Identifying, forecasting, and managing state changes (also known as thresholds, tipping points, or regime shifts) are central challenges in many fields. Preventing stressed ecosystems from collapsing into altered states that do not provide useful ecosystem services is a major environmental challenge. This project will identify markers for, and potential means to manage, tipping points in aquatic ecosystems such as lakes, rivers, and streams. Nutrients will be added to aquatic microecosystems that form within water-filled leaves of northern pitcher plants in a series of experiments mimicking nutrient pollution and resultant ecosystem collapse seen in larger lakes. Critical thresholds, beyond which intervention cannot stop the breakdown of the system, will be identified. Quantitative methods will be used to identify protein biomarkers that can serve as early warning indicators of ecosystem collapse. Protein biomarkers are hypothesized to be better indicators than traditional ones such as oxygen levels or algal blooms, which reflect impending state changes too late to reverse them or after they have already occurred.
Documenting, understanding, forecasting, and averting state changes is of widespread and immediate importance not only to ecologists and environmental scientists, but also to economists, social scientists, policy makers, and environmental managers. Nutrient enrichment from fertilizers, runoff, and atmospheric deposition can cause lakes, rivers, and streams to switch to dramatically different, low oxygen states characterized by algal blooms and fish die-offs. The most significant broader impact of the proposed research will be to provide empirical tests of regime shifts that will help to convince the broader public that scientists can detect and manage state changes. Future applications of this work could lead to the development of simple water-quality test kits that can forecast ecosystem tipping points early enough to prevent them. Resources will be devoted to educating K-12 teachers, undergraduate students and postdoctoral researchers through their continuous involvement in basic ecological research.
