July 19, 2010
Oil Spill Could Have Long-term Effect On Marine Life
The massive BP oil spill has scientists and experts fearing a decades-long "cascading" effect on marine life that could lead to alterations in the entire biological network in the Gulf of Mexico.
With more than 400 species at risk in the Gulf -- from bacteria to shrimp and crabs, sea turtles, marine birds and sperm whales -- experts warn that the impact of oil and chemical dispersants on the food chain has already set in, and could grow exponentially.Ron Kendall, director of the Institute of Environmental and Human Health at Texas Tech University, told the AFP news agency that a "major environmental experiment is underway."
"We are already impacting the base of the food chain," he said, including plankton, which provide crucial food for fish, and juvenile shrimp in intertidal marshes along the Gulf Coast.
Kendall helped study effects of the 1989 Exxon Valdez oil disaster on wildlife in Alaska's Prince William Sound. With that disaster, a finite amount of oil poured into the sea -- about one 17th of that which has gushed from the Gulf of Mexico ruptured well -- and rose to the surface to coat the shoreline.
"This is so much more complex, what we're dealing with now," he said.
The nearly 2 million gallons of chemical dispersants used to fight the spill have kept some oil from contaminating shores, but have also created potentially drastic problems by breaking up the oil into droplets that may never be recovered.
Kendall explained that the dispersants release aromatic hydrocarbons and allow small oil droplets to be consumed by marine life, which can potentially threaten the food supply for humans.
No contaminated Gulf seafood has reached markets yet, according to experts, but authorities have closed 35 percent of all fishing waters, threatening the livelihoods of thousands and putting the region's seafood industry in peril.
Researchers say they have observed major die-offs of organisms such as pyrosomes, cucumber-shaped creatures that are favorite meals of endangered sea turtles, which have been dying by the hundreds.
"We're at the early stages of documenting the scientific effects of what's occurring," said Kendall, who acknowledged that species shifts are very possible.
The US government and BP say they have found more than 2,600 dead marine birds, mammals and turtles, but that could only be the tip of the iceberg, warned Doug Inkley, senior scientist at the National Wildlife Federation.
Many fish and sharks sink when they die, so their numbers may never be accounted for.
Inkley fears there may be a delayed disaster in the Gulf, similar to when Prince William Sound's Pacific herring population collapsed four years after the Exxon Valdez spill, likely due to few of the herring that spawned in 1989 reached maturity.
Many marine and bird species were beginning their breeding season in April when the Deepwater Horizon rig exploded and sank, setting off the huge disaster. It is possible that a population crash may occur later "because of the failure of many of the young to survive this year," Inkley said, adding that he expects the impact on wildlife "will last for years, if not decades."
Congressman Ed Markey, chairman of a House subcommittee on energy and the environment, said in a letter to the FDA that evidence showed "the marine food chain in the Gulf of Mexico has already been contaminated." He pointed out research that has found uncovered oil droplets found inside crab larvae harvested in the Gulf.
"This finding is particularly disconcerting because these larvae are a source of food for numerous aquatic species and this is therefore the first sign that hydrocarbons have entered into the food web," Markey said.
Complicating the scenario, the Gulf will soon host millions of fowl on autumn and winter migrations.
"Who knows what impact that will bring?" Kendall lamented.
Image Caption: A controlled burn of oil from the Deepwater Horizon/BP oil spill sends towers of fire hundreds of feet into the air over the Gulf of Mexico June 9. Coast Guard Photo by Petty Officer First Class John Masson.
On the Net:
- Government Response Website
- Institute of Environmental and Human Health, Texas Tech University
- National Wildlife Federation