Phosphorus Availability Determines the Response of Tundra Ecosystem Carbon Stocks to Nitrogen Enrichment
Phosphorus Availability Determines the Response of Tundra Ecosystem Carbon Stocks to Nitrogen Enrichment
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DOI：
10.1007/s10021-017-0209-x
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发表时间：
2018-09
期刊：
影响因子：
3.7
通讯作者：
L. Street;Nora Mielke;S. Woodin
中科院分区：
文献类型：
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作者：
L. Street;Nora Mielke;S. Woodin
北方永久冻土层含有重要的碳储量。本文报道了北极矮灌木苔原碳储量对短期低水平养分富集的长期响应。实验添加氮20年后，植被和有机土壤中的碳储量几乎减少了一半。相比之下，当磷和氮一起添加时，碳储量增加了50%以上。这些反应可以用苔藓和有机土层深度的变化来解释。氮明显促进苔藓分解，减少碳储量，而磷和氮共同促进苔藓生产力，增加有机质积累。苔藓和土层结构的改变改变了土壤热状态，这可能进一步影响土壤碳的分解。如果气候变暖增加了磷的可用性，那么由于土壤变暖或北极地区人类活动扩大而导致的氮富集的任何增加都可能导致碳固存的增加。然而，在冻土带地区磷含量有限的地方，氮的富集可能导致碳的损失。
Northern permafrost soils contain important carbon stocks. Here we report the long-term response of carbon stocks in high Arctic dwarf shrub tundra to short-term, low-level nutrient enrichment. Twenty years after experimental nitrogen addition, carbon stocks in vegetation and organic soil had almost halved. In contrast, where phosphorus was added with nitrogen, carbon storage increased by more than 50%. These responses were explained by changes in the depths of the moss and organic soil layers. Nitrogen apparently stimulated decomposition, reducing carbon stocks, whilst phosphorus and nitrogen co-stimulated moss productivity, increasing organic matter accumulation. The altered structure of moss and soil layers changed soil thermal regimes, which may further influence decomposition of soil carbon. If climate warming increases phosphorus availability, any increases in nitrogen enrichment from soil warming or expanding human activity in the Arctic may result in increased carbon sequestration. Where phosphorus is limiting in tundra areas, however, nitrogen enrichment may result in carbon loss.