2019 Benjamin Franklin Medal in Earth and Environmental Science presented to Gene E. Likens, Ph.D.

A watershed is the land area that supplies water to a particular river from topographic high points; small watersheds join together to make large ones that eventually lead to outflow points such as reservoirs, bays, and the ocean. Watershed management has become important in terms of flood control, pollution control, ecosystem energy and material flow, and regulatory oversight. Gene E. Likens was instrumental in bringing together scientists from different backgrounds to use a comparative watershed approach in the Hubbard Brook Experimental Forest. In helping to understand this ecosystem complexity, Likens has used the metaphor: A physician uses the chemistry of blood and urine to examine the health of a patient. Can the chemistry of stream water be used to diagnose complicated ecological functions (i.e., "health") of watershed ecosystems? The work at Hubbard Brook provided carefully collected long-term data to establish the cause of low pH rainwater and its impact on the environment. Likens and his team "re-coined" the term "acid rain," which drew attention from the public and policy makers in North America. Likens led scientists in efforts to educate the general public and the U.S. Congress on this and other environmental issues; his impact has been far-reaching, from publishing highly-cited research papers and books, founding a research institute that launched many careers, providing leadership to scientific societies in multiple disciplines, and helping produce real-work legislation to combat acid rain.