Abstract
Biogenic volatile organic compounds (BVOCs) are major precursors of both ozone and secondary organic aerosols (SOA) in the troposphere and represent a non‐negligible portion of the carbon fixed by primary producers, but long‐term ecosystem‐scale measurements of their exchanges with the atmosphere are lacking. In this study, the fluxes of 46 ions corresponding to 36 BVOCs were continuously monitored along with the exchanges of mass (carbon dioxide and water vapor) and energy (sensible and latent heat) for an entire year in a poplar (Populus) short‐rotation crop (SRC), using the eddy covariance methodology. BVOC emissions mainly consisted of isoprene, acetic acid, and methanol. Total net BVOC emissions were 19.20 kg C ha−1 yr−1, which represented 0.63% of the net ecosystem exchange (NEE), resulting from −23.59 Mg C ha−1 yr−1 fixed as CO 2 and 20.55 Mg C ha−1 yr−1 respired as CO 2 from the ecosystem. Isoprene emissions represented 0.293% of NEE, being emitted at a ratio of 1 : 1709 mol isoprene per mol of CO 2 fixed. Based on annual ecosystem‐scale measurements, this study quantified for the first time that BVOC carbon emissions were lower than previously estimated in other studies (0.5–2% of NEE) on poplar trees. Furthermore, the seasonal and diurnal emission patterns of isoprene, methanol, and other BVOCs provided a better interpretation of the relationships with ecosystem CO 2 and water vapor fluxes, with air temperature, vapor pressure deficit, and photosynthetic photon flux density.
Highlights
Plants exchange a wide array of biogenic volatile organic compounds (BVOCs) with the atmosphere (Kesselmeier & Staudt, 1999)
This study aimed (i) to quantify the net annual carbon emitted as BVOCs in a poplar short-rotation crop (SRC), while at the same time evaluating the individual contributions of each BVOC species, (ii) to calculate the year-based ratio of carbon emitted as BVOCs to the net ecosystem exchange of carbon, and (iii) to investigate the relationships of the fluxes of isoprene and other major BVOCs with CO2 fluxes and meteorological variables
The amount of net C emitted as BVOCs was 19.20 kg C haÀ1 yrÀ1, which represented 0.63% of net ecosystem exchange (NEE)
Summary
Plants exchange a wide array of biogenic volatile organic compounds (BVOCs) with the atmosphere (Kesselmeier & Staudt, 1999). Photosynthesis and isoprene emission are closely linked as photosynthetic carbon is the main source of isoprene (Sharkey & Yeh, 2001). The high photosynthetic capacity (10–20 lmol mÀ2 sÀ1) that characterizes the Populus genus might explain its high isoprene emission rates (20–45 nmol mÀ2 sÀ1) in leaf cuvettes at optimal temperature and under saturating light (Guidolotti et al, 2011; Rasulov et al, 2015). The release of carbon into the atmosphere in the form of BVOCs from vegetation is estimated around 0.1–2% of the carbon assimilated by photosynthesis (Sharkey & Yeh, 2001) while these values may reach 1–3% in poplar species (Goldstein et al, 1998)
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call