Little Deming Lake doesn’t get much notice from visitors to Itasca State Park in Minnesota. There’s better boating on nearby Lake Itasca, the headwaters of the Mississippi River. My colleagues and I need to maneuver hundreds of pounds of equipment down a hidden path made narrow by late-summer poison ivy to launch our rowboats.
But modest Deming Lake offers more than meets the eye for me, a geochemist interested in how oxygen built up in the atmosphere 2.4 billion years ago. The absence of oxygen in the deep layers of Deming Lake is something this small body of water has in common with early Earth’s oceans.
