Atmospheric aerosols elevated ecosystem productivity of a poplar plantation in Beijing, China

Abstract

Atmospheric aerosols can influence energy allocation, environmental factors, and thus, canopy photosynthesis. However, the regulations of aerosols on ecosystem productivity are not well understood. Here, we applied the optical properties of aerosols to quantify the effects of aerosol type and concentration on the environmental factors and associated gross primary productivity (GPP) of a poplar (Populus euramericana) plantation during the months of June to August from 2014 to 2016 in Beijing, China. As aerosol optical depth (AOD) increased from 0 to 2.5, total photosynthetically active radiation (PAR) decreased by 29%, while the diffuse PAR increased by 39%. Although there was no significant impact of aerosols on air temperature (p > 0.05), aerosols decreased vapor pressure deficit by more than 40%. We found that the plantation GPP changed exponentially with AOD, indicating that aerosols elevated GPP by about 37% under severe aerosol pollution (AOD ≥ 1) compared with background aerosol (AOD < 0.4). Aerosols type also had a significant effect on GPP. We concluded that aerosols could increase the GPP of the poplar plantation, and the promotion effect of aerosols on poplar plantation would not be significantly reduced until AOD was <1 under the projected decrease in aerosol loading in the future.