CSIC, Global Ecology Unit CREAF-CSIC-UAB, CSIC, Bellaterra, 08193 Barcelona, Catalonia, Spain; CREAF, Cerdanyola del Vallès, 08193 Barcelona, Catalonia, Spain.
CSIC, Global Ecology Unit CREAF-CSIC-UAB, CSIC, Bellaterra, 08193 Barcelona, Catalonia, Spain; CREAF, Cerdanyola del Vallès, 08193 Barcelona, Catalonia, Spain.
Sci Total Environ. 2024 Jan 1;906:167354. doi: 10.1016/j.scitotenv.2023.167354. Epub 2023 Sep 27.
Biogenic volatile organic compounds (BVOCs) play critical roles in ecosystems at various scales, influencing above- and below-ground interactions and contributing to the atmospheric environment. Nonetheless, there is a lack of research on soil BVOC fluxes and their response to environmental changes. This study aimed to investigate the impact of drought, nitrogen (N) fertilization, and litter manipulation on soil BVOC fluxes in a Mediterranean forest. We assessed the effects of drought and N fertilization on soil BVOC exchanges and soil CO fluxes over two consecutive years using a dynamic chamber method, and solid-phase microextraction was utilized to quantify soil BVOCs in one year. Our findings revealed that the soil acted as an annual net sink for isoprenoids (1.30-10.33 μg m h), with the highest uptake rates observed during summers (25.90 ± 9.36 μg m h). The increased summer uptake can be attributed to the significant concentration gradient of BVOCs between atmosphere and soil. However, strong seasonal dynamics were observed, as the soil acted as a source of BVOCs in spring and autumn. The uptake rate of isoprenoids exhibited a significant positive correlation with soil temperature and atmospheric isoprenoid concentrations, while displaying a negative correlation with soil moisture and soil CO flux. The effects of drought and N fertilization on soil BVOCs were influenced by the type of VOCs, litter layer, and season. Specifically, drought significantly affected the exchange rate and quantities of sesquiterpenes. N fertilization led to increased emissions of specific BVOCs (α-pinene and camphene) due to the stimulation of litter emissions. These findings underscore the importance of the soil as a sink for atmospheric BVOCs in this dry Mediterranean ecosystem. Future drought conditions may significantly impact soil water content, resulting in drier soils throughout the year, which will profoundly affect the exchange of soil BVOCs between the soil and atmosphere.
生物源挥发性有机化合物（BVOCs）在不同尺度的生态系统中发挥着关键作用，影响着地上和地下的相互作用，并对大气环境产生影响。尽管如此，对于土壤 BVOC 通量及其对环境变化的响应的研究还很缺乏。本研究旨在调查干旱、氮（N）施肥和凋落物管理对地中海森林土壤 BVOC 通量的影响。我们使用动态室法在连续两年内评估了干旱和 N 施肥对土壤 BVOC 交换和土壤 CO 通量的影响，并在一年内使用固相微萃取法量化了土壤 BVOCs。我们的研究结果表明，土壤在一年内是异戊二烯的净汇（1.30-10.33μg m h），夏季的吸收速率最高（25.90±9.36μg m h）。夏季吸收量增加是由于大气和土壤之间的 BVOC 浓度梯度显著。然而，由于春季和秋季土壤是 BVOC 的源，因此观察到了强烈的季节性动态。异戊二烯的吸收速率与土壤温度和大气异戊二烯浓度呈显著正相关，与土壤湿度和土壤 CO 通量呈负相关。干旱和 N 施肥对土壤 BVOCs 的影响受到 VOC 类型、凋落物层和季节的影响。具体来说，干旱显著影响了倍半萜烯的交换速率和数量。N 施肥由于刺激凋落物排放，导致特定 BVOC（α-蒎烯和莰烯）的排放量增加。这些发现强调了土壤作为这个干燥地中海生态系统中大气 BVOCs 汇的重要性。未来的干旱条件可能会显著影响土壤含水量，导致全年土壤更加干燥，这将深刻影响土壤和大气之间的土壤 BVOC 交换。
