Ludwick Lecturer Uses Unique Chemical Tracers to Study the Changing Ocean

Radioactive isotopes released decades ago by atmospheric nuclear weapons tests were damaging to the environment in some ways, but over time these same substances have proven to be useful to oceanographers such as William Jenkins of Woods Hole Oceanographic Institution.

Jenkins, who will deliver the annual John C. Ludwick Memorial Lecture of Old Dominion University's Department of Ocean, Earth and Atmospheric Sciences on Thursday, April 8, has been a pioneer in the use of these isotopes as unique tracers of physical and biogeochemical processes in the oceans. The more scientists know about these processes, the better they can understand and predict global climate change.

Jenkins, senior scientist at Woods Hole, will speak at 3 p.m. April 8 in the first-floor auditorium of the E.V. Williams Engineering and Computational Sciences Building. His lecture, titled "What Goes Down Must Come Up - An Old Oceanographer's Saying," is free and open to the public.

The speaker is one of the world's foremost experts on the application of so-called transient tracers to oceanography. Transient tracers are man-made substances that are gradually moving through the global environment. For example, in addition to radioactive isotopes from nuclear weapons tests, they include the chlorofluorocarbons that once were widely used in refrigerators, air conditioners and spray cans.

Transient tracers of interest to Jenkins were introduced into the atmosphere within a known time frame and can be detected and followed as they settle into the oceans and move around due to currents and other processes. These tracers can be used to examine, for example, how carbon dioxide moves from the atmosphere into the ocean. By illuminating the large-scale mixing of the ocean, the tracers can also give scientists information about the propagation of climatic changes into the deep oceans.

An article co-written by Jenkins sums up this work: "Transient tracers provide us with a unique opportunity to visualize the effects of the changing climate on the ocean. They trace the pathways climate anomalies follow as they enter and move through the ocean and give us valuable information about rates of movement and amounts of dilution. This knowledge is important for developing ocean-climate models to predict long term climate changes."

Jenkins is a fellow of the American Geophysical Union, the Geochemical Society and the European Association of Geochemistry. He is also a recipient of the Rosenstiel Award, the Huntsman Award for Excellence in Marine Science and the Bigelow Medal in Oceanography.

For more information about the lecture, call 683-4285.