Automatic high-frequency measurements of full soil greenhouse gas fluxes in a tropical forest

• Published in: Biogeosciences 2019-02, Vol.16 (3), p.785-796
• Main Authors: Courtois, Elodie Alice, Stahl, Clement, Burban, Benoit, Van den Berge, Joke, Berveiller, Daniel, Brechet, Laetitia, Soong, Jennifer Larned, Arriga, Nicola, Penuelas, Josep, Janssens, Ivan August
• Format: Article
• Language: English
• Subjects: Air pollution; Analysis; Anesthetics; Appropriate technology; Automation; Carbon dioxide; Carbon dioxide estimation; Carbon dioxide flux; Ecological research; Ecosystems; Environmental aspects; ENVIRONMENTAL SCIENCES; Fluxes; Greenhouse effect; Greenhouse gases; High frequency; Life Sciences; Measurement; Methane; Nitrogen oxides; Nitrous oxide; Rain forests; Rainforests; Soil; Soil carbon; Soil chemistry; Soil gases; Tropical climate; Tropical forests
• ISSN: 1726-4189; 1726-4170; 1726-4189
• DOI: 10.5194/bg-16-785-2019

Measuring in situ soil fluxes of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) continuously at high frequency requires appropriate technology. We tested the combination of a commercial automated soil CO2 flux chamber system (LI-8100A) with a CH4 and N2O analyzer (Picarro G2308) in a tropical rainforest for 4 months. A chamber closure time of 2 min was sufficient for a reliable estimation of CO2 and CH4 fluxes (100 % and 98.5 % of fluxes were above minimum detectable flux – MDF, respectively). This closure time was generally not suitable for a reliable estimation of the low N2O fluxes in this ecosystem but was sufficient for detecting rare major peak events. A closure time of 25 min was more appropriate for reliable estimation of most N2O fluxes (85.6 % of measured fluxes are above MDF ± 0.002 nmol m−2 s−1). Our study highlights the importance of adjusted closure time for each gas.