Climate and Deep-Sea Communities 2012 Expedition

November 12-18, 2012

Deep-sea ecologist Ken Smith and his research team continue their 23-year-long time-series study of the coupling of open-ocean food supplies and the responses of seafloor communities at Station M, approximately 200 kilometers (125 miles) off the coast of Point Conception in the eastern North Pacific Ocean. Large algal blooms are common in the surface waters at this site in the spring and summer. The organic material formed during these blooms eventually sinks down through the water column and feeds many of the animals that live on and in the seafloor.

Recent research has shown that climate variation can affect levels of photosynthetic activity at the sea surface. In turn, photosynthetic activity levels affect the quantity and quality of organic carbon that sinks to the seafloor as detritus, or marine snow. Variations in the amount of marine snow deposited on the seafloor can affect the size and abundance of the animals nourished by this food source, as well as the deep-sea community at large.

On this cruise, Smith’s research team will retrieve and redeploy the deep-sea observation equipment and the Benthic Rover they left on the seafloor in June 2012. They will also be deploying equipment designed to measure the respiration of the seafloor communities.

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Continuing their 23-year-long time-series study of the coupling of open-ocean food supplies and the responses of seafloor communities, Ken Smith and his research team will retrieve and redeploy deep-sea observation equipment and the Benthic Rover at Station M, approximately 200 kilometers (125 miles) off the coast of Point Conception in the eastern North Pacific Ocean. The seafloor at Station M, 4,100 meters (13,500 feet) below the ocean’s surface, is flat and muddy and composed of silty clay sediment and seasonal deposits of detritus.

Time-lapse photography at Station M has revealed abundant evidence of bioturbation—the mixing of sediment by organisms burrowing into the seafloor—and other activity by animals living on and in the sediment such as trails, furrows, and mounds that can be centimeters to meters across. Smith and his colleagues will now have the opportunity to analyze a new set of time-lapse photographs taken by a camera mounted on the deep-sea observatory they deployed in June 2012 and will recover on this expedition. They will also process samples from the observatory’s sediment traps to obtain values for organic carbon and nitrogen, as an estimate of the food supply to the benthic community. A sedimentation event sensor (SES) that photographs settling particles for comparison with the sediment traps will also be recovered.

On this cruise, Smith’s research team will once again deploy the free vehicle grab respirometer (FVGR) to measure the oxygen consumption of the seafloor sediment community. Additionally, the team will retrieve then redeploy the Benthic Rover to conduct similar measurements but in a linear transect. The Benthic Rover has been traversing the seafloor for the past five months.

The remotely operated vehicle (ROV) Doc Ricketts will be used to conduct transects of the seafloor in order to assess the abundance and size of seafloor animals. The ROV will also be used to collect seafloor animals and place them in respirometers on the seafloor. The respirometers measure the animals’ oxygen consumption, an indicator of how much food the animals consume.

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Videos

The vast muddy expanses of the abyssal plains occupy about 60 percent of the Earth’s surface and are important in global carbon cycling. Changes in the Earth’s climate can cause unexpectedly large changes in deep-sea ecosystems. Based on 18 years of studies, MBARI’s Ken Smith and his coauthors showed that such ecosystem changes occur over short time scales of weeks to months, as well as over longer periods of years to decades.

This video shows a series of time-lapse still images of animals on the deep seafloor. The images were taken at one-hour intervals over a period of about three months in spring 2007. These images were taken at “Station M,” a long-term research site about 4,000 meters below the surface and 220 kilometers west of Point Conception, on the Central California Coast. MBARI marine ecologist Ken Smith has been conducting research at Station M since about 1990.

Logbook

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.

Rover recovery and recharge

The Benthic Rover was called up from abyssal depths and brought on board through careful orchestration between the ship’s crew and the science team.
All members of the science and engineering teams worked together to prepare the FVGR for deployment. Photo: Carola Buchner.

Helping hands for free vehicles

All science and engineering members were awake by 6:00 a.m. to assist with preparations for deploying the free vehicle grab respirometer (FVGR) and the benthic elevator.
The free vehicle grab respirometer (FVGR) sits ready to be deployed early Tuesday morning as the ship steams away from Moss Landing. Photo: Carola Buchner.

No idle hands in this calm weather

By 8:30 a.m. Moss Landing Harbor and the iconic towers of the Moss Landing power plant were nothing but tiny reminders on the horizon of our land-based start.