Looking deeper into the soil: biophysical controls and seasonal lags of soil CO<sub>2</sub>production and efflux: Fid-Bau Portal

Looking deeper into the soil: biophysical controls and seasonal lags of soil CO₂production and efflux

Vargas, Rodrigo / Baldocchi, Dennis D. / Allen, Michael F. / Bahn, Michael / Black, T. Andrew / Collins, Scott L. / Yuste, Jorge Curiel / Hirano, Takashi / Jassal, Rachhpal S. / Pumpanen, Jukka / ... [mehr]

Abstract

We seek to understand how biophysical factors such as soil temperature (Ts), soil moisture (θ), and gross primary production (GPP) influence CO2fluxes across terrestrial ecosystems. Recent advancements in automated measurements and remote‐sensing approaches have provided time series in which lags and relationships among variables can be explored. The purpose of this study is to present new applications of continuous measurements of soil CO2efflux (F0) and soil CO2concentrations measurements. Here we explore how variation inTs, θ, and GPP (derived from NASA's moderate‐resolution imaging spectroradiometer [MODIS]) influenceF0and soil CO2production (Ps). We focused on seasonal variation and used continuous measurements at a daily timescale across four vegetation types at 13 study sites to quantify: (1) differences in seasonal lags between soil CO2fluxes andTs, θ, and GPP and (2) interactions and relationships between CO2fluxes withTs, θ, and GPP. Mean annualTsdid not explain annualF0andPsamong vegetation types, but GPP explained 73% and 30% of the variation, respectively. We found evidence that lags between soil CO2fluxes andTsor GPP provide insights into the role of plant phenology and information relevant about possible timing of controls of autotrophic and heterotrophic processes. The influences of biophysical factors that regulate dailyF0andPsare different among vegetation types, but GPP is a dominant variable for explaining soil CO2fluxes. The emergence of long‐term automated soil CO2flux measurement networks provides a unique opportunity for extended investigations intoF0andPsprocesses in the near future.