Jeff Jeremiason

Jeff Jeremiason is a chemist and chair of the environmental studies program at Gustavus. His current research focuses on mercury and lead in the environment.

Jeff writes: I have studied transport of trace metals like mercury and lead from a bog in northern Minnesota for the last several decades. Surprisingly, while Pb (lead) export from the bog has declined due to phasing out leaded gasoline, Hg (mercury) flowing out of the bog has increased recently.

How is this about climate change? One hypothesis for this increase is that higher temperatures in the bog have increased microbial activity, leading to more plant and other decaying organic matter being broken down into what we call “dissolved organic matter.” Hg in the bog is bound to that organic matter and is mobilized and transported out of the bog when attached to dissolved organic matter.

We are also studying how Pb, Hg, and other metals in a sediment core from Lake Challa in Africa reflect the regional (and potentially global) climate. Lake Challa is a crater lake located at the base of Mount Kilamanjaro and has been accumulating sediment for over 250,000 years, encompassing the last two interglacial periods. We have just begun this research, so we do not yet have even preliminary findings. Here are images from the work at Lake Challa .