The effects of cross-scale interactions on freshwater ecosystem state across space and time
We are an interdisciplinary group of researchers funded by a US NSF Macrosystems Biology grant (2011-2017; EF-1065786 to MSU, EF-1065649 to ISU, and EF-1065818 to UW). We have conducted research on a key problem in macrosystems ecology – namely, the identification and study of cross-scale interactions (CSIs) at sub-regional to continental scales. A CSI exists where a driver at one scale, such as local land use, interacts with a driver at another scale, such as regional climate. These CSIs can lead to nonlinear and often unexpected relationships between drivers and responses. We use lakes and their major nutrients (phosphorus, nitrogen, and organic carbon) as a model system because lakes are affected by many of the main classes of drivers postulated to be a part of CSIs (e.g., connectivity, land use, and climate), and because there is a wealth of existing data and knowledge from small-scale studies regarding possible mechanisms through which drivers could interact across scales. We have compiled existing chemistry data on ~9,000 lakes in 17 US states across the last 30 years. We use this model system to study the general properties of CSIs and ask our overarching question: What are the cross-scale interactions that regulate spatial heterogeneity and temporal dynamics of lake nutrients at sub-continental scales? To adequately answer this question, we also conduct additional research related to the local and regional controls of major nutrients in lakes that will inform our understanding of CSIs and lake nutrients. For more information about this project and our team, visit our project website LAGOSlakes.org.