Today we made the most of the good weather. In the morning we launched the remotely operated vehicle (ROV) Doc Ricketts, which descended at 35 meters (115 feet) per minute to make its way to Station M by around breakfast time.
The dive had several missions. The first was to recover deep-sea sponges that are part of a growth-rate study. Last November, collaborator Amanda Kahn used the ROV to put chambers over these sponges and inject dye into the water. We picked up the chambers a few days later, hoping the sponges had taken the dye into their tissues and formed a distinct growth ring that Amanda can trace back to known dates. Today we picked up one of those sponges. We will mail it back to Amanda once we’re back on shore, and she will measure how much the sponge has grown since it was dyed. After picking up the sponges, we put sea cucumbers into the respirometry chambers on the elevator, and then videotaped three kilometers (1.8 miles) of the seafloor. In collaboration with MBARI’s video lab team, we will use this video to identify and count the animals living at Station M. Over time we can use ROV footage to measure changes in diversity and abundance in animal communities.
A low-resolution frame grab from the high-definition video taken by the ROV Doc Ricketts. This marker helped the ROV pilots relocate the exact same sponge that was dyed in November 2012 (the sponge is the white disc at the base of the marker).
The next objective for today was to redeploy the camera tripod and sediment-trap mooring. While the ROV was in the water, Henry Ruhl and Rich Henthorn were in the control room with the ROV pilots overseeing operations on the bottom. At the same time, the engineers were on deck and in the lab preparing the camera tripod, and I was preparing the sediment traps for deployment this afternoon. We downloaded data, checked software, changed batteries, cleaned O-rings, reprogrammed the equipment, and put cups back on the sediment traps (so they can catch a new batch of sediment every 10 days). By the time the ROV was on deck we were ready to deploy the mooring.
The first sediment trap is redeployed. The entire mooring—floats, lines, and all—is about 800 meters (half a mile) long and takes about two hours to place carefully into the water. Each instrument needs to be staged on deck and deployed in a specific order. The last item to go in the water is the camera tripod (on the right).
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.