Using Power Plant Cooling Lakes As Replicated Model Systems to Examine the Effects of Climate Change in Freshwater Ecosystems

Due to the difficulties of establishing long-term heated aquatic systems, research on the impact of climate change is often limited to studying instantaneous effects on aquatic organisms. Here, we use multiple power plant cooling lakes and ambient control lakes (n=3 each) to explore the effects of sustained heating (≈5°C) over many decades on the ecosystem, as well as individual organism response. Community assemblages of zooplankton shifted towards smaller-bodied organisms and phenological timing changes in phytoplankton blooms alter ecosystem function. In common-garden experiments, physiological mechanisms controlling life-histories in largemouth bass were investigated, and suggest rapid adaptive evolution of growth, metabolism, and thermoregulatory behaviors in response to increased temperatures, but not maximum thermal tolerance. Our studies suggest that future climate-associated warming will affect entire ecosystems, causing assemblage shifts and altering functions. However, population-specific adaptations can occur rapidly and may alleviate some of these negative impacts, but not all.