The state of the Gulf: Resilient but scarred

(AP) -- From above, five years after the BP well explosion, the Gulf of Mexico looks clean, green and whole again, teeming with life — a testament to the resilience of nature.

But there’s more than surface shimmering blue and emerald to the aftermath of the Deepwater Horizon spill. And it’s not as pretty a picture — nor is it as clear.

There is no single, conclusive answer to how the Gulf of Mexico is doing, but there are many questions. Here are some of them:

WHAT HAPPENED TO DOLPHINS?
Common bottlenose dolphins have been dying at a record rate in northern parts of the Gulf of Mexico since the BP spill, according to NOAA and other scientists who have published studies on the figures. From 2002 to 2009, the Gulf averaged 63 dolphin deaths a year. That rose to 125 in the seven months after the spill in 2010 and 335 in all of 2011, averaging more than 200 a year since April 2010.
That’s the longest and largest dolphin die-off ever recorded in the Gulf. But the number of deaths has started to decline, said Stephanie Venn-Watson, a veterinary epidemiologist at the Marine Mammal Foundation and a lead author of studies on the dolphin mortality.

WHAT HAPPENED TO TURTLES?
The endangered Kemp’s Ridley sea turtle used to look like a success story for biologists. It was in deep trouble and on the endangered list, but a series of actions, such as the use of turtle excluder devices, had the population soaring and it was looking like the species soon would be upgraded to merely threatened, said Selina Saville Heppell, a professor at Oregon State University.
Then, after the spill, the number of nests dropped 40 percent in one year in 2010.

WHAT HAPPENED TO FISH?
University of South Florida marine scientist Steve Murawski sees problems — tumors, lesions and oil traces in internal organs — in key fish such as red snapper, kingsnake eels and especially tilefish. Carcinogenic chemicals associated with oil appear to have gotten through the skin of these bottom-dwelling fish, he said.
“These bottom-feeding fish are still being impacted by the blowout,” Joye said. “Their livers have fresh Macondo oil in them. Clearly that’s a persistent impact.”
BP’s report said commercial catches for finfish “continue to exceed immediate pre-spill levels.”

WHAT HAPPENED TO BIRDS?
There have been at least two surveys of bird populations in Barataria Bay, the scene of the heaviest oiling and an important stopping place for numerous migratory bird species. Those surveys of shore birds and migratory birds found no obvious problems. But a recent study of native seaside sparrows in Barataria has found bird counts down.
HOW ARE THE MARSHES?
An entire mangrove island, an important bird colony, has nearly disappeared under the water. Satellite imagery shows that about a foot of marsh has been eaten away along many shorelines here. In the plants and animals scientists have identified oil contamination and they are tracking its progression in fish, birds, mice, dolphins and insects.
BP said by 2014, “only 0.7 miles remained heavily oiled.”
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WHAT HAPPENED TO TURTLES?
The federal government used a team of scientists to calculate that about 172 million gallons spilled into the Gulf. That figure was peer-reviewed by outside scientists and confirmed by independent researchers, but BP put the number much lower, closer to 100 million gallons.

WHERE DID THE OIL GO?
“It’s not all gone,” said former U.S. Geological Survey chief Marcia McNutt. Her team calculated that most of the oil evaporated, dissolved or dispersed. Two peer-reviewed studies by separate respected teams in 2014 and 2015 found that up to 10 million gallons of oil is left on the seafloor; one of them compared it to a bathtub ring. BP disputed those figures.
“I saw it; I’ve got video of it,” University of Georgia’s Joye said. It’s not liquid or a layer, she said, but splotches like the spatter from a paintball gun.