Monterey Bay Aquarium Research Institute

 


Gas Hydrates
Day 2: Active gas vents at Eel Slump South
August 23, 2011

Location: 2 miles south of Eel Canyon
Latitude: 40.535792° N
Longitude: -124.784675° W

Today was a very eventful and mostly successful day. We dove on a very interesting feature, Eel Slump South, which is located south of the Eel Canyon bend. Eel Slump South is a large scar that we think was left by a landslide. It has an oblong mound at its base with a rough texture suggesting the presence of gas in the seafloor. The sediment near and on top of the mound was black. This is indicative of a reducing environment with high organic activity and high oxygen consumption. Throughout the dive we saw chemosynthetic clam beds and active vents bubbling gas and releasing oil droplets.

High-resolution multibeam data collected by our mapping AUV allowed us to navigate to the exact spot on a seafloor feature where we collected gas and sediment samples. This map shows in amazing detail the mound that turned out to have several large gas plumes. The red dot shows our first dive site.

Our main objective for this dive was achieved with the collection of three gas samples from plumes emanating from the seafloor and the collection of several vibracores and push cores. During our ascent, the sonar image of this feature showed many columns of gas originating at the mound surface. We got only a taste of what this site has to offer.

A snapshot of the control-room monitors showing our first gas sample being collected. As the gas is captured in the funnel it combines with the seawater to form a crystalline structure called gas hydrate. A metal finger in the center of the funnel is heated to decompose the gas so it can be siphoned into a gas canister for future analysis.
While collecting a push core, oil droplets (bright blue bubbles) rose from the hole left by the core tube and rose to the surface.

A little more than halfway through our dive, the main manipulator arm—the "Schilling" arm—on ROV Doc Ricketts, lost power. Thankfully, the ROV pilots were able to save the day working with only one manipulator arm. Once on board, this skillful team of pilots was able to restore power to the arm, and we are ready to dive tomorrow at the next site, the Eel River Bend.

— Eve Lundsten, Krystle Anderson, Roberto Gwiazda



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Leg 4
 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 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 we bring these cores back to the surface, we typically look for living animals and organic material in the sediments.

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.


Biobox

The box fits in a partition in the sample drawer. It is shown open, with an animal being placed into it by the ROV's manipulator. When the lid is closed, the box will hold water to protect the animals inside.


Vibracores

Vibracoring is a common technique used to obtain samples from water-saturated sediment. These corers work by attaching a motor that induces high frequency vibrations in the core liner that in turn liquefies the sediment directly around the core cutter, enabling it to pass through the sediment with little resistance.


CTD Rosette

A CTD rosette is a cylindrical frame holding a group of plastic water-sampling tubes. Attached to this frame are instruments for measuring water temperature and conductivity (salinity) at various depths. Also attached to the rosette are instruments for measuring parameters such as chlorophyll, nutrients, and particulate matter in the water. As the frame is lowered over the side of a ship, water samples are taken automatically at various depths. Then the frame is raised to the surface again.


 Crew

R/V Western Flyer

Ian Young
Master


 

George Gunther
First Mate


 

Matt Noyes
Chief Engineer


 

Andrew McKee
Second Mate


 

Lance Wardle
First Engineer


 

Olin Jordan
Oiler


 

Paul Tucker
Second Engineer


 

Vincent Nunes
Bosun


 

Dan Chamberlain
Electronics Officer


 

Patrick Mitts
Steward


 

ROV Doc Ricketts

Knute Brekke
Chief ROV Pilot


 

Mark Talkovic
Senior ROV Pilot


 

Randy Prickett
Senior ROV Pilot


 

Bryan Schaefer
ROV Pilot/Technician


 

Eric Martin
ROV Pilot/Technician


 

 Research Team

Charlie Paull
Chief 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. 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 responsible 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.

Eve Lundsten
Research Technician
MBARI

Eve Lundsten works with Charlie Paull in the Continental Margins Lab. Eve's background is in hydrology but she uses her mapping skills, and some of her technical skills to help Charlie Paull understand the processes that are creating the features we see on the sea floor. One of her main responsibilities on this expedition will be running the GIS system. We use Arc GIS and our high resolution, AUV collected bathymetric maps to help direct our research to the precise location of interest on the sea floor. Eve will also help out with processing and cataloguing sediment samples and vibracores. Eve is very excited to participate in this cruise and is looking forward to many exciting discoveries.

