Maximizing the information obtained from chamber-based greenhouse gas exchange measurements in remote areas

Abstract Measurements of greenhouse gas (GHG) fluxes, particularly methane (CH 4 ) and nitrous oxide (N 2 O) in mountain ecosystems are scarce due to the complexity and unpredictable behavior of these gases, in addition to the remoteness of these ecosystems. In this context, we measured CO 2 , CH 4 , and N 2 O fluxes in four semi-natural pastures in the Pyrenees to investigate their magnitude and range of variability. Our interest was to study GHG phenomena at the patch-level, therefore we chose to measure the gas-exchange using a combination of a gas analyzer and manual chambers. The analyzer used is a photoacoustic field gas-monitor that allows multi-gas instantaneous measurements. After implementing quality control and corrections, data was of variable quality. We tackled this by categorizing data as to providing quantitative or only qualitative information: • 50% and 59% of all CH 4 and N 2 O data, respectively, provided quantitative information above the detection limit. • We chose not to discard data providing only qualitative information, because they identify highest- and lowest-flux peak periods and indicate the variability of the fluxes, along different altitudes and under different climatic conditions. • We chose not to give fluxes below detection limit a quantitative value but to acknowledge them as values identifying periods with low fluxes.