Environmental change alters nitrogen fixation rates and microbial parameters in a subarctic biological crust

Together, Biological Soil Crust (BSC) and other cryptogamic groundcovers can contribute up to half of the global nitrogen (N) fixation. BSC also stabilizes the soil (reducing erosion and dust emissions), fixes carbon (C), retains moisture, and acts as a hotspot of microbial diversity and activity. Much of the knowledge about how climate change is affecting the composition and functioning of BSC comes from hot arid and semiarid regions. The comparatively smaller body of research on BSC from cold and mesic environments has been primarily observational, for example along chronosequences after a glacier retreat. Few studies have experimentally investigated the effects of the environment on BSC from high latitudes. Such experiments allow unraveling of relationships at a resolution that can only be achieved by controlling for confounding factors. We measured short-term (2-4 days) responses of a liverwort-based (Anthelia juratzkana) BSC from the south of Iceland to a range of temperature, mois...生物土壤结皮（Biological Soil Crust, BSC）与其他隐花植物地被共同贡献了全球近一半的氮（N）固定量。生物土壤结皮还可稳定土壤（减少侵蚀与扬尘排放）、固碳（C）、保持土壤水分，并作为微生物多样性与活性的热点区域。目前关于气候变化如何影响生物土壤结皮的组成与功能的认知，大多来自炎热干旱与半干旱地区的研究。针对寒冷与中生环境中生物土壤结皮的研究相对较少，且多为观测性研究，例如沿冰川退缩后的演替序列开展的研究。目前鲜有研究通过实验手段探究环境变化对高纬度地区生物土壤结皮的影响。这类实验能够通过控制混杂变量，以更高的分辨率厘清各变量间的关联。本研究测定了冰岛南部以安氏叶苔（Anthelia juratzkana）为优势类群的生物土壤结皮在2~4天的短期时间内，对一系列温度、水分的响应。