DAVID A. DZOMBAK is the Walter J. Blenko Sr. Professor of Environmental Engineering in the Department of Civil and Environmental Engineering at Carnegie Mellon University. He is also Faculty Director of the Steinbrenner Institute for Environmental Education and Research. He has published numerous articles in leading environmental engineering and science journals, book chapters, articles for the popular press, and has authored two books. François M. M.

Morel, the Albert G. Blanke Professor of Geosciences, is a world leader in the chemistry of natural waters and one of the founders of the field of biogeochemistry. His research demonstrated that aquatic chemistry, biochemistry, genetics, and microbiology are critical for understanding the oceans, in the process helping to establish the field of marine biogeochemistry.