CSI:Limnology | cross-scale interactions in freshwater landscapes

Macrosystems Biology Research in US lakes across space and time

We are an interdisciplinary group of researchers conducting 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 will collect existing chemistry data on ~8,000 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?

One of the analytical approaches we will use is multi-level (i.e., hierarchical) Bayesian modeling. This approach quantifies CSIs, allows for explicit testing of alternative potential drivers responsible for CSIs, and facilitates the effective communication of these complex dynamics driving ecosystem state.

cross-scale interactions. Lake Erie algal bloom image courtesy of NOAA.
CSI:Limnology Home CSI:Limnology Home