Autonomous underwater vehicle to study Deepwater Horizon oil spill
With the latest attempt to stem the oil flow from the Deepwater Horizon oil well by pumping heavy drilling liquids into the well having failed, there is still no end in sight to the disaster that began more than a month ago. To help shed some light on where oil is spilling beneath the ocean surface and to aid biologists and others understand the effects of this catastrophic event, the Monterey Bay Aquarium Research Institute’s (MBARI’s) Division of Marine Operations has sent a high-tech robotic submersible to the oily waters of the Gulf.
Under an agreement with the National Oceanic and Atmospheric Administration (NOAA), MBARI’s autonomous underwater vehicle (AUV) was launched into the waters of the Gulf for the first time on May 28 from the NOAA Ship Gordon Gunter. Although there’s no shortage of satellite and aircraft imagery showing the extent of the spill at the surface, the AUV will help researchers understand the nature and extent of any plumes of oil that may be hidden beneath the surface of the ocean.
AUV’s are robotic, untethered submersibles that are programmed at the surface, then navigate through the water on their own, collecting data as they go. The MBARI AUV can measure physical characteristics of the water, such as temperature, salinity, and dissolved oxygen, detect chlorophyll from microscopic marine algae, and measure concentrations of small particles (or oil droplets) in the water.
The MBARI AUV is unique in that it carries "gulper" samplers that can collect up to ten 1.8-liter water samples while traveling through the water (or through the plume in this case) – and gives the vehicle its nickname of “the Gulper”. The AUV also uses cutting-edge artificial intelligence software to decide where to go and when to collect its water samples. Engineers can program the on-board computers to help the AUV find a plume and then map its boundaries, as well as to take water samples both within and outside the plume.
The Gunter will sail to the vicinity of the well head and begin a systematic survey using its 18 and 38 kHz sonar to define the shape and extent of the underwater plume. University of New Hampshire Joint Hydrographic Center scientists onboard will explore the feasibility of using mid-water mapping sonar to image the submerged plume in combination with new software that could result in 3-D images of what is happening underneath the surface.
If potential plumes are identified, the Gunter will deploy the Gulper to take discrete water samples at various depths to allow precise characterization of any oil, dispersants, or other substances in the plume. These samples may also be subjected to DNA analysis to determine what types of algae, bacteria, or other microorganisms are present.
This MBARI AUV can dive to 1,500 meters (5,000 feet) below the surface - deep enough to collect water samples near the seafloor in the vicinity of the oil spill. The vehicle typically follows a "roller-coaster" path through the water, which allows its instruments to monitor a cross-section of the ocean.
The MBARI team is excited by the prospect that their vehicle may be useful in understanding the Gulf oil spill.
"MBARI's AUV and gulper system provides a surveillance and sample collection capability that is complementary to other tools being deployed to understand the fate of the subsurface plume of oil and dispersant." said MBARI President and Chief Executive Officer Chris Scholin. "Coordinating this response in partnership with government and academic institutions is not only important for providing much-needed fundamental information on the spill and its impacts, but also serves as a valuable learning experience for understanding how to respond to such incidents in the future."