Monterey Bay Aquarium Research Institute

 


Deep-sea chemistry
Michael Riedel's Cruise Summary
August 18, 2011

My participation in this expedition was sparked by earlier scientific collaboration between MBARI and the Geological Survey of Canada, University of Victoria, and NEPTUNE-Canada. In 2009, I was onboard the Western Flyer with MBARI scientist Dr. Charles Paull investigating cold vents and associated seafloor gas expulsion in this area. Dr. Brewer, chief scientist of this expedition, invited me to sail on this cruise to help find suitable locations for his experiments of ocean geochemistry.

One of the most fundamental scientific questions we are pursuing is unravelling the linkages between tectonic activity and fluid expulsion, as well as changes in sediment geochemistry, and the biology of the vent sites at the seafloor. In 2009, we started a long-term observation strategy in collaboration with Dr. Laura Lapham from Florida State University, deploying instruments to study natural gas and oil expulsion. In 2009, two of these sampling instrument packages were deployed at Barkley Canyon and at a vent-field, informally named “Bubbly Gulch”. This year’s expedition gave us the opportunity to expand the time-series analysis on the same sites and help answer the question if earthquakes spark fluid expulsion and gas release.

Also, this cruise was another opportunity to further explore the exciting vent locations we previously found, and study their evolution with time. We learned from these two MBARI cruises that these sites are changing quickly, and that it does not take long for an area with gas venting to become inhabited by chemosynthetic communities including bacterial mats, clams, and tube-worms. The combined results from both cruises will help us understand the dynamics of vent sites and prepare for more detailed long-term observation strategies that can be added to the NEPTUNE-Canada cabled observatory.

Dr. Brewer also allowed me to explore a completely new area of suspected gas venting, which has been discovered only by chance in 2010 during a seismic monitoring experiment of the Geological Survey of Canada. A full day of exploring these areas this week showed that the area must have been active for several thousand years to account for the massive build-up of carbonate exposed on the seafloor. The results of this one day of exploration will be sufficient to plan for future visits with ROVs, dedicated mapping, and possibly an expansion of the NEPTUNE-Canada monitoring and long-term observation strategy in Barkley Canyon.

While the various scientific experiments were conducted over the course of the expedition, I took the opportunity to use the echo sounders mounted on the hull of the Western Flyer and on the remotely operated vehicle to chase gas bubble plumes in the water. An overall enigma and yet not fully understood process is the discharge of methane at the seafloor and how much of this methane may end up in the atmosphere and possibly impact climate change.

Another unique event happened during this cruise, which turned out to be one of the highlights of the entire expedition. I had received an email from NEPTUNE-Canada with a request if we could help and fix a recently-occurred problem on one of their instrument platforms of a seismometer near Bullseye Vent. After some days of exchanging information and making sure our ROV pilots were familiar with the equipment and procedures, we set out to find the equipment and carry out the maintenance operations on Sunday, August 15. I was on the phone with NEPTUNE-Canada representative Dr. Martin Heesemann linking our ROV pilots with the shore-base NEPTUNE-Canada crew to carry out the required repairs. After about half an hour the problems with the NEPTUNE-Canada equipment were fixed and data from the NEPTUNE-Canada seismometer were again flowing into the national and international earthquake data bases. A very successful operation for everyone involved, further strengthening the bonds between all the various teams and agencies taking part in this undertaking.

— Michael Riedel



Previous log

Leg 1
 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.

Laser Raman spectrometer DORISS2

By bouncing a specially tuned laser beam off of almost any object or substance—solid, liquid, or gas—a laser Raman spectrometer can provide information about that object's chemical composition and molecular structure.

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.

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.

CO2 accumulator

Carbon dioxide is a liquid at the temperatures and pressures on the seafloor where hydrates are known to occur. Because of this, one cannot simply take down a tank of gas and expect to be able to release it at depth. Instead, the CO2 piston accumulator is used to deliver precise volumes of liquid CO,2 to experiments on the seafloor. The valves are operated hydraulically by remote control and hydraulic pressure is used to expel the liquid CO2 and deliver it to the experiments.

