Mote Underwater Robots Search For Oil

Mote scientists have launched underwater robots to patrol off the Continental Shelf in the Gulf of Mexico for oil. One of them, nicknamed Waldo, stopped phoning home and has been replaced off the Florida Keys.

To Date, Mote Autonomous Underwater Vehicles have Detected No Oil

Waldo, an autonomous underwater vehicle or AUV, was sent on a mission to patrol the Continental Shelf for oil just north and west of Key West. The robot was tasked with looking underwater for evidence of the spill in an area that oil might be expected to appear if it is carried south in the Loop Current.

But Waldo ran into some problems during its mission, according to Dr. Gary Kirkpatrick, manger of Mote's Phytoplankton Ecology Program and the scientist overseeing Mote's AUV research. "On Friday, it entered the pass between the Dry Tortugas and Rebecca Shoal and it couldn't swim against the strong currents there," Kirkpatrick said.

These gliding AUVs are propelled through the water column using only buoyancy and are not equipped with any kind of propeller to move them through the water. While that gives them a much longer battery life — allowing them to patrol the ocean for weeks at a time instead of hours - it does make them vulnerable in areas with strong currents, Kirkpatrick said.

When it was clear that Waldo would be unable to continue on its patrol mission in that particular area, the robot was recovered by Mote and staff with the National Park Service and taken to the Dry Tortugas where it spent the night at historic Fort Jefferson. "I think Waldo actually spent the night in a cell in the old jail," Kirkpatrick said. (A little history lesson: Fort Jefferson was constructed as a military fortress in the mid-19th century by the U.S. to protect the shipping channel and it served as prison during the Civil War. Its most famous prisoner was Dr. Samuel Mudd, who was convicted of conspiracy after treating President Lincoln's assassin, John Wilkes Booth.)

Kirkpatrick decided to alter Waldo's route and worked with Park Staff to re-deploy the robot further north of its original mission where currents would be less of an issue. "Then we had problems with the satellite communications - basically, we couldn't talk to Waldo and it couldn't talk to us, so we decided to bring that AUV back to Mote and substitute a new one," Kirkpatrick said.

Strong community support helped with the AUV exchange. Key West Seaplane Charters transported Waldo back to Key West and Key West Express, a ferry service from Fort Myers Beach to Key West, transported the new AUV and Mote staff to Key West so the new AUV could be deployed. This new AUV, called UD134, was sent to Mote help out in the search for oil by the University of Delaware.

So far, neither Waldo nor the first AUV Mote deployed off of Venice have detected underwater evidence of oil. The first AUV Mote deployed, a Rutgers University AUV called RU21, has been patrolling the Continental Shelf down to about 300 feet and is currently on track. RU21 has about 12 days of battery power left.

Mote also expects to be deploying additional AUVs - particularly Nemo, which will be equipped to look at the phytoplankton community instead of looking for oil. Phytoplankton form the basis of the entire food web and changes in the phytoplankton community could signal widespread disruption for other larger marine species from fish to mammals. "We want to get as many measurements about the phytoplankton community as possible so that if oil does come ashore here, we have a better understanding of how the ecosystem has been affected," Kirkpatrick said.

• Individuals can make donations to Mote's Oil Spill Emergency Fund online at www.mote.org/oildonation.
• Click here to learn more about Mote's response to the Deepwater Horizon oil spill in the Gulf of Mexico.
  

Quick Facts: The AUVs and their Payloads

• Name: Slocum Glider, after Joshua Slocum, the first man to single-handedly sail around the world.
• Conceived by: Douglas C. Webb and supported by Henry Stommel and others.
• Produced by: Teledyne Webb Research
• What they Do: Travel autonomously throughout the water column for 15 to 30 days at a time gathering data that is then beamed to a satellite network and then sent on to a destination site on earth. At Mote, that destination site is called SO COOL - the Sarasota Operations of the Coastal Oceans Observation Laboratory.
• How they Travel: In simplest terms, the Slocum Glider uses buoyancy to move throughout the water column in a vertical zigzag pattern, taking in water to move down through the water column and expelling water to return to the surface to send data. Each glider has angled wings so that as it takes on or releases water it is propelled forward instead of just going up or down.
• Size: About 6 feet long and 8 inches in diameter
• Weight: About 110 pounds
• About the Glider's Payload: The gliders are designed so that they can carry a variety of scientific instruments, or payloads. Mote created a special payload called a BreveBuster that can detect Florida's red tide in the water. Another type of payload - the one being used to detect oil - is a called a fluorometer. A fluorometer measures the light emitted - or fluorescence - of the water as the AUV travels in the water column. In simplest terms, the fluorometer has an LED (light-emitting diode) that sends out ultraviolet light. If the water contains certain chemical components of oil, these chemicals will absorb the light and then re-emit it as fluorescence. A detector will see this light emission and report its presence.
• What the Fluorometer is Looking for: The fluorometer, which is about the size of a hockey puck, is looking for polycyclic aromatic hydrocarbons, or PAH's, and the dispersants used to break the oil down. PAHs are the chemical components of oil that are extremely toxic or carcinogenic, affecting reproduction, immune function and the health of organisms that do not die from acute exposure.

If the AUVs encounter oil, Mote can alert resource managers so they can act to protect important ecological resources and shorelines, Kirkpatrick said. This is believed to be the first time that an AUV has been equipped a payload that can detect oil and sent on a patrol mission.

In addition to supporting the glider missions, the funding from the Gulf Coast Community Foundation of Venice will help Mote researchers:

• Take samples of water, sediments, bottom dwelling organisms, and sea grass
• Sample mollusks (primarily clams and oysters)
• Sample the phytoplankton community
• Create a detailed oil response plan that covers a number of different scenarios so that our area will be well-positioned to receive federal or British Petroleum funds.

"We can't thank the Gulf Coast Community Foundation of Venice enough for this lead gift," said Dr. Kumar Mahadevan, president of Mote Marine Laboratory and Aquarium. "The impact from this spill is going to be tremendous and as the response progresses, the need for funding to understand the impact is going to be great. This grant will help cover the costs associated with doing some initial planning and fact-finding but the scope of work to determine the effects of the spill on our region's environment is quite enormous."

• Individuals can make donations to Mote's Oil Spill Emergency Fund online at www.mote.org/oildonation.
• Click here to learn more about Mote's response to the Deepwater Horizon oil spill in the Gulf of Mexico.