David Richardson, SUNY New Paltz – Warming Lakes

A clue to a changing climate could be in your nearest lake.

David C. Richardson, associate professor in the biology department at the State University of New York at New Paltz, discusses how lakes can show signs of a warmer planet.

David Richardson is an Associate Professor of Biology at SUNY New Paltz. David Richardson conducts research on the ecology of aquatic ecosystems including lakes, rivers, and streams. Broadly speaking, Richardson seeks to understand how aquatic ecosystems function and the direct or indirect effect that humans have on aquatic food webs, water quality, and biogeochemistry. Many of his studies revolve around using environmental sensors and technology to understand aquatic ecosystems and involve collaborative science with regional, national, and global partners. Richardson’s lab focuses on undergraduate research and he teaches course on freshwater biology, ecology, and statistics. His website is https://faculty.newpaltz.edu/davidrichardson/ and he tweets from @DRichardsonLab.

Warming Lakes

Lakes provide us with drinking water, food, and recreation for a refreshing swim. At the same time, lakes can serve as important gauges for changes in the world around us. For example, lakes collect heat from the atmosphere and water from the surrounding landscape. Each year, in northern locations, lake surface waters warm slowly from spring to summer, just as air temperatures do. Lakes can develop a warm surface layer that can be a few feet up to 100 feet thick depending on the size of the lake. However, the bottom of the lake stays much colder even in the summertime. This is temperature based layering or stratification. If you have ever been swimming in a lake and find your feet much colder than your shoulders, you are experiencing stratification.

Recently, my colleagues and I have looked across the broad region of northeastern North America – from Pennsylvania to Maine and west into Ontario, Canada – to examine how lake temperature and stratification patterns respond to the rapidly changing climate over the past 15 to 40 years with data collected from over 200 lakes by state governmental organizations, professors, students, non-profit organizations, and citizen scientists.

Ninety percent of the lakes across this region showed increasing stratification and warming surface waters, by, on average, 1 degree Fahrenheit per decade. This is comparable to some of the most rapidly warming lakes around the world.

Surprisingly, the deepest parts of the lakes were not warming consistently with the surface waters. Lake characteristics, such as the shape of the lake, can regulate how deep water responds to warming surface water and air.

As a result of the changing climate, summers are getting longer and winter ice cover is getting shorter. Warm water fish, like bass, are succeeding while cold water fish, like trout, are finding it harder to survive. Harmful algal blooms are increasing and negatively affecting water quality. Climate change is warming lakes and rapidly modifying the ecological resources that we want and value.