Baggesen Nanna S, Davie-Martin Cleo L, Seco Roger, Holst Thomas, Rinnan Riikka
Terrestrial Ecology Section, Department of Biology University of Copenhagen Copenhagen Ø Denmark.
Center for Permafrost (CENPERM) University of Copenhagen Copenhagen K Denmark.
J Geophys Res Biogeosci. 2022 Jun;127(6):e2021JG006688. doi: 10.1029/2021JG006688. Epub 2022 Jun 20.
Biogenic volatile organic compound (BVOC) flux dynamics during the subarctic autumn are largely unexplored and have been considered insignificant due to the relatively low biological activity expected during autumn. Here, we exposed subarctic heath ecosystems to predicted future autumn climate scenarios (ambient, warming, and colder, dark conditions), changes in light availability, and flooding, to mimic the more extreme rainfall or snowmelt events expected in the future. We used climate chambers to measure the net ecosystem fluxes and bidirectional exchange of BVOCs from intact heath mesocosms using a dynamic enclosure technique coupled to a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS). We focused on six BVOCs (methanol, acetic acid, acetaldehyde, acetone, isoprene, and monoterpenes) that were among the most dominant and that were previously identified in arctic tundra ecosystems. Warming increased ecosystem respiration and resulted in either net BVOC release or increased uptake compared to the ambient scenario. None of the targeted BVOCs showed net release in the cold and dark scenario. Acetic acid exhibited significantly lower net uptake in the cold and dark scenario than in the ambient scenario, which suggests reduced microbial activity. Flooding was characterized by net uptake of the targeted BVOCs and overruled any temperature effects conferred by the climate scenarios. Monoterpenes were mainly taken up by the mesocosms and their fluxes were not affected by the climate scenarios or flooding. This study shows that although autumn BVOC fluxes on a subarctic heath are generally low, changes in future climate may strongly modify them.
北极地区秋季生物源挥发性有机化合物（BVOC）通量动态在很大程度上尚未得到探索，并且由于预计秋季生物活性相对较低，一直被认为微不足道。在这里，我们将北极地区的石南丛生生态系统暴露于预测的未来秋季气候情景（环境、变暖以及更寒冷、黑暗的条件）、光照可用性变化和洪水之中，以模拟未来预期的更极端降雨或融雪事件。我们使用气候箱，通过耦合质子转移反应飞行时间质谱仪（PTR-ToF-MS）的动态封闭技术，测量完整石南丛生中宇宙的BVOC净生态系统通量和双向交换。我们重点关注六种BVOC（甲醇、乙酸、乙醛、丙酮、异戊二烯和单萜），它们是最主要的，并且之前已在北极苔原生态系统中被鉴定出来。与环境情景相比，变暖增加了生态系统呼吸作用，导致BVOC净释放或吸收增加。在寒冷和黑暗情景中，没有一种目标BVOC显示出净释放。乙酸在寒冷和黑暗情景中的净吸收量明显低于环境情景，这表明微生物活性降低。洪水的特征是目标BVOC的净吸收，并且排除了气候情景带来的任何温度影响。单萜主要被中宇宙吸收，其通量不受气候情景或洪水的影响。这项研究表明，尽管北极地区石南丛生地秋季的BVOC通量通常较低，但未来气候的变化可能会对其产生强烈影响。
