scholarly journals Diffusion flux of phosphorus nutrients at the sediment–water interface of the Ulansuhai Lake in northern China

2017 ◽  
Vol 75 (6) ◽  
pp. 1455-1465 ◽  
Author(s):  
Shengnan Zhao ◽  
Xiaohong Shi ◽  
Changyou Li ◽  
Sheng Zhang ◽  
Biao Sun ◽  
...  
Keyword(s):  
Interstitial Water ◽  
Diffusion Flux ◽  
Northern China ◽  
Inorganic Phosphorus ◽  
Exchange Capacity ◽  
Internal Source ◽  
Water Interface ◽  
Overlying Water ◽  
Water And Sediment ◽  
Exchange Flux

Overlying water and sediment samples were collected from 11 locations in Ulansuhai Lake in June of 2012 to determine the concentration of dissolved inorganic phosphorus (DIP) in the interstitial water, overlying water and sediment and to estimate the diffusion flux of DIP at the sediment–water interface. The DIP levels in overlying water were 0.004–0.185 mg/L (average = 0.062 mg/L), while they were 0.05–0.25 mg/L (average = 0.124 mg/L) in the interstitial water in the 0–2 cm surface sediment. Moreover, the annual mean exchange flux of DIP in the sediment was between −0.092 mg/m2·d and 0.053 mg/m2·d, and this occurred via internal source action in most areas. After area weighting, it is estimated that the exchange capacity of DIP at the sediment–water interface of the Ulansuhai Lake is 1.30 t/a. These findings indicate internal loading of phosphorus in sediment of the Ulansuhai Lake; thus, the diffusion of DIP in the interstitial water has effects on the lake, with a degree of influence of 2.7% to 81.5%.

scholarly journals Determination of Water Quality Characteristics and Nutrient Exchange Flux at the Sediment–Water Interface of the Yitong River in Changchun City, China

Water ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 3555
Author(s):  
Ke Zhao ◽  
Hang Fu ◽  
Qian Wang ◽  
Hai Lu
Keyword(s):  
Water Quality ◽  
Interstitial Water ◽  
Diffusion Flux ◽  
Pollution Index ◽  
Ammonia Nitrogen ◽  
Water Interface ◽  
Nitrogen And Phosphorus ◽  
Overlying Water ◽  
Nitrogen Pollutants ◽  
Exchange Flux

In this paper, the characteristics of water pollution in Yitong River were analyzed by the comprehensive pollution index method. Combined with the pore water concentration gradient method and Fick’s first law, the release characteristics of nutrients at the sediment–water interface of Yitong River (Jilin Province, China) were studied. The results showed that the distribution trend of nitrogen and phosphorus content in the overlying and interstitial water of the Yitong River was the same, and the highest values appeared at the S3 and S5 points in the urban section. The water quality was mainly affected by nitrogen pollutants in domestic sewage. The evaluation results of the water quality comprehensive pollution index showed that the pollution degree of interstitial water in urban areas was much higher than that of the overlying water, and the endogenous nitrogen and phosphorus pollutants had the risk of diffusion to the overlying water. The exchange flux analysis of ammonia nitrogen (NH4+-N), total dissolved nitrogen (TDN), and total dissolved phosphorus (TDP) in water showed that the diffusion flux of NH4+-N ranged from 0.03 to 6.52 mg·(m2·d)−1, and the sediment was the “source” of ammonia nitrogen pollutants. The range of TDN diffusion flux was −1.57 to 11.6 mg·(m2·d) −1, and the difference between points was large. The sediment was both the “source” and “sink” of nitrogen pollutants. The range of TDP diffusion flux was −0.05 to 0.22 mg·(m2·d) −1. Except for point S8, the TDP diffused from sediment into the water body. Among all the sampling points, the diffusion fluxes of NH4+-N, TDN, and TDP at the S3 point were the largest, the release rate of endogenous pollutants was the most rapid, and the pollution to the water quality was the most serious. The results are of great significance to the exchange flux of nutrients at the sediment–water interface of rivers and the prevention and control of water eutrophication. It also provides a reference for the study of nutrient exchange flux at the sediment–water interface of rivers and other surface water bodies worldwide.

