Gulf oil spill: NOAA taking samples deeper in water column
The National Oceanic and Atmospheric Administration has redirected a mission that was to examine deep-sea corals to the Gulf of Mexico, where oil has been gushing into the sea at 200,000 gallons a day since April 22.
The research ship will collect seafloor and water column data and obtain core sediment samples from the seafloor in areas near the Deepwater Horizon spill source. The samples are expected to provide important information about the abundance of marine organisms and the presence of chemicals in ocean water and sediments for a baseline against which to measure change if those areas are affected by sinking oil.
NOAA already is taking samples of seafood and analyzing them to establish a baseline from which it could determine if future samples are contaminated by the oil.
The university fleet research vessel Pelican, operated by the Louisiana Universities Marine Consortium, departed Cocodrie, La., late Tuesday and arrived at the spill source Wednesday, NOAA reported.“This sampling mission is one of many NOAA responses to the oil spill,” acting NOAA assistant administrator for NOAA Research Craig McLean said. “It fills an important gap in researching the interaction of spilled oil and the ocean environment. The samples will help us better understand affected ocean resources.”
“We plan to sample as close to the well head as is safe, reasonable and allowable,” said Ray Highsmith, executive director of the National Institute for Undersea Science and Technology and principal investigator for both the original and the revised mission. “We then plan to travel northwestward toward our long-term study site.”
That study site is about nine miles from the oil spill source and the home of the Gulf of Mexico Consortium’s Methane Hydrate Seafloor Observatory. In the seven years of the observatory’s development, scientists have collected a wealth of geologic, physical, chemical, and biological data describing the area — data that could be important in measuring changes there that stem from the oil spill.
The research team brought aboard a large box corer used to take seafloor sediment samples and installed a large reel of cable to allow the corer to operate at depths equal to the spill source at 5,000 feet. An instrument called a CTD (Conductivity-Temperature-Depth) will measure the water’s conductivity, temperature, density and oxygen concentration at various water column depths, while bottles on the CTD obtain water samples.
-- Geoff Mohan