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首页> 外文学位 >The biogeochemical properties of dissolved organic matter in a hardwood forest ecosystem: Their influence on the retention of nitrogen, phosphorus, and carbon.
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The biogeochemical properties of dissolved organic matter in a hardwood forest ecosystem: Their influence on the retention of nitrogen, phosphorus, and carbon.

机译：硬木森林生态系统中溶解有机物的生物地球化学特性：它们对氮，磷和碳保留的影响。

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The leaching of dissolved organic matter (DOM) in forest ecosystems serves both to export organic matter and to redistribute it within the ecosystem. This dissertation is concerned with the role of DOM as a vehicle for the transport of the N and P atoms associated with the DOM. In a deciduous forest watershed in the Southern Appalachian Mountains, the average annual output from the forest floor in the form of dissolved organic matter was 21, 31, and 5.9% of the input in solid litterfall for C, N, and P, respectively. In solution percolating from the forest floor, 94% of the N and 64% of the P was organic. Leaching from the forest floor was not a source of inorganic N and P for the mineral soil. Instead, the forest floor was a sink for the removal of these inorganic nutrients delivered in the throughfall. In contrast, the forest floor was an abundant source to the mineral soil for N and P in the form of DOM.; The chemical properties and interactions of dissolved organic matter with soil surfaces are crucial in determining the mobility of these organic nutrients. Most of the dissolved organic carbon (DOC) was in the organic acid fractions with the hydrophobic acids composing 35 to 57% of the DOC in all samples except summer throughfall.; Over 95% of this DOM was removed as the water percolated through the soil profile and left the ecosystem in streamwater. We examined the importance of decomposition in the removal of DOC and DON. Samples of DOM from all ecosystem strata were adjusted to a common initial DOC concentration and incubated in solution for 134 days. Throughfall samples decomposed most rapidly. In general only 14 to 33% of the DOC in forest floor, soil solution, and stream samples decomposed during the incubation period. The relative order of average decomposition of DOC from the various strata was, from greatest to least: throughfall, Oi (forest floor) Oa (forest floor), B horizon, stream, AB horizon, and upper A horizon. (Abstract shortened with permission of author.)
机译：森林生态系统中溶解性有机物（DOM）的浸出既可用于出口有机物，也可用于在生态系统中重新分配有机物。本论文涉及DOM作为与DOM相关的N和P原子的运输媒介的作用。在阿巴拉契亚山脉南部的落叶森林流域中，以溶解有机物形式的森林地表的年平均产量分别为C，N和P固体凋落物投入的21％，31％和5.9％。从林地渗出的溶液中，N的94％和P的64％是有机的。从林地浸出并不是矿质土壤中无机氮和磷的来源。取而代之的是，森林地面是一个水池，用于清除穿透物中输送的这些无机养分。相反，森林地层以DOM的形式丰富了N和P矿质土壤。溶解的有机物与土壤表面的化学性质和相互作用对于确定这些有机养分的流动性至关重要。大部分溶解的有机碳（DOC）都在有机酸馏分中，其中疏水酸占所有样品中DOC的35％至57％（夏季通降除外）。由于水中的水渗透穿过土壤剖面，从而将生态系统留在了河水中，因此去除了超过95％的DOM。我们研究了分解在去除DOC和DON中的重要性。将来自所有生态系统各层的DOM样品调整为共同的初始DOC浓度，并在溶液中孵育134天。穿透样品分解最快。通常，在孵化期间，森林地表，土壤溶液和溪流样品中只有14％到33％的DOC分解。从各个层次来看，DOC的平均分解的相对顺序从最大到最小为：贯穿，Oi（森林底）Oa（森林底），B视线，河流，AB视线和上A视线。 （摘要经作者许可缩短。）

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