The turnover of phosphorus （P） in lake sediments, a major cause of eutrophication and subsequent deterioration of water quality, is in need of deep understanding. In this study, effects of resuspension on P release ...The turnover of phosphorus （P） in lake sediments, a major cause of eutrophication and subsequent deterioration of water quality, is in need of deep understanding. In this study, effects of resuspension on P release were studied in cylindrical microcosms with Yshape apparatus. The results indicated that there was a positive correlation between flux of suspended substance across sediment-water interface （Fss） and the wind speed, and an increasing Fss during each wind process followed by a steady state. The maximal Fss under fight, moderate, and strong wind conditions were 299.9±41.1,573.4±61.7, and 2093.8±215.7 g/m^2, respectively. However, flux of P across sediment-water interface （Fp） did not follow a similar pattern as Fss responding to wind intensity, which increased and reached the maximum in initial 120 rain for fight wind, then decreased gradually, with maximal flux of 9.4±1.9 mg/m^2. A rapid increase of Fp at the first 30 rain was observed under moderate wind, with maximal flux of 11.2±0.6 mg/m^2. Surprisingly, strong wind caused less Fp than under light and moderate wind conditions with maximal flux of 3.5±0.9 mg/m^2. Fss in water column declined obviously during the sedimentation process after winds, but Fp varied with wind regime. No obvious difference was detected on Fp after 8 h sedimentation process, compared with the initial value, which means little redundant P left in the water column after winds.展开更多
This paper presents a review of the state-of-the-art research and its applications developed at Hohai University relating to the hydrodynamic and morphological processes in the Yangtze Estuary. Longitudinal, lateral, ...This paper presents a review of the state-of-the-art research and its applications developed at Hohai University relating to the hydrodynamic and morphological processes in the Yangtze Estuary. Longitudinal, lateral, and horizontal flow circulations have been revealed based on the measurements with acoustic Doppler current profilers （ADCP）. The hydrodynamic mechanism at diversion points as well as the changing patterns of flow and sediment flux in the Yangtze Estuary has been investigated through long-term data analysis. A field survey has been carried out to detect the saltwater intrusion from the North Branch to South Branch. Different numerical models of flow motion, sediment transport, and saltwater intrusion have been developed to simulate the complicated processes and to evaluate the effects of engineering projects. The morphological processes of wetlands over a time scale of decades have been analyzed with an established database. Ideas for further research on the bio-geomorphological model system and long-term evolution mechanisms are put forward.展开更多
To identify the distribution pattern of macrofaunal assemblages of the Dafeng intertidal flats in response to hydrodynamic and sediment dynamic processes in the northern Jiangsu coast,East China,macrofauna sampling an...To identify the distribution pattern of macrofaunal assemblages of the Dafeng intertidal flats in response to hydrodynamic and sediment dynamic processes in the northern Jiangsu coast,East China,macrofauna sampling and hydrodynamic observations were carried out simultaneously across the mud flat,mixed mud-sand flat,and silt-sand flat of the intertidal zone in June 2018.Results show that there was a clear zonal distribution pattern of the macrofaunal communities,as is controlled by local hydrological and sedimentary environments.Principal component analysis(PCA)revealed three types of intertidal area in terms of hydrological and surficial sediment parameters.Similarly,three distinct groups of the macrofaunal communities,i.e.,mud flat,mix mud-sand,and silt-sand groups,were recognized at similarity level of 24%based on the CLUSTER analysis in similarity profile(SIMPROF)test.Correlation analysis upon best variables stepwise search(BVSTEP)indicated the importance of the hydrodynamics(e.g.,water temperature and salinity,tidal duration,flow speed,suspended sediment concentration,and wave height)in the differentiation of macrofaunal communities with different taxonomic classes over the intertidal zone.Therefore,macrofaunal assemblages,similar to hydrology and surficial sediment,have a unique zonation pattern.Small-sized deposit feeders adapt better to low energy environments,thus dominated the upper part of the intertidal flat,whilst the heavy and large-sized filter feeders and deposit feeders were dominant over the middle and lower parts.The hydrodynamic and sediment processes cause biota-niche separation,which affected the biological processes across the intertidal flat.展开更多
Nonlocal physics is applied for investigation of the tsunami wave movement. It is established that tsunami movement and the Hubble effect of the Universe expansion can be considered in the frame of the same mathematic...Nonlocal physics is applied for investigation of the tsunami wave movement. It is established that tsunami movement and the Hubble effect of the Universe expansion can be considered in the frame of the same mathematical theory. Moreover, it can be said that tsunami is Hubble effect in the Earth conditions. The corresponding results of mathematical modeling are shown.展开更多
基金Project supported by the National Natural Science Foundation of China(No. 20577053) the Pilot Project of Knowledge Innovation Program of Chinese Academy of Sciences(No. KZCX3-SW-348)the Hi-Tech Research and Development Program(863)of China(No.200560101005).
