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The mechanisms of contaminants release due to incipient motion at sediment-water interface

Science China(Physics,Mechanics & Astronomy) 2014年第8期57卷 1563-1568页

作者： ZHU HongWei CHENG PengDa ZHONG BaoChang WANG DaoZeng Shanghai Institute of Applied Mathematics and Mechanics Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai University Key Laboratory of waterway Dredging Technology Ministry of Transport PRC Shanghai Waterway Engineering Design and Consulting Co. Ltd of CCGRP School of Mechatronical Engineering and Automation Shanghai University

sediments in many rivers and lakes are subjected to resuspension due to a combination of hydrodynamics. However, the roles of contaminant-contained dissolved and particulate sediments during the resuspension release are rarely studied. This study focuses on the release quantity of contaminants in both water phase and solid phase. Conservative tracer （NaC1） and reactive tracer （Phosphorus） were respectively added to cohesive fine-grained sediments and non-cohesive coarse-grained sediments. A range of typical shear stress was conducted to characterize the time-depended release of contaminants in a laboratory flume. When the sediment started to move, the concentration of contaminant in the overlying water increased with the bed shear stress, but the dissolved contaminants responded faster than the particulate ones. The observed contaminant release process can be divided into three main stages： the initial two hours fast mixing： the release contribution of pore water could reach up to 75%; the middle 4-6 h adsorption： the partitioning coefficient of contaminant between water phase and solid phase decreased over the time, and the adsorption of contaminates from resuspended sediment dominated the negative release; the last equilibrium stage： the desorption and adsorption reached equilibrium, and the reactive contaminant made an impact on the water quality in the solid phase. The existing formulas to evaluate the release flux are far from practice meaning as the sediment contaminants undergo a very complex release process.

关键词： sediment resuspension suspended particle pore water sediment-water interface contaminants

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The Effect of Bioturbation Activity of the Ark Clam Scapharca subcrenata on the Fluxes of Nutrient Exchange at the sediment–water interface

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Journal of Ocean University of China 2020年第1期19卷 232-240页

作者： ZHANG Shuo FANG Xin ZHANG Junbo YIN Fang ZHANG Hu WU Lizhen KITAZAWA Daisuke College of Marine Sciences Shanghai Ocean UniversityShanghai 201306China Key Laboratory of Sustainable Exploitation of Oceanic Fisheries Resources Ministry of EducationShanghai Ocean UniversityShanghai 201306China National Demonstration Center for Experimental Fisheries Science Education(Shanghai Ocean University Shanghai 201306China National Engineering Research Center for Oceanic Fisheries Shanghai Ocean UniversityShanghai 201306China College of Ocean Science and Engineering Shanghai Maritime UniversityShanghai 201306China Maine Fisheries Research Institution of Jiangsu Nantong 226000China Lianyungang City Oceanic and Fishery Administration Lianyungang 222002China Institute of Industrial Science The University of Tokyo5-1-5 KashiwanohaKashiwaJapan

Filter-feeding shellfish are common benthos and significantly affect the biogeochemical cycle in the shallow coastal *** clam Scapharca subcrenata is one of the widely cultured bivalve species in many coastal areas owing to its tremendous economic ***,there is little information regarding the effects of the bioturbation of *** on the fluxes of nutrient exchange in the sediment-water interface(SWI).In this regard,*** was sampled during October 2016 to determine the effects of its bioturbation activity on the nutrient exchange flux of the *** results showed that the biological activity of *** could increase the diffusion depth and the rate of the nutrients exchange in the *** bioturbation of *** could allow the nutrients to permeate into the surface sediments at 6-10cm and increase the release rate of nutrients at the *** releasing fluxes of DIN and PO43−-P in the culture area were found to be around three times higher than that in the non-cultured *** culture of *** has been proved to be an important contributor to nutrient exchange across the SWI in the farming area of Haizhou *** exchange in the SWI contributes a part of 86%DIN,71%PO43−-P and 18%SiO32−-Si for the aquaculture farm.

关键词： bioturbation nutrients exchange flux ark clam sediment-water interface

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Seasonal response of nitrogen exchange fluxes to crab disturbance at sediment-water interface in coastal tidal wetlands

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water Science and Engineering 2024年第2期17卷 129-138页

作者： Guo-fen Hua Shang-qing Liu Xiang-dong Liu Jin-li Li Yue Fang Wen-ting Xie Xiang Xu College of water Conservancy and Hydroelectric Power Hohai UniversityNanjing 210098China College of Renewable Energy Hohai UniversityNanjing 210098China

Coastal wetlands are hotspots for nitrogen(N)cycling,and crab burrowing is known to transform N in intertidal marsh ***,the underlying mechanisms remain *** study conducted field experiments and used indoor control test devices to investigate the seasonal response of nitrogen to crab disturbance at the sediment-water interface in coastal tidal flat *** results showed that crab disturbance exhibited significant seasonality with large seasonal differences in cave density and *** to crab disturbance,nitrogen fuxes at the sediment-water interface were much greater in the box with crabs than in the box without *** summer,NH-N showed a positive flux from the sediment to the overlying water,but NO2-N and NOg-N showed positive fluxes from the sediment to the overlying water only in early *** winter,NH-N showed a positive flux from the sediment to the overlying water,but NO-N and NO,-N both exhibited positive and negative *** results indicated that the presence of crab burrows can cause the aerobic layer to move downward by approximately 8-15 cm in summer and directly promote nitrification at the sediment surface.

