"CSI: Gulf of Mexico"
Seems like the folks who run the oil industry and prosper handsomely from it would like us to believe that as well. Not so fast say researchers at the Woods Hole Oceanographic Institution. (GW)
Woods Hole scientists probe seafloor
WOODS HOLE — Consider it "CSI: Gulf of Mexico."
A team of scientists, including researchers from the Woods Hole Oceanographic Institution, spent 10 days this month exploring dead and dying coral on the seafloor near BP's ruptured Deepwater Horizon oil well, which leaked millions of gallons of oil into the Gulf.
The expedition was a collaborative effort that included personnel from Temple University and Pennsylvania State University and was funded by the National Science Foundation. The mission was to record the effects of the oil spill on plant and animal life in the deep sea and determine if the oil from BP's well — known as Macondo 252 — is to blame for the degradation of plants and animals living in the deep ocean.
"We're treating it like we effectively have a crime scene here," said Timothy Shank, a WHOI biologist and co-investigator on the expedition.
The Deepwater Horizon oil spill occurred on April 20 and is one of the worst in history. According to the WHOI expedition website, the well spewed 152 million gallons of oil into the Gulf over three months before it was capped.
Laying the groundwork
Chris Reddy, a WHOI marine chemist who has studied the Gulf oil spill at length, did not participate in the trip but said the work his colleagues are doing is "unprecedented," because an oil spill of this magnitude has never occurred in the deep ocean.
Reddy, who served as a national spokesman for WHOI in the months following the Gulf spill, said identifying where the oil went and the potential impacts on deep-sea ecosystems is a crucial component to the area's eventual recovery.
It also provides scientists a "living laboratory" in which they can view how sea life responds if it has been exposed to oil, Reddy said.
"This investigation will help lay the groundwork regarding the damage and how this might affect the rest of the Gulf and on what scale," Reddy said. "It's hard to find a silver lining in this awful cloud, but at the end of the day, we have an opportunity to expand science and help decision-makers make new policy."
The team found dead and dying coral covered in a "brown substance" roughly seven miles southwest of the spill site, at a depth of approximately 4,500 feet, Shank said.
They used the famed submersible Alvin to view the corals firsthand and collect evidence. The samples retrieved from the site show "a mixture of characters that suggest impact," such as "tissue sloughing off and exposed skeleton," Shank said.
Although tests have not officially determined what the substance is or why the coral is dying, Shank said it is a curious sight.
"Coral secretes mucous, so we thought maybe it's just stressed out from predators," he said. "But the reality is we've never seen the brown stuff before."
Robots down under
But before scientists could determine what, if any, damage was caused by the spill, Shank said they first had to know where to look.
The most effective way to accomplish that was a two-pronged approach using a pair of WHOI's most valuable submersibles — Alvin and Sentry.
Alvin — famous for being used to explore RMS Titanic in 1986 — is a manned submersible that allows scientists to explore at depths of up to 2.8 miles.
But before Alvin goes in the water, the autonomous Sentry paves the way.
Operating at depths of 3 miles, Sentry can travel on its own for nearly an entire day. Using sonar and an array of sensors, it laboriously maps the sea floor and lets the Alvin researchers know where they should dive.
This is important, Shank said, because 90 percent of the Gulf's seafloor is mud. But the coral communities sought by researchers are on the "hard bottom," Shank said.
Even though Alvin gathered samples, those samples are essentially useless without an understanding of the underwater community's biological processes.
Prolonged observations of the way these animals colonize, grow, reproduce and die is critical when attempting to understand how they may recover from an oil spill, or not.
Researchers were hoping to gather that knowledge by picking up a sediment trap placed at the site in June. As any potential oil or dispersants drifted down to the seafloor, the trap was supposed to collect it to give scientists insight into how material accumulates on the ocean bottom.
But when the trap was retrieved, Shank said, water seeped into the pressure housing that protects the control unit. As a result, none of the bottles rotated into position, and no samples were collected.
Although the result was disappointing, a time-lapse camera was set up at the site that will take a picture every hour for the next two months, Shank said. Researchers will then be able to see either the stages of death or how the coral colonies recover step by step.
With all the attention the BP spill received, Shank admitted his crew felt "the eyes of the nation upon us."
Strict protocols and chains of custody were developed for all samples hauled up from the deep, and everything was documented and imaged several times over, Shank said.
Pictures and videos could not be altered in any way and had to be turned over to the U.S. Department of the Interior's National Resource Damage Assessment and Restoration program, Shank said. Researchers were told to be mindful of documenting everything so that it would stand up in a court of law if necessary.
Crew members had no communication with BP officials during the expedition, Shank said, and will report their findings without bias.
"Things were much more complex and difficult than we're used to, but no one was complaining," Shank said. "We're all here to do the right thing."
Tests on the coral are expected to released in the next few weeks, Shank said, and he is already trying to plan a trip back to the Gulf in February to retrieve the time-lapse camera.
mission at a glance
- 23 feet long, 12 feet tall, 8.5 feet wide
- Weight: 37,000 pounds
- Dives up to 2.8 miles deep
- Travels at speed of 2 knots
- Allows scientists up to 11 hours under water
- 10 feet long, 6 feet tall, 7 feet wide
- Weight: 2,750 pounds
- Dives up to 3.1 miles deep
- Travels at speed of 2.3 knots
- Operates for 24 hours at a time
For more information and a day-by-day description of the mission, go to http://divediscover.whoi.edu.
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