文摘The turnover of phosphorus （P） in lake sediments, a major cause of eutrophication and subsequent deterioration of water quality, is in need of deep understanding. In this study, effects of resuspension on P release were studied in cylindrical microcosms with Yshape apparatus. The results indicated that there was a positive correlation between flux of suspended substance across sediment-water interface （Fss） and the wind speed, and an increasing Fss during each wind process followed by a steady state. The maximal Fss under fight, moderate, and strong wind conditions were 299.9±41.1,573.4±61.7, and 2093.8±215.7 g/m^2, respectively. However, flux of P across sediment-water interface （Fp） did not follow a similar pattern as Fss responding to wind intensity, which increased and reached the maximum in initial 120 rain for fight wind, then decreased gradually, with maximal flux of 9.4±1.9 mg/m^2. A rapid increase of Fp at the first 30 rain was observed under moderate wind, with maximal flux of 11.2±0.6 mg/m^2. Surprisingly, strong wind caused less Fp than under light and moderate wind conditions with maximal flux of 3.5±0.9 mg/m^2. Fss in water column declined obviously during the sedimentation process after winds, but Fp varied with wind regime. No obvious difference was detected on Fp after 8 h sedimentation process, compared with the initial value, which means little redundant P left in the water column after winds.
基金supported by the National Basic Research Program of China(973Program,Grant No.2010CB429002)the Fundamental Research Funds for the Central Universities(Grant No.2012B06514)+1 种基金the Special Fund of the State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering at Hohai University(Grant No.2009585812)the Qing Lan Project of Jiangsu Province
文摘This paper presents a review of the state-of-the-art research and its applications developed at Hohai University relating to the hydrodynamic and morphological processes in the Yangtze Estuary. Longitudinal, lateral, and horizontal flow circulations have been revealed based on the measurements with acoustic Doppler current profilers （ADCP）. The hydrodynamic mechanism at diversion points as well as the changing patterns of flow and sediment flux in the Yangtze Estuary has been investigated through long-term data analysis. A field survey has been carried out to detect the saltwater intrusion from the North Branch to South Branch. Different numerical models of flow motion, sediment transport, and saltwater intrusion have been developed to simulate the complicated processes and to evaluate the effects of engineering projects. The morphological processes of wetlands over a time scale of decades have been analyzed with an established database. Ideas for further research on the bio-geomorphological model system and long-term evolution mechanisms are put forward.
基金Supported by the National Natural Science Foundation of China(Nos.41576154,41625021)the National Key Basic Research Program of China(No.2013CB956500)。
文摘To identify the distribution pattern of macrofaunal assemblages of the Dafeng intertidal flats in response to hydrodynamic and sediment dynamic processes in the northern Jiangsu coast,East China,macrofauna sampling and hydrodynamic observations were carried out simultaneously across the mud flat,mixed mud-sand flat,and silt-sand flat of the intertidal zone in June 2018.Results show that there was a clear zonal distribution pattern of the macrofaunal communities,as is controlled by local hydrological and sedimentary environments.Principal component analysis(PCA)revealed three types of intertidal area in terms of hydrological and surficial sediment parameters.Similarly,three distinct groups of the macrofaunal communities,i.e.,mud flat,mix mud-sand,and silt-sand groups,were recognized at similarity level of 24%based on the CLUSTER analysis in similarity profile(SIMPROF)test.Correlation analysis upon best variables stepwise search(BVSTEP)indicated the importance of the hydrodynamics(e.g.,water temperature and salinity,tidal duration,flow speed,suspended sediment concentration,and wave height)in the differentiation of macrofaunal communities with different taxonomic classes over the intertidal zone.Therefore,macrofaunal assemblages,similar to hydrology and surficial sediment,have a unique zonation pattern.Small-sized deposit feeders adapt better to low energy environments,thus dominated the upper part of the intertidal flat,whilst the heavy and large-sized filter feeders and deposit feeders were dominant over the middle and lower parts.The hydrodynamic and sediment processes cause biota-niche separation,which affected the biological processes across the intertidal flat.
文摘Nonlocal physics is applied for investigation of the tsunami wave movement. It is established that tsunami movement and the Hubble effect of the Universe expansion can be considered in the frame of the same mathematical theory. Moreover, it can be said that tsunami is Hubble effect in the Earth conditions. The corresponding results of mathematical modeling are shown.
