Distribution and dynamics of soil organic matter in an Antarctic dry valley
Distribution and dynamics of soil organic matter in an Antarctic dry valley
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DOI：
10.1016/j.soilbio.2005.12.011
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发表时间：
2006-10-01
影响因子：
9.7
通讯作者：
Greenfield, L. G.
中科院分区：
文献类型：
--
作者：
Elberling, B.;Gregorich, E. G.;Greenfield, L. G.
南极干旱河谷的陆地生态系统在极端寒冷和干燥的气候条件下运作，严重限制了C和N的循环，并且像其他极地地区一样，可能对环境变化敏感。为了研究南极干旱河谷土壤有机碳（SOC）和氮在不同景观要素中的分布和动态特征，我们测定了维多利亚地南部一个相对较小的河谷--加伍德河谷（Garwood Valley）的土壤剖面有机碳和有机氮储量、无机氮（NH 4 N和NO3 N）、土壤CO2排放量、土壤含水量和土壤温度。我们还进行了实验室测量的基础呼吸从山谷中收集的土壤。土壤有机碳和呼吸速率较低，土壤有机碳在土壤剖面中高度分层，在地表附近观察到最大值。SOC储量和土壤CO2排放量的显着变化之间的景观要素和空间变异密切相关的距离湖泊，主要网站的初级生产力。最快的SOC周转率（停留时间c。30年）被发现在湖泊边缘的土壤中，缓慢的速度被发现在靠近湖泊的景观元素（c。52-67岁），以及其他景观元素（c. 84-123岁）。有机碳的质量平衡表明，固定在湖泊中的碳的数量，积累在湖边缘，暴露，随后在14年的基础上位移可以解释近地表SOC营业额在整个山谷。我们的结论是，来自湖泊的有机质的位移是一个重要的外部来源，在这些土壤中的微生物过程在景观尺度。然而，需要进一步的调查，以评估的重要性相比，其他营养素（如N）的空间控制观察到的土壤呼吸速率的位移C。(c)2006爱思唯尔有限公司保留所有权利。
Terrestrial ecosystems in the Antarctic dry valleys function under extremely cold and dry climatic conditions that severely constrain C and N cycling and, like other polar regions, are likely to be sensitive to environmental change. To characterize the distribution and dynamics of soil organic C (SOC) and N in the various landscape elements of an Antarctic dry valley, we measured soil profile organic C and organic N stocks, inorganic N (NH4\-N and NO3-N), Soil CO2 effluxes, water contents and soil temperatures in the Garwood Valley, a relatively small valley in southern Victoria Land. We also conducted laboratory measurements of basal respiration on soils collected from the Valley. SOC and respiration rates were low and SOC was highly stratified in the soil profile, with the largest values observed near the surface. Significant variations of SOC stocks and Soil CO2 effluxes were observed between landscape elements and spatial variability was closely related to the distance from the lake, the major site of primary production. The fastest rate of SOC turnover (residence time c. 30 years) was found in the soils at the lake edge, slower rates were found in landscape elements close to the lake (c. 52-67 years), and the slowest rates in other landscape elements (c. 84-123 years) further away. A mass balance of organic C indicates that the quantity of C fixed in the lake, accumulated on the lake edge, exposed and subsequently displaced on a 14-year basis can explain the near-surface SOC turnover within the entire valley. We conclude that the displacement of organic matter derived from the lake is an important external source for the microbial processes in these soils at a landscape scale. However, further investigations are needed in order to evaluate the importance of displaced C compared to other nutrients (e.g. N) on the spatial control of observed soil respiration rates. (c) 2006 Elsevier Ltd. All rights reserved.