Heat-flow probe

MBARI's heat-flow probe is mounted on the side of the ROV Doc Ricketts inside the vertical stainless steel box. This both protects the delicate probe and provide the track so that the probe can be inserted into the sediment along a totally straight path.  The probe contains five high precision platinum sensors which are used to measure the vertical temperature gradient in the sediments. This gradient along with some knowledge of the heat capacity of the sediment allows scientists to calculate the rate of heat loss from the sediments into the ocean.

 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

Peter Brewer
Chief Scientist
MBARI

Peter has taken part in more than 30 deep-sea cruises, and has served as chief scientist on major expeditions and on more than 90 ROV dives with MBARI ships and vehicles. His research interests include the ocean geochemistry of the greenhouse gases. He has devised novel techniques both for measurement and for extracting the oceanic signatures of global change. At MBARI his current interests include the geochemistry of gas hydrates, and the evolution of the oceanic fossil fuel CO2 signal. He has developed novel techniques for deep ocean laser Raman spectroscopy, and for testing the principles and impacts of deep ocean CO2 injection.

Ed Peltzer
Senior Research Specialist
MBARI

Ed is an ocean chemist who has been with MBARI since 1997. He has been involved in developing in situ laser Raman spectrometry instruments and lab based analytical techniques to study the composition of gases in gas hydrates and deep-sea vents. He has collaborated on the development of new instrumentation for the measurement of temperature and pH from ROVs and deep-sea observatories. As the group's project manager, Ed is also responsible for expedition planning and logistics.

Peter Walz
Senior Research Technician
MBARI

Peter has worked as a research technician for a variety of scientists at MBARI. Most recently he has supported the research efforts of Dr. Peter Brewer and his interests in the ocean chemistry of greenhouse gases such as methane and carbon dioxide. Peter assists with the design, testing and deployment of the ocean going science hardware and works closely with the marine operations group to integrate new equipment to work with MBARI's ROV's.

Andreas Hofmann
Postdoctoral Fellow
MBARI

Andreas is a MBARI Postdoctoral Fellow in the Brewer lab. He obtained a PhD in marine biogeochemistry in the Netherlands after his biology undergraduate and bioinformatics graduate studies in Germany. Andreas' specialty is pelagic and benthic biogeochemical modeling with a focus on pH and proton cycling. At MBARI, Andreas is working amongst others on the characterization of marine hypoxic and suboxic zones, focusing on the explicit description of physical limitations to aerobic respiration. On this cruise, Andreas will be involved in obtaining and processing Raman spectra, as well as in various other tasks supporting the objectives of the group.

Nancy Barr
Web/Print Project Manager
MBARI

Nancy manages the editing, design, and production of the MBARI annual report and participates in a variety of editorial and communication projects. She also oversees the institute website. Nancy has been to sea with several MBARI research groups, helping them to carefully remove worms from whale bones, annotate video, sift seafloor sediment, and collect and process water samples. For this expedition she will be in charge of the daily reports that will be posted to this website and will assist with other science crew tasks.

Elizabeth Coward
Summer Intern
MBARI

Elizabeth is an MBARI summer intern in the Brewer lab. She is a senior at Haverford College, PA, where she is obtaining her undergraduate joint degree in biology and chemistry. Elizabeth's prior research has been principally concerned with the bioavailability and geochemical dynamics of oil in marine sediments. Her interest in oceanic fossil fuels and greenhouse gases has brought her to the Brewer lab, where she will be using laser Raman spectroscopy to investigate methane and carbon dioxide signatures, the dynamics of gas hydrates and ocean acidification.

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.

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.

Jon Furlong
University of Victoria

Jon is a graduate student at the University of Victoria studying with Michael Riedel. His bachelor's degree was completed in Earth Sciences from Memorial University in Newfoundland before he moved from one coast to the other. Jon's research focuses on neo-tectonic faulting offshore Vancouver Island and its links to gas hydrate formation and fluid migration.