Monterey Bay Aquarium Research Institute
2009 Pacific Northwest Expedition


Leg 3 Logbook - Gas Hydrates
Day 3 — Getting from here to there
August 4, 2009

We spent today motoring at a leisurely pace up the coast of Oregon and Washington, heading toward a spot about 96 kilometers (60 miles) off Vancouver Island. Our world has become a rolling gray sea and flat gray sky, with a few sea birds and fishing boats for variation. We haven’t seen the coast, but we figure that somewhere over there it must have been a normal Tuesday, with people driving around on freeways, working in offices and such. It already seems a long way away.

This was our second day at sea, and the science crew was starting to get used to life on board. We had a little motion from the swells last night and this morning, but by this evening both the sea conditions and people’s stomachs had pretty much settled down. It has also taken us a while to get used to eating at very specific times (7:30-8:30 a.m., 11:30-12:30 p.m., and 5:00-6:00 p.m.), but Patrick Mitts’s meals always make it worthwhile. We were treated to fresh-caught albacore tuna for dinner tonight.

The ROV pilots spent most of the day repairing and strengthening the swing arm on the ROV, which broke off yesterday, along with our vibracore rack. As usual, they pulled off this tricky repair job as if it were easy. Just after dinner we loaded a new set of core tubes into the rack. Hopefully we’ll not only be able to collect some vibracores tomorrow, but actually bring them to the surface as well.

The ROV pilots have a small well-equipped workshop on the ship. They can repair almost anything on the ROV using stainless steel fittings, aluminum stock, zip-ties, and lots of ingenuity.

The science crew spent the morning working on water, rock, and mud samples that we collected during yesterday’s ROV dive. The mud from the push cores didn’t appear very interesting when we emptied it out of the cores last night. But after closer examination, Charlie decided that it would be very useful to find out how much carbonate the mud contains and how old it is (when it was first deposited on the seafloor).

With this in mind, Mary McGann will take samples of the mud back to her lab on shore. There she will use a microscope to identify the remains of microscopic animals called foraminifera that lived in the mud when it was exposed on the seafloor. Due to environmental changes and evolutionary processes, the species of “forams” living on the seafloor have changed over time (millions of years). Thus, by identifying exactly which forams are in the mud, Mary may be able to tell when the mud was originally deposited on the seafloor.

Charlie Paull records information on the samples of mud from yesterday’s push cores while Yirang Cho prepares jars to store bits of mud for future analysis.

It turns out that we also got extremely lucky in our rock collecting yesterday. We only picked up two rocks during the entire dive. We couldn’t tell when we collected it, but one of these rock samples included both the light-colored carbonate and dark mudstone. Looking closely at this sample, we could see how the mudstone and the carbonate were in intimate contact, which suggests that the carbonate formed within the surrounding mud, rather than in seawater. Thus, we managed to collect exactly the sample we needed to support Charlie’s hypothesis about how carbonate mounds form (which I described in yesterday’s log).

After we finished processing samples from yesterday’s dive, the research team took advantage of the down day to read some of the extensive scientific literature about the areas where we’ll be diving later this week. Last night Charlie threw down the gauntlet—placing a half-inch-high stack of research papers on the middle of the table in the dry lab. We’ve been trying to assimilate them as time permits. This is in addition to background reading for classes, which occupied the students on board.

When not in the ROV control room or working in the “wet lab,” the researchers on board often gather in the “dry lab” to analyze data, read scientific papers, or write articles for future publication.

Tomorrow will be a long dive day at Barkley Canyon. We’ll probably put the ROV in the water at around 6 a.m. and finish our last dive by 6 p.m. Chances are we’ll be collecting a lot of samples that we’ll be working on until late in the evening. But I’m looking forward to seeing actual methane hydrates in their natural habitat.

Geochemist Bill Ussler prepares dozens of water samples from yesterday’s dive for chemical analysis. Some of these analyses he will perform in his mobile analytical laboratory, which is located in a shipping container strapped to the deck of the Western Flyer.

—Kim Fulton-Bennett

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Leg 3
 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, 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.

R/V Zephyr

R/V Zephyr is the primary support vessel for MBARI's autonomous underwater vehicle (AUV) program. This 26-meter vessel is also used to maintain environmental moorings, collect time-series data along the California Current, and support scuba divers as they study near-shore habitats.

AUV D.Allan.B.

