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首页> 外文期刊>Earth Surface Processes and Landforms: The journal of the British Geomorphological Research Group >Export of fine particulate organic carbon from redwood-dominated catchments
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Export of fine particulate organic carbon from redwood-dominated catchments

机译：从红木为主的流域出口细颗粒有机碳

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Recently, researchers have recognized the significant role of small mountainous river systems in the transport of carbon from terrestrial environments to the ocean, and the scale of such studies have ranged from channel bed units to continents. In temperate zones, these mountain river systems commonly drain catchments that are largely forested. However, the magnitude of carbon export from rivers draining old-growth redwood forests has not been evaluated to date. Old-growth redwood stands support some of the largest quantities of biomass in the world, up to 350 000Mg of stem biomass km(-2) and soil organic carbon can reach 46 800Mgkm(-2). In north coastal California, suspended sediment samples were collected at three gaging stations for two to four years on streams draining old-growth redwood forests. Carbon content, determined through loss-on-ignition tests, was strongly correlated with turbidity, and continuous turbidity records from the gaging stations were used to estimate annual carbon exports of 1 . 6 to 4 . 2Mg km(-2) yr(-1). These values, representing 13 to 33% of the suspended sediment load, are some of the highest percentages reported in the global literature. The fraction of organic carbon as part of the suspended sediment load decreased with discharge, but reached an asymptote of 5 to 10% at flows 10 to 20 times the mean annual flows. Although larger rivers in this region exhibit high sediment yields (up to 3600Mgkm(-2) yr(-1)), mainly attributed to high rates of uplift, mass movement, and timber harvest, the small pristine streams in this study have sediment yields of only 8 to 100Mgkm(-2) yr(-1). Because the current extent of old-growth redwood stands is less than 5% of its pre-European-settlement distribution, the present organic carbon signature in suspended sediment loads in this region is likely different from that in the early 20th century. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.
机译：最近，研究人员已经认识到山区山区河流系统在碳从陆地环境到海洋的运输中的重要作用，而且这种研究的规模从河床床到大陆。在温带地区，这些山区河流系统通常会排放大部分森林茂密的集水区。但是，迄今为止，尚未评估过从流失旧有红木森林的河流中排放的碳的数量。旧生长的红木林支持着世界上最大量的生物量，茎生物量km（-2）高达350 000Mg，土壤有机碳可达到46800Mgkm（-2）。在加利福尼亚州北部沿海地区，在排水旧木的红木森林的溪流中，在三个测量站收集了两到四年的悬浮沉积物样本。通过燃烧损失测试确定的碳含量与浊度密切相关，并且使用来自计量站的连续浊度记录来估算每年的碳排放量为1。 6至4。 2Mg km（-2）yr（-1）。这些值占悬浮沉积物负荷的13％至33％，是全球文献中报告的最高百分比。随着排放的增加，作为悬浮泥沙负荷一部分的有机碳比例下降，但在年平均流量的10至20倍时达到了5至10％的渐近线。尽管该地区较大的河流具有较高的沉积物产量（高达3600Mgkm（-2）yr（-1）），这主要归因于较高的隆升，大量运动和木材采伐，但本研究中的少量原始河流具有沉积物产量仅8至100Mgkm（-2）yr（-1）。由于目前的老龄红木林分还不到欧洲沉降前分布的5％，因此该地区目前悬浮物中的有机碳特征可能与20世纪初有所不同。 2015年发布。本文是美国政府的工作，在美国属于公共领域。

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