Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio Campus, PO Box 1627, FI-70211 Kuopio, Finland.
Terrestrial Ecology Section, Department of Biology, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen Ø, Denmark; Center for Permafrost (CENPERM), University of Copenhagen, Øester Voldgade 10, DK-1350 Copenhagen K, Denmark.
Sci Total Environ. 2017 Feb 15;580:1056-1067. doi: 10.1016/j.scitotenv.2016.12.060. Epub 2016 Dec 15.
Monoterpenes emitted from plants have an important role in atmospheric chemistry through changing atmospheric oxidative capacity, forming new particles and secondary organic aerosols. The emission rates and patterns can be affected by changing climate. In this study, emission responses to six years of climatic manipulations (elevated CO, extended summer drought and night-time warming) were investigated in a temperate semi-natural heath ecosystem. Samples for monoterpene analysis were collected in seven campaigns during an entire growing season (April-November, 2011). The results showed that the temperate heath ecosystem was a considerable source of monoterpenes to the atmosphere, with the emission averaged over the 8month measurement period of 21.7±6.8μgmgroundareah for the untreated heath. Altogether, 16 monoterpenes were detected, of which the most abundant were α-pinene, δ-3-carene and limonene. The emissions of these three compounds were positively correlated with light, chamber temperature and litter abundance, but negatively correlated with soil temperature. Elevated CO tended to decrease the average monoterpene emissions by 40% over the whole growing season, and significantly reduced emissions in August. Extended summer drought significantly decreased the emission right after the drought treatment period, but also in the late growing season. Night-time warming significantly increased the total emissions (mainly α-pinene) in April, and tended to mitigate the decrease caused by drought. The inhibition effects of elevated CO on emissions were diminished when the treatment was combined with drought or warming. The emission responses to different treatments were not explained by vegetation changes, and the monoterpene emission profile was only moderately related to plant species coverage. The emission responses to these long-term climate manipulations varied over the growing season (with strong correlation with litter abundance) and the observed antagonistic effects in the combined treatments underlie the importance of long-term studies with multiple factors acting in concert.
植物释放的单萜通过改变大气氧化能力、形成新粒子和二次有机气溶胶，在大气化学中发挥着重要作用。排放率和排放模式会受到气候变化的影响。本研究在温带半自然石楠灌丛生态系统中，研究了六年气候处理（升高 CO、延长夏季干旱和夜间增温）对单萜排放的响应。在整个生长季（2011 年 4 月至 11 月）的 7 次采样活动中收集了用于单萜分析的样品。结果表明，温带石楠灌丛生态系统是大气中单萜的重要来源，未经处理的石楠灌丛在 8 个月的测量期内，平均排放 21.7±6.8μg m−2 h−1。共检测到 16 种单萜，其中最丰富的是α-蒎烯、δ-3-蒈烯和柠檬烯。这三种化合物的排放与光照、箱内温度和凋落物丰度呈正相关，与土壤温度呈负相关。整个生长季，升高 CO 平均使单萜排放减少 40%，8 月的排放量显著减少。延长夏季干旱显著降低了干旱处理期后的排放，但也降低了后期的排放。夜间增温显著增加了 4 月的总排放量（主要是α-蒎烯），并倾向于缓解干旱造成的减少。当处理与干旱或增温相结合时，CO 升高对排放的抑制作用减弱。不同处理的排放响应不能用植被变化来解释，单萜排放特征与植物物种覆盖率只有中等相关性。对这些长期气候处理的排放响应随生长季而变化（与凋落物丰度密切相关），在综合处理中观察到的拮抗作用表明，多因素协同作用的长期研究非常重要。
