Day 6: Instruments working together for long-term monitoring
November 17, 2012
Officers on the bridge charted our progress as we steamed across Station M today, recovering and redeploying instruments. Photo: Carola Buchner
Today marked the final day at Station M, which means several instruments were returned to continue monitoring the area until the next Smith lab cruise. The camera tripod and sediment traps were the first instruments redeployed today. Review of the last five months’ deployment showed records of changes in sea cucumber, urchin, and sponge behavior; animal abundances; jelly blooms; changes in current speed and direction; and food pulses to the seafloor.
Meanwhile, correlations between the activity on the seafloor and what is raining down from surface waters above are possible because of the sediment traps moored above the camera tripod. Traps located 50 and 600 meters above the seafloor act like rain gauges for marine snow, collecting falling particles to see how much carbon, or food, reaches the seafloor. Abundances of many different animals on the abyssal plain do correlate with changes in the amount of carbon falling from above: sea cucumbers, urchins, macrofauna living within the sediments, and sponges are all found to increase when the amount of incoming food increases, but with a time lag. The time lag occurs because it takes time for the food to sink, so the time that surface waters produce more food and the time when that food reaches the seafloor can be months apart..
Ken Smith, Alana Sherman, John Ferreira, and Paul McGill prepare the camera tripod mooring for its redeployment. The tripod mooring will remain at Station M until the next cruise, gathering information about animal activity on the seafloor. Photo: Carola Buchner
Next, the sediment event sensor (SES) was redeployed. The SES provides greater resolution to the information obtained from the sediment traps: one can measure the quantity of carbon sinking to the seafloor with the sediment traps, but the SES adds information about the quality of that carbon: whether it comes from photosynthetic organisms or zooplankton, and if its source can be distinguished from a photo.
Henry Ruhl and John Ferreira move the SES in preparation for its second long-term deployment at Station M. Photo: Carola Buchner
Meanwhile, the free vehicle grab respirometer (FVGR) was acoustically recalled to the surface and was brought back on the ship, along with the floats and spar buoy that make up the mooring. The spar buoy is a giant floating flag and beacon that help the crew find the instrument at the surface. The spar buoy, all of the floats, and the FVGR are connected with lines. To bring the FVGR back on the ship, a grappling hook was used to capture the line between the spar buoy and the first block of foam. That line was connected to a winch on the ship and everything was carefully pulled up on board.
A grappling hook is thrown over the line between the spar buoy and the first float. The spar buoy is then led to the aft of the ship where it can be recovered. Photo: Carola Buchner
The elevator holding the respiration chambers was sent down at the beginning of the cruise, then sat at the seafloor until it was recovered today, with the help of the ROV Doc Ricketts.
ROV Doc Ricketts heads into the water to release the weights holding the elevator down at the seafloor. With the weights released, the elevator drifted up to the surface, ready to be recovered. Photo: Carola Buchner
This cruise, however, has come to a close; the Western Flyer will head back to Moss Landing tonight and will arrive at MBARI tomorrow. All hands will help unload the ship, then everyone will disperse, but all will work up the data from the expedition in the coming months.
Thank you to everyone for reading and following along with our expedition! To learn more about Station M, the research conducted by the Smith lab, or the different instruments deployed, check out the equipment, people, and background sections of this cruise log website.
November 16, 2012
Experiments in the deep ocean Day 4
November 15, 2012
Recovering long-term sampling equipment Day 3
November 14, 2012
Rover recovery and recharge Day 2
November 13, 2012
Helping hands for free vehicles Day 1
November 12, 2012
No idle hands
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.
Free vehicle grab respirometer (FVGR)
Oxygen consumption (a measure of biological activity) of the organisms living in the sediment is measured using a free vehicle grab respirometer (FVGR) which retrieves sediments for faunal examination and chemical analyses.
Lagrangian Sediment Trap (LST)
The Lagrangian Sediment Traps or LSTs are used to collect sinking material at specific depths. Once they are deployed they will sink to a programmed depth and float along with the current. After a few days the sample cups will close and the LST will activate its variable ballast system to rise to the surface to be 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.
Alana specializes in instrumentation. On this cruise she will be deploying three instruments: the Benthic Rover, the time-lapse camera tripod, and Lagrangian sediment traps.
Research Technician, MBARI
As lab technician, Jake's responsibility is to make sure everything runs smoothly so samples can be collected at sea and analyzed in the laboratory. He'll organize much of the equipment being taken to sea, and will ensure everything works during the cruise. Once ashore he'll take all the samples and analyze them in a variety of ways with the goal of achieving a better understanding of how the ocean works.
Mechanical Engineering Technician, MBARI
John will help with all the mechanical maintenance and repair of the Benthic Rover, the sediment traps, and the seafloor camera tripod.
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.
Senior Research Technician, MBARI
Crissy completed a post-doc in MBARI’s Midwater Ecology lab, after which she worked for Conservation International Indonesia supporting marine protected area monitoring efforts. She has just returned to MBARI, as a senior research technician in Ken Smith’s lab, and on this cruise is learning about the lab’s shipboard operations and instruments.
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.
University of Alberta
Amanda studied plate sponges at Station M as an intern in the Smith lab. She is now pursuing a Ph.D. at the University of Alberta, studying the growth, energetics, and impacts of hexactinellid sponges that form reefs in the straits of western Canada. Her interests outside of research include scuba diving, martial arts, and science blogging.
Engineer of Biotechnology
Carola has worked for many years in the field of microscopy and volunteered on one of Ken Smith´s Sargasso Sea expeditions earlier in 2012. On this trip she will help in the lab. Her interests outside the work are photography and scuba diving.