Date:

2016-2022

Abstract:

Arctic lakes support biological processes and critical habitat at all trophic levels; however, climatic warming threatens to alter the structure and function of aquatic communities and overall system production. Arctic ecosystems are warming at some of the fastest rates observed on earth, and arctic lakes are experiencing more frequent years of warmer surface water and deeper mixing. However, the ability to quantify ecosystem effects and specific biological responses (e.g. bacterial diversity, invertebrate production, fish growth) to these climatic changes has been primarily limited to non-mechanistic modeled scenarios and observational studies in uncontrolled environments. Predicting the impacts of climate change on freshwater fishes has mainly focused on how changing temperatures will impact species distributions, but changes in temperature will also alter physiological processes such as consumptive demand and potentially the ecosystem effects of fishes. In our most recent efforts, we simultaneously tested effects of food availability and temperature on growth, consumption, respiration, and excretion, and effects of temperature on habitat use and growth of a common, but understudied, mid-level consumer in arctic lakes in an experimental setting. We also used bioenergetics modeling to predict consumptive demand under warming scenarios. Our results suggest an interactive effect of temperature and food availability on fish growth rates and nutrient excretion. We predicted a 9% increase in consumption is required to maintain observed growth under a 4 °C climate warming scenario. These results highlight considering changes in food resources and other associated indirect effects of fish (e.g., excretion) that accompany changing temperatures with climate change.

Funding:

• National Science Foundation
• Department of Watershed Sciences, PhD Fellowship
• US Geological Survey – Utah Cooperative Fish and Wildlife Research Unit (in-kind)
• The Ecology Center at Utah State University

Investigators:

• Dr. Phaedra Budy, USGS UCFWRU, USU
• Dr. Casey Pennock, Dept. of Watershed Sciences, Utah State University

Other Collaborators:

• Dr. George Kling, Dept. of Ecology and Evolutionary Biology, University of Michigan
• Dr. Sarah Null, Dept. of Watershed Sciences, Utah State University
• Dr. Jiming Jin, Dept. of Watershed Sciences, Utah State University
• Dr. Byron Crump, College of Earth, Ocean, and Atmospheric Sciences, Oregon State University
• Dr. Anne Giblin, Ecosystems Center, Marine Biological Laboratory