干湿交替条件下鄱阳湖洲滩湿地土壤磷形态转化与释放风险研究  

Phosphorus speciation,transformation,and release risk in Poyang Lake wetland soil during dry-wet alteration

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

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

出　　处：《环境科学学报》2024年第3期365-376,共12页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金(No.42267029,42161022);江西省自然科学基金(No.20212BAB213041,20232BAB213072);江西省科学院省级科研项目经费包干制试点示范项目(No.2021YSBG22030,2023YSBG21005,2023YRCS001,2023YJC2005);江西省科学院引进博士项目(No.2020-YYB-24);长江生态环境保护修复联合研究二期项目(No.2022-LHYJ-02-0505-01)。

摘　　要：鄱阳湖洲滩湿地季节性淹水/裸露,这种土壤干湿交替条件对洲滩湿地土壤磷的形态与内源释放的影响目前尚不明确.本文于退水期、枯水期、涨水期、丰水期采集了季节性淹水洲滩湿地土壤和常年淹水沉积物,测定其磷形态、磷吸附/解吸平衡浓度(EPC_(0)),探讨了干湿交替对土壤/沉积物磷形态与内源释放潜力的影响.研究结果表明:①不同水文时期,泥滩土壤和砂滩土壤总磷主要赋存形态为中活性磷(Fe/Al-Pi、PA-P_(o))以及非活性磷(NA-P_(o)),淹水期间(涨水期、丰水期)泥滩和砂滩土壤PA-P_(o)含量显著高于裸露期(退水期、枯水期),且干湿交替土壤PAP_(o)含量显著高于常年淹水沉积物;②不同水文时期泥质和砂质洲滩土壤EPC0均大于水体溶解态活性磷(SRP),表明干湿交替的洲滩土壤是水体磷的“源”,且淹水时期(涨水期、丰水期)具有更高的磷释放潜能,而常年淹水沉积物同时作为水体磷的“源”和“汇”;③干湿交替过程可促进土壤中活性磷(Fe/Al-Pi等)转化为更易释放的活性磷(PA-P_(o)等),使得土壤具有更高的磷释放潜能(EPC0值越高),并向上覆水体释放有机磷,导致鄱阳湖水体具有较高的有机磷组分(平均占比47.93%).Due to the rapid changes in water level,Poyang Lake wetlands are currently experiencing seasonal dry-wet alternations.However,the impact of these fluctuations on soil phosphorous(P)speciation,transformation,and release risk remain unclear.In this study,the seasonal inundation wetland and permanent inundation sediment were sampled during water recession,dry,water level raising,and flooding seasons in Poyang Lake.P speciation,equilibrium P concentration(EPC_(0))were measured to reveal the effects of dry-wet alternation on soil P speciation and endogenous release potential.The results indicated that:①Among the four hydrological seasons,the primary P forms in muddy and sandy soil were medium active P(Fe/Al-Pi,PA-Po)and non-active P(NA-Po).During inundation periods(water level raising and flooding seasons),PA-Po in muddy and sandy soil significantly exceeded levles during bare periods(water recession and dry seasons),with permanent inundation sediment containing significantly less PA-Po compared to dry-wet wetland soils.②During different hydrological seasons,the EPC_(0) of muddy and sandy soils surpassed the concentration of soluble reactive P in water,indicating that the dry-wet wetland soils act as P"source",and the endogenous release risk is higher during inundation periods.In contrast,permanent inundation sediment serves as both"source"and"sink"of P.③The process of dry-wet alternation promotes the transformation of medium-active P(Fe/Al-Pi)into active P(PA-Po)and induces higher P release potential(elevated EPC_(0) value).Consequently,the release of organic P from soils further results in a higher average organic P content in overlying water(47.93%).

关 键 词：总磷分级 磷转化 干湿交替 洲滩湿地 鄱阳湖 

分 类 号：X523[环境科学与工程—环境工程]