Bolek Abdullah, Schlutow Mark, Yazbeck Theresia, Triches Nathalie, Heimann Martin, Göckede Mathias
Max Planck Institute for Biogeochemistry, Biogeochemical Signals, Jena, Germany.
Institute for Atmospheric and Earth System Research, University of Helsinki, Helsinki, Finland.
Glob Chang Biol. 2025 Jul;31(7):e70346. doi: 10.1111/gcb.70346.
With Arctic amplification, hydrological conditions in Arctic permafrost regions are expected to change substantially, which can have a strong impact on carbon budgets. To date, detailed mechanisms remain highly uncertain due to the lack of continuous observational data. Considering the large carbon storage in these regions, understanding these processes becomes crucial for estimating the future trajectory of global climate change. This study presents findings from 8 years of continuous eddy-covariance measurements of carbon dioxide ( ) and methane ( ) fluxes over a wet tussock tundra ecosystem near Chersky in Northeast Siberia, comparing data between a site affected by a long-term drainage disturbance and an undisturbed control site. We observed a significant increasing trend in roughness lengths at both sites, indicating denser and/or taller vegetation; however, the increase at the drained site was more pronounced, highlighting the dominant impact of drainage on vegetation structure. These trends in aboveground biomass contributed to differences in gross primary production (GPP) between the two sites increasing over the years, continuously reducing the negative effect of the drainage disturbance on the sink strength for . In addition, carbon turnover rates at the drained site were enhanced, with ecosystem respiration and GPP consistently higher compared to the control site. Because of the artificially lower water table depth (WTD), emissions at the drained site were almost halved. Furthermore, drainage altered the ecosystem's response to environmental controls. Compared to the control site, the drained site became slightly more sensitive to the global radiation ( ), resulting in higher uptake under the same levels of . Meanwhile, emissions at the drained site showed a higher correlation with deep soil temperatures. Overall, our findings from this WTD manipulation experiment show that changing hydrological conditions will significantly impact the Arctic ecosystem characteristics, carbon budgets, and ecosystem's response to environmental changes.
随着北极地区的气候加速变暖，预计北极永久冻土区的水文条件将发生显著变化，这可能对碳收支产生重大影响。迄今为止，由于缺乏连续的观测数据，详细的机制仍高度不确定。鉴于这些地区巨大的碳储量，了解这些过程对于估计全球气候变化的未来轨迹至关重要。本研究展示了在西伯利亚东北部切尔斯基附近的湿草甸苔原生态系统上进行的8年连续涡度协方差测量二氧化碳（ ）和甲烷（ ）通量的结果，比较了受长期排水干扰的站点和未受干扰的对照站点的数据。我们观察到两个站点的粗糙度长度均呈现显著增加趋势，表明植被更密集和/或更高；然而，排水站点的增加更为明显，突出了排水对植被结构的主要影响。地上生物量的这些趋势导致多年来两个站点之间的总初级生产力（GPP）差异增大，持续降低了排水干扰对 汇强度的负面影响。此外，排水站点的碳周转率提高，生态系统呼吸和GPP始终高于对照站点。由于人为降低了地下水位深度（WTD），排水站点的 排放量几乎减半。此外，排水改变了生态系统对环境控制的响应。与对照站点相比，排水站点对全球辐射（ ）变得略微更敏感，导致在相同 水平下有更高的 吸收。同时，排水站点的 排放与深层土壤温度的相关性更高。总体而言，我们从这个WTD操纵实验中得出的结果表明水文条件的变化将显著影响北极生态系统特征、碳收支以及生态系统对环境变化的响应。