scholarly journals Spatial–temporal variation of nitrogen and diffusion flux across the water–sediment interface at the hydro-fluctuation belt of Danjiangkou reservoir in China

2020 ◽  
Vol 20 (4) ◽  
pp. 1241-1252
Author(s):  
Han Wang ◽  
Yuping Han ◽  
Lide Pan
Keyword(s):  
Diffusion Flux ◽  
Sample Collection ◽  
Sediment Pore Water ◽  
Overlying Water ◽  
Danjiangkou Reservoir ◽  
Water And Sediment ◽  
Water Quality Deterioration ◽  
Nitrogen Contents ◽  
And Diffusion ◽  
Sediment Interface

Abstract Based on overlying water and sediment sample collection from 15 sites during July, September, November 2018 and January 2019 in the hydro-fluctuation belt of Danjiangkou reservoir China, the variation of nitrogen (N) was studied. And the concentrations of NH4+-N, NO3−-N and NO2−-N in the sediment, pore water and overlying water were determined to evaluate the diffusion flux across the water–sediment interface. The results showed that the lowest sediment N concentration was 36.54 mg/L in July, and the highest one was 145.93 mg/L in November. Spatially, the sediment N concentrations were higher in tidal soil and loam than in sandy soil. According to the diffusion fluxes of NH4+, NO3− and NO2−, sediments at all sites tend to release N to the overlying water except in the sampling month of November, when the sediment acts as a sink of NO3−. The highest release rates of NH4+-N and NO3−-N were 17.66 mg m−2·d−1 and 80.15 mg m−2·d−1, respectively, which are much higher than the release rate of NO2−-N (0.29 mg m−2·d−1). The findings indicate that hydro-fluctuation belt sediment contributes a lot to the nitrogen contents in the overlying water, and internal pollution is a main reason for the water quality deterioration and even eutrophication.

scholarly journals The Effects of Concentration Gradient of Nitrogen Compounds on the Ammonium-nitrogen and Nitrate-nitrogen Fluxes at Sediment-Water Interface

2021 ◽  
Author(s):  
Han Wang ◽  
Qing Wu ◽  
Yuping Han
Keyword(s):  
Nitrate Nitrogen ◽  
Diffusion Flux ◽  
Ammonium Nitrogen ◽  
Nutrient Concentrations ◽  
Water Interface ◽  
Incubation Experiment ◽  
Concentration Gradients ◽  
Overlying Water ◽  
Average Diffusion ◽  
Nitrogen Concentrations

Abstract The incubation experiments focused on altering concentration gradients of nitrogen between sediment and overlying water to examine the diffusion flux of ammonium-nitrogen (NH4+) and nitrate-nitrogen (NO3-) at sediment-water interface. In this study, the diffusion flux can be estimated based on calculating the average of the net change rate of nutrient concentrations in the overlying water. For the incubation experiment of different TN concentrations in the sediment, the results showed that the diffusion flux of ammonia at sediment-water interface is -52.57~84.57 mg·m-2·d-1, and for nitrate diffusion flux, the changing range during the incubation experiment is -110.13~143.25 mg·m-2·d-1. For the incubation experiment of different nitrogen concentrations in the overlying water, the results of NH4+-N diffusion flux in L, M, H treatment were 3.37, -4.94, -3.84 mg·m-2·d-1, respectively. And the average diffusion flux of nitrate in L (0 mg NO3--N, 0 mg NH4+-N), M (0.5 mg NO3--N, 1.5 mg NH4+-N) and H (1 mg NO3--N, 2.5 mg NH4+-N) treatment were 12.30, 10.39 and 7.11 mg·m-2·d-1. Results highlighted that concentrations gradient of nutrients were indeed an important factor affecting the diffusion flux at sediment-water interface. In addition, the diffusion of nutrients at sediment-water interface in aquatic ecosystem is not only controlled by concentration gradients, some other factors such as incoming water, hydrodynamics, dissolved oxygen content, sediment structure, biological disturbance, horizontal migration and diffusion of nutrients and turbulent diffusion caused by wind and wave, are equally important.