关键词： Coastal tidal flat wetland Crab disturbance Nitrogen flux Nitrification Denitrification sediment-water interface

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Influential factors on the exchange rate of dissolved inorganic nutrients at the sediment-water interface in Jiaozhou Bay, China

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Chinese Journal of Oceanology and Limnology 2007年第3期25卷 270-276页

作者：王修林蒋凤华石晓勇祝陈坚韩秀荣 College of Chemistry and Chemical Engineering Ocean University of China The First Institute of Oceanography State Oceanic Administration

Incubation experiments are carried out to study the exchange rates of dissolved inorganic nutrients including silicate, phosphate, ammonium, nitrite, and nitrate (vSiO3-Si, vPO4-P, vNH4-N, vNO2-N and vNO3-N) at the sediment-water interface in the Jiaozhou Bay. Major factors influencing the exchange rates are discussed in detail, which include the dissolved inorganic nutrient concentrations in porewater (Cpw), water and clay contents, and grain size of the sediments (CH2O, Cclay and GSsed). The results may provide insight into the dynamics of nutrient transport and the environmental capacity of nutrients in Jiaozhou Bay, and should be beneficial to solving the problems caused by excessive nutrient input this area.

关键词： influential factor exchange rate dissolved inorganic nutrients sediment-water interface Jiaozhou Bay

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Experimental research on the impact of Corbicula flumineaon DIN exchange at a tidal flat sediment-water interface

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Chinese Journal of Oceanology and Limnology 2007年第4期25卷 434-443页

作者：刘杰陈振楼许世远郑祥民 Ministry of Education Key Laboratory of Geo-information Science East China Normal University

Based on a simulative experiment and a comparison analysis, the effect of bivalve Corbiculafluminea activity on sediment-water exchange of dissolved inorganic nitrogen （DIN） is studied. The areas included three intertidal flat sites of the Changjiang （Yangtze） River estuary in China. The interface exchange flux of ammonium, nitrate and nitrite in the short experiment （6 h） was -46.4-40, -74.8-929.1 and 2.5-14.6 μmol/（m^2·h）, respectively. It was found that the burrowing activities of C. fluminea increased NH4 and NOi release from sediments to overlying water in the short-term experiment. During long-term incubation, NH4 and NOi released in turn from the sediments. At the beginning of incubation, bioturbation by C. fluminea could accelerate NH2 release from sediments 2-17 times in different sites, resulting in stronger nitrification and increased NOi concentrations in the overlying water. sediment profile analysis post-incubation shows that organic matter mineralization and sediment-water NH4 exchange had been stimulated by C. fluminea bioturbation and bioirrigation during the experiment. Therefore, C. fluminea activities such as excretion, burrowing, irrigation and turbation can effectively alter nitrogen dynamics and accelerate and stimulate nitrogen exchange and cycling at the sediment-water interface.

关键词： Corbicula fluminea sediment-water interface DIN impact Changjiang (Yangtze) Riverestuary

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Nitrogen and Phosphorus Diffusive Fluxes Across the sediment-water interface in Estuarine and Coastal Tidal Flats

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Marine Science Bulletin 2002年第1期4卷 34-41页

作者：刘敏侯立军许世远张斌亮欧冬妮刘巧梅 Department of Geography East China Normal University and Open Laboratory of Urban and Environmental Dynamic Process of the Ministry of Education Shanghai 200062

Nitrogen and phosphorus contents are analyzed in the overlying waters and pore waters taken from the Changjiang Estuary and Shanghai coastal tidal flats in this study. In addition, the diffusion fluxes of nitrogen and phosphorus across the sediment-water interface in tidal flats are estimated according to the nutrient concentration gradients at the interface. It has been indicated that the concentrations of ammonium, nitrite, nitrate and dissolved phosphorus in overlying waters range from 0.0082-2.56, 0.03-0.58, 0.69-5.38 and 0.035-0.53 mg/L, respectively, while 0.0025 - 1.35 mg /L for NH^-N, 0. 0055 ~0.20mg/L for NO2-N, 0.61-1.14 mg/L for NO3-N and 0.11~0.53mg/L for DP insurface pore *** findings have revealed that ammonium, nitrite, nitrate and dissolved phosphorus diffusionfluxes across the sediment-water interface are between -0.024~0.99, -0.39~ -0.0019, -3.09--0.12 and -0.48- 0.12 ug/ (cm.d ) respectively, showing that the sediment in tidal flats is the source of phosphorus and an important sink for nitrogen in the waters.

