High precipitation causes large fluxes of dissolved organic carbon and nitrogen in a subtropical montane Chamaecyparis forest in Taiwan
High precipitation causes large fluxes of dissolved organic carbon and nitrogen in a subtropical montane Chamaecyparis forest in Taiwan
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DOI：
10.1007/s10533-010-9470-1
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发表时间：
2010-06
期刊：
影响因子：
4
通讯作者：
Bettina H. M. Schmidt;Chiao‐Ping Wang;Shih-Chieh Chang;E. Matzner
中科院分区：
文献类型：
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作者：
Bettina H. M. Schmidt;Chiao‐Ping Wang;Shih-Chieh Chang;E. Matzner
溶解有机碳（DOC）和氮（DON）的通量可能对森林生态系统土壤中碳和氮的损失发挥重要作用，特别是在高降水条件下。我们研究了台湾亚热带山地 Chamaecyparisobtusavar.formosana 森林中 DOC 和 DON 通量和浓度与降水强度的关系。我们的目标是量化 DOC 和 DON 通量，并了解高降水量对该生态系统中 DOC 和 DON 输出的作用。从 2005 年到 2008 年，我们对大量降水、径流、森林地面渗透物和渗漏（60 厘米）进行了采样，并分析了 DOC、DON 和矿物质 N 浓度。土壤中的平均 DOC 通量极高（森林地面渗透物和渗漏物中分别为 962 和 478 kg C ha−1year−1），而 DON 通量与其他（亚）热带生态系统相似（分别为 16 和 8 kg N ha−1year−1）。土壤中的总氮通量以 DON 为主。森林地表渗滤液中溶解的有机碳和氮浓度与水通量无关。没有看到稀释效应。相反，潜在可溶性 DOC 和 DON 的池大小是可变的，如相似降水量下森林地面渗透物中不同的 DOC 和 DON 浓度所示。因此，我们假设，从长远来看，这些池不太可能耗尽。大量降水中的水通量与森林地表渗滤液中的 DOC 和 DON 通量之间呈正相关（分别为 DOCr= 0.908，DONr= 0.842，Spearman 等级相关）。我们得出的结论是，降水是亚热带山地森林 DOC 和 DON 损失的重要驱动因素，并且这些 DOC 损失在该生态系统的土壤碳循环中发挥着重要作用。此外，我们发现，当纳入来自（亚热带）生态系统的这些通量的附加数据时，温带生态系统森林地面渗透物中的大量降水与 DOC 和 DON 通量之间的线性关系并不成立。
Fluxes of dissolved organic carbon (DOC) and nitrogen (DON) may play an important role for losses of C and N from the soils of forest ecosystems, especially under conditions of high precipitation. We studied DOC and DON fluxes and concentrations in relation to precipitation intensity in a subtropical montaneChamaecyparisobtusavar.formosanaforest in Taiwan. Our objective was, to quantify DOC and DON fluxes and to understand the role of high precipitation for DOC and DON export in this ecosystem. From 2005 to 2008 we sampled bulk precipitation, throughfall, forest floor percolates and seepage (60 cm) and analyzed DOC, DON and mineral N concentrations. Average DOC fluxes in the soil were extremely high (962 and 478 kg C ha−1year−1in forest floor percolates and seepage, respectively) while DON fluxes were similar to other (sub)tropical ecosystems (16 and 8 kg N ha−1year−1, respectively). Total N fluxes in the soil were dominated by DON. Dissolved organic C and N concentrations in forest floor percolates were independent of the water flux. No dilution effect was visible. Instead, the pool size of potentially soluble DOC and DON was variable as indicated by different DOC and DON concentrations in forest floor percolates at similar precipitation amounts. Therefore, we hypothesized, that these pools are not likely to be depleted in the long term. The relationship between water fluxes in bulk precipitation and DOC and DON fluxes in forest floor percolates was positive (DOCr= 0.908, DONr= 0.842, respectively, Spearman rank correlation). We concluded, that precipitation is an important driver for DOC and DON losses from this subtropical montane forest and that these DOC losses play an important role in the soil C cycle of this ecosystem. Moreover, we found that the linear relationship between bulk precipitation and DOC and DON fluxes in forest floor percolates of temperate ecosystems does not hold when incorporating additional data on these fluxes from (subtropical) ecosystems.