Evident elevation of atmospheric monoterpenes due to degradation-induced species changes in a semi-arid grassland.
Biogenic volatile organic compounds (BVOCs) emitted from plants have substantial effects on atmospheric chemistry/physics and feedbacks on ecosystem function. The on-going climate change and anthropogenic disturbance have been confirmed to cause the evident degradation of grassland with shift of plant community, and hence BVOCs emissions were suspected to be altered due to the different BOVCs emission potentials of different species. In this study, we investigated BVOCs concentration above ground surface during growing season in a degraded semi-arid grassland (41°2' N-45°6' N, 113°5'-117°8') in Inner Mongolia. The observed monoterpenes' concentrations varied from 0.10 to 215.78 μg m(-3) (34.88 ± 9.73 μg m(-3) in average) across 41 sites. Compared to non-degraded grassland, concentrations of monoterpenes were about 180 times higher at the sites dominated by subshrub--Artemisia frigida, a preponderant species under drought stress and over-grazing. The biomass of A. frigida explained 51.39% of the variation of monoterpenes' concentrations. α-pinene, β-pinene and γ-terpinene dominated in the 10 determined monoterpenes, accounting for 37.72 ± 2.98%, 14.65 ± 2.55% and 10.50 ± 2.37% of the total monoterpenes concentration, respectively. Low isoprene concentrations (≤ 3.25 μg m(-3)) were found and sedge biomass contributed about 51.76% to their spatial variation. α-pinene and isoprene emissions at noon were as high as 515.53 ± 88.34 μg m(-2)h(-1) and 7606.19 ± 1073.94 μg m(-2) h(-1) in A. frigida- and sedge-dominated areas where their biomass were 236.90 g m(-2) and 72.37 g m(-2), respectively. Our results suggested that the expansion of A. frigida and sedge caused by over-grazing and climatic stresses may increase local ambient BVOCs concentration in grassland.
State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Xiangshan, Beijing 100093, China; State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China. Electronic address: hjwang78@gmail.com.
Hongjun
H
Wang
State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
Xinming
X
Wang
State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
Yanli
Y
Zhang
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
Yujing
Y
Mu
State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Xiangshan, Beijing 100093, China; State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110164, China.
Xingguo
X
Han
D000393:Air Pollutants / Q000032:analysis*; D001272:Atmosphere; D002681:China; D057231:Climate Change; D004784:Environmental Monitoring; D065948:Grassland; D039821:Monoterpenes / Q000032:analysis*; D012621:Seasons; D012987:Soil / Q000737:chemistry; D055549:Volatile Organic Compounds / Q000032:analysis*
D000393:Air Pollutants; D039821:Monoterpenes; D012987:Soil; D055549:Volatile Organic Compounds
Artemisia frigida; Biogenic volatile organic compounds; Isoprene; Monoterpene; Sedge; Steppe