Today the sea is a field of oil rigs. But, depending on where we are there are occasional curious-looking brown pelicans and blood-orange sunsets to enjoy.
After a few days in port due to mechanical issues and a crew change, we set sail in the early morning hours last Thursday, through the Southwest Passage to the Gulf of Mexico. With Captain George at the wheel, we headed west of the well head to begin our sediment sampling operations. Our skilled, sampling crew consists of four scientists: Lead Sampler Ken Cerreto of Exponent, Carl Johnsen also of Exponent, and John Kizhakethil and Ed Atkin both of Oil Spill Response.
The scientists work together at each station to conduct CTD and fluorometry casts. To do this, a CTD and fluorometer are lowered together by a ship-side winch. The devices are lowered and raised three times through the water column. Next, those devices are removed from the winch and Go Flow containers (containers for collecting water samples) are loaded onto the winch. The Go Glow containers collect water samples at the mid-depth and bottom of the water column. The samplers are lowered to the appropriate depth and then opened to collect the sample when they’re at the appropriate depth. We also collect surface samples with a pole from the ship.
But we’re a busy ship. In addition to all of that other stuff, we’re also taking sediment samples using a grab sampler. The grab sampler is a box-shaped apparatus that drop off of the A-frame on the aft (near the stern or back) of the ship. The grab sampler drops much faster to the sea floor than the multi-corers that some of the other ships are using. When it touches the bottom it makes one big scoop. We do this twice and each time we take the top two centimeters of sediment from each sample. These are then placed in a large bowl and stirred to create a composite sample. (No, we’re not making mud pies out here.) All of our samples are stored in a refrigerated unit we have on the deck.
Tomorrow we’ll explain another apparatus we have on board: the LISST.