Monterey Bay Aquarium Research Institute

Deep-Sea Chemistry Logbook
Day 1: Nothing ventured, nothing gained
March 14, 2012

One may not doubt that somehow good
Shall come of water and of mud
And sure the reverent eye must see
A purpose in liquidity.

           —Rupert Brooke
The Fish

After three days in port to refuel, switch out some crew members, and mobilize the next group of scientists and their equipment, the Western Flyer set sail from La Paz early this morning. The principal goal of the day was to transit to our group’s test site and conduct a brief test of a new piece of equipment before moving to our primary target.

Early in the day the team received the latest map created by our colleagues working with the autonomous underwater vehicle (AUV) D. Allan B. on the R/V Zephyr. The detail provided by this new map was stunning. Data gathered with the mapping AUV produces maps with details as small as one meter (3.3 feet) across. Previous maps available for this area provided no better resolution than 50 meters (164 feet).

The blurry image at the left is all that could be seen of a pit in the seafloor in maps previously created with sonar mounted on surface ships. The image at right shows the exact same area at the same size, created with data collected with MBARI’s mapping AUV yesterday. Note all the details not previously visible. At its widest spot, this pit is about one kilometer (3,280 feet) across.

As it turned out, the area covered by the new map was just a little bit deeper than this team’s equipment is rated for so it was not used to locate today’s work site.

Every year ocean chemist Peter Brewer and his group make improvements to their laser Raman spectrometer system to enhance its precision in measuring the chemistry of "pore water"—the water that occupies the space between seafloor sediment particles. One of the latest such efforts was the addition of a “liquid-core waveguide” which had proven in the lab to provide a much stronger signal of the chemical components in the pore water. The waveguide includes a coil of tubing; the laser is aimed to hit precisely within the tube, giving a longer sample of the water for the light to pass through, thereby amplifying the signal. By watching the Raman spectra—a graph constantly updated as the laser Raman system moved through the water—it would be obvious if the results were any better. Unfortunately, the high-definition reading did not materialize due to a micrometer-size mismatch in alignment that could not be fixed in the field.

Trying out new methods and instruments is part and parcel of MBARI’s mission. This liquid-core waveguide was worth testing out to see if it might augment our arsenal of tools to learn about the ocean and its mysteries. It didn’t pan out today, but the team learned a little more about what works, and will at some time in the near future have an opportunity to revise it.

Research technician Peter Walz inspects the coil of tubing on the liquid-core waveguide prior to sending it down to 2,000 meters (6,500 feet) for testing. It looked perfect on deck, but when it got to depth, it wasn’t quite as good as hoped for.
Close-up of the liquid-core waveguide.

Before leaving the seafloor, a couple of sediment cores were collected as a trial run for several members of the science group who hope to collect more such samples later in the expedition. The sediment in the particular area where the remotely operated vehicle (ROV) had landed turned out to be a shallow layer of mud on top of hard volcanic rock. This may bode well for our colleagues who study volcanic processes, but this group needs to find deep mud for inserting the laser probe. Tonight we are sailing north a bit, aiming for a better research site for tomorrow, again close to where the marvelous new maps are being created.

—Nancy Barr

Next log

Deep-Sea Chemistry
 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.

CTD Rosette

The CTD measures conductivity (which helps determine salinity), temperature, and density (which helps determine depth). This particular CTD runs profiles of the water column (surface to bottom) and along the way, collects discrete water samples (at specific predetermined depths) using the rosette of niskin bottles. Each bottle can collect a water sample. The transmissometer measures the number of particles in the water and the oxygen sensors tell us how much dissolved oxygen is present. Both of these instruments go onto the CTD rosette and give us a profile of the water column.

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.

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


 

Andrew McKee
First Mate


 

Matt Noyes
Chief Engineer


 

Cole Davis
Second Mate


 

Lance Wardle
First Engineer


 

Shaun Summer
Relief First Engineer


 

Olin Jordan
Oiler


 

Craig Heihn
Relief Deckhand


 

Jason Jordan
Relief Deckhand


 

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.

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. 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.

Peter Walz
Senior Research Technician
MBARI

Peter has worked as a research technician for several scientists at MBARI. For the past 10 years he has supported the research efforts of Peter Brewer and his interests regarding the ocean chemistry of greenhouse gases such as methane and carbon dioxide. Peter is responsible for the design, testing, maintenance, and deployment of the oceangoing science hardware and works closely with the marine operations group to integrate new equipment and technology with MBARI's ROVs.

Martín Hernández Ayón
Collaborator
Universidad Autónoma de Baja California

Martín Hernández Ayón is a chemical oceanographer. His research is focused on the inorganic carbon system, ocean acidification and biogeochemistry in the coastal regions of Baja California, the Sea of Cortez, the subtropical region where the oxygen minimum zone is located, and, more recently, the Gulf of Mexico.

Gabriela Y. Cervantes
Graduate Student
Universidad Autónoma de Baja California

Gaby is a graduate student in the coastal oceanography program at the University of Baja California in Ensenada, Mexico. She is doing her graduate studies on the dynamics of CO2 in seawater from a coastal monitoring site known as Ensenada Station.

Abbey Chrystal
Graduate Student
University of California, Santa Cruz

Abbey Chrystal is a graduate student in earth and planetary sciences at the University of California, Santa Cruz. Her research focuses on reconstructing long-term records of past ocean carbonate chemistry parameters. On this cruise she will be collecting sediment push cores and bottom water samples to help calibrate the relationship between the shell chemistry of benthic foraminifera and the chemistry of the bottom water and porewater chemistry in which they grow.

Joseph Murray
Graduate Student
University of California, Santa Cruz

Joseph Murray is a first year ocean sciences Ph.D. student in the lab of Dr. Adina Paytan at the University of California, Santa Cruz. He is interested in coastal marine chemistry and the impact of submarine groundwater discharge on marine biogeochemical cycles. His current research is focused on using oxygen and nitrogen isotopes in nitrate to study sources and cycling of nitrogen in the coastal ocean. As part of this cruise, he plans to collect samples in order to study the impact of anthropogenic fertilizer runoff from the Yaqui Valley on the marine nitrogen cycle in the Gulf of California, including assessing the role groundwater discharge plays in this process.



Last updated: Mar. 17, 2012