关键词： Nitrogen and phosphorus diffusion fluxes pore waters sediment-water interface the Changjiang Estuary and coastal area

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Methane emission via sediment and water interface in the Bohai Sea,China

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Journal of Environmental Sciences 2022年第4期34卷 465-474页

作者： Kunpeng Zang Gen Zhang Xuemei Xu Nan Zheng Haoyu Xiong Haixiang Hong Kai Jiang Miao Liang College of Environment Zhejiang University of TechnologyHangzhou 310014China State Key Laboratory of Severe Weather&Key Laboratory of Atmospheric Chemistry of China Meteorological Administration Chinese Academy of Meteorological SciencesBeijing 100081China Key Laboratory for Ecological Environment in Coastal Areas National Marine Environmental Monitoring CenterDalian 116023China Meteorological Observation Center China Meteorological AdministrationBeijing 100081China

sediment is recognized as the largest reservoir and source of methane(CH_(4))in the ocean,especially in the shallow coastal *** date,few data of CH_(4)concentration in sediment have been reported in the China shelf *** this study,we measured CH_(4)concentration in sediment and overlying seawater columns,and conducted an incubation experiment in the Bohai Sea in May ***_(4)concentration was found to be ranged from 3.075 to 1.795μmol/L in sediment,which was 2 to 3 orders of magnitude higher than that in overlying seawater *** surface sediment was an important source of CH_(4),while bottom seawater acted as its ***,the net emission rate via sediment water interface(SWI)was calculated as 2.45μmol/(m^(2)·day)based on the incubation experiment at station73,and the earthquake may enhance CH_(4)release from sediment to seawater column in the eastern Bohai Sea.

关键词： Methane Porewater sediment-water interface Rhizon sampler Earthquake

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Environmental geochemistry of arsenic in sediment-water interface of Poyang Lake, China

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Acta Geochimica 2006年第S1期 142-143页

作者： Mengxia LIAO1, Tianlong DENG1,2 1 College of Chemistry and Chemical Engineering, Chengdu University of Technology, Chengdu 610059, China2 Qinghai Institute of Salt Lakes, Chinese Academy of Sciences,Xining 810008, China

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Numerical research on the mechanism of contaminant release through the porous sediment-overlying water interface

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Journal of Hydrodynamics 2014年第6期26卷 971-979页

作者：郭加宏曹洋郑淑君 Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai Institute of Applied Mathematics and Mechanics Shanghai University

After the pollutant discharged into the river or lake has been reduced, the release of the contaminant from the sediment to the overlying water may cause the river and lake be contaminated again. On the condition that the overlying water flow does not lead to sediment suspension, numerical researches are carried out for the mechanism of contaminant release through the sedimentoverlying water interface. The overlying water flow is calculated as turbulence. The sediment is regarded as isotropic homogeneous porous medium, therefore the seepage field in the porous sediment layer is obtained by solving Darcy＇s equations. Coupled two dimensional steady flows of the overlying water and the pore water in the sediment are calculated. Based on the flow fields obtained, the unsteady contaminant solute transportation process in the pore water in the sediment and the overlying water is numerically simulated, as the shapes of the sediment-overlying water interface are flat or periodic triangular respectively. Numerical results show that the exchange of the pore water and the overlying water is an important factor which decides the release flux of the contaminant from the sediment to the overlying water. The pressure distribution produced by the overlying water flow along the sedimentoverlying water interface, as it is not flat, may induce the seepage of the pore water in the sediment and through the sedimentoverlying water interface, which may increase the release flux of the contaminant from the sediment to the overlying water.

关键词： numerical research sediment-water interface contaminant release pore water

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Experimental investigation on diffusive contaminant release from permeable sediment layer under unidirectional unsteady flow

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Journal of Hydrodynamics 2014年第6期26卷 965-970页

作者：樊靖郁王道增 Shanghai Institute of Applied Mathematics and Mechanics Shanghai University

The interfacial diffusive contaminant（phosphorus） release from permeable sediment layer into overlying water column under a unidirectional unsteady（periodic） flow condition was experimentally measured and analyzed. The experimental results indicate that the gross diffusive contaminant release rate is substantially enhanced as compared to that under a steady flow condition, and this enhancement trend is much more pronounced in an immediate release stage. The interfacial diffusive contaminant release rate tends to increase with the increasing flow velocity, decreasing period and augmenting amplitude for the case of the unsteady flow. The additional interfacial diffusive contaminant release under the unsteady flow condition may be related to the hydrodynamic response of the diffusive boundary layer to the flow unsteadiness of the overlying water, depending upon not only the periodic thickness variation of the diffusive boundary layer immediately above the sediment-water interface modulated by the temporal flow velocity of the overlying water column but also the intensified turbulent mixing between the overlying water and the pore-water within the superficial sediment layer induced by an alternate acceleration/deceleration fluctuation during each period.

关键词： unsteady flow contaminant sediment diffusive release sediment-water interface

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