Stream Organic Matter Budgets: An Introduction
Stream Organic Matter Budgets: An Introduction
复制标题
DOI：
10.2307/1468223
复制
发表时间：
1997-03
影响因子：
--
通讯作者：
J. Webster;J. Meyer
中科院分区：
文献类型：
--
作者：
J. Webster;J. Meyer
本研究之目的有三：1）探讨溪流之物理特性与其集水区之关系（气候，地貌）和流有机物动态使用的数据从一个广泛的地理区域; 2）比较流有机物动态在不同的数组流，以建议观察到的模式的决定因素; 3）揭示现有河流有机物动态数据的不足。在这项分析中纳入溪流并不代表溪流类型的全球多样性，而是因为可以获得有机物数据。在介绍性章节中，我们描述了各种数据包括每个流，并提供了以前公布的有机物数据流的比较分析，但没有在个别章节中描述的简要说明。接下来的16章介绍了北美、欧洲、澳大利亚和南极洲河流的有机物数据。大部分的溪流都位于北美洲的温带地区。所提供的数据包括气候和地貌变量以及有机物质投入、输出和现存作物。在个别溪流的章节之后是7章，分析这些溪流的物理特征和有机物预算的具体组成部分。流的大小，水温和降水量是最重要的变量设置的物理模板发生在流中的有机物过程。流域面积是最好的预测总初级生产力（GPP），这增加了流域面积。流域面积，流量和可溶性活性磷浓度解释了71%的GPP的变化。气候（纬度）和植被类型更重要的比流的顺序在预测凋落物输入在广泛的地理范围内的流，虽然，在一个流域内，凋落物减少流的顺序增加。回归底栖有机物（BOM）和纬度和降水量证明是有用的，在预测BOM在大陆尺度的流中的现存量，虽然BOM也与通道特性，如梯度和木质残体。底栖呼吸急剧增加，随着温度的升高（Q10=7.6），这表明不仅与新陈代谢，但也在BOM质量的变化，在植被的纬度变化的反应。陆地和河岸植被被认为在调节悬浮颗粒有机物（POM）的浓度和出口发挥了重要作用，观察到较高的值在森林溪流和低梯度流广泛的洪泛区。河道坡度是溶解性有机物（DOM）浓度和输出的最佳预测因子，这可能是因为它与河岸湿地和水文流径的关系。在最后一章，有机质收支的综合，我们得出了两个结论：1）在全球范围内，河流有机质动态主要是由气候通过其对陆地植被的影响。2)尽管在理解有机物的流程流的重大进展，我们发现流之间的许多差异反映了遗漏的重要组成部分的预算，特别是准确的措施，河床面积，异养呼吸，常备库存的罚款BOM，和地下水输入的DOM。
This analysis of organic matter dynamics in streams has 3 objectives: 1) to explore the relationships between physical characteristics of streams and their watersheds (climate, geomorphology) and stream organic matter dynamics using data from a broad geographic area; 2) to compare stream organic matter dynamics in a diverse array of streams in order to suggest determinants of observed patterns; and 3) to reveal deficiencies in currently available data on organic matter dynamics in streams. Streams were included in this analysis not to represent the global diversity of stream types but because organic matter data were available. In the introductory chapter we describe the kinds of data included for each stream and provide brief descriptions of previously published organic matter data for streams included in the comparative analysis but not described in individual chapters. The next 16 chapters present organic matter data for streams from North America, Europe, Australia, and Antarctica. Most of the streams represented are in the temperate zone of North America. Data presented include climate and geomorphic variables and organic matter inputs, exports, and standing crops. The chapters on individual streams are followed by 7 chapters analyzing physical features of these streams and specific components of the organic matter budgets. Stream size, water temperature, and precipitation were the most important variables setting the physical template for organic matter processes occurring in the streams. Watershed area was the best predictor of gross primary productivity (GPP), which increased with increasing watershed area. Watershed area, discharge, and soluble reactive phosphorus concentration explained 71% of the variation in GPP. Climate (latitude) and vegetation type were more important than stream order in predicting litter inputs across a broad geographic range of streams, although, within a river basin, litterfall decreased with increasing stream order. Regression of benthic organic matter (BOM) and latitude and precipitation proved useful in predicting BOM standing crop in streams at a continental scale, although BOM was also related to channel characteristics such as gradient and woody debris. Benthic respiration increased dramatically with increasing temperature (Q10=7.6), suggesting a response related not only to metabolism but also to changes in BOM quality in response to latitudinal shifts in vegetation. Terrestrial and riparian vegetation was found to play an important role in regulating suspended particulate organic matter (POM) concentration and export, with higher values observed in forested streams and in lower gradient streams with extensive floodplains. Channel slope was the best predictor of dissolved organic matter (DOM) concentration and export, probably because of its relationship with riparian wetlands and hydrologic flowpaths. In the final chapter, a synthesis of the organic matter budgets, we reached two conclusions: 1) At a global level, stream organic matter dynamics are driven primarily by climate through its effect on terrestrial vegetation. 2) Despite significant progress in understanding organic matter processes in streams, many of the differences we found among streams reflect omissions of important components of the budget, especially accurate measures of streambed area, heterotrophic respiration, standing stock of fine BOM, and groundwater inputs of DOM.