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

本研究旨在阐明控制北极高海拔陆地生态系统碳循环时空变化的因素，并构建一个估算气候变化对碳循环影响的模型。出于这些目的，我们在斯瓦尔巴特冰川前陆进行了以下研究：(1)研究了从新冰川消融区延伸到植被覆盖良好的演替后期的三条2.6公里长的线上植被与土壤因子的关系。(2)考察了演替后期生态系统净生产量的控制因素。(3)考察了青海苔藓的光合作用特性，以评估其对生态系统初级生产力的贡献。(4)测定了3种优势维管植物的光合作用特性，研究了生产力的空间变异。(5)沿地形梯度考察了甲烷排放速率的控制因素。(6)对采集自斯瓦尔巴特群岛和加拿大北极高原的土壤样品进行了土壤磷脂脂肪酸含量与植被的关系研究。(7)测定了零度以下雪表面和叶凋落物的CO2排放速率。(8)研究了土壤微生物生物量和土壤呼吸对碳和/或氮改良剂的响应，以了解土壤微生物活性是否受底物有效性的限制。(9)通过测定土壤深层的ATP含量来了解这些层中是否存在活的微生物生物量。(10)采用包含主要碳流和碳库的分室模型来研究生态系统的碳循环。

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.