WHOI Scientists Win a Boatload of Honors for Pioneering Research

Article excerpt

Ralph A. Stephen was named a Fellow of the American Acoustical Society, the premier international scientific society in acoustics. He was cited for "for contributions to seafloor elastic wave propagation."

Stephen is a senior scientist in the WHOI Geology and Geophysics Department. The ASA has nearly 7,000 members in theoretical and applied fields, ranging from physicists, engineers and oceanographers to architects, musicians, and speech and hearing researchers.

Nobumichi Shimizu was elected by peers as a Fellow of the American Association for the Advancement of Science (AAAS). Shimizu was selected for his pioneering work in the development and application of secondary ion mass spectrometers in the field of geochemistry and for furthering our knowledge of mantle differentiation.

Shimizu is a senior scientist in the WHOI Department of Geology and Geophysics, as well as founder and director of the Northeast National Ion Microprobe Facility. AAAS is the world's largest general scientific society, and publisher of the journal Science.

Jim Ledwell won the 2007 Alexander Agassiz Medal by the U.S. National Academy of Sciences. Ledwell, a senior scientist in the Department of Applied Ocean Physics and Engineering, specializes in the use of chemical tracers to observe currents in the ocean.

Established in 1913, the Agassiz Medal is awarded every three years to an individual scientist for original and fundamental contributions to oceanography. The academy cited Ledwell for his "innovative and insightful tracer experiments using sulfur hexafluoride to understand vertical diffusivity and turbulent mixing in the open ocean."

To measure the mixing and stirring effects of eddies and internal waves, Ledwell "marks" parcels of water by releasing harmless dyes or chemicals from ships and then measures the subsequent dispersion (sometimes for several years). Such work aids oceanographers in understanding the circulation of the ocean and the transport of nutrients, plankton, and pollutants in ocean ecosystems-all of which are important to marine life and to the ocean's role in climate change. …