Abstract. Around half of the Earth's soil organic carbon (SOC) is presently stored in the Northern Hemisphere permafrost region. In polar permafrost regions, low temperatures particularly inhibit both the production and biodegradation of organic matter. Under such conditions, abiotic factors such as mesoclimate, pedogenic substrate or altitude are thought to be more important for soil development than biological factors. In Antarctica, biological factors are generally underestimated in soil development due to the rare occurrence of higher plants and the short time since deglaciation. In this study, we aim to assess the relationship between SOC and other soil properties related to the pedogenic factors or properties. Nine plots were investigated along the altitudinal gradient from 10 to 320 m in the deglaciated area of James Ross Island (Ulu Peninsula) using a parallel tea-bag decomposition experiment. SOC contents showed a positive correlation with the content of easily extractable glomalin-related soil protein (EE-GRSP; Spearman r=0.733, P=0.031) and the soil buffering capacity (expressed as ΔpH; Spearman r=0.817, P=0.011). The soil-available P was negatively correlated with altitude (Spearman r=-0.711, P=0.032), and the exchangeable Mg was negatively correlated with the rock fragment content (Spearman r=-0.683, P=0.050). No correlation was found between the available mineral nutrients (P, K, Ca and Mg) and SOC or GRSP. This may be a consequence of the inhibition of biologically mediated nutrient cycling in the soil. Therefore, the main factor influencing nutrient availability in these soils does not seem to the biotic environment; rather, the main impact appears to stem from the abiotic environment influencing the mesoclimate (altitude) or the level of weathering (rock content). Incubation in tea bags for 45 d resulted in the consumption and translocation of more labile polyphenolic and water-extractable organic matter, along with changes in the C content (increase of up to +0.53 % or decrease of up to −1.31 % C) and a decrease in the C:N ratio (from 12.5 to 7.1–10.2), probably due to microbial respiration and an increase in the abundance of nitrogen-binding microorganisms. Our findings suggest that one of the main variables influencing the SOC/GRSP content is not the altitude or coarse-fraction content (for which a correlation with SOC/GRSP was not found); rather, we suspect effects from other factors that are difficult to quantify, such as the availability of liquid water.

中文翻译：

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沿詹姆斯罗斯岛（南极洲）海拔梯度的土壤有机质相互作用


摘要。目前，地球大约一半的土壤有机碳 （SOC） 储存在北半球永久冻土区。在极地永久冻土区，低温特别抑制有机物的产生和生物降解。在这种情况下，中气候、成因基质或海拔等非生物因素被认为比生物因素对土壤发育更重要。在南极洲，由于高等植物很少出现并且冰川消融后的时间短，因此在土壤发育中通常低估了生物因素。在本研究中，我们旨在评估 SOC 与其他与成因因素或特性相关的土壤特性之间的关系。采用平行茶包分解实验，在詹姆斯罗斯岛 （Ulu Peninsula） 冰川消融区沿 10 至 320 m 海拔梯度研究了 9 个样地。SOC 含量与易提取 glomalin 相关土壤蛋白 （EE-GRSP;Spearman r=0.733，P=0.031）和土壤缓冲能力（以 ΔpH 表示;Spearman r=0.817，P=0.011）。土壤速效 P 与海拔呈负相关 （Spearman r=-0.711，P=0.032），可交换 Mg 与岩石碎片含量呈负相关 （Spearman r=-0.683，P=0.050）。未发现有效矿物营养物质 （P、K、Ca 和 Mg） 与 SOC 或 GRSP 之间存在相关性。这可能是土壤中生物介导的养分循环受到抑制的结果。 因此，影响这些土壤中养分可用性的主要因素似乎与生物环境无关;相反，主要影响似乎源于影响中气候（海拔）或风化水平（岩石含量）的非生物环境。在茶包中孵育 45 天导致更不稳定的多酚和水可萃取有机物的消耗和易位，以及 C 含量的变化（增加高达 +0.53 % 或减少高达 -1.31 % C）和 C：N 比的降低（从 12.5 到 7.1-10.2），这可能是由于微生物呼吸和氮结合微生物丰度的增加。我们的研究结果表明，影响 SOC/GRSP 含量的主要变量之一不是海拔或粗馏分含量（未发现与 SOC/GRSP 的相关性）;相反，我们怀疑其他难以量化的因素的影响，例如液态水的可用性。