调水调沙对黄河下游颗粒有机碳输运的影响  

Effect of Water and Sediment Regulation on the Transport of Particulate Organic Carbon in the Lower Yellow River

作　　者：张婷婷[1,2] 姚鹏[1,3,4] 王金鹏[1,2] 潘慧慧[1,2] 高立蒙 赵彬[1,2] 李栋[1,2] 

机构地区：[1]中国海洋大学海洋化学理论与工程技术教育部重点实验室,青岛266100 [2]中国海洋大学化学化工学院,青岛266100 [3]海洋科学与技术青岛协同创新中心,青岛266100 [4]中国海洋大学海洋有机地球化学研究所,青岛266100

出　　处：《环境科学》2015年第8期2817-2826,共10页Environmental Science

基　　金：国家自然科学基金项目(41176063;41221004)

摘　　要：流域内各种自然过程及人为活动对河流有机碳的输运都会产生影响,而正确认识河流有机碳的输运过程是全球碳循环研究的重要方面.于2012年调水调沙期间(6月19日至7月20日)在黄河利津采集了表层悬浮颗粒物,进行了粒度组成、颗粒有机碳(particulate organic carbon,POC)及其稳定同位素丰度(δ13C)等参数的分析,用来研究调水调沙期间POC的来源、组成和丰度的变化规律与影响因素.结果表明,2012年黄河调水调沙可以根据径流量和输沙量的变化分为排水和排沙两个阶段,这两个阶段黄河水沙及POC和δ13C的变化,体现了调水调沙对颗粒物及其赋存有机碳来源的影响.排水阶段径流量高达4 270 m3·s-1,下游河道被冲刷,使底层泥沙再悬浮,因此这一阶段颗粒物粒径较粗(平均中值粒径13.9μm),有机碳含量较低(平均0.38%),δ13C偏正且稳定(-24.2‰±0.3‰),可能与底层泥沙中POC年龄较老、降解程度高有关;排沙阶段含沙量大(可达17.8 kg·m-3),颗粒物较细(平均中值粒径5.9μm),有机碳含量较高(平均0.50%),δ13C偏负且波动较大(-24.8‰±0.6‰),这与颗粒物主要来自上游水库和下游暴雨冲刷河岸,POC相对新鲜有关.2012年调水调沙期间POC日通量与输沙量的变化一致,总输送量约为1.13×105t,占全年POC输送量的12%.与往年相比,2012年黄河调水调沙时期径流量增大,但输沙量和POC通量有所减小.由此可见,调水调沙对黄河颗粒有机碳的输运有重要影响,而颗粒有机碳在调水调沙期间不同阶段也有明显不同的来源、组成和输运模式.Both natural processes and human activities in river basins have important impacts on the transport of riverine organic carbon( OC). Better understanding of the riverine OC transport processes is critical for the studies of global carbon cycling. Suspended particulate matters collected from the Lijin Station in the lower Yellow River during the water and sediment regulation( WSR) period in2012( 19 June-20 July) were analyzed for grain size,particulate OC( POC) and stable carbon isotopic ratios( δ13C) to investigate the sources,composition,abundance of POC and the effect of WSR on the transport of POC. The results showed that the WSR in 2012 could be divided into two stages according to the variation of water and sediment discharges: the water-release stage( WRS) and the sediment-release stage( SRS). Variations of the water discharge,sediments,POC and δ13C in these two stages reflected the impacts of WSR on the sources of particulate matters and associated OC. The water discharge in the WRS stage was the highest( 4 270 m3·s-1),and the sediments scoured from the riverbed in the lower reaches were the major source of suspended particulate matters in this stage,therefore the particles were characterized by relatively coarse grain size( 13. 9 μm in average of median grain size),low POC( avg.0. 38%) and relatively enriched and constant δ13C(-24. 2‰ ± 0. 3‰),probably because POC in the sediments scoured from the riverbed had old radiocarbon ages and high degradation. The suspended particulate matters in the SRS stage were mainly derived from the upstream reservoirs and flushed riverbanks due to local rainstorm,and the POC age was relatively young,thus this stage was characterized by high concentration of suspended particulate matters( up to 17. 8 kg·m-3),fine particles( 5. 9 μm in average of median grain size),high POC( avg. 0. 50%),and depleted and varied δ13C values(-24. 8‰ ± 0. 6‰). Variation of daily POC flux had similar pattern with sediment discharge,and the total POC flux during the water and se

关 键 词：黄河 调水调沙 颗粒有机碳 稳定碳同位素 输运 

分 类 号：X143[环境科学与工程—环境科学]