Shapotou Desert Experiment and Research Station, Northwest Institute of Eco-Environmental and Resources, Chinese Academy of Sciences, Lanzhou, China.
Shapotou Desert Experiment and Research Station, Northwest Institute of Eco-Environmental and Resources, Chinese Academy of Sciences, Lanzhou, China; University of Chinese Academy of Sciences, Beijing, China.
Sci Total Environ. 2022 Jul 15;830:154805. doi: 10.1016/j.scitotenv.2022.154805. Epub 2022 Mar 24.
There is much uncertainty about how climate warming will impact greenhouse gases (GHG) budget in dry environments due to the lack of available data for desert biocrust soil. We implemented a 2.5-year field measurement of CO, CH and NO effluxes in cyanobacteria-dominated, moss-dominated and mixed (cyanobacteria, moss and lichen) biocrust soils using open-top-chambers to simulate climate warming (1.2 °C on average). Desert biocrust soils generally acted as a weak sink of atmospheric CH and NO. Although warming effects on daily CO, CH, and NO effluxes varied depending on sampling date and biocrust soil, there was no significant difference in daily, monthly and seasonal average CO, CH and NO effluxes between warming and control in most cases for three biocrust soils. However, warming caused a marginal (p = 0.06) decrease (14.2%) in annual accumulative CO efflux in moss-dominated biocrust soil due to the drought effects caused by warming indirectly and OTC sheltering of precipitation directly, while there was no significant difference between warming and control for cyanobacteria-dominated and mixed biocrust soils, implying a neutral response of GHG effluxes to climate warming. These results suggest that the GHG budget in arid desert biocrust soil would not be significantly changed in the warmer future when the direct negative effects of drought on CO effluxes were excluded. Therefore, a marginal decrease of accumulative CO effluxes in response to warming coupled with drought for moss-dominated biocrust soil might offer a weak negative feedback to warming and drier climate change pattern.
由于缺乏沙漠生物结皮土壤的数据，对于气候变暖将如何影响温室气体（GHG）预算，在干燥环境中存在很大的不确定性。我们使用开顶式气室（OTC）模拟气候变暖（平均升温 1.2°C），对蓝藻占主导、苔藓占主导和混合（蓝藻、苔藓和地衣）生物结皮土壤中的 CO、CH 和 NO 排放通量进行了为期 2.5 年的野外测量。沙漠生物结皮土壤通常是大气 CH 和 NO 的弱汇。尽管变暖对每日 CO、CH 和 NO 排放通量的影响因采样日期和生物结皮土壤而异，但在大多数情况下，三种生物结皮土壤的每日、每月和季节性平均 CO、CH 和 NO 排放通量在变暖和对照之间没有显著差异。然而，由于变暖间接导致干旱效应以及 OTC 直接遮蔽降水，苔藓占主导的生物结皮土壤中的年累积 CO 排放通量减少了 14.2%（p = 0.06），这是一个边缘效应；而蓝藻占主导和混合生物结皮土壤中，变暖与对照之间没有显著差异，这意味着 GHG 通量对气候变暖的响应呈中性。这些结果表明，在未来更温暖的时期，如果排除干旱对 CO 通量的直接负面影响，干旱沙漠生物结皮土壤的 GHG 预算不会发生显著变化。因此，苔藓占主导的生物结皮土壤对变暖的响应以及与干旱相关的累积 CO 排放通量的减少可能会对变暖及更干燥的气候变化模式提供一个微弱的负反馈。
