硫随森林溪流水体流动是生态系统硫源汇过程的重要内容,是认识森林-水体连续体中物质循环和能量流动的重要组分.为了了解森林溪流硫输出的潜在能力,以川西典型高山森林为研究对象,于2015年7月溪流径流量最大的降雨季节,在集水区4.31 km2的范围内,调查了所有15条溪流从源头到入河口的硫变化特征和输出特征.结果表明,调查区域中,所有溪流水体中总硫贮量为598.57 g,单位溪流面积贮量为0.78 g·m-2,溪流沉积物中总硫贮量为176.18 kg,单位溪流面积沉积物硫贮量为0.23 kg·m-2.单位集水区面积和单位溪流面积总硫输出量分别为0.02和104.55g·m-2·d-1,集水区潜在最大年总硫输出量为7.3 g·m-2·y-1.溪流中硫含量的检出限在0.12-2.46 ug· ml-1之间,入河口硫含量占源头的比值在0.40-4.82之间,均值为1.27.溪流入河口硫贮量占源头贮量的比值在0.45-8.55之间,所有森林溪流入河口硫贮量占源头贮量比值平均为1.79.这意味着,森林溪流从源头到入河口的汇流过程中硫贮量在逐渐累积.这些结果为深入认识高山森林硫的迁移途径及其对下游生态系统的潜在影响提供了新的思路.%Forest stream is the bond of bioelement biogeochemical cycles which links mountain forest and butted river.However,far less information has been available on sulfur distribution and output characteristics in the water flow of alpine forest headwater streams.In order to know the potential of sulfur output in the alpine forest streams,this study was conducted in a typical alpine forest catchment in the eastern Qinghai Tibet Plateau in July 2015.The concentrations of sulfur in water flow and sediment were investigated from the source to the end in 15 streams in the 4.31 km2 catchment.The stream water stored a total of 598.57 g sulfur in the catchment,and averaged 0.78 g · -2m-2.Meanwhile,the stream sediment in the catchment stored 176.18 kg sulfur,and converted into 0.23 kg · m sulfur.The maximum potential of total sulfur output was estimated at 7.3g · m-2 · Y-1 in the catchment,while the total sulfur output in the alpine forest catchment and stream was 0.02g · m-2 · d-1 and 104.55g · m-2 · d-1 respectively.Total sulfur concentration in stream water varied from 0.12 to 2.46 ug · ml-1 depending on sampling locations in the streams.The average ratio of the sulfur concentration ratio of stream end to source was 1.79,and ranged from 0.40 to 4.82.Similarly,the ratios of sulfur storage in the stream end to source varied from 0.45 to 8.55,with an average ratio of 1.79.The results suggested that total sulfur storage in the streams obviously increased with the increase of length and width of streams,which provided a new idea in understanding sulfur transferring ways in the alpine forests and its potential impact on downstream ecosystems.
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