Wetter is Better: Rewetting of Minerotrophic Peatlands Increases Plant Production and Moves Them Towards Carbon Sinks in a Dry Year
Wetter is Better: Rewetting of Minerotrophic Peatlands Increases Plant Production and Moves Them Towards Carbon Sinks in a Dry Year
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DOI：
10.1007/s10021-020-00570-z
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发表时间：
2020-03
期刊：
影响因子：
3.7
通讯作者：
S. Schwieger;J. Kreyling;J. Couwenberg;M. Smiljanić;Robert Weigel;M. Wilmking;G. Blume‐Werry
中科院分区：
文献类型：
--
作者：
S. Schwieger;J. Kreyling;J. Couwenberg;M. Smiljanić;Robert Weigel;M. Wilmking;G. Blume‐Werry
泥炭地是有效的碳汇，因为在普遍的缺氧条件下产生的生物量多于分解的生物量。排干泥炭地再加上变暖会释放储存的碳，随后的再湿润可能会也可能不会恢复原来的碳汇。然而，在重新湿润的泥炭地，植物生产和分解的模式，以及它们如何比较排水条件仍然在很大程度上未被探索。在这里，我们测量了每年的地上和地下生物量的生产和分解在三个不同的排水和再润湿泥炭地类型：桤木森林，渗滤沼泽和沿海沼泽在一个非常干燥的年份。我们还使用标准植物材料来比较不同地点的分解情况，而不考虑当地植物材料的可分解性。再湿润的网站表现出较高的根和芽生产的渗滤沼泽和沿海沼泽较高的根生产，但类似的根和叶生产的桤木森林。在排水和再湿润的网站，分解速率一般相似，只有在渗滤沼泽和桤木林地上凋落物分解速度更快的排水网站。再润湿渗滤沼泽和两个沿海网站的有机质积累的最高预测潜力。根系占总生物量的23-66%，地下生物量，而不是地上生物量，是特别重要的有机质积累在沿海沼泽。这突出了根作为这些禾本科占主导地位的沼泽泥炭地的主要泥炭形成元素的重要性及其在碳循环中的关键作用，并表明即使在干旱年份，高生物量生产也支持泥炭地作为碳汇的功能。
Peatlands are effective carbon sinks as more biomass is produced than decomposed under the prevalent anoxic conditions. Draining peatlands coupled with warming releases stored carbon, and subsequent rewetting may or may not restore the original carbon sink. Yet, patterns of plant production and decomposition in rewetted peatlands and how they compare to drained conditions remain largely unexplored. Here, we measured annual above- and belowground biomass production and decomposition in three different drained and rewetted peatland types: alder forest, percolation fen and coastal fen during an exceptionally dry year. We also used standard plant material to compare decomposition between the sites, regardless of the decomposability of the local plant material. Rewetted sites showed higher root and shoot production in the percolation fen and higher root production in the coastal fen, but similar root and leaf production in the alder forest. Decomposition rates were generally similar in drained and rewetted sites, only in the percolation fen and alder forest did aboveground litter decompose faster in the drained sites. The rewetted percolation fen and the two coastal sites had the highest projected potential for organic matter accumulation. Roots accounted for 23–66% of total biomass production, and belowground biomass, rather than aboveground biomass, was particularly important for organic matter accumulation in the coastal fens. This highlights the significance of roots as main peat-forming element in these graminoid-dominated fen peatlands and their crucial role in carbon cycling, and shows that high biomass production supported the peatlands’ function as carbon sink even during a dry year.