The phosphorus paradox

Headshot image of Stephen CarpenterStephen Carpenter, director emeritus of the Center for Limnology at UW-Madison, is a leader of whole-ecosystem experiments and adaptive ecosystem management focused on freshwaters.

Distinguished Speaker in Life Sciences shares phosphorus impact on freshwater Oct. 26 at UWL

Phosphorus is an essential nutrient for agricultural production and human sustainability, yet excess phosphorus pollution is a serious problem for freshwater resources, human health and sustainability.

Stephen R. Carpenter, Alfred Forbes professor emeritus at UW-Madison, will present “The Phosphorus Paradox: Global Change in Freshwaters” at 6:30 p.m. Thursday, Oct. 26, at the Affeldt Auditorium, room 1309, in UW-La Crosse’s Centennial Hall. Carpenter will also give a scientific talk, “Measuring Resilience: Whole Ecosystem Experiments,” at 5:30 p.m. Friday, Oct. 27, at Skogen Auditorium, 1400 Centennial Hall.

Carpenter’s visit is part of a UWL Distinguished Speaker in the Life Sciences.

During his public talk, Carpenter will share how the phosphorus cycle has been altered by human action more than any global element cycle, yet there is great heterogeneity in phosphorus supply around the planet. Some agricultural soils are phosphorus deficient, and some freshwaters are seriously polluted by phosphorus. Conservation and recycling in phosphorus-rich areas can help resolve the imbalance.

During his scientific talk, Carpenter will discuss the massive changes in ecosystems that can have significant consequences for natural resources, but are difficult to predict in advance. Resilience indicators based on statistical changes in time series or spatial maps have been proposed to anticipate impending changes. Whole lake experiments have been conducted to test resilience indicators. Generally, the resilience indicators have performed as expected from theory. However, more sophisticated empirical models, such as time varying autoregressions, may be more useful than resilience indicators for identifying critical transitions in ecosystems. Despite these promising results with resilience indicators, the best way to avoid unwanted ecological regime shifts is to increase the resilience of ecosystems through appropriate management.

Biography

Carpenter, director emeritus of the Center for Limnology at UW-Madison, is a leader of whole-ecosystem experiments and adaptive ecosystem management focused on freshwaters. He is a member of the U.S. National Academy of Sciences, a Fellow of the American Academy of Arts and Sciences, and a foreign member of the Royal Swedish Academy of Sciences. Carpenter is the 2011 laureate of the Stockholm Water Prize. His other notable awards include a Pew Fellowship in Conservation and Environment, the G. Evelyn Hutchinson Medal of the American Society of Limnology and Oceanography, the Robert H. MacArthur Award from the Ecological Society of America, the Excellence in Ecology Prize from the Ecology Institute and the Naumann-Thienemann medal of the International Society for Limnology. The event is sponsored by the UWL College of Science and Health.