September 25, 06

Vol. 22 , No. 02   

View Entire Issue (Vol. 22 , No. 02)

Mono Lake: A Geological and Biological Wonder

According to current estimates by the LADWP, the city of Los Angeles uses 2.2 x 1011 gallons of water annually. Since 1941, LA has been diverting water from Mono Lake 300 miles north of the city to satisfy its demands. Mono Lake is a terminal lake – water flows in via streams, but leaves only through evaporation. As water evaporates, previously dissolved solutes are left behind. As a result of both evaporation and diversion of water, Mono Lake is 2-3 times as salty as sea water. It supports a highly unusual and very restricted suite of organisms that can tolerate the high salt levels. Those species that are able to tolerate such conditions can exist in extremely high densities. Brine shrimp in the water during the summer are estimated to reach densities in the trillions and the migratory birds they support can reach numbers into the hundreds of thousands.

One of Professor Timothy Bradley’s major areas of study is the characterization and elucidation of the mechanisms of salt and water regulation in saline-water insects. Dr. Bradley’s research is motivated by a desire to understand both the ecological significance of physiological mechanisms and the evolutionary processes by which physiological differentiation occurs in species. His work on Mono Lake brine flies has lead to an understanding of salinity tolerance in this species and an appreciation of other ecological factors that affect their survival and reproduction. His studies have management implications for the lake and its watershed.

Dr. Bradley and his lab are also highly active in studies of evolutionary physiology and physiological ecology. Bradley is a Fellow of the American Association for the Advancement of Science and received an Excellence in Teaching Award from the University of California, Irvine in 1999. He is the co-editor of a book on ion transport and metabolism in insects, and the author of eight book chapters and close to 100 research papers. This lecture is the fourth and final talk in the series Life at the Limits: The Physiology of Extremophiles, which has been made possible through the collaborative efforts of the Joint Science Department of the The Claremont Colleges, the biology departments of Harvey Mudd College and Pomona College, and the Athenaeum.