蓝藻生消对沉积物-水界面磷、铁、硫耦合循环的影响  

Effect of cyanobacterial growth and decline on phosphorus-iron-sulfur coupled cycling at sediment-water interface

作　　者：王计超 黄涛[1] 孙婷婷 包妍 陶鹏良 孙庆业[1] WANG Jichao;HUANG Tao;SUN Tingting;BAO Yan;TAO Pengliang;SUN Qingye(Anhui Province Key Laboratory of Wetland Ecosystem Protection and Restoration,School of Resources and Environmental Engineering,Anhui University,Hefei 230601)

机构地区：[1]安徽大学资源与环境工程学院,湿地生态保护与修复安徽省重点实验室,合肥230601

出　　处：《环境科学学报》2024年第7期231-240,共10页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金区域创新发展联合基金(No.U22A20616)。

摘　　要：通过构建微宇宙实验模拟了为期52 d的蓝藻生长与消亡过程,利用薄膜扩散梯度技术(DGT)分析了蓝藻生消过程沉积物-水界面(SWI)有效态磷、铁、硫的分布及其扩散通量变化.结果表明,实验周期内加藻组上覆水的溶解氧(DO)和pH均高于对照组,藻类生长和消亡显著改变了界面理化性质.蓝藻萌发期(1~4 d)和快速生长期(15~19 d)SWI有效态磷和有效态铁显著正相关表明,沉积物磷的释放主要受控于铁磷的还原.蓝藻快速生长阶段(15~19 d),有效态铁、有效态硫扩散通量的同步升高指示铁、硫循环耦合了内源磷的释放;此外,沉积物碱性磷酸酶活性(APA)的上升和烧失量(LOI)的下降指示了有机磷矿化释放的另一途径.蓝藻快速衰亡阶段(23 d),藻类有机质降解磷释放导致了沉积物有效态磷和铁的解耦.蓝藻衰亡后期(41~52 d),硫酸盐还原介导的磷释放减弱,有效态磷和有效态铁的显著正相关指示沉积物铁磷的还原再次成为磷释放的主要机制,但释放水平显著降低.本研究表明,蓝藻生消显著影响了沉积物-水界面铁、硫、磷耦合循环,对认识湖泊内源污染释放规律与富营养化治理具有科学参考价值.A 52-day microcosm experiment of cyanobacterial growth and decline was constructed to study its effect on phosphorus-iron-sulfur coupled cycling at sediment-water interface(SWI) by using the diffusive gradients in thin-film technique(DGT).The dissolved oxygen(DO) and pH in algal addition group water were higher than those in control group,indicating that algal growth and decline changed the physicochemical properties of SWI substantially.During the cyanobacterial incubation stage(day 1~4) and rapid growth(day 15~19),significant and positive correlations between DGTferrous iron and DGT-phosphorus indicated that phosphorus released from sediments mainly through the reduction of iron-bound phosphorus.During the rapid cyanobacterial growth(day 15~19),the synchronous increased diffusive fluxes of iron and sulfur suggested a coupled iron-sulfur-phosphorus recycling;Meanwhile,the increases of alkaline phosphatase activity(APA) and decreases of loss on ignition(LOI) in sediments indicated an additional internal phosphorus release from organic matter mineralization.During the rapid cyanobacterial decline(day 23),uncoupled ironphosphorus recycling at SWI indicated increasing impact of organic matter mineralization on phosphorus release.During the late decay phase of cyanobacteria(day 41~52),the phosphorus release mediated by sulfate reduction diminished;significant and positive correlation between bioavailable phosphorus and iron indicated that the reduction of iron-bound phosphorus in sediments evolves again as the primary mechanism for phosphorus release,just with a very low strength.Our study shows that cyanobacterial growth and decline affects the phosphorus-iron-sulfur coupled cycling importantly at SWI,and provides an understanding for internal nutrients release in aquatic ecosystem and the mitigation of eutrophication.

关 键 词：蓝藻水华 沉积物-水界面 薄膜扩散梯度技术(DGT) 内源磷 有机质矿化 

分 类 号：X142[环境科学与工程—环境科学] X524