The Influence of Emergent Macrophytes on Porewater PO43- Distribution and Physic Transport in the Estuary Wetlands

2012 ◽  
Vol 610-613 ◽  
pp. 2683-2687
Author(s):  
Xiao Zhi Gu ◽  
Kai Ning Chen ◽  
Wei Huang ◽  
Xiang Bai ◽  
Cheng Xin Fan
Keyword(s):  
Phragmites Australis ◽  
Diffusion Flux ◽  
Typha Latifolia ◽  
Benthic Flux ◽  
Benthic Organism ◽  
Water Interface ◽  
Emergent Macrophytes ◽  
Overlying Water ◽  
Core Sediments ◽  
Incubation Experiments

Emergent macrophytes growth and development are believed to play an important role in nutrients physical transport processes and biogeochemical cycles. In the present study, a high-resolution in-situ sampling technology (Porewater equilibrators, Peepers) was employed to obtain vertical porewater PO43- profiles from the vegetated and the non-vegetated sediments, and accurately quantify benthic flux across sediment-water interface by Fick's first law applying porewater profiles of peepers, and coupled with core sediments incubation experiments as comparison. In addition, to distinguish benthic organism contribution to measured apparent benthic flux, we used HgCl2 (0.5% by weight) to suppress bottom fauna activity during the experiment. The results showed that porewater PO43- concentrations were far lower in vegetated than in the non-vegetated sediments, and also significantly lower in overlying water than in porewater. Whereas, porewater PO43- distribution fluctuated sharply at the upper sediments and kept an approximative constant below 8cm depth. Additionally, the average molecular diffusion flux applying Fick's first law fluctuated slightly within the range of 0.004 to 0.018 mg m-2 d-1(i.e., PO43- from porewater diffused into overlying water), which was higher in typha latifolia site, but lower in zizania latifolia site. PO43- average apparent diffusion flux based on core sediments incubation experiments varied between 1.03 and 6.78 mg m-2 d-1, and an opposite pattern was observed with respect to emergent macrophyte effects, as the PO43- flux at phragmites australis site was low (only 19% of control), but reached as high as 126% of the control in typha latifolia site. In unsterilized treatments (i.e., benthic organism participation), PO43- average net fluxes were lower up to an order of magnitude and more variable compared with those in sterilized treatments. Our results highlighted emergent macrophytes (e.g., phragmites australis) in estuary wetlands could efficiently relieved release risk from sediments, and reduce dissolved reactive phosphorus diffusion physical barrier crossed sediment-water interface by adding porosity in surface sediment.

scholarly journals Changes in the concentration of selected metals in sediments of the River Chotla in northwest Poland in its section affected by various anthropogenic factors

2015 ◽  
Vol 15 (2) ◽  
pp. 77-82
Author(s):  
Małgorzata Włodarczyk ◽  
Hanna Siwek ◽  
Anna Buchwał ◽  
Edyta Rafacz
Keyword(s):  
Bottom Sediment ◽  
Interstitial Water ◽  
Anthropogenic Factors ◽  
Alkaline Ph ◽  
River Section ◽  
Water And Sediment ◽  
Fish Breeding ◽  
Accumulation Of Metals ◽  
Water Accumulation ◽  
The Village

