Organic carbon cycling in Taylor Valley, Antarctica: quantifying soil reservoirs and soil respiration
Organic carbon cycling in Taylor Valley, Antarctica: quantifying soil reservoirs and soil respiration
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DOI：
10.1046/j.1365-2486.2001.00393.x
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发表时间：
2001-01-01
影响因子：
11.6
通讯作者：
Wall, DH
中科院分区：
文献类型：
--
作者：
Burkins, MB;Virginia, RA;Wall, DH
对地球上大多数主要生物群落的土壤有机碳库和呼吸速率进行了计算，揭示了与温度、降水和位置有关的模式。然而，来自地球上最寒冷、最干燥、最南端的土壤生态系统之一，南极洲麦克默多干谷的数据，目前还不属于这个全球数据库的一部分。在本文中，我们提出了第一个区域计算的帆有机碳库在干旱的山谷生态系统（泰勒谷）和报告测量南极土壤中的CO2流出。我们的分析表明，尽管没有可见的积累，在大多数泰勒谷的干旱土壤中的有机质，这种土壤环境中包含了显着的百分比（高达72%）的季节性解冻的有机碳库在陆地生态系统。泰勒谷土壤CO2-排放的现场测量用于评估生物呼吸，平均值为0.10 +/- 0.08 μ mol CO2 m（-2）s（-1）。实验室土壤微宇宙表明，这种呼吸速率是敏感的温度，湿度和碳的增加。最后，有机碳在泰勒谷土壤中的平均停留时间的稳态计算为23年。由于这一数值与目前已知的干旱河谷土壤碳循环速率相矛盾，我们认为干旱河谷土壤碳动态不是稳定状态。相反，我们认为，动态是复杂的，至少有两个（短期和长期）有机碳库。我们还认为，在干旱河谷土壤环境中的有机碳可能是更重要的，并在长期的生态系统过程中发挥更积极的作用，比以前认为的。
Organic carbon reservoirs and respiration rates in soils have been calculated for most major biomes on Earth revealing patterns related to temperature, precipitation, and location. Yet data from one of the Earth's coldest, driest, and most southerly soil ecosystems, that of the McMurdo Dry Valleys of Antarctica, are currently not a part of this global database. In this paper, we present the first regional calculations of the sail organic carbon reservoirs in a dry valley ecosystem (Taylor Valley) and report measurements of CO2 efflux from Antarctic soils. Our analyses indicate that, despite the absence of visible accumulations of organic matter in most of Taylor Valley's arid soils, this soil environment contained a significant percentage (up to 72%) of the seasonally unfrozen organic carbon reservoir in the terrestrial ecosystem. Field measurements of soil CO2-efflux in Taylor Valley soils were used to evaluate biotic respiration and averaged 0.10 +/- 0.08 mu mol CO2 m(-2) s(-1). Laboratory soil microcosms suggested that this respiration rate was sensitive to increases in temperature, moisture, and carbon addition. Finally, a steady-state calculation of the mean residence time for organic carbon in Taylor Valley soils was 23 years. because this value contradicts all that is currently known about carbon cycling rates in the dry valleys, we suggest that the dry valley soil carbon dynamics is not steady state. Instead, we suggest that the dynamic is complex, with at least two (short- and la,ng-term) organic carbon reservoirs. We also suggest that organic carbon in the dry valley soil environment may be more important, and play a more active role in long-term ecosystem processes, than previously believed.