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

Elodie A Courtois (1, 2, 3) , Clement Stahl (4) , Benoît Burban (4) , Joke van den Berge (1, 3) , Daniel Berveiller (5) , Laëtitia Bréchet (4, 1, 3) , Jennifer Larned Soong (6, 1, 3) , Nicola Arriga (1, 3) , Josep Penuelas (7) , Ivan August Janssens (1, 3)

1 Department of Biology
2 LEEISA - Laboratoire Ecologie, Evolution, Interactions des Systèmes amazoniens
3 UA - University of Antwerp
4 UMR ECOFOG - Ecologie des forêts de Guyane
5 ESE - Ecologie Systématique et Evolution
6 LBNL - Lawrence Berkeley National Laboratory [Berkeley]
7 UAB - Universitat Autònoma de Barcelona = Autonomous University of Barcelona = Universidad Autónoma de Barcelona

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.

Mots clés: land-use change; rain-forest; chamber measurements; spatial variation; co2; n2o; respiration

Mots clés: nitrous-oxide; biogeochemical controls; emissions

Domaines: Sciences du Vivant [q-bio]

Elodie A Courtois, Clement Stahl, Benoît Burban, Joke van den Berge, Daniel Berveiller, et al.. Automatic high-frequency measurements of full soil greenhouse gas fluxes in a tropical forest. Biogeosciences, 2019, 16 (3), pp.785-796. ⟨10.5194/bg-16-785-2019⟩. ⟨hal-02628755⟩