Research in action: David Valentine tracks oil and gas in the Gulf of Mexico

 

David Valentine took this photograph of Alvin, the famed ocean explorer owned and operated by the Woods Hole Oceanographic Institution. Valentine and some of his students discovered large undersea asphalt volcanoes while using Alvin to explore the Santa Barbara Channel during a research expedition in 2007. That same year, Valentine was recognized by Chancellor Henry Yang for his outstanding mentoring of undergraduates in his research group.

2010 began as a busy year for David Valentine. A professor in UCSB’s Department of Earth Science and specialist in marine geochemistry, Valentine was busy teaching, writing, leading his research group, and planning his next marine research expedition. He had just published his first book, with his father, and one of his scientific papers, on the discovery of underwater asphalt volcanoes in the Santa Barbara Channel, was receiving considerable media attention. All in all, it was already shaping up to be a busy year for the scientist. Then on April 20, 2010, the Deepwater Horizon exploded and oil and gas began spewing into the Gulf of Mexico. Realizing within days how serious the impact would be, Valentine immediately made arrangements to visit the area on the first of five eventual research expeditions to the Gulf. His findings, which have appeared in publications in the journals Science, Nature, and Environmental Science and Technology, have made significant contributions to understanding how the ocean responded to this event and to the ongoing assessment of the damage caused by the oil leak.

A marine geochemist, Valentine studies what happens to gas and oil in natural underwater seeps, including the formation of hydrates (methane crystals) in water. After the explosion, he understood almost immediately that there was a high gas content in the oil spewing into the deep water. A colleague who was on site within a few days of the explosion saw what was coming out of the ruptured well and confirmed what Valentine suspected: about one third of the total material coming out of the break was natural gas. He predicted in the Los Angeles Times that BP’s idea for a “top hat” to cap the leak would not work because the pipes would be clogged with gas hydrates, and was unfortunately proven right a week later when that attempt failed.
 

 

Burning oil rig in the Gulf of Mexico, June 14, 2010. Photo by David Valentine.

Realizing that the oil and gas were likely to spill for weeks or months, Valentine quickly made plans to begin collecting samples and to visit the Gulf himself. He acquired a RAPID award from the National Science Foundation (which funds his oil-related research), enabling him to bring in a post-doctoral researcher, Dr. Molly Redmond, to study the “oil side of the puzzle,” and to send Dr. Redmond and other members of his lab on multiple trips to the Gulf. He also received funds from the Department of Energy (which funds his methane research) for him and two graduate students to collect samples. members of his lab were on site as the oil began to reach the shore in April, with oceanographic expeditions also in May and June. One of his collaborators, John Kessler, an assistant professor at Texas A&M University, received a RAPID award to provide time on a research vessel for their team’s expedition to examine the oil spill. The team, including Valentine and two of his graduate students, was on site from June 11 to 21, with other members of the Valentine Lab at UCSB participating long distance.

Once in the Gulf, they were “right in the thick of things”, said Valentine, at distances ranging from 10 miles to as close as 500 meters to the flowing well head. The team did instrument sampling, vertical sampling of the water, and tracked the dissolved gas in the deep water. They found initially that the methane and other natural gas was entirely dissolved in the deep water, but that microbes were respiring the propane and ethane components, causing oxygen decline in the water. Valentine spent the month of July examining the data they gathered, which resulted in a key publication in Science, "Propane respiration jump-starts microbial response to a deep oil spill," which appeared in September.

Throughout the spill BP and government officials struggled to determine how much oil was spilling into the water, and in response Valentine published an opinion piece in Nature suggesting that plumes of dissolved gas be used to determine how much oil had leaked into the Gulf, and urging the studies be done quickly. This approach later proved useful for tracking and estimating the gas released from the well. In press interviews around the same time, he also expressed concern about the unknown long-term effects of the chemical dispersants being used to break up the spill, and in January 2011 published a paper with Dr. Elizabeth Kujawinski from Wood’s Hole Oceanographic Institution that was first to define the fate and transport of dispersant released at the ruptured well.

At the request of NOAA, Valentine returned to the Gulf with Kessler and undertook a second research expedition early in September, to learn if there was still oil that was “actionable” and could be cleaned up. With just seven days’ notice, Valentine was able to assemble a team including Dr. Redmond, two UCSB graduate students, Stephanie Mendes and Stephani Shusta, and two undergraduates who were members of his research group, Christie Villanueva and Lindsay Werra. The team spent two weeks tracking the deep water plume, examining the respiration rate of bacteria and their consumption of oil and gas, and the water’s oxygen deficit. They found that diluted oil remained in the water but all the gas, including methane, had been consumed by bacteria. The results of this research were published in Science in January 2011.

