Any physical process that disturbs the soil—like a footstep or a chamber closing directly onto the soil—will cause a puff of CO2 to come out of the soil.
To address this, LI-8100A chambers never sit directly on top of the soil collars, meaning the chambers do not disturb the collars when the chambers close. A gasket ring fits outside the collar, sealing the collar to the chamber baseplate. The chamber closes onto the baseplate without touching the collar. This helps keep the collar stable over time, so the measurement process itself does not cause bursts of CO2 when the chamber closes.
To reduce the impact of the chamber base plate on soil, vents holes in the base plate allow gases, water, and sunlight to pass through to the soil surrounding the soil collar.
Diffusion simulation (Fick's Law), showing a representation of CO2 flux rates at the soil-air interface (red = low flux rate, blue = high flux rate). A solid baseplate shows suppressed flux rates with a nearly uniform effect under the baseplate.
Perforations in the baseplate greatly reduce this effect, preventing a concentration gradient-induced impedance of soil CO2 flux.