Station M Servicing Expedition 2018

MBARI Expedition #451

Expedition goal: The Pelagic-Benthic Coupling Group is conducting yearly servicing of the autonomous instruments working approximately 4,000 meters deep at Station M. These instruments collect data as part of a 29-year time series study of climate influences on deep-sea carbon supply and demand.

Expedition dates: October 17- 25, 2018

Ship: R/V Western Flyer

Research technology:  ROV Doc Ricketts, Benthic Rover, sediment trap moorings, Sedimentation Event Sensor, and CTD rosette

Expedition chief scientist: Ken Smith

Established in 1989, Station M (4,000 meters depth) is one of three long-term abyssal time-series study sites worldwide, and the only site where carbon supply and demand have been recorded as a time series. Persistent monitoring by autonomous instruments has revealed the influence of climate and surface conditions on abyssal communities. Our ultimate goal is to model the carbon cycle from the surface to the seafloor. Our recent results have shown an increase in very large carbon-supply events, during which months- to years-worth of marine snow (i.e., food for marine communities) fell to the seafloor over short periods. These events are important to the carbon cycle, but they are not currently accounted for in models used to assess oceanic carbon sequestration. Our current focus is to understand what drives these important events, and how they impact abyssal communities.

During this cruise, we will bring the suite of instruments deployed at Station M up to the surface to change their batteries, download data, clean their o-rings, and make repairs if needed. This is not a small feat as the list of instruments includes: the Benthic Rover, two sediment trap moorings with time-lapse cameras at the base, the Sedimentation Event Sensor, and an ADCP current meter!

Senior Mechanical Technician Johnny Ferreira poses with the Benthic Rover on the back deck of the R/V Western Flyer. The Benthic Rover is an autonomous vehicle that cruise along the seafloor at nearly 4,000 meters deep!

We will also use the ROV Doc Ricketts to collect animals for food web studies, sediment for carbon and molecular studies, and video transects for studying change in animal community ecology. The ROV Doc Ricketts pilots will also deploy grab respirometers for studying oxygen consumption during the cruise, and larval settlement traps (for collaborator Luciana Génio), which we plan to bring back to the surface next year. Finally, we plan to use the CTD rosette to collect water for midwater molecular studies. This will be a busy cruise for sure.

Updates from researchers on the R/V Western Flyer:

Tuesday, October 30, 2018
Research Specialist Christine Huffard

The cruise activities don’t end when we get back to shore. Next, comes the data analyses, interpretation, and communication through peer-reviewed research papers, social media, and press releases. The sediment traps and Sedimentation Event Sensor recorded another period during which large amounts of marine snow reached the seafloor. Interestingly, data from the Benthic Rover, time-lapse camera, and Sedimentation Event Sensor hint to significant differences between this event and previous “high-carbon” periods at Station M. With help from MBARI Research Specialist Chris Preston and collaborator Colleen Durkin (research faculty at Moss Landing Marine Laboratories), we will use these data and samples to evaluate what made this event unique, and why so much marine snow has fallen to the abyss since 2011.

On the steam back from Station M, we packed most of our gear into large plastic pallet boxes, which the crew helped us offload using a crane once we got back to the dock, and cleaned up the wet lab for the next group going out to sea. The same space we used for servicing instruments, other groups will use to photograph midwater organisms or sort geological samples. After everything was packed and cleaned, we hand-carried samples across the street to our lab space at MBARI. We look forward to moving back onto the R/V Western Flyer next October for another cruise to Station M. In the meantime, the Wave Glider will occasionally check on the Benthic Rover, which is out there working away at 4,000 meters deep while we’re here on shore.

Wednesday, October 24, 2018
University of Aveiro (Portugal) Postdoctoral Researcher Luciana Genio

Knowing where and for how long the pelagic larvae of deep-sea benthic animals live in the water column is extremely important to understand how populations respond to natural (e.g., climate and food supply) and human (e.g., pollution, overfishing, mining) disturbances. On this cruise, we deployed a series of larval traps and settlement frames on the seafloor and at one and 50 meters above the bottom. These traps collect passively drifting larvae and study the colonization of different biogenic substrates (wood, carbonates, and bones) typically found on the seafloor.

The diverse suite of instrumentation and one of the longest abyssal time-series studies make Station M an exceptional site to test new sampling methods, which may be developed around the world, to give us a global view of ocean’s health over space and time.

Tuesday, October 23, 2018
Research Specialist Christine Huffard

Over the 30-year (and counting) time-series study at Station M, we have seen changes in the biological carbon pump with changing sea surface conditions along the California coast. The abyss is not the invariable environment most people once envisioned. Short-term processes and events can have major impacts on long-term patterns.

Every two hours, the Sedimentation Event Sensor (SES) takes fluorescence readings and a picture of the marine snow (organic materials drifting from the surface to the seafloor) that settled on a slide (at the base of the funnel). With this information, we gain a detailed look into short-term variation in carbon delivery to the abyss.

Friday, October 19, 2018
Research Specialist Christine Huffard

The Benthic Rover is a fully autonomous underwater vehicle that collects data for the Pelagic-Benthic Coupling Lab’s studies of seafloor carbon consumption. Capable of yearlong deployments, it is the only untethered underwater rover in the world operating at abyssal depths. The Rover has transited over 11 kilometers of abyssal seafloor at 4,000 meters depth since it was first deployed at Station M in 2011. Using acoustic communications, we recalled the Rover to the surface on October 17. Forty-eight hours later, engineers had the Benthic Rover ready to re-deploy for another year.