Mark Warner - Faculty Spotlight

Mark Warner - Faculty Spotlight image

Mark Warner - Faculty Spotlight image

Associate Professor Mark Warner

About myself

Like many people in my generation, my goal to become a marine biologist was sparked by watching TV specials following the adventures of Jacques Cousteau. I had spent childhood vacations at the Jersey Shore, and always was fascinated by the ocean and the nearshore sea life. I learned to scuba dive while in high school and explored many of the local dive spots. They were not quite as exciting and interesting as those explored by Jacques Cousteau. At the same time, I was discovering that I enjoyed classes in chemistry more than those in biology. I decided that becoming a chemical oceanographer was my career goal, and I applied to the few undergraduate programs that offered B.S. degrees in the field.

I spent four years in the undergraduate oceanography program at Florida Institute of Technology earning a degree in Oceanography with a focus on chemistry. While there, I had my first experiences in the laboratory and in the field. I worked for a faculty member that was measuring polyaromatic hydrocarbons in drilling muds using HPLC (high- pressure liquid chromatography). I found that I enjoyed being at sea more than I enjoyed spending time in the lab - especially working with carcinogenic compounds.

I attended graduate school at Scripps Institution of Oceanography where I was advised by Dr. Ray Weiss. His specialty is making high- precision measurements of trace compounds in the atmosphere and dissolved in seawater, and then interpreting these distributions. At the time, he and Dr. John Bullister were developing an improved technique for measuring the chlorofluorocarbons, based upon the analytical techniques developed at NOAA-PMEL by Richard Gammon, Dave Wisegarver, and Joel Cline. Recent studies had shown the potential of these compounds to be useful as tracers of ocean circulation. My first small project was to precisely and accurately measure the solubilities of CFC-11 and CFC-12 as functions of temperature and salinity. With these solubility functions, it was possible to show that the CFCS in the surface ocean were at or near equilibrium with the overlying atmosphere, and it enabled us to convert measured distributions of the CFCs in the ocean into distributions of apparent ages.

Tracer oceanography

The interdisciplinary field of tracer oceanography became my career. Although the measurement of CFCs and other tracers involves the development of analytical chemistry techniques, the interpretation of the measured distributions of these anthropogenic compounds relies on a strong understanding of the large-scale circulation and the processes by which the ocean is ventilated. Since the CFCs can only enter the ocean through gas exchange at the surface and they are not destroyed within the ocean, their distributions reflect how the ocean interior exchanges with the atmosphere on the time scale since the post-World World II increase in production of these compounds. Any water parcel which has detectable CFCs has been in contact with the atmosphere in the past 60 years or so. Since we also can reconstruct what the surface CFC concentrations must have been over that time, we can convert the measured concentrations into an estimate of the time since that water parcel was at the surface. However there are many complicating factors in interpreting the CFCs in this simple manner (e.g. undersaturation at the surface, mixing) which require numerical modeling to help quantitatively understand the observations.

Unfortunately for those of us who measure CFCs (and fortunately for the world as a whole), the production and use of CFCs were banned under the Montreal Protocol in the late 1980s and the concentrations of CFC-11 and CFC-12 have begun to decrease in the atmosphere leading to further complications in interpretation of the measurements. After casting about for other compounds which would make useful tracers and which could also be measured in relatively small volumes of water, we have now added sulfur hexafluoride to the suite of measured compounds.

It is detectable at very small concentration levels in the ocean and its atmospheric concentrations are still increasing.

I love that there is still a sense of adventure in oceanography.

My path to the School of Oceanography

I came to UW as a JISAO post-doctoral research associate in 1989 after a short post-doctoral appointment (and another cruise) at SIO. Thanks to Prof. R. Gammon, I was able to take over his CFC analytical laboratory. I transitioned to become a Research Assistant Professor in 1992.

Teaching

I have been teaching the Ocean 220: Introduction to Field Oceanography course off and on over the past 10 years. Since I enjoy fieldwork, I try to pass that excitement on to the students. It is also a challenge for me and the students as a major part of the course is learning about interpreting data they have collected. It is very different for the students in that there is no right answer (as there is in, for example, chemistry labs).

field experiences

I love the challenge of making very difficult measurements aboard a ship. Not only is there the excitement of being at sea and traveling to faraway places, there is also the satisfaction of making the first (and best) measurements of the transient tracers in the ocean. As a graduate student, I participated in 6 cruises - spending 194 days at sea making measurements of the CFCs. The CFCs were the exciting new measurement and were added to many hydrographic cruises that were designed to cross the major ocean basins. These were the first measurements of these compounds in the ocean so there was also the excitement of learning something new about the ocean.

I continue to have an active field program - spending on average about one month per year at sea. I just returned from a 38-day expedition along 32 deg S between Papeete, Tahiti, French Polynesia and Valparaiso, Chile.

One of the most interesting cruises I've been on was a 72-day expedition on the R.S.V. Aurora Australis, an Australian icebreaker, in and out of Hobart, Tasmania. We occupied eight north-south sections from 63 deg. S onto the Antarctic continental shelf between 80 deg E and 150 deg E. The scenery and the wildlife were incredible. In addition to the wonderful experience of seeing Antarctica and getting the opportunity to visit an Australian base, the food was very good and the pub on board the ship was open 24 hours.

On the other end of the spectrum, at least for comfort, was a 45-day trip on the Russian research vessel, Akademik Lavrentyev, in the Sea of Okhotsk. Fortunately, the Russian crew and scientists were wonderful to sail with and the scientific results were great.