“Is Walden Okay?: Patterns of Phosphorous and Oxygen in the Pond"

Sunday, September 17, 2017 - 3:00pm to 4:30pm
Thoreau Farm

John M. Nevison will talk about the effects of phosphorous and dissolved oxygen on Walden Pond. The interaction of these two elements is the root cause of modern toxic algae blooms such as those that have occurred on White Pond. This talk will demonstrate a simple dynamic model that ties together the data on these elements and illustrates the level of the current threats to the well-being of Walden Pond.

The talk will also demonstrate that when the modern high levels of phosphorous are removed, the model reveals the probable pattern of the Pond's function in earlier times. The surprising finding is that, even in the late autumn of 1846 when Thoreau lived beside it, Walden Pond, at its deepest points, probably ran out of oxygen.

This event is free and open to the public. Email margaretcb@thoreaufarm.org to make a reservation. Sponsored by Thoreau Farm and the Thoreau Society.

John M. (Jack) Nevison is president of New Leaf Project Management and lives within a half-mile of Walden Pond. He is the author of six books and numerous articles on computing and management. His first simulation model, about a watershed ecosystem, was published in 1974. His most recent white paper explains the ideal seasonal fluctuation in the water level of Walden Pond.