Collaborative Research: Whole Ecosystem Test of Restoring Resilience in Lakes

University Of Virginia Main Campus, Charlottesville VA

Investigators

Abstract

Ecosystems are at widespread risk of losing resilience due to environmental changes from climate and other human actions. Resilience is the ability of an ecosystem to maintain its current state in the face of variability. The loss of resilience harms human well-being because it can lead to the loss of land and water resources. Being able to measure and manage resilience is essential for adapting to these large changes. The researchers will perform an ecosystem experiment aimed at increasing resilience to algal blooms in lakes. Algal blooms threaten drinking water, reduce tourism, and harm wildlife. The primary goal of the experiment is to test if resilience can be enhanced and assess the performance of three resilience metrics. This experiment will advance our understanding of ecosystem resilience, evaluate methods for tracking environmental change critical for policymaking, and provide management insight. The results and the evaluation of the resilience metrics will be shared with lake managers through workshops hosted by the research team. The research is not only applicable to lakes but could be applied to manage other ecosystems such as grasslands and forests. To test if light availability changes resilience to nutrient loading, the researchers will experimentally add nitrogen and phosphorus to two lakes to encourage an algal bloom. One of the lakes is highly stained and therefore has low light availability. The other is relatively clear with higher light availability. A third lake that will not receive nutrient additions will serve as a reference ecosystem. The researchers will measure algal pigments, dissolved oxygen, and pH at a high frequency to monitor algal blooms. Resilience will be evaluated with ecosystem models, dynamic statistical indicators, and mean exit time. These three methods for quantifying resilience provide a new approach to evaluating ecosystem change. The expectation is that resilience of algal blooms to nutrient additions will be higher in the stained lake compared to the clear lake due to lower light availability. To test this hypothesis, in the second year of the experiment the researchers will add a commercial dye to the clear lake, designed to absorb light. The expectation is that this will make the clear lake more resilient algal blooms from nutrient additions, similar to the stained lake. The results of this experiment and the evaluation of the resilience metrics will be shared with lake managers through workshops hosted by the research team. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.