UNCERTAINTY QUANTIFICATION FOR ECOLOGICAL DYNAMICS: MODELING HETEROGENEOUS ICE ALGAL BLOOMS
Abstract: When parameterizing dynamical systems models of biological processes, we often use summary statistics (e.g., the mean) reported in experimental or observational studies. However, these summary statistics are abstractions, concealing variation occurring over space, time, or among individuals. Further, we know that the behavior of a nonlinear model using mean parameter values will differ from the mean model behavior if the parameter is instead treated as a random variable. Algae growing within polar sea ice provides an example of a system where extreme local heterogeneity in environmental conditions results in local heterogeneity in algal growth rates. Ignoring this and using a fixed, mean growth parameter to approximate regional dynamics can result in incorrect predictions of bloom timing and magnitude. Instead, algal growth rates at a given location should be treated as a random variable capturing the known heterogeneity. In this talk, I will provide an introduction to generalized polynomial chaos methods as an elegant, computationally efficient method for incorporating heterogeneous growth rates into standard algal bloom models, resulting in improved predictions of bloom dynamics. This method is broadly applicable for any system where local heterogeneity needs to be accounted for when considering aggregate dynamics over larger scales.
This talk is appropriate for faculty, undergraduate students, and a more general audience.
Biography: Dr. Jody Reimer is an Assistant Professor at the University of Utah in both the Department of Mathematics and the School of Biological Sciences. She received her PhD in 2019 from the University of Alberta, Canada, working with Mark Lewis and Andrew Derocher, and an MSc as a Rhodes scholar at the University of Oxford, working with Philip Maini and Michael Bonsall. Her research interests include population dynamics, uncertainty quantification, integrating models and data, and optimal control theory. Much of her work is motivated by the biology of polar regions--from polar bears to ice algae--and, more recently, by the ecology of the Great Salt Lake.
Contact: jody.reimer@utah.edu