Maxed-out Trace Gas Sensor

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 its maximum reading, 9,999 parts per million (ppm), indicating that the concentration of carbon dioxide has risen above what the sensor can measure. 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.