Monterey Bay Aquarium Research Institute
2009 Pacific Northwest Expedition


Leg 3 Logbook - Gas Hydrates
Day 1 — Getting ready to go to sea
August 2, 2009

It’s been a day of continuous, if not quite feverish activity, and we haven’t even put out to sea yet. At around 9:00 this morning, the science crew assembled on board the Western Flyer—eleven scientists from eight different research institutions, flying and driving to Newport, Oregon, from all over North America. Some folks arrived around 1:00 this morning, but all are busy getting their experimental gear ready discussing our planned ROV dives.

This photo of the Western Flyer at the dock in Newport Harbor could have been taken at 6 a.m., noon, or 7:30 p.m. The lighting hasn’t changed much all day. It’s not too different from Moss Landing in that regard.

As we gathered for an impromptu science meeting, I looked around the room. Three of us—chief scientist Charlie Paull, geochemist Bill Ussler, and myself—are from MBARI. Our Canadian contingent includes Ross Chapman from the University of Victoria and Michael Riedel from the Canadian Geological Survey. From the U.S. Geological Survey we have microbiologist Mary McGann. Laura Lapham is a geochemist at the University of Florida. Craig Joseph and Tess Menotti are graduate students at Oregon State University and Stanford, respectively, and Yirang Cho is an undergraduate at University of California, Davis. Quite a diverse group, both in research interests and levels of experience!

Chief scientist Charlie Paull describes geological features on a beautiful color map of the seafloor created using data that MBARI’s AUV collected just a few weeks ago.

At the science meeting, Charlie pulled out a stack of beautifully colored maps showing the seafloor areas we’ll be exploring over the next two weeks. These maps are brand new. They were created just a few days ago by Eve Lundsten at MBARI, using data that was collected in late July by MBARI’s underwater mapping AUV (autonomous underwater vehicle). As we gathered around to look at the maps, several of the researchers commented that they’ve been studying this area for years, but could see features on these maps that they didn’t even know existed.

The two areas where we’ll be spending much of our time—Hydrate Ridge and Barkley Canyon—constitute some of the most well-studied seafloor in the Pacific Northwest. Researchers had a general idea of the shape of the seafloor in these areas thanks to soundings from ships. But where the ship surveys might show objects the size of a small house, our AUV surveys can (in the best case) show objects the size of a washing machine.

The reason scientists are so interested in Hydrate Ridge and Barkley Canyon is because they are prime locations to study methane hydrate deposits. Methane hydrate is a weird mixture of a gas (natural gas, aka methane) and a liquid (water), but takes the form of a solid under the immense pressures and near-freezing temperatures of the deep sea. Methane hydrate looks a lot like ice. But if you put a match to it, it will burn with a pale blue flame, just like the flame on a gas stove (if you don’t believe me, check out the photos from the cruise log for Leg 1 of this expedition).

Lots of scientists (including several of our science party) have studied the chemistry and geology of the hydrate deposits at Hydrate Ridge and Barkley Canyon. Charlie’s main goal is to try and understand how these hydrate deposits affect the shape (and stability) of the seafloor. So we’ll be spending a lot of time looking at bumps and pits in the muddy seafloor, as well as collecting two-meter-long “sediment cores” around these features. These cores will allow us to see what’s happening, chemically and geologically, below the seafloor, and may help us understand how the bumps and pits formed.

Such questions are of more than academic interest. For one thing, methane hydrates are generally considered to be chemically unstable. This means that it’s not a good idea to place offshore oil platforms or telecommunications cables in seafloor areas that might be underlain by methane hydrate deposits. In addition, methane hydrates could themselves be used as a fuel. Although major feasibility and environmental questions remain, some geologists have estimated that methane hydrate deposits could supply a significant fraction of our country’s future energy needs.

After our meeting, we all set to work on the mundane and often repetitive tasks that are required for any kind of scientific fieldwork—checking and calibrating instruments, labeling sample jars, etc. I spent most of the afternoon erasing the numbers from one set of aluminum core tubes and writing new numbers on another set of core tubes with a large permanent marker. Although attention to detail is essential in such work, it also provides opportunities for us to chat and get to know one another. We also got to know the ship’s crew and ROV pilots, as we inevitably needed to ask them for tools and advice on getting our gear to work smoothly with the ROV Doc Ricketts.

We’ll be heading out tomorrow morning around 9:00, and hope to get at least one (perhaps two) ROV dives in before the end of the day. This means two sets of samples to process. So we’ll be busy. But we’re looking forward to getting out there!

Tess Menotti, Craig Joseph, and Yirang Cho share a joke while writing numbers on about 300 sample jars. By doing this somewhat tedious work now, we will save ourselves time and confusion when we’re processing and sorting samples of seafloor sediment from each ROV dive.

Laura Lapham prepares long-term water-sampling instruments called osmosamplers, which she will place on the seafloor to study changes in the amounts of methane in seafloor sediments over time. Osmosamplers were invented by MBARI senior research specialist Hans Jannasch, and can collect continuous water samples for months or even years, drawing the water slowly into thin spools of copper tubing that can be more than a kilometer long.

—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