Moss-nitrogen input to boreal forest soils: Tracking 15N in a field experiment
Moss-nitrogen input to boreal forest soils: Tracking 15N in a field experiment
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DOI：
10.1016/j.soilbio.2014.01.031
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发表时间：
2014-05
影响因子：
9.7
通讯作者：
Kathrin Rousk;David L. Jones;T. DeLuca
中科院分区：
文献类型：
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作者：
Kathrin Rousk;David L. Jones;T. DeLuca
蓝藻附生生活在原始的，未受污染的地区的苔藓固定大量的大气氮（N），因此代表了氮有限的北方森林的主要来源。然而，这种N的命运是不清楚的，特别是，如何固定N2进入土壤，成为生态系统提供。在这项研究中，我们将15 N-氯化铵（15 N-NH 4Cl）应用于羽藓Pleurozium schreberi的地毯上，并随着时间的推移将15 N标记追踪到绿色（活的）和棕色（衰老的）苔藓以及上层土壤。此外，我们放置在苔藓和土壤之间的过滤器，以评估苔藓相关真菌的作用，N-转移到土壤中。该实验在瑞典北方的N2固定梯度的终点进行。羽藓保留了所施加的氮在绿色苔藓部分长达1年，并没有增加过量的15 N被发现在棕色苔藓部分或在同一时间范围内的土壤中。过滤处理没有改变苔藓或土壤中的15 N分布。氮保留在苔藓是相似的，无论位置沿着N2固定梯度。我们的研究结果表明，苔藓代表了一个短期的无机氮库，并转移到土壤中的N是不方便真菌菌丝。
Cyanobacteria living epiphytically on mosses in pristine, unpolluted areas fix substantial amounts of atmospheric nitrogen (N) and therefore represent a primary source of N in N-limited boreal forests. However, the fate of this N is unclear, in particular, how the fixed N2enters the soil and becomes available to the ecosystem. In this study, we applied15N-ammonium chloride (15N-NH4Cl) onto carpets of the feather mossPleurozium schreberiand traced the15N label into green (living) and brown (senescent) moss and into the upper soil layer over time. Further, we placed filters between moss and soil to assess the role of moss-associated fungi for N-transfer to the soil. The experiment was conducted at endpoints of a N2fixation gradient in Northern Sweden. Feather moss retained the applied N in the green moss parts for up to 1 year and no increase of excess15N was found in the brown moss parts or in the soil within that same time frame. The filter treatment did not alter the15N-distribution in moss or soil. Nitrogen retention in the moss was similar regardless of position along the N2fixation gradient. Our results suggest that mosses represent a short-term inorganic N sink and that transfer of N to the soil is not facilitated by fungal hyphae.