of nests nests (thousands) (thousands)
30 30
20 20
10 10
Gulfof ofMexico Mexico Gulf Gulf of Mexico Deepwater Deepwater Deepwater HorizonHorizon oilspill spill oil spill Horizon oil
30
Afterthe the 2010 dip, nestdip, numbers After 2010 dip, nest numbers After the 2010 nest numbers 20 bouncedbounced backinin2011 2011 and 2012, but bounced back 2012, but backand in 2011 and 2012, but dippedagain again 2013.The The drop looks dipped inin2013. drop looks dipped again in 2013. The drop looks likelyto tohave havecontinued continued 2014 in 2014 likely inin2014 likely to have continued 10
00 0 1980 1980 1980
1990 1990
1990 Year Year
2000 2000 2000 Year
SOURCE: MARINE TURTLE NEWSLETTER 143:1-7, 2014/WWW.NMFS.NOAA.GOV SOURCE: MARINE TURTLE NEWSLETTER 2014/WWW.NMFS.NOAA.GOV SOURCE: MARINE TURTLE143:1-7, NEWSLETTER 143:1-7, 2014/WWW.NMFS.NOAA.GOV
16 | NewScientist | 25 April 2015
2010 2010
2010
changes in their immune system that left them more vulnerable to bacterial infections, especially Brucella, which is linked with newborn dolphin deaths. And six sperm whales, tracked between 2010 and 2013, didn’t forage in a region of the seabed that covered 4000 square kilometres and included the spill site, an area whales had been tracked visiting between 2001 and 2005. This could be because contamination has reduced bottom-dwelling fish and the squid that feed on them, which are in turn prey for whales.