摘要
以新安江水库及其相关河段为研究对象,对沿程上游河段、库区河段、中心库区及坝后河段沉积物中的磷、氮地球化学形态、含量及分布特征进行了研究.结果表明:受上游颗粒物的沉积作用和水产养殖的影响,库区河段的总磷(total phosphorus,TP)、总氮(total nitrogen,TN)分别比上游河段增加了37.3%,34.2%.受到大坝的拦截作用,库区和坝后河段中的磷、氮含量明显降低,坝后沉积物中的TP,TN分别比坝前降低了39.5%,74.1%.在磷的各形态中,钙结合磷(Ca-P)(13.8%~31.9%)和铁结合磷(Fe-P)(11.5%~26.2%)在TP中所占比例仅次于有机磷(organic phosphorus,OP)(48%~69%).受水库蓄水顶托的作用,大量沉积的有机磷逐渐矿化降解,并向铁结合磷转化,导致坝前、坝后沉积物中的磷形态组成发生了明显改变.有机氮(organic nitrogen,ON)为TN的主要形态,在上游河段中ON含量较低,但在库区河段迅速升高,而在下游河段迅速降低,而氨氮(NH+4-N)含量变化较小.研究结果表明,水库对磷、氮具有明显的拦截效应,并改变了营养元素之间的化学计量比.
The Xinanjiang Reservoir and the related river reaches were investigated. Sed- iments were collected along the upstream, reservoir backwater area, central reservoir and downstream the dam. The geochemical phases of phosphorus and nitrogen were deter- mined. The results show that the total phosphorus (TP) and total nitrogen (TN) concen- trations in backwater area sediments increase by 37.3% and 34.2% respectively as compared to that in upstream sediments, for the reason of sedimentation and aquaculture input. Due to the impacts of impounding, phosphorus and nitrogen concentrations in downstream sediments decrease by 39.5% and 74.1% respectively as compared to that in reservoir sediments. Among the various forms of phosphorus, the ratio of Ca-bound phosphorus (Ca-P) (13.8%~31.9%) and Fe-bound phosphorus (Fe-P) (11.5%-26.2%) in total phosphorus were next only to organic phosphorus (OP) (48%-69%). The organic phosphorus deposited in the backwater area and central reservoir sediments is gradually decomposed and transformed to Fe-P, leading to the variation in phosphorus forms along the river course. Meanwhile, organic nitrogen (ON) is the main form of TN. Its content is low in the upper reaches sediments, and increases rapidly downward toward the central reservoir, but decreases significantly in the downstream sediments. The percentage of the content of ammoniac nitrogen (NH4+-N) in TN has less changed along the river channel. The results reveal that the presence of dam has an obvious retention effect on phosphorus and nitrogen, which also changes the stoichiometric ratio of nutrients in sediments.
出处
《上海大学学报(自然科学版)》
CAS
CSCD
北大核心
2015年第1期72-80,共9页
Journal of Shanghai University:Natural Science Edition
基金
国家自然科学基金资助项目(41273128
40873066)
上海市教委基金资助项目(12YZ017)
关键词
新安江流域
沉积物
磷、氮形态
Xinanjiang Basin
sediment
phosphorus and nitrogen forms