Eutrophication Thresholds – Assessment, Mitigation, and Resilience in Landscapes and Lakes

EPA Grant Number: R832445
Title: Eutrophication Thresholds – Assessment, Mitigation, and Resilience in Landscapes and Lakes
Investigators: Carpenter, Stephen R. , Foley, Jonathan A. , Turner, Monica G.
Institution: University of Wisconsin Madison
EPA Project Officer: Hiscock, Michael
Project Period: September 1, 2005 through June 30, 2007 (Extended to August 31, 2008)
Project Amount: $299,999
RFA: Exploratory Research: Understanding Ecological Thresholds In Aquatic Systems Through Retrospective Analysis (2004) RFA Text |  Recipients Lists
Research Category: Aquatic Ecosystems , Ecosystems , Water


Eutrophication, a persistent environmental problem characterized by turbid water, toxic algae, fish kills, waterborne disease, and loss of ecosystem services, may be related to important thresholds in the phosphorus (P) cycle. We will address two main questions: (1) what thresholds in the transport and cycling of P in linked terrestrial-aquatic ecosystems cause lakes to switch between clear-water and eutrophic states? (2) How can thresholds for transport and recycling of P be manipulated to mitigate eutrophication, or increase resilience of clear-water lakes against eutrophication? The research will conduct a retrospective analysis of the Yahara watershed and its major lakes (near Madison, Wisconsin), using a substantial historical data base of land characteristics and limnology. Changes in this watershed are emblematic of those in many agricultural, urbanizing regions of the United States.


Research methods include statistical analyses of three different types of lake models and simulation studies using a Terrestrial-Aquatic P model. The project will describe thresholds related to eutrophication with respect to landscape, biogeochemical, and statistical characteristics. We will (1) establish whether thresholds are likely to produce important changes in eutrophication, (2) determine how key controlling variables such as climate, landscape characteristics, land use/cover change, agricultural practices, and management actions, affect thresholds, (3) evaluate prospects for mitigating eutrophication through interventions that utilize thresholds, and (4) assess changes in controlling variables that would increase or decrease resilience of clear-water and eutrophic regimes. Better understanding of thresholds related to Eutrophication is a prerequisite for correcting this persistent problem in order to improve ecosystem condition, human health, and livelihoods.

Expected Results:

Our research will contribute basic scientific knowledge of eutrophication thresholds: their spatial extent and location on the landscape; their biogeochemical characteristics; and the prospects for manipulating abiotic, biotic, and human factors that influence thresholds in order to mitigate eutrophication and increase the resilience of landscapes to lake eutrophication.

Publications and Presentations:

Publications have been submitted on this project: View all 8 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 4 journal articles for this project

Supplemental Keywords:

soil, sediments, risk, health effects, ecological effects, bioavailability, vulnerability, susceptibility, cumulative effects, chemicals, toxics, pathogens, indicators, restoration, scaling, Bayesian ecology, physics, environmental chemistry, modeling, Midwest, Wisconsin, WI, EPA Region 5,, RFA, Scientific Discipline, Air, Ecosystem Protection/Environmental Exposure & Risk, Aquatic Ecosystems & Estuarine Research, climate change, Air Pollution Effects, Aquatic Ecosystem, Environmental Monitoring, Ecological Risk Assessment, Atmosphere, anthropogenic stress, estuarine research, eutrophication, landscape change, ecological thresholds, anthropogenic impact, ecosystem indicators, modeling ecosystem change, lakes, aquatic ecosystems, water quality, ecosystem stress, trophic interactions, ecosystem response, environmental history

Progress and Final Reports:

  • 2006 Progress Report
  • 2007 Progress Report
  • Final Report