What can we learn from the muck at the bottom of Walden Pond?

The Transcendentalism Council of First Parish in Concord, The Thoreau Society, and Walden Pond State Reservation will host Curt Stager, a professor at Paul Smith’s College, NY, who uses sediment cores sampled from lakes to look at historical changes in the environment. His 2018 book “Still Waters: The Secret World of Lakes” features Walden Pond in its first chapter and discusses how the lake environment has changed since Henry David Thoreau’s stay. His 2018 article, “Climate variability and cultural eutrophication at Walden Pond during the last 1750 years” made world news for its discussion of climate change and possible swimmers’ impact on the nutrient budget.