Leaching characteristics of anions and cations from evergreen leaves supplied to the stream bed and influences on stream water composition in the Southern Kyusyu Mountains Hirokazu Kitamura
Leaching characteristics of anions and cations from evergreen leaves supplied to the stream bed and influences on stream water composition in the Southern Kyusyu Mountains Hirokazu Kitamura
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南九州山北村宏和供应河床的常绿树叶阴阳离子的淋溶特征及其对河水成分的影响
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发表时间：
2010
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通讯作者：
H. Kitamura
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作者：
H. Kitamura
据估计，每年从陆地河岸森林进入河流生态系统的外来物质的数量是相当可观的，来自落叶分解的物质被认为对河流水质有重要影响。本研究的目的是澄清万年青树种，主要是在河岸带的调查流的叶凋落物的淋溶特性，并检查淋溶液对山溪水离子组成的影响，通过实验室淋溶实验和现场测量。将5片新鲜落叶和10种主要万年青树种的落叶置于装有500 cc蒸馏水的烧杯中，在25~30 ℃的环境温度下放置30 d。用蒸馏水充分洗涤后，在室温下干燥一周，然后在80 ℃下烘干。在浸泡1天和30天后，测定电导率（EC）、氢离子浓度（pH）、阳离子（Li、Na、NH_4、K、Ca和Mg）和阴离子（F、Cl、NO、Br、NO、PO_4和SO_4）的浓度。在现场测量中，从四个不同的环境（泉，浅滩，池和边池）收集的溪流水样品，并被运送到我们的实验室和EC，pH值和阳离子和阴离子的浓度进行了测量。从2006年4月至2007年3月每月进行实地测量。EC，pH值，阳离子和阴离子浓度，继续增加，在所有样品的30天后，浸泡的万年青树叶在蒸馏水中的一些成分的浸出归因于。结果表明，含沉水绿色山矾的水样EC值随时间的延长而降低。et Zucc.叶片超过150 S/cm，pH值上升后迅速下降后立即淹没，从6.0到7.0。水样中最主要的阳离子是K，占大多数样品沃茨中所有阳离子的70%以上。淹水后30 d，绿色叶片平均阳离子释放速率顺序为K > Mg > Ca > Na，与前人的实验结果一致。平均阴离子释放量的顺序为Cl > PO 4> SO 4。与淋溶实验中水中的高K比率相反，溪流水中的月K浓度相对低于其他阳离子和阴离子。在生长季节的溪流中的K浓度较低，这表明生物群和溪流沉积物对K的利用存在差异，它们是去除水中渗滤液的重要试剂。因此，沉积物中的粘土成分可以作为化学结合钾的储库，如果生物量有一些净增加，生物区系也可以提供钾的储库。EC值是在春季低于其他环境中，K，Mg和Ca的浓度是相当高的浅滩，池和边池，其中提供了凋落物，比在春季的落叶不沉积。这些结果表明，主要来源的离子是岩石风化在春季和多源同步离子负载发生在浅滩，池和边池和落叶是在溪流中的K，Mg和Ca的主要来源之一。基于这些结果，它表明，阴离子和阳离子浓度在整个流达到不总是均匀的，由于从树叶渗滤液所造成的离子材料的非均匀分布，虽然流水已被视为提供一个统一的连续体的离子材料，和水的组成变化，由于自然输入和随后的沥滤从落叶进行了预测。
The amount of allochthonous material that enters lotic ecosystems annually from terrestrial riparian forests is estimated to be considerable, and substances derived from the decomposition of leaf litter are thought to have an important impact on stream water quality. The purpose of the present study is to clarify the leaching characteristics of leaf litter of the evergreen species that are dominant in the riparian zone of the investigated stream and to examine the influence of leachates on mountain stream water ionic composition by laboratory leaching experiments and field measurements. Five fresh fallen leaves and fallen leaves of ten species of evergreen trees dominant in the riparian zone of the investigated reach were placed into a beaker filled with 500cc of distilled water and allowed to stand for 30 days at ambient temperature between 25~30 。 C after well washing with distilled water, air-dried for one week and oven-dried at 80 。 C for 48 hours and the electric conductivity (EC), hydrogen ion concentration (pH) and the concentrations of cations (Li, Na, NH4, K, Ca and Mg) and anions (F, Cl, NO, Br, NO, PO4 and SO4) were measured at 1 and 30 days after submersion. On the field measurements, stream water samples were collected from four different environments (springs, riffles, pools and side-pools) and were transported to our laboratory and EC, pH and the concentrations of the cations and anions were measured. The field measurements were conducted monthly from April 2006 to March 2007. EC, pH, and cation and anion concentrations, continued to increase in all samples for 30 days following the immersion of evergreen tree leaves in distilled water for being attributed to the leaching of some components from the leaves. The EC values of water samples containing submerged green Symplocos theophrastifolia Sieb. et Zucc. leaves exceeded 150 S/cm, and pH values increased following the rapid decrease immediately after submergence, from 6.0 to 7.0. The most dominant cation in the water samples was K, accounting for more than 70% of all cations in most sample waters. On the 30th day after submergence, the order of average cation release rates from green leaves was K > Mg > Ca > Na, which coincided to the experimental results in previous studies. The order of average anion release was Cl > PO4 > SO4. In contrast to the high K ratios in the water of the leaching experiments, the monthly K concentrations in the stream water were relatively lower than those of the other cations and anions. The lower concentration of K in the stream water during the growing season would suggest that there is a differential utilization of K by the biota and stream sediment acts as an important agent for removal of leachate from water. Therefore, the clay component of the sediment may serve as a reservoir of chemically bound K and biota may also provide a reservoir for K if there is some net increase in biomass. The EC value is lower in the spring than in the other environments and that the K, Mg and Ca concentrations are considerably higher in the riffle, pool and side-pool, in which litter had been supplied, than in the spring where leaf litter is not deposited. These results indicate that the primarily source of ions is rock weathering in the spring and simultaneous ion loading from multiple sources occurs in the riffle, pool and side-pool and that leaf litter is one of the primary sources of K, Mg and Ca in the stream water. Based on these results, it is demonstrated that anion and cation concentrations throughout the stream reach are not always uniform due to heterogeneous distribution of ionic material caused by leachate from leaves, although stream water has been regarded as providing a uniform continuous body for the ionic materials, and changes in water composition due to the natural input and subsequent leaching from leaf litter were predicted.