Trace Gas Sensor by Fumarole

A trace gas sensor sits at the mouth of a fumarole: a crack in the Earth's surface that passively emits gases from the volcanic system beneath. The sensor displays a reading of 8,734 parts per million (ppm), which will diffuse into the hundreds within feet. CRATER ecologist Joshua Fisher and his team placed sensors at locations across the forest to measure emissions, in an effort to understand how vegetation responds to elevated levels of carbon dioxide.