Valentine returned to the Gulf for a third time in September, again at NOAA’s request, to try and determine how much oil was on the sea floor. Using a special camera that was towed behind the ship, the team took over 8000 images in the vicinity of the well head but saw no visual evidence of oil, and found little evidence of oil in the core samples they collected. Valentine remains confident that the oil is there in different areas than where they looked and hopes to return to the Gulf to find these pockets of oil and to see how rapidly microorganisms are consuming the oil and what compounds are left over. Because there is also natural oil seepage in the Gulf area, they also mapped natural seeps that cross the deep water plume to see where they may overlap with the spilled oil.

Valentine has since returned to the Gulf as chief scientist on additional cruises as part of a government effort to assess the lasting damage caused by the spill. In the long term, he says, there will likely be different effects of the spill in different parts of the Gulf, and he hopes his ongoing research will help to define where these areas are, and how significantly they are affected.

Read an interview with David Valentine and fellow UCSB scientists Ira Leifer and Igor Mezic about their work responding to the Gulf oil spill in Convergence, UCSB's magazine of engineering and the sciences. Valentine and John Kessler are also featured in  "The Gulf War," by Raffi Khatchadourian, published in The New Yorker, March 14, 2011.
 

Researcher, teacher and mentor

How did David Valentine become a national expert on the critical intersection of oil, gas, and water?

As an undergraduate and then master’s degree student in chemistry and biochemistry at UC San Diego, he developed an interest in environmental policy. But he was advised by Professor Gordon J.F. MacDonald, a geophysicist and adviser to four U.S. Presidents, to gain experience in science before moving into the policy arena. Following this advice he enrolled in a fledgling Ph.D. program at UC Irvine in the interdisciplinary field of Earth Systems Science, which encompassed the atmosphere, the ocean, and earth science. He became interested in combining chemical and biological research in earth systems, and his research focused on the metabolism of organisms and the processes they perform in nature, their distribution and impact on chemical reactivity, and trends of their metabolisms in the ocean and elsewhere. Over the three and a half years of his Ph.D. studies he found immense joy in the aspect of discovery in science, and shifted his goals from environmental policy to basic scientific research.

As a second-year graduate student, Valentine was invited on a research cruise to study the oil seeps off Santa Barbara. Among the cruise participants was Professor Jim Kennett, now emeritus professor of earth science, who was studying methane hydrates and their role in climate change. This was Valentine’s introduction both to UCSB (except for one Halloween he had spent in IV as an undergraduate!), to the offshore environment, and to sea floor oil seepage, all of which were critical to his later research. After receiving his Ph.D. in 2000, Valentine joined the UCSB faculty but deferred his first two years to complete a fellowship from the National Science Foundation to study microbiology at the Scripps Institute of Oceanography at UC San Diego. He began teaching at UCSB in fall 2002, and in less than 10 years has had an enormous impact on the campus.

Valentine gives as much emphasis to mentoring his undergraduate students as many professors give to their graduate students. His classes range from an introduction to oceanography for non-science majors, with 250 students, to a specialized course in earth systems, which covers oceans and the atmosphere and provides a global-scale view of how the climate cycle affects the planet. He teaches the latter differently than more traditional courses, since the material covers chemistry, geology, physics and biology, and the students need some background in all of the areas to understand the concepts of the course.

One of the most important undergraduate courses he teaches is field studies in marine biogeochemistry, a two-quarter course sequence followed by a summer research expedition, in which all the students take part. He is currently teaching the course for the fourth time, which means that this summer he will again be heading out to sea with his students. The number of students taking part depends on the size of the ship he can reserve, but ranges form 10 to 14. The ships are administered by the National Oceanographic Laboratory System (UNOLS), a consortium of 61 academic institutions and national laboratories involved in oceanographic research which is funded in part by the NSF and NOAA. Before planning the expedition, Valentine must first receive a grant from the National Science Foundation to cover the entire cost of the expedition and the related scientific project, including all costs for his students. Most of his cruises have been off the coast of California, between San Francisco and San Diego, and usually last  16-19 days. There are about 60 people on each ship, including a crew of 30, and in addition to his students Valentine includes colleagues from other universities. During his 2009 expedition, six UCSB undergraduate students dove with him in the famed deep diving submarine Alvin.

In recognition of support for his undergraduates, in 2009 David Valentine received the Chancellor's Award for Mentorship of Undergraduate Research, which is presented annually to one faculty member with a distinguished record of mentoring undergraduate students in their research projects. Valentine received the award in recognition of his outstanding teaching and research contributions and for providing "career-changing experiences" by fully integrating undergraduates into research activities. He was cited for enabling students to play key roles on research vessels and in fieldwork, supporting their professional development at academic conferences, and including students on scholarly publications, sometimes as lead author.

March 2011

News Date: 

Tuesday, March 1, 2011