Monterey Bay Aquarium Research Institute

2012 Climate and Deep-sea Communities Expedition

 

Day 3: Rover recovery and recharge
November 14, 2012

The Benthic Rover has been traversing Station M in our absence since the previous cruise, about five months ago. As its name suggests, the Rover roams the seafloor of Station M following a pre-programmed course, measuring oxygen concentrations in the overlying sediments at intervals along its path. Like the free vehicle grab respirometer (FVGR), the Rover estimates sediment community oxygen consumption (SCOC), which is an indicator of biological activity in the sediments of the abyssal plain. However, unlike the FVGR, the Rover can travel, occupying 68 sites over the five-month deployment.

The Rover was called up from abyssal depths and brought on board through careful orchestration between the ship’s crew and the science team. The Rover will spend one day at the surface before returning to the seafloor. Photo: Carola Buchner

Creating an instrument that can function by itself for up to a year until it is recalled to the surface is not a trivial undertaking. Since there are no recharging stations on the abyssal plain, the Rover runs on batteries, which means that it cannot demand much energy to move even though it is the size of a small car. It also cannot demand much energy for the science work it accomplishes: sealing off areas of sediment to photograph and to measure oxygen drawdown by the sediment community, plus taking still images of the seafloor every meter during its transit to new sampling points. The Rover also has gauges to measure temperature, current speed and direction, and oxygen within the chambers as well as in ambient seawater. It also has plug-ins available for more equipment to be added at a later time.

The chambers pictured here are lowered into the sediment and used to measure sediment community oxygen consumption. Photo: Carola Buchner

After the Rover arrived on deck, John Ferreira, Rich Henthorn, Paul McGill, and Alana Sherman—MBARI engineers who have worked alongside Ken Smith since 2005 to build the Rover—set to work to prepare it for another deployment. They spent the day downloading data and photos, changing out its batteries, ensuring compartments are still well sealed, and analyzing some of the data the Rover logged to see if anything needs to be corrected before redeploying.

Ken Smith and John Ferreira examine the Rover during its day at the surface. The Rover will be deployed back to the seafloor for another five months tomorrow morning. Photo: Carola Buchner

Meanwhile, Henry Ruhl and I set up seafloor experiments using the remotely operated vehicle (ROV) Doc Ricketts. The ROV descended down to the elevator, upon which equipment for their experiments had been deployed yesterday. First, pilots deployed two in situ dyeing chambers for me. The chambers will each isolate a single sponge and release a fluorescent marker that labels regions of new growth. Following that, Henry Ruhl collected holothurians (sea cucumbers) of the genus Peniagone, which were put into chambers to measure their respiration rates in the deep sea.

Amanda Kahn watches as ROV pilots carefully place a dye chamber over a plate sponge. The chamber will incubate the sponge in a fluorescent dye used for studying growth. Photo: Carola Buchner

Following those experiments, ROV Doc Ricketts traveled a long video transect across the seafloor, passing by various holothurians, sea urchins, anemones, crinoids, sponges, and fish. Near the end of the transect, a patch of seafloor was found covered by small sea cucumbers in numbers not seen at Station M in the 23 years of data collection. Such observations are what make the time-series so valuable: long-term changes in animal populations can be observed and, when accompanied by measurements of physical conditions at Station M, encourage hypotheses to be tested regarding what causes such aggregations to occur.

—Amanda Kahn

For more information about the Benthic Rover, check out this news release.

Previous log Next log

 Logbook

Day 5
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

 Equipment

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.

Push cores

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.

Benthic Rover

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.

Benthic elevator

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.

Camera mooring

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.
 Research Team

Ken SmithKen Smith
Senior Scientist, MBARI

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 Sherman Alana Sherman
Electrical Engineer, MBARI

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.

jake ellena Jacob Ellena
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.

John FerreiraJohn Ferreira
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 henthorn Rich Henthorn
Software Engineer, MBARI

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.

Crissy HuffardCrissy Huffard
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 McGill Paul McGill
Electrical Engineer, MBARI

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.

Henry Ruhl Henry Ruhl
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.

Amanda Kahn Amanda Kahn
Graduate Student
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.

Carola Buchner Carola Buchner
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.