BVOCs emission in a semi-arid grassland under climate warming and nitrogen deposition

Abstract

Biogenic volatile organic compounds (BVOCs) profoundly affect atmospheric chemistry and ecosystem functioning. BVOCs emission and their responses to global change are still unclear in grasslands, which cover one quarter of the Earth's land surface and are currently undergoing the largest changes. Over two growing seasons, we conducted a field experiment in a semi-arid grassland (Inner Mongolia, China) to examine the emission and the responses of BVOCs emissions to warming and nitrogen deposition. The natural emission rate (NER) of monoterpene (dominant BVOCs here) is 107 ± 16 μg m<sup>−2</sup> h<sup>−1</sup> in drought 2007, and 266 ± 53 μg m<sup>−2</sup> h<sup>−1</sup> in wet 2008, respectively. Warming decreased the standard emission factor (SEF) by 24% in 2007, while increased it by 43% in 2008. The exacerbated soil moisture loss caused by warming in dry season might be responsible for the decrease of SEF in 2007. A possible threshold of soil moisture (8.2% (v/v)), which controls the direction of warming effects on monoterpene emission, existed in the semiarid grassland. Nitrogen deposition decreased the coverage of <i>Artemisia frigida</i> and hence reduced the NER by 24% across the two growing seasons. These results suggest that the grasslands dominated by the extended <i>Artemisia frigida</i> are an important source for BVOCs, while the responses of their emissions to global changes are more uncertain since they depend on multifactorial/in-situ/conditions

Evident elevation of atmospheric monoterpenes due to degradation-induced species changes in a semi-arid grassland

“…Gas emission was determined by static chamber technique (Wang et al, 2012) every 1-3 h at Duolun Restoration Ecology Research Station (42°50′ N, 116°18′ E) in Inner Mongolia. Our gas chamber contained an upper chamber and pedestal ( Supplementary Fig.…”

“…In this study, we reliably detected isoprene and α-pinene. The analysis methods in detail were described by Wang et al (2012).…”

“…The newly dominant species, which adapt to stressed conditions, may substantially impact the community-level BVOCs emission and hence the ambient BOVCs concentration. A study in a semi-arid grassland of Inner Mongolia discovered that subshrub -A. frigida, as an overgrazing indicator, is an important monoterpene emitter, whose emission factor based on dry biomass was about 20 times higher than grass (Wang et al, 2012). A. frigida is a common subshrub in North American and Eurasian grasslands and its abundance tends to increase globally under elevated CO 2 concentration and anthropogenic disturbance (Liu, 2003;Morgan et al, 2007;Werger and van Staalduinen, 2012).…”

Deficit Irrigation-Based Improvement in Growth and Yield of Quinoa in the Northwestern Arid Region in China

“…Drought, in particular, is a major climate disaster in arid regions that severely limits agricultural productivity [4]. Due to water scarcity, efficient water-saving measures have become crucial, and researchers have been focusing on the optimization of irrigation systems for different crops to cope with the lack of water resources [5,6]. Quinoa, a drought-tolerant, cold-resistant, nutrient-rich crop [7][8][9], is considered a preferred solution for food security [10,11], especially in arid regions [12,13].…”