 Leg 1 Logbook - Laser Raman Spectroscopy
Day 10 – Operation Deep Probe
July 16, 2009 0900 hours – On-station at Barkley Canyon, west of Vancouver Island, Canada. Unlike yesterday’s dive plan where we attempted to visit as many gas hydrate mounds as time allowed and to poke each in hopes of finding free gas or oil, today’s dive plan was to systematically study just two or three mounds making pore-water profile measurements on top of, beside, and in a line away from each mound. 
View through the A-frame on the fan tail of the R/V Western Flyer. One cannot see the coast, but if you look carefully you might see the tops of the mountains in British Columbia. A day this clear and bright is rare here but a welcome relief from the overcast and fog.
Inside the ROV control room, Peter Brewer directs the team investigating gas hydrate mounds in the deep sea. From left: Randy Prickett (ROV pilot), Peter Brewer, Ed Peltzer, and Keith Hester.
The day began bright and sunny which is unusual weather for this area but very much welcomed by all. So, while the crew looked for ways to work outside today, the ROV pilots and science team were stuck inside watching video monitors in the dark (above), although no one was complaining as these are the opportunities that we strive for. Today’s work was a series of carefully designed in situ pore-water measurements (below) that we designed to carefully peel back the conditions under which these mounds form and persist. While we methodically went about our business, we were visited by various denizens of the deep. Our most frequent visitor was the black cod or sablefish (Anopoploma fimbria) (below) and occasionally a flatfish would swim by (see below). As you can see by their close approaches, our analytical methods are totally benign. We often attract animals around our experiments and whether they have a equally strong passion for our work or are merely curious is anyone’s guess. 
A black cod (Anoploploma fimbria) swims by as the ROV pilots carefully insert the laser Raman pore-water sampler into the sediment next to a gas hydrate mound.
A black cod comes in close to see what we are up to and offer some words of advice. 
A flatfish (?Microstomus pacificus) swims by totally unaware of the world-class science happening just a meter or so away.
After a successful day sampling pore-waters around and on top of several hydrate mounds we moved off-site so that the Danish cable laying ship Lodbrog and the R/V Atlantis from Woods Hole Oceanographic Institution could install some of the undersea components of the NEPTUNE cabled observatory (below). NEPTUNE stands for the North-East Pacific Time-series Underwater Networked Experiments. 
The Danish cable laying ship Lodbrog and the R/V Atlantis from Woods Hole Oceanographic Institution slowly emerge from the fog as they install some of the undersea components of the NEPTUNE cabled observatory.
If all goes well and they finish their work tonight, we will return to this site tomorrow. Otherwise we will yield to their needs and head off to another part of the canyon for a day of exploring. Stay tuned. 
The tether management system on the R/V Western Flyer consists of a motion-compensating crane, a tension winch and the large drum that holds over four kilometers of tether. For those of you who saw last week’s photo question on how well you know the R/V Western Flyer, here is the answer: Those mysterious bumps were grease stalagmites that form underneath the tether winch. As the ROV draws power through the tether, the wires on the drum get warm softening the grease and allowing it to slowly drip onto the deck below (see above and below). 
If you look closely underneath the tether drum, you can see some grease stalagmites slowly forming. But don’t get too close, it is really greasy under there and deck crew gets quite upset if you track it throughout the ship.
On Friday, we will have one more mystery photo. - Ed Peltzer
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Track the ship
Equipment
 R/V Western FlyerThe 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 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.
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.
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.
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.
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.
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. Research Team
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 is an ocean chemist who has been with MBARI since 1997. He has been involved in developing instrumentation and analytical techniques to study the composition of gases in gas hydrates and deep-sea vents. He has also collaborated on the development of new instrumentation for the measurement of temperature and pH from an ROV. As the group's project manager, Ed is also responsible for expedition planning and logistics.
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.
Xin Zhang is a Ph.D. student from the Ocean University of China and is now studying at MBARI with Peter Brewer and Bill Kirkwood. He has been involved in the development of a Deep-Sea Raman Probe for the measurement of sediment pore water geochemistry. In this expedition, he will focus on obtaining the in situ pore water Raman spectra and the collection of pore water samples for subsequent shipboard analyses by ion and gas chromatography.
Keith is currently an associate engineer with ConocoPhillips focused on natural gas hydrates. Keith received his PhD in Chemical Engineering from the Colorado School of Mines in 2007. This was followed by a two-year postdoctoral fellowship at the Monterey Bay Aquarium Research Institute with Dr. Peter Brewer. His research interests include the use of carbon dioxide to replace methane in natural hydrates.
John has been a staff member at the NRC since 1974, first with the Division of Chemistry, then with the Steacie Institute for Molecular Sciences upon its establishment in 1991. His research focuses on the chemical applications of solid state nuclear magnetic resonance (NMR) spectroscopy, the development of multi-technique approaches to the characterization of materials, supramolecular chemistry, porous materials, clathrates, gas hydrates, and other guest-host materials. He has nearly 500 publications and six patents and is often an invited speaker at special events. |
