Dissolved oxygen (DO) is a fundamental component of lake ecosystems. It is an important attribute of habitat in that low levels make habitat unsuitable for most aerobic organisms like fish. In addition, because of its role in redox reactions, DO strongly influences water chemistry. Low oxygen can result in internal loading of limiting nutrients, accumulation of the greenhouse gas methane, as well as formation of the toxic form of mercury in the water column. Therefore, changes to lake DO strongly impact the functioning of lake ecosystems with implications for drinking water quality, biodiversity, and possibly, fish toxicity. In theory, DO should respond to warming surface waters through a variety of mechanisms. This talk will summarize recently published work that used long-term and geographically extensive lake water quality data to explore the relationship between warming of surface waters and DO.
