描述:Since the construction of the Three Gorges Dam,the Poyang Lake hydrological characteristics obviously changed.During the impoundment period of the Three Gorges Reservoir,the hydrodynamic factors of Poyang Lake varied.Water level dropped,the velocity decreased and water exchange time lengthened,which changed the release of phosphorous from sediments.In order to investigate how the hydrodynamic factors influence the release of phosphorous from sediments,we used a two-way annular flume device to simulate the release characteristics of phosphorous from sediments under variable water levels and velocities.We found that both water level rising and velocity increasing could enhance the disturbance intensity to sediments,which caused the increase of suspended solids(SS)concentration,total phosphorus(TP)concentration in the overlying water,and the ability that phosphorus released to overlying water from sediments enhanced as well:when overlying water velocity maintained 0.3 m/s,SS concentration increased to 4035.85 mg/L at the water level25 cm which was about 25 times compared to the minimum value and TP concentration in the overlying water also reached the maximum value at the water level 25 cm which was 1.2times that of the value at 10 cm;when water level maintained 15 cm,SS concentration increased to 4363.35 mg/L at the velocity of 0.5 m/s which was about 28 times compared to the value of 0 m/s,and TP concentration in the overlying water increased from 0.11 mg/L to 0.44mg/L.When the water level maintained 15 cm,the phosphorous release rate reached the maximum value of 4.86 mg/(md)at 0.4 m/s.The concentration of total dissolved phosphorous(TDP)and soluble reactive phosphate(SRP)both in overlying water and sediment-water interface were negatively correlated with p H.Using the parabolic equation,the optimum water level at a velocity of 0.3 m/s was calculated to be 0.57 cm,and the optimum velocity at water level of 15 cm was found to be 0.2 m/s.
全文:Since the construction of the Three Gorges Dam,the Poyang Lake hydrological characteristics obviously changed.During the impoundment period of the Three Gorges Reservoir,the hydrodynamic factors of Poyang Lake varied.Water level dropped,the velocity decreased and water exchange time lengthened,which changed the release of phosphorous from sediments.In order to investigate how the hydrodynamic factors influence the release of phosphorous from sediments,we used a two-way annular flume device to simulate the release characteristics of phosphorous from sediments under variable water levels and velocities.We found that both water level rising and velocity increasing could enhance the disturbance intensity to sediments,which caused the increase of suspended solids(SS)concentration,total phosphorus(TP)concentration in the overlying water,and the ability that phosphorus released to overlying water from sediments enhanced as well:when overlying water velocity maintained 0.3 m/s,SS concentration increased to 4035.85 mg/L at the water level25 cm which was about 25 times compared to the minimum value and TP concentration in the overlying water also reached the maximum value at the water level 25 cm which was 1.2times that of the value at 10 cm;when water level maintained 15 cm,SS concentration increased to 4363.35 mg/L at the velocity of 0.5 m/s which was about 28 times compared to the value of 0 m/s,and TP concentration in the overlying water increased from 0.11 mg/L to 0.44mg/L.When the water level maintained 15 cm,the phosphorous release rate reached the maximum value of 4.86 mg/(md)at 0.4 m/s.The concentration of total dissolved phosphorous(TDP)and soluble reactive phosphate(SRP)both in overlying water and sediment-water interface were negatively correlated with p H.Using the parabolic equation,the optimum water level at a velocity of 0.3 m/s was calculated to be 0.57 cm,and the optimum velocity at water level of 15 cm was found to be 0.2 m/s.
描述:根据鄱阳湖沉积岩芯ZK01有机碳同位素以及沉积特征等环境指标的综合分析,并同鄱阳湖湖口地区孢粉组合特征相结合,重建鄱阳湖地区5 ka B.P.以来的古气候演变.结果表明:5.0~4.2 ka B.P.,气候以暖湿为主;4.2~3.9 ka B.P.以冷湿为主;3.9~3.2 ka B.P.,气候转温和,以温偏于气候为主;3.2~3.0 ka B.P.,气候凉偏干;3.0~2.8 ka B.P.,暖偏于气候为主;2.8~2.2 ka B.P.,以凉偏湿为主;2.2~1.2 ka B.P.,较长时期的温暖湿润气候;1.2~0.2 kaB.P.,对应的冷湿气候特征;0.2 ka B.P.到现在,气候又开始变得越来越温暖,可能是人类活动的影响所致.
全文:根据鄱阳湖沉积岩芯ZK01有机碳同位素以及沉积特征等环境指标的综合分析,并同鄱阳湖湖口地区孢粉组合特征相结合,重建鄱阳湖地区5 ka B.P.以来的古气候演变.结果表明:5.0~4.2 ka B.P.,气候以暖湿为主;4.2~3.9 ka B.P.以冷湿为主;3.9~3.2 ka B.P.,气候转温和,以温偏于气候为主;3.2~3.0 ka B.P.,气候凉偏干;3.0~2.8 ka B.P.,暖偏于气候为主;2.8~2.2 ka B.P.,以凉偏湿为主;2.2~1.2 ka B.P.,较长时期的温暖湿润气候;1.2~0.2 kaB.P.,对应的冷湿气候特征;0.2 ka B.P.到现在,气候又开始变得越来越温暖,可能是人类活动的影响所致.
描述:根据鄱阳湖沉积岩芯ZK01有机碳同位素以及沉积特征等环境指标的综合分析,并同鄱阳湖湖口地区孢粉组合特征相结合,重建鄱阳湖地区5 ka B.P.以来的古气候演变.结果表明:5.0~4.2 ka B.P.,气候以暖湿为主;4.2~3.9 ka B.P.以冷湿为主;3.9~3.2 ka B.P.,气候转温和,以温偏于气候为主;3.2~3.0 ka B.P.,气候凉偏干;3.0~2.8 ka B.P.,暖偏于气候为主;2.8~2.2 ka B.P.,以凉偏湿为主;2.2~1.2 ka B.P.,较长时期的温暖湿润气候;1.2~0.2 kaB.P.,对应的冷湿气候特征;0.2 ka B.P.到现在,气候又开始变得越来越温暖,可能是人类活动的影响所致.
全文:根据鄱阳湖沉积岩芯ZK01有机碳同位素以及沉积特征等环境指标的综合分析,并同鄱阳湖湖口地区孢粉组合特征相结合,重建鄱阳湖地区5 ka B.P.以来的古气候演变.结果表明:5.0~4.2 ka B.P.,气候以暖湿为主;4.2~3.9 ka B.P.以冷湿为主;3.9~3.2 ka B.P.,气候转温和,以温偏于气候为主;3.2~3.0 ka B.P.,气候凉偏干;3.0~2.8 ka B.P.,暖偏于气候为主;2.8~2.2 ka B.P.,以凉偏湿为主;2.2~1.2 ka B.P.,较长时期的温暖湿润气候;1.2~0.2 kaB.P.,对应的冷湿气候特征;0.2 ka B.P.到现在,气候又开始变得越来越温暖,可能是人类活动的影响所致.