Day two was calm enough for a few operations. This morning we deployed the benthic elevator outfitted with respirometry chambers, and a new sediment trap funnel that we’re pressure-testing. Once the elevator was placed overboard and released, it took about two hours to sink to the bottom. Even though it weighs almost 1,300 pounds in air, it needs additional dense weight in order to sink in seawater. The marine operations team adds 150 pounds, just enough to help it sink slowly so as not to crash land. Stay tuned for tomorrow’s plan to see what goes into the respirometry chambers.
Benthic elevator with respirometry chambers and depth-testing a new sediment trap funnel.
After we deployed the elevator we recovered the mooring. At the base of the mooring is a camera tripod, above which are two sediment traps. Floats keep these instruments held upright underwater once they land on the seafloor, but also, once we send the instrument an acoustic signal to drop its weights at the end of the mission, the floats help it rise slowly to the surface. These floats must be able to withstand sinking down thousands of meters under water, and remain buoyant down where pressure is over 315 times that at the surface (use this website to calculate how much pressure there is at various depths http://www.calctool.org/CALC/other/games/depth_press). These floats are made out of syntactic foam, a material that can handle the pressures of the deep sea, remain buoyant at all of their working depths, and are very heavy at the surface.
Surface recovery of the mooring starts by throwing grappling lines to catch the mooring line, and hauling the top syntactic foam floats to the ship.
Chief Scientist Ken Smith directing the recovery operations. The syntactic foam floats used at Station M are far too heavy to lift onto the ship by hand, and must be raised by a winch.
June 19, 2013
Preparing for the next mission Day 5
June 18, 2013
The sediment event sensor Day 4
June 17, 2013
Recovering the Benthic Rover Day 3
June 16, 2013
Making the most of good weather Day 2
June 15, 2013
Deploying the elevator Day 1
June 14, 2013
R/V Western Flyer
The R/V Western Flyer is a small water-plane area twin hull (SWATH) oceanographic research vessel measuring 35.6 meters long and 16.2 meters wide. It was designed and constructed for MBARI to serve as the support vessel for ROV operations. Her missions include the Monterey Bay as well as extended cruises to Hawaii, the Gulf of California, and the Pacific Northwest.
ROV Doc Ricketts
ROV Doc Ricketts is MBARI's next generation ROV. The system breaks new ground in providing an integrated unmanned submersible research platform with many powerful features providing efficient, reliable, and precise sampling and data collection in a wide range of missions.
Long-term sediment trap
Sequencing conical sediment traps, each with an effective mouth opening of 0.25 m2, are moored at 600 meters and 50 meters above the bottom at 3,500- and 4,050-meter depths, respectively. Trap sequencers are programmed to collect sinking particulate matter in sampling cups every 10 days. In the laboratory, the collected particulate matter is analyzed in duplicate for total and inorganic carbon.
A push-core is a clear plastic tube with a rubber handle on one end. Just as its name implies, the push core is pushed down into loose sediment using the ROV's manipulator arm. As the sediment fills up the core, water exits out the top through one-way valves. When the core is pulled up again, these valves close, which (most of the time) keeps the sediment from sliding out of the core tube. When the cores are brought back to the surface, scientists typically look for living animals and organic material in the sediments.
The Benthic Rover is a mobile physiology lab. In a series of experiments, the rover measures how much oxygen seafloor animals are using. Precise motors lower two 30-centimeter-wide (12-inch) sample chambers into the sediment, where probes record oxygen levels. Two acoustic scanners use ultrasound (in 4-MHz pulses) to look 10 centimeters (four inches) deep into the sediment for large animals, such as worms.
High-frequency suction samplers
This midwater toolsled contains a High-Frequency Suction Sampler (HFSS). You can see one of the 12 collection buckets in this image. This sampler acts like a vacuum cleaner sucking up samples and depositing them into one of the 12 buckets.
The benthic elevator allows us to carry more than the ROV itself can carry. Loaded with sediment enrichers, it is deployed from the ship before the dive and free-falls to the bottom where the ROV pulls the equipment from the elevator for use. After the ROV is recovered, the elevator anchor's acoustic release is triggered from the ship, and the elevator freely ascends to the surface and is recovered.
The time-lapse camera consists of a Benthos 377 camera mounted on a titanium frame at an angle of 31 degrees from horizontal with the lens approximately two meters above the seafloor. The camera is equipped with a 28-millimeter Nikonos lens, providing angular coverage of 50 degrees in the horizontal and 35 degrees in the vertical plane, and holds 400 feet of 35-millimeter color-negative film. Up to 3,500 images can be collected in 4.6 months. Two strobe lights, one mounted on either side of the camera housing, illuminate approximately 20 square meters of the seafloor beginning at a distance of 1.8 meters from the camera frame and extending approximately 6.5 meters from the base of the camera frame. In June 2007 a high-resolution digital camera was added to the frame.
Ken is an open-ocean ecologist with 40 of years experience going to sea and studying extreme ecosystems ranging from the deep ocean to Antarctic icebergs. The main thrust of his research is to understand the impact of a changing climate on deep-sea and polar ecosystems. On this cruise, he will coordinate the deployments of autonomous instruments to continue long time-series studies at Station M on the Monterey Deep-Sea Fan at 4,000 meters depth.
Rich has been at MBARI since 2000 working on many types of projects, but mostly writing software for MBARI's autonomous vehicles. On this cruise Rich is responsible for the control system on the Benthic Rover. The Rover will be retrieved from the seafloor and then redeployed for six more months.
Paul specializes in underwater vehicles and instrumentation. On this cruise he'll help prepare, deploy, and recover the drifters, crawlers, and landers being used to study the deep ocean at Station M.
Head, DEEPSEAS Group
National Oceanography Centre, Southampton
Researching the links between climate variation and deep-sea ecology has been a primary focus for Henry. In particular he's interested in understanding how changes in climate are related to the role of the deep ocean as a carbon sink. During the cruise he will be researching the abundance and distribution of animals on the seafloor, as well as their respiration rates using specialized chamber systems. Respiration is a good indicator of carbon utilization and provides key input into estimates of carbon flow and the importance of biodiversity at the seafloor.