Technical note: Skirt-chamber – An open dynamic method for the rapid and minimally-intrusive measurement of greenhouse gas emissions from peatlands

Abstract. We present a reliable and robust open dynamic chamber for measuring greenhouse gas exchange in peatlands with minimal disturbance of the ground. This chamber, called "skirt-chamber", is based on a transparent plastic film, placed above an open frame made of sparse interwoven wires, and expanded around the base of the chamber below a steel chain that ensures contact to the ground, avoiding damage, trenching or cutting vegetation. Gas exchange is determined using a portable gas analyzer from a mass balance in which the imperfect sealing of the chamber to the ground is quantified through the injection a methane pulse. The method was tested on a pristine peatland dominated by Sphagnum magellanicum located on Navarino Island at the subantarctic Magellanic ecoregion in Chile. Our results indicate that, the skirt-chamber allowed determining methane fluxes and ecosystem respiration, in about 20 minutes, with a limit of detection of 0.185 mg CH₄ m^-2 h^-1, and 173 mg CO₂ m^-2 h^-1, respectively. We conclude that the skirt-chamber is a minimally-intrusive, fast, portable, and inexpensive method that allows the quantification of greenhouse gas emissions with high spatial resolution in remote locations and without delay.