Lakes and wetlands are believed to contribute substantially to global carbon cycling, and may play an especially important role in production of methane gas. However, the biological and physical mechanisms that control rates of methane emission from lakes are poorly understood. This project will study the diversity of bacteria that consume methane in lakes (methanotrophs) and examine how they respond to changes in lake mixing caused by seasonal changes in temperature and by disruptive events. Methane consumed by methanotrophs in lakes would otherwise be released into the atmosphere. Since methane is created and accumulates largely near the bottom of lakes, mixing of the lake water column should disrupt the activities of methanotrophs and accelerate methane emission. This project will employ a novel, whole lake mixing manipulation to study how methanotrophs respond to turbulent mixing, and compare that response to the more gradual mixing that occurs seasonal in most lakes. Methane is a potent greenhouse gas that contributes to global warming by increasing absorption of solar energy in Earth's atmosphere. By studying how lake mixing impacts the methanotroph assemblage and methane emission, this project addresses an important feedback linking lake ecosystems and global climate warming. This project supports the thesis research of a doctoral student, and also contributes to a larger outreach effort that engages K-12 teachers in lake ecology and climate change.
