Separating direct and indirect effects of rising temperatures on biogenic volatile emissions in the Arctic.
Separating direct and indirect effects of rising temperatures on biogenic volatile emissions in the Arctic.
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DOI：
10.1073/pnas.2008901117
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发表时间：
2020-12-22
影响因子：
11.1
通讯作者：
Schurgers G
中科院分区：
文献类型：
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作者：
Rinnan R;Iversen LL;Tang J;Vedel-Petersen I;Schollert M;Schurgers G
植物向大气中释放活性气体，即所谓的挥发性有机化合物(VOCs)。植物释放的VOCs依赖于温度，并受植被组成的控制，因为不同的植物物种释放出不同的VOCs混合物。我们对在整个北极地区收集的生态系统VOC释放数据使用了建模方法，北极正在经历快速变暖和植被变化。我们发现，气候变暖强烈地刺激了植物来源的VOCs的释放，植被的变化也增加了VOC的释放，尽管直接低于温度，而且泛北极地区的地理差异很大。从北极冻土带到大气的挥发性有机碳通量的增加可能通过气候反馈产生影响，例如，通过在这些人为影响较小的地区形成粒子和云。生物来源中的挥发性有机化合物(VOCs)是以依赖温度的方式释放的。因此，随着气候持续变暖，北极生态系统的VOC排放量预计将大幅增加，而气候变暖的速度是全球气温上升的两倍。在这里，我们展示了持续的气候变暖对北极挥发性有机碳排放产生了强烈的、不断增加的影响。结合对北极冻土带气候变暖实验数据的统计模拟和动态生态系统模拟，我们将温度和土壤水分的影响分为直接影响和通过植被组成和生物量变化的间接影响。在14年模式模拟期间，气候变暖对VOC排放的间接影响是显著的，但小于直接影响。此外，植被的变化也会导致排放化学形态的变化。直接和间接影响都导致了北极变暖地区VOC排放响应的巨大地理差异，这取决于当地的植被覆盖和气候动态。我们的结果概述了当地气候、植被和生态系统-大气相互作用之间的复杂联系，以及可能对大气组成的局部到区域影响。
Plants release to the atmosphere reactive gases, so-called volatile organic compounds (VOCs). The release of VOCs from vegetation is temperature-dependent and controlled by vegetation composition because different plant species release a distinct blend of VOCs. We used modelling approaches on ecosystem VOC release data collected across the Arctic, which is experiencing both rapid warming and vegetation changes. We show that warming strongly stimulates release of plant-derived VOCs and that vegetation changes also increase VOC release, albeit less than temperature directly, and with large geographic differences in the Pan-Arctic area. The increasing VOC flux from the Arctic tundra to the atmosphere may have implications via climate feedbacks, for example, through particle and cloud formation in these regions with low anthropogenic influence. Volatile organic compounds (VOCs) are released from biogenic sources in a temperature-dependent manner. Consequently, Arctic ecosystems are expected to greatly increase their VOC emissions with ongoing climate warming, which is proceeding at twice the rate of global temperature rise. Here, we show that ongoing warming has strong, increasing effects on Arctic VOC emissions. Using a combination of statistical modeling on data from several warming experiments in the Arctic tundra and dynamic ecosystem modeling, we separate the impacts of temperature and soil moisture into direct effects and indirect effects through vegetation composition and biomass alterations. The indirect effects of warming on VOC emissions were significant but smaller than the direct effects, during the 14-y model simulation period. Furthermore, vegetation changes also cause shifts in the chemical speciation of emissions. Both direct and indirect effects result in large geographic differences in VOC emission responses in the warming Arctic, depending on the local vegetation cover and the climate dynamics. Our results outline complex links between local climate, vegetation, and ecosystem–atmosphere interactions, with likely local-to-regional impacts on the atmospheric composition.