The MBARI Mapping AUV is a torpedo-shaped vehicle equipped with four mapping sonars that operate simultaneously during a mission. The multibeam sonar produces high-resolution bathymetry (analogous to topography on land), the sidescan sonars produce imagery based on the intensity of the sound energy's reflections, and the subbottom profiler penetrates sediments on the seafloor, allowing the detection of layers within the sediments, faults, and depth to the basement rock.

Push cores

A push core looks like 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 ROV Tiburon'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 we bring these cores back to the surface, we typically look for living animals and organic material in the sediments.

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.

Niskin bottles

Niskin bottles are used to collect water samples as well as the tiny bacteria and plankton in the water. The caps at both ends are open until the bottles are tripped, when the caps snap closed.


Heat flow probe

Held by the ROV's manipulator, the wire on the right is placed into the fluid emitted from a hydrothermal vent to record the temperature.


 Research Team

Charlie Paull
Senior Scientist, MBARI

Charlie Paull has been a marine geologist and geochemical stratigrapher at MBARI since January 1999. The central theme of Charlie's work involves investigating the fluxes of fluids and gases through continental margins. Over the past decade his primary focus has been gas hydrate research on the Blake Ridge gas hydrate field on the continental rise off of southeastern North America. Assessing the global distribution of gas hydrate and interstitial gas is a continuing interest as well as the development of new techniques to detect the presence of gas hydrate in marine sediments. Charlie's other ongoing work is focused on the geology associated with seafloor seepage sites, including investigating the deposits associated with chemosynthetic communities, determining the processes that occur at the methane-sulfate boundary, and understanding the origin of pockmarks and other potential seafloor fluid venting sites.

Bill Ussler
Senior Research Specialist, MBARI

During expeditions, Bill Ussler is primarily responsibility for the operation of the custom-built, portable chemistry lab van which contains a complete analytical laboratory for the analysis of the fluids and gases contained in marine sediments. Along with colleague Charlie Paull, Bill studies how methane (natural gas) forms and moves within seafloor sediments.

Michael Riedel
Research Scientist
Natural Resources Canada - Geological Survey of Canada

Michael Riedel was part of an international team of scientists supported by the Integrated Ocean Drilling Program (IODP) which completed a unique research expedition in 2005 aimed at recovering samples of gas hydrate, an ice-like substance hidden beneath the seafloor off Canada's western coast. As IODP Expedition 311's co-chief scientist, Michael explored his interest in gas hydrate; he believes such deposits have played an important role in ancient global climate change.

Ross Chapman
Professor, University of Victoria

Ross's research interests are in seismo-acoustic propagation, with specific application to the study of marine gas hydrates, and development and application of acoustic inverse methods for estimation of geophysical properties of the ocean bottom and for source localization. (Note: At the last minute Ross was unable to participate in the cruise, although he did attend the initial science meeting before the ship left the dock.)

Mary McGann
Geologist, United States Geological Survey

As a member of the USGS Coastal and Marine Geology Program, Mary McGann's professional interests include: foraminiferal and pollen biostratigraphy, paleoecology and biogeography; sedimentary paleoenvironment mapping, quaternary paleoclimatology; and AMS C-14 chronostratigraphy.

Laura Lapham
Postdoctoral Researcher, National Energy Technology Lab, U.S. Department of Energy

Laura's research is concentrated on studying methane cycling at cold seeps, biogeochemcial cycling of methane and sulfer in deep sea sediments, development of deep sea instrumentation to collect novel samples, stable isotope geochemistry, modeling of biogeochemical processes and temporal variability of dissolved methane concentrations. The focus of her research has been mainly on gas hydrate environments, but she is also interested in other systems that relate to the carbon cycle. Her research seeks to understand how methane is distributed between different pools, e.g. dissolved or hydrate phases, and also to understand how local biogeochemical processes affect this methane, mostly through anaerobic methane oxidation.

Kim Fulton-Bennett
Communications Associate, MBARI

Kim helps people outside of the institute to understand MBARI's research and development efforts. He does this by writing news releases and articles about MBARI research, as well as by helping members of the press who want to write their own articles or create video stories about MBARI. His academic background is in marine geology, environmental planning, and science writing.

Yirang Cho
Student, University of California, Davis

Yirang is an undergraduate at UC Davis in Environmental Studies and Ecological Engineering. She is an exchange student from Korea University who is interested in methane hydrates as an alternative energy source and in the ecological communities around methane seeps. She is very happy to have the opportunity to go on this cruise.


Tess Menotti
Graduate Student, Stanford University

 


Craig Joseph
US Department of Energy
Graduate Student, Oregon State University