Contaminants resuspension in sediments induced by wind-wave could influence the water quality in shallow lakes. Resuspension of surface sediments from the Zhushan Bay, Taihu Lake was simulated under different wind for...Contaminants resuspension in sediments induced by wind-wave could influence the water quality in shallow lakes. Resuspension of surface sediments from the Zhushan Bay, Taihu Lake was simulated under different wind forcing by using a pneumatic annular flume in this study. Acoustic Doppler Velocimeter （ADV） was used to measure flow velocity at each wind speed, and the characteristics of sediment resuspension were studied with the layered sampling technology. The experimental results show that the flow velocity increases with wind speed obviously and 6m/s is a critical wind speed which affected hydrodynamic conditions significantly. The distribution of flow velocity and water depth is different from that in ordinary open channel. With the enhanced hydrodynamic factors, the Suspended Solids Concentration （SSC） in water increases accordingly, and the incipient velocity of sediment resuspension is about 0.21 m/s. Based on the analysis of wind speed and average SSC in water column, the quantitative relationship is obtained. The SSC of the bottom layer is higher than the content of surface layer under different hydrodynamic conditions, and there are similar distributions between SSC and flow velocity in different water layers.展开更多
Taste and odor compounds(T&Os),which is often associated with plankton in water sources,pose significant challenges to water quality in the world.Identifying the potential producers and understanding the driving f...Taste and odor compounds(T&Os),which is often associated with plankton in water sources,pose significant challenges to water quality in the world.Identifying the potential producers and understanding the driving factors are critical for effective treatment.While most studies focused on outbreak of T&Os linked with summer cyanobacterial blooms,questions remain about the mechanisms and environmental factors driving spring outbreaks when cyanobacteria are typically in low abundance.Therefore,changes in the concentrations of T&Os,i.e.,2-methylisoborneol(2-MIB)and three others,in relation to the phytoplankton community,the physico-chemical and hydrological conditions in a mesotrophic reservoir surrounded by hills in East China were investigated from March to June 2023.Results show that 2-MIB was the main T&O during the spring outbreak of phytoplankton,and peaked at 96.10 ng/L,which is nearly 10 times of its odor threshold concentration(OTC)of 10 ng/L.The filamentous cyanobacterium Pseudanabaena sp.was identified as the primary producer of 2-MIB,and the cell concentration of 4000 cells/mL of Pseudanabaena sp.could potentially result in 10 ng/L of 2-MIB in this reservoir.The abundance of Pseudanabaena sp.and 2-MIB were correlated significantly with turbidity,suggesting that a lower light environment might be critical to promote the dominance of Pseudanabaena sp.and the subsequent production of 2-MIB.Moreover,the combination of consistently decreased water level,moderate water stratification,optimal water temperature ranging~14-23℃,the increase of the chemical oxygen demand using permanganate as an oxidant(CODMn)and total nitrogen(TN)concentration were likely to drive the accumulation and outbreak of 2-MIB.The hydrodynamic disturbance(i.e.,a sudden rapid flow of water)triggered the abrupt disappearance of both Pseudanabaena sp.and 2-MIB.This study suggests that proliferation of Pseudanabaena sp.in spring is important in contributing to 2-MIB outbreak,and flushing may be an effective approach to mitigate T&O issues in w展开更多
基金supported by the National Key Basic Research Development Program of China (973 Program, Grant No.2008CB418203)the National Key Program of National Natural Science Foundation of China (Grant No. 50830304)the National Natural Science Foundation of China (Grant No. 50909035)
文摘Contaminants resuspension in sediments induced by wind-wave could influence the water quality in shallow lakes. Resuspension of surface sediments from the Zhushan Bay, Taihu Lake was simulated under different wind forcing by using a pneumatic annular flume in this study. Acoustic Doppler Velocimeter （ADV） was used to measure flow velocity at each wind speed, and the characteristics of sediment resuspension were studied with the layered sampling technology. The experimental results show that the flow velocity increases with wind speed obviously and 6m/s is a critical wind speed which affected hydrodynamic conditions significantly. The distribution of flow velocity and water depth is different from that in ordinary open channel. With the enhanced hydrodynamic factors, the Suspended Solids Concentration （SSC） in water increases accordingly, and the incipient velocity of sediment resuspension is about 0.21 m/s. Based on the analysis of wind speed and average SSC in water column, the quantitative relationship is obtained. The SSC of the bottom layer is higher than the content of surface layer under different hydrodynamic conditions, and there are similar distributions between SSC and flow velocity in different water layers.
基金Supported by the National Natural Science Foundation of China(Nos.42271080,U2340209)the Science and Technology Planning Project of NIGLAS(Nos.NIGLAS2022GS03,NIGLAS2022TJ08)。
文摘Taste and odor compounds(T&Os),which is often associated with plankton in water sources,pose significant challenges to water quality in the world.Identifying the potential producers and understanding the driving factors are critical for effective treatment.While most studies focused on outbreak of T&Os linked with summer cyanobacterial blooms,questions remain about the mechanisms and environmental factors driving spring outbreaks when cyanobacteria are typically in low abundance.Therefore,changes in the concentrations of T&Os,i.e.,2-methylisoborneol(2-MIB)and three others,in relation to the phytoplankton community,the physico-chemical and hydrological conditions in a mesotrophic reservoir surrounded by hills in East China were investigated from March to June 2023.Results show that 2-MIB was the main T&O during the spring outbreak of phytoplankton,and peaked at 96.10 ng/L,which is nearly 10 times of its odor threshold concentration(OTC)of 10 ng/L.The filamentous cyanobacterium Pseudanabaena sp.was identified as the primary producer of 2-MIB,and the cell concentration of 4000 cells/mL of Pseudanabaena sp.could potentially result in 10 ng/L of 2-MIB in this reservoir.The abundance of Pseudanabaena sp.and 2-MIB were correlated significantly with turbidity,suggesting that a lower light environment might be critical to promote the dominance of Pseudanabaena sp.and the subsequent production of 2-MIB.Moreover,the combination of consistently decreased water level,moderate water stratification,optimal water temperature ranging~14-23℃,the increase of the chemical oxygen demand using permanganate as an oxidant(CODMn)and total nitrogen(TN)concentration were likely to drive the accumulation and outbreak of 2-MIB.The hydrodynamic disturbance(i.e.,a sudden rapid flow of water)triggered the abrupt disappearance of both Pseudanabaena sp.and 2-MIB.This study suggests that proliferation of Pseudanabaena sp.in spring is important in contributing to 2-MIB outbreak,and flushing may be an effective approach to mitigate T&O issues in w
基金Supported by the Key Program of Hydrodynamics of China(No.9140A14030712JB11044)the Postgraduate Innovation Scholarship in Naval University of Engineering