Roberto Gwiazda
Research Specialist
MBARI

Roberto is a geochemist by training, and his interests lie at the intersection of marine geology and sediment and water chemistry. On this expedition, Roberto will be responsible for collection and analytical measurements of pore water chemistry on samples taken from sediment cores, and will participate in the collection and analysis of methane from gas vents on the seafloor.

Krystle Anderson
Research Assistant
MBARI

Krystle Anderson is a research assistant working for Charlie Paull in the Continental Margins Lab. Krystle's background is primarily in the acquisition and processing of seafloor mapping data. She came from CSUMB Seafloor Mapping Lab where she obtained her data processing and GIS skills. Krystle spends a majority of her time processing and creating high-resolution maps of multibeam data collected from the mapping AUV. The high-resolution maps Krystle helps create will then be used to aid navigation for the ROV to explore particular areas of interest. On this expedition Krystle will assist with running the GIS system, processing and cataloguing sediment samples and vibracores. This is Krystle's first research expedition with MBARI and she is very excited to be involved in this deep sea excursion.

Philip Barnes
Marine Geologist
National Institute of Water & Atmospheric Research
New Zealand

Philip's specialist interests are in active margin plate boundary processes, including submarine neotectonics, sedimentary basins and sequences, and geohazards. He has undertaken research on subduction, thrust, strike-slip, and rift tectonic systems, sequence stratigraphy and sedimentation processes, submarine landslides, canyon systems, and fluid seepage. Recent initiatives have included the development of on-fault submarine paleoseismic techniques, earthquake source characterisation for national seismic hazard assessment, fluid seepage along the Hikurangi subduction margin, slip rate assessment on the offshore Alpine fault, and submarine canyon development in central and eastern New Zealand. Since the devastating February 2011 earthquakes in Christchurch City, he has been leading seismic reflection studies of active faulting as part of an urgent earthquake risk and recovery work program.

Mary McGann
U.S. Geological Survey
Pacific Coastal and Marine Science Center

Mary is a micropaleontologist/ biologist with the USGS Pacific Coastal and Marine Science Center. Her interests focus on using microbiota (primarily foraminifera but also pollen) in climate, geohazards, sediment transport, and paleotsunami investigations, as well as in biomonitoring marine pollution sites and for AMS C-14 chronostratigraphy.

Brian Edwards
U.S. Geological Survey
Pacific Coastal and Marine Science Center

Brian Edwards, a sedimentologist with the USGS Pacific Coastal and Marine Science Center, has more than 30 years of sea-going experience on 60-plus coring and geophysical cruises along the west coast of the United States and in high-latitude environments (the Ross Sea [Antarctica], the North Pacific Ocean, the Bering Sea, and the Arctic Ocean). Brian specializes in sedimentary processes and stratigraphy, integrating insights gleaned from seafloor rock and sediment samples with information from remote-mapping products, such as close-up photographs of the seafloor, high-resolution bathymetric maps, and seismic-reflection profiles. His recent studies have focused on how sediment moves from the land to the deep sea, processes controlling submarine landslides, saltwater intrusion into coastal aquifer systems, marine pollution, seafloor habitats, and the Cenozoic history of the Arctic Ocean.

Andreia Afonso
Task Group for Maritime Affairs
Portugal

Andreia Afonso has a degree in Marine Sciences from the Lusofona University where she has specialized in the field of Physical Oceanography. Since 2008, Andreia has been working within the former EMEPC (Task Group for the Extension of the Continental Shelf), now called EMAM (Task Group for the Maritime Affairs), where she received ROV pilot and engineer training and has integrated the 6000m rated ROV LUSO technical team. She has participated in five multidisciplinary missions, dominantly in the scope of the Continental Shelf Extension Project involving deep sea research. Andreia is very interested and motivated by the conceptualization, development and implementation of new sea technologies and tools. Apart from EMAM's ROV Team related tasks, she is now project coordinator at EMAM for the development of a modular buoy as a ground for the development of a near shore marine environmental monitoring observatory.

Saulwood Lin
Sediment Biogeochemist
Institute of Oceanography
National Taiwan University

Saulwood Lin is interested in diagenesis in sediments. He has been working on biogeochemical processes associated with gas hydrate and chemical weathering of small river drainage basins. In one ROV cruise he participated, he found a unique cold seep environment in the passive margin off Taiwan. To better understand gas seeps and chemosynthesis community, he joins the MBARI cruise for the purposes of learning ROV instrumentations, sampling and operation of ROV and AUV to facilitate Taiwan's gas hydrate research.