A recently published long-term study by Carl Watra from the University of Wisconsin-Madison Center for Limnology has spurred on a broader look at mercury in Wisconsin.
Climate change causes “roller coaster” mercury levels in Wisconsin fish as reported by the Cap Times, June 9, 2019. The article brings attention to the connection between climate change, mercury mobilization and fluctuating mercury levels in our states fish. Alarmingly, one of the conclusions this article’s investigation brings up is that our states fish advisories can be woefully unable to follow these changing levels in the 15,000 lakes and numerous streams in our state.
Mercury in our environment is understood to have doubled because of human behavior since industrial times. Currently, one-third of mercury emissions are new to the environment while historical mercury accounts for the balance. The single largest new source of mercury is coal burning for electrical generation.
The relationship between climate change and mercury complicates the picture and is significant. Lake levels go up and down killing and decomposing vegetation, which contains mercury accumulated from atmospheric deposition. Forest fires and hotter temperatures, associated with climate change; also increase the volatilization of legacy mercury.
Traveling around Northeastern Wisconsin seeing forests of black ash trees in our wetlands killed by Emerald Ash Borer also lends further concern to more mercury being mobilized.
My personal reminder of climate change and associated risks is a lone maple tree that sits outside our home on the channel in Sturgeon Bay. It is on the shoreline and with the rising water levels, associated with our changing climate, is showing stress of its drowning. While I will miss this tree my neighbor will soon enjoy a better view but he might not want his grandchildren to eat the fish they catch off his dock.
Sturgeon Bay, Wisconsin