Hydrologic Controls on Peat Permafrost and Carbon Processes: New Insights From Past and Future Modeling
Hydrologic Controls on Peat Permafrost and Carbon Processes: New Insights From Past and Future Modeling
复制标题
DOI：
10.3389/fenvs.2022.892925
复制
发表时间：
2022-05
期刊：
影响因子：
--
通讯作者：
C. Treat;Miriam C. Jones;J. Alder;S. Frolking
中科院分区：
文献类型：
--
作者：
C. Treat;Miriam C. Jones;J. Alder;S. Frolking
在气候变暖的情况下，永久冻土泥炭地的土壤碳（C）很容易随着融化而分解。碳损失的数量和形式可能取决于永久冻土融化后的地点水文，但泥炭积累过程中的前期条件也可能很重要。我们使用基于过程的潮湿和干燥景观环境中的泥炭地动力学模型，测试了不同水文条件对北极苔原沼泽泥炭积累速率、永久冻土形成和对变暖的响应的作用，该模型从全新世中期的泥炭形成一直持续到公元2100年和公元2300年的未来模拟。潮湿和干燥景观环境的气候条件均由相同的缩小比例的 TraCE-21ka 瞬态古气候模拟和 CCSM4 RCP8.5 气候驱动因素驱动。景观环境控制着泥炭堆积、永久冻土形成的速度以及对气候变暖和永久冻土融化的响应。干燥景观情景具有较高的初始泥炭积累率（11.7 ± 3.4 毫米十年−1）和快速的永久冻土退化，但总碳储量与湿润景观情景相似。与干燥景观情景相比，湿润景观情景对 21 世纪变暖温度的适应能力更强，并且到 2100 年，碳损失减少了 60%，泥炭碳净新增量增加了 70%。模拟响应的差异表明，由于永久冻土对分解的控制，最大的影响与景观环境和流域水文有关，这表明对径流模式变化的重要敏感性。这些微妙的水文影响在环极地尺度上很难捕捉到，但对于未来气候变暖下永久冻土泥炭地的碳平衡很重要。
Soil carbon (C) in permafrost peatlands is vulnerable to decomposition with thaw under a warming climate. The amount and form of C loss likely depends on the site hydrology following permafrost thaw, but antecedent conditions during peat accumulation are also likely important. We test the role of differing hydrologic conditions on rates of peat accumulation, permafrost formation, and response to warming at an Arctic tundra fen using a process-based model of peatland dynamics in wet and dry landscape settings that persist from peat initiation in the mid-Holocene through future simulations to 2100 CE and 2300 CE. Climate conditions for both the wet and dry landscape settings are driven by the same downscaled TraCE-21ka transient paleoclimate simulations and CCSM4 RCP8.5 climate drivers. The landscape setting controlled the rates of peat accumulation, permafrost formation and the response to climatic warming and permafrost thaw. The dry landscape scenario had high rates of initial peat accumulation (11.7 ± 3.4 mm decade−1) and rapid permafrost aggradation but similar total C stocks as the wet landscape scenario. The wet landscape scenario was more resilient to 21st century warming temperatures than the dry landscape scenario and showed 60% smaller C losses and 70% more new net peat C additions by 2100 CE. Differences in the modeled responses indicate the largest effect is related to the landscape setting and basin hydrology due to permafrost controls on decomposition, suggesting an important sensitivity to changing runoff patterns. These subtle hydrological effects will be difficult to capture at circumpolar scales but are important for the carbon balance of permafrost peatlands under future climate warming.