典型枯水年长江干流硅的分布、输送与滞留  

Distribution,transport and retention of silica in the main channels of the Yangtze River in exceptionally low water discharge year

作　　者：冉祥滨[1,2] 刘军[1] 于志刚[1] 姚庆祯[1] 郭鸿博[1,3] 陈洪涛[1] 

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]国家海洋局第一海洋研究所海洋生态研究中心,青岛266061 [3]天津环境监测中心,天津300191

出　　处：《湖泊科学》2017年第3期740-752,共13页Journal of Lake Sciences

基　　金：国家自然科学基金项目(41211120435;41106073;30490232)资助

摘　　要：于特枯水情年对三峡水库溶解硅和长江干流自涪陵至河口段悬浮颗粒物、溶解硅、生物硅和叶绿素a浓度等进行调查.研究表明,在平水期和汛期末,长江干流水体溶解硅和生物硅浓度和通量在其上游受大坝"滞留"效应的影响呈现沿程降低的趋势,中、下游受"两湖"和汉江等的补充作用有明显升高.在枯水年,长江干流水体生物硅浓度占活性硅(溶解硅和生物硅之和)浓度的2%~5%,显著低于平水年的比例(13%),同时也低于世界河流的平均水平(16%).三峡水库在4-12月份减少溶解硅向下游的输送通量,而在1-3月份增加溶解硅的输送通量;水库在枯水年滞留了大约3%~6%的溶解硅.三峡水库内低的初级生产水平和高的生物硅再生速率是其难以对溶解硅形成有效滞留的主要因素.大坝下游会因清水下泄产生潜在的滞留效应,不过还需要更多的数据去量化.Water samples were obtained in the Three Gorges Reservoir （TGR） and Fuling to Jiangyin reaches of the Yangtze （Changjiang） River from April 2006 to March 2007 after the TGR filling, in order to explore the reservoir influence on silica trans- port in the Yangtze River. The results reveal that the TGR would affect the silica delivery from the Yangtze River. In April and Sep- tember-October, the dissolved silicate （DSi） concentration decreases along the reservoir due to the retention by the man-made lake, and increases in downstream reaches of the TGD due to the contributions from tributaries in the middle Yangtze River. The TGR trapped approximately 3% -6% DSi in 2006. The huge reservoir tends to remove DSi from the water column during the period between April and December; while it would add DSi from January to March. Biogenic silica （BSi） accounted for 2% -5% of total reactive silica in the Yangtze River. The diatom production plays a minor role in controlling BSi level in the Yangtze River. The re- tention of DSi loading in downstream reaches of the TGD was observed after imooundment, which would be concerned in the future.

关 键 词：三峡水库 溶解硅 生物硅 滞留效应 长江 

分 类 号：P342[天文地球—水文科学]