干湿交替对湖泊沉积物中磷的形态及释放速率影响  

Effects of dry-wet alternations on form and release rate of phosphorus in lake sediments

作　　者：吴虎彬 李荣富 吴永明[1,2] 姚忠[2] 刘亚军 刘丽贞[2] WU Hubin;LI Rongfu;WU Yongming;YAO Zhong;LIU Yajun;LIU Lizhen(School of Resources and Environment,Nanchang University,Nanchang 330031,China;Institute of Microbiology,Jiangxi Academy of Sciences,Nanchang 330096,China)

机构地区：[1]南昌大学资源与环境学院,江西南昌330031 [2]江西省科学院微生物研究所,江西南昌330096

出　　处：《人民长江》2024年第2期57-64,76,共9页Yangtze River

基　　金：国家自然科学基金项目(42267029,42161022,42261020);江西省科学院省级科研项目经费包干制试点示范项目(2021YSBG22030,2023YSBG21005,2023YRCS001,2023YJC2005);长江生态环境保护修复联合研究二期项目(2022-LHYJ-02-0505-01)。

摘　　要：沉积物是湖泊水环境磷的重要内源,由于气候变化和人类活动的影响,鄱阳湖季节性水位波动剧烈,这种季节性干湿交替对沉积物磷的内源释放的影响目前尚不明确。选择鄱阳湖抚河入湖口为研究对象,采集了6根粉砂壤土沉积柱与6根砂土沉积柱,室内模拟干湿交替及长期淹水两种情景并开展了45 d的培养试验,探讨了干湿交替对沉积物磷的形态与内源释放速率的影响。结果表明:(1)干湿交替促进沉积物向上覆水释放磷,释放磷的主要组分为有机磷,粉砂壤土与砂土沉积物总磷释放速率最大可达2.59 mg/(m^(2)·d)与1.97 mg/(m^(2)·d),是长期淹水沉积物总磷释放速率的4~5倍;(2)干湿交替条件下沉积物中铁铝结合态无机磷(Fe/Al-Pi)减少,弱吸附态无机磷(WA-Pi)、潜在活性有机磷(PA-Po)等易释放的磷含量增加,中活性有机磷(MA-Po)增加,钙结合态无机磷(Ca-Pi)、非活性有机磷(NA-Po)等较稳定的磷无显著变化;(3)长期淹水沉积物中Fe/Al-Pi增加,与Fe/Al-Pi能够相互转化的MA-Po减小,易释放的磷(WA-Pi、PA-Pi、PA-Po)及较稳定的磷(Ca-Pi、NA-Po)无显著变化。分析表明干湿交替条件会促进Fe/Al-Pi向MA-Po转化,并进一步转化为易释放的WA-P、PA-Po,促进底泥内源磷释放。Sediment is an important endogenous source of phosphorus for the lake water environment.Due to climate change and human activities,the water level of Poyang Lake shows dramatic seasonal fluctuation.However,the effect of these seasonal dry-wet alternations on the endogenous release of phosphorus(P)from sediment remains unclear.In this paper,six silty loam sediment columns and six sand sediment columns were collected from the Fuhe River estuary into the Poyang Lake.Dry-wet alteration and long-term flooding scenarios were simulated respectively in the laboratory over a 45-day incubation to explore the effect of dry-wet alteration on sediment P form and endogenous release rate.The results showed that:①dry-wet alteration promoted the release of P in sediments,with organic-P as the main form.The maximum P release rates of silty loam and sandy sediments under dry-wet alteration could reach up to 2.59 mg/(m^(2)·d)and 1.97 mg/(m^(2)·d)respectively,4~5 times higher than those in long-term flooding conditions.②Under dry-wet alteration,iron-aluminum bound P(Fe/Al-P i)in sediment decreased,while weakly adsorbed P(WA-P),potentially active organic-P(PA-P o)and moderately active organic-P(MA-P o)increased.Calcium bound P(Ca-P i)and non-active P(NA-P o)remained stable.③During long-term flooding,Fe/Al-P i increased,while MA-P o which can be mutually transformed with Fe/Al-P i decreased.The easily released P(WA-P,PA-P)and inactive P(Ca-P i,NA-P o)showed no significant changes.Those results suggest that dry-wet alteration promotes the transformation of Fe/Al-P i to MA-P o,further converting into easily released P(WA-P i and PA-P o),thereby facilitating endogenous P release in the sediment.

关 键 词：沉积物 磷形态 内源释放 干湿交替 鄱阳湖 

分 类 号：X524[环境科学与工程—环境工程]