东洞庭湖沉积物覆水后磷形态变化及其释放量  

Influence of rewetting process on distribution and release of phosphorus in sediments of East Lake Dongting

作　　者：王婷[1,2] 王坤[1,2] 姜霞[1,2] 

机构地区：[1]中国环境科学研究院,湖泊水污染治理与生态修复技术国家工程实验室,北京100012 [2]中国环境科学研究院,环境基准与风险评估国家重点实验室,北京100012

出　　处：《湖泊科学》2018年第4期937-947,共11页Journal of Lake Sciences

基　　金：国家自然科学基金项目(41503101,41403102); 国家重点基础研究发展计划(2012CB417004)联合资助

摘　　要：研究干燥覆水后低流速条件下东洞庭湖沉积物中磷的形态变化及释放量,可以为轻度富营养化湖泊中磷的生物地球化学循环提供基础数据,为季节性湖泊內源营养盐的迁移转化规律研究、內源营养盐的释放风险评价提供理论依据.本文采集处于干湿交替状态的东洞庭湖表层沉积物,利用室内模拟装置,研究风干沉积物低流速条件下覆水后沉积物及上覆水中磷的形态变化.结果表明,低流速覆水后东洞庭湖沉积物中的磷向上覆水及大气中迁移释放,上覆水中磷的释放量随覆水时长增大,释放速率随覆水时长减小,上覆水流速和磷释放量相关性显著.上覆水循环过程中释放到上覆水中的溶解态有机磷比溶解态活性磷更容易吸附于颗粒物而转化为颗粒态磷.覆水后沉积物中各形态有机磷、无机磷及磷的生物有效性均发生转变,覆水初期沉积物中无机磷向有机磷转化,磷的生物可利用性增大;上覆水循环过程中有机磷向无机磷转化,磷的生物可利用性减小;覆水后沉积物的无机磷的主要组分由铝磷转变为铁磷,有机磷的主要组分有从中活性有机磷向活性有机磷转变的趋势.Fractions and release amount of phosphorus in sediment from East Lake Dongting were analyzed in the process of rewetting with low flow velocities,to provide evidence for phosphorus biogeochemical recycle,risk assessment of endogenous phosphorus release and eutrophication control scheme in seasonal lakes. In this paper,sediments collected in Eastern Dongting were air dried before rewetted. Phosphorus fractions in sediments and water were analyzed and indicated that phosphorus in sediments transported into water and air during rewetting process. Release amount of phosphorus in sediments increased and release rate decreased during the rewetting process. Significant positive correlation was observed between phosphorus release amount and water velocity. Dissolved organic phosphorus had relatively stronger absorption ability onto suspended particulate matter,thus they transformed into particle phosphorus more quickly than dissolved reactive phosphorus. Inorganic phosphorus in sediments transformed into organic phosphorus,and bioavailable phosphorus in sediments increased in the beginning of rewetting process. However,in the following stage of rewetting process,organic phosphorus in sediments transformed to inorganic phosphorus,and bioavailable phosphorus decreased. The dominate component of inorganic phosphorus in sediments transformed from aluminum-bound phosphate to iron-bound phosphorus.And the dominate component of organic phosphorus transformed from moderately labile organic phosphorus to labile organic phosphorus in rewetting process.

关 键 词：洞庭湖 磷形态 释放量 干湿交替 沉积物 

分 类 号：X524[环境科学与工程—环境工程]