Ecological study of the factors controlling spatial and temporal variations of carbon cycle in a High Arctic terrestrial ecosystem

本研究旨在明确高寒陆地生态系统碳循环时空变化的控制因素，并构建气候变化对碳循环影响的模型。为此，我们在斯瓦尔巴群岛的冰川前陆进行了以下研究。(1)研究了3条2.6km线的植被与土壤因子的关系，这3条线从冰川消融初期延伸到植被覆盖较发达的后期演替阶段。(2)分析了后期生态系统净产量的控制因素。(3)研究了delisei地衣的光合特性，估算了其对生态系统初级生产的贡献。(4)测定3种优势维管植物的光合特性，研究其生产力的空间变异。(5)沿地形梯度考察了控制甲烷排放速率的因素。(6)研究了土壤磷脂脂肪酸含量（微生物群落结构指标）与植被的关系。(7)测定了零度以下积雪面和凋落叶的CO2排放速率。(8)研究了微生物生物量和土壤呼吸对碳和/或氮修正的响应，以了解土壤微生物活性是否受到基质有效性的限制。(9)测定深层土壤ATP含量，了解深层微生物生物量的存在。（10）生态系统碳循环采用主要碳流和碳库相结合的隔室模型。

This research aims to clarify the factors controlling spatial and temporal variations of carbon cycle in a High Arctic terrestrial ecosystem and to construct a model for estimating the impact of climate change on the cycle. For these purposes, we conducted following studies on a glacier foreland in Svalbard.(1) The relationships between vegetation and soil factors were investigated along three 2.6km lines which extended from newly deglaciated area to later succesional stages with well-developed vegetation cover.(2) Factors controlling net ecosystem production in the latter successinal stage were examined.(3) Photosynthetic characteristics of the lichen Cetrariella delisei were examined to estimate its contribution to the primary production of the ecosystem.(4) Photosynthetic characteristics of three dominant vascular plants were determined to study the spatial variation of productivity.(5) Factors controlling methane emission rate was examined along topographical gradients.(6) The relation of soil phospholipid fatty acid content (an index of microbial community structure) to vegetation was examined for soil samples collected from Svalbard and Canadian High Arctic.(7) CO2 emission rates from snow surface and those from leaf litter at subzero temperatures were determined.(8) Responses of microbial biomass and soil respiration to carbon and/or nitrogen amendments were examined to ask whether soil microbial activity was limited by substrate availability.(9) ATP content in deep soil layers was determined to know the presence of living microbial biomass in these layers.(10) Ecosystem carbon cycle was examined by a compartment model that incorporated major carbon flow and pools.