More than methane: quantifying melt-driven biogas production and nutrient export from Eurasian Arctic lowland permafrost (LowPerm)

在广阔的北极沉积低地，两个关键的弱点削弱了我们对区域温室气体（GHG）通量的生物和物理驱动因素的理解：1)缺乏对内在水文、地貌和生态因素如何影响活土层及其与上层永久冻土界面的沼气和养分循环/释放的定量认识；2)缺乏对活土层特征和功能的此类变化如何影响邻近沿海海洋生态系统的认识。只有当这些关键问题通过定量估计得到解决时，才能可靠地预测永久冻土变化对北极温室气体收支的直接和间接影响。定量描述系统内相关过程及其相互作用的必要建模平台已经存在，需要新的过程理解来预测对气候变化的动态影响是最迫切需要考虑的。因此，我们组建了一个具有水文学专业知识的国际多学科联盟（Solovyanova）；冻土动力学和地貌学（Christiansen），生物地球化学（Hodson和Yde），氧化还原地球化学（Thornton, Finster）和微生物学（Finster）提供这些信息。区域建模（Romanovsky, De'Ath），生态系统变化和生物地球化学（Rysgaard， Tranter和Vincent）以及同位素地球化学（Heaton和Bennett）方面的领先专家进一步增强了该项目，他们作为项目合作伙伴为项目增加了重要价值。我们将对从相对温暖的挪威斯瓦尔巴群岛，向东到寒冷的西伯利亚，覆盖整个北极永久冻土带梯度的地点进行综合实地、实验室和模型研究。在湿地梯田、冰楔多边形、海生湿地、三角洲等重要解冻环境建设“野外观测站”。在每种情况下，我们将收集岩心进行实验室研究，并进行现场监测，以构建描述其综合温室气体强迫势的质量平衡模型。实验室研究将确定(i)从活土层到永久冻土，生物地球化学和微生物条件如何随深度变化，以及（iii）温度和湿度制度的变化如何影响这些深度的微生物群落及其对C和营养物质加工的功能潜力。通过这种方式，我们将定量地将生物地球化学条件与永久冻土类型之间的物理和功能差异联系起来，确定其微生物介导的温室气体产生和营养物质向海洋生态系统输出的潜力。然后，将通过修正来自不同实地观测站的径流的海水孵育，来估计低地永久冻土输出的营养物和有机物对海洋生态系统生产的潜在影响。两个研讨会将为建立将永久冻土温室气体反馈整合到下一代区域生物地球物理模型中提供重要论坛，同时也使我们的科学贡献及其更广泛的社会重要性得以展示。我们还将建立实地观测站，作为未来访问斯瓦尔巴北极大学的学生的创新学习资源。

In the extensive Arctic sedimentary lowlands two crucial weaknesses undermine our understanding of the biological and physical drivers of regional greenhouse gas (GHG) fluxes: i) poor quantitative understanding of how intrinsic hydrological, geomorphological and ecological factors influence biogas and nutrient recycling/release in the active layer and its interface with the upper permafrostii) poor knowledge on how such changes in permafrost characteristics and function of the active layer influence the adjacent coastal marine ecosystems. The direct and indirect impact of permafrost changes on the Arctic GHG budget can only be reliably predicted when these key problems have been resolved with quantitative estimates. The necessary modelling platforms to quantitatively describe the relevant processes and their interactions within the system already exist, and it is the need for new process understanding to forecast dynamic impacts on climate change that is the most urgent consideration. We have therefore assembled an international multidisciplinary consortium with expertise in hydrology (Solovyanova); permafrost dynamics and geomorphology (Christiansen), biogeochemistry (Hodson and Yde), redox geochemistry (Thornton, Finster) and microbiology (Finster) to provide this information. It is further augmented by leading experts in regional modelling (Romanovsky, De'Ath), ecosystem change and biogeochemistry (Rysgaard, Tranter and Vincent) and isotope geochemistry (Heaton and Bennett), who add significant value as Project Partners. We will conduct an integrated field, laboratory and modelling study of sites from relatively warm Svalbard in Norway, eastwards into colder Siberia, covering the entire Arctic permafrost gradient. We will construct "field observatories" in important thaw environments, including yedoma terraces, ice wedge polygons, raised marine wetlands and deltas. In each case we will collect cores for laboratory studies and conduct field monitoring to construct mass balance models that describe their integrated GHG forcing potential. Laboratory studies will determine (i) how biogeochemical and microbiological conditions change with depth, from the active layer into the permafrost, and (iii) how changing temperature and moisture regimes influence the microbial communities and their functional potential for C and nutrient processing at these depths. In this way we will quantitatively link the biogeochemical conditions to the physical and functional differences between the permafrost types, establishing their potential for microbially-mediated GHG production and nutrient export to marine ecosystems. The potential impact of nutrient and organic matter export from lowland permafrost on marine ecosystem production will then be estimated by amending incubations of sea water with runoff from the different field observatories. Two workshops will provide crucial fora for establishing the integration of permafrost GHG feedbacks into the next generation of regional biogeophysical models, while also allowing our scientific contribution and its wider societal importance to be showcased. We will also establish the field observatories as innovative learning resources for future students visiting the Arctic university of Svalbard.