Abstract The purpose of the paper was to assess the changes in the concentration of selected metals in the bottom sediment and interstitial water of the River Chotla in northwest Poland. The research was conducted on the river section flowing through Zaspy Małe and a salmonid fish breeding farm. Samples of water and bottom sediment were taken in four control and measurement points, located above and below the village and on a backwater above the trouteries and below the fish breeding ponds. The pH and the concentration of the metals potassium, iron, calcium, manganese and zinc were determined in the water and sediment samples. The lowest concentrations of the metals were found in the samples collected above and below Zaspy Małe, while the highest concentrations of metals in the water and sediment were found in the samples taken in the backwater, above the fish breeding ponds. Exceptions were calcium and potassium, with the highest concentrations of metals in the water being found in the samples taken below the fish breeding ponds. The content of metals in sediments of the analysed section of the River Chotla was mainly determined by the content of organic matter, which varied as it is dependent on water accumulation processes and the operation of nearby fishery facilities. The slightly alkaline pH facilitated long-lasting accumulation of metals in sediments.

scholarly journals Behaviour of Metal(loid)s at the Sediment-Water Interface in an Aquaculture Lagoon Environment (Grado Lagoon, Northern Adriatic Sea, Italy)

2021 ◽  
Vol 11 (5) ◽  
pp. 2350
Author(s):  
Elisa Petranich ◽  
Matteo Crosera ◽  
Elena Pavoni ◽  
Jadran Faganeli ◽  
Stefano Covelli
Keyword(s):  
Sediment Cores ◽  
Fish Farm ◽  
Trophic Chain ◽  
Water Interface ◽  
Northern Adriatic Sea ◽  
Overlying Water ◽  
Northern Adriatic ◽  
In Situ Experiments ◽  
Diffusive Fluxes ◽  
Lagoon Environment

The cycling of metal(loid)s at the sediment–water interface (SWI) was evaluated at two selected sites (VN1 and VN3) in an active fish farm in the Grado Lagoon (Northern Adriatic, Italy). In situ experiments using a transparent benthic chamber and the collection of short sediment cores were performed, to investigate the behavior of metal(loid)s in the solid (sediments) and dissolved (porewaters) phases. Total and labile concentration of metal(loid)s were also determined in sediments, to quantify their potential mobility. Comparable total concentrations were found at both sites, excluding As, Mn, Pb and V, which were higher at VN3. Metal(loid) porewater profiles showed a diagenetic sequence and a close dependence with redox (suboxic/anoxic) conditions in the surface sediments. Positive diffusive fluxes along with benthic fluxes, particularly at the more oxic site, VN1, were found for almost all metal(loid)s, indicating their tendency to migrate towards the overlying water column. Despite sediments at two sites exhibiting high total metal(loid) concentrations and moderate effluxes at the SWI, the results suggest that they are hardly remobilized from the sediments. Recycling of metal(loid)s from the SWI would not constitute a threat for the aquatic trophic chain in the fish farm.

scholarly journals Sediment-water column fluxes of carbon, oxygen and nutrients in Bedford Basin, Nova Scotia, inferred from <sup>224</sup>Ra measurements

2013 ◽  
Vol 10 (1) ◽  
pp. 53-66 ◽  
Author(s):  
W. J. Burt ◽  
H. Thomas ◽  
K. Fennel ◽  
E. Horne
Keyword(s):  
Organic Matter ◽  
Nova Scotia ◽  
Water Column ◽  
Explicit Knowledge ◽  
Dissolved Inorganic Carbon ◽  
Chemical Constituents ◽  
Water Interface ◽  
Benthic Fluxes ◽  
Pore Waters ◽  
Overlying Water

Abstract. Exchanges between sediment pore waters and the overlying water column play a significant role in the chemical budgets of many important chemical constituents. Direct quantification of such benthic fluxes requires explicit knowledge of the sediment properties and biogeochemistry. Alternatively, changes in water-column properties near the sediment-water interface can be exploited to gain insight into the sediment biogeochemistry and benthic fluxes. Here, we apply a 1-D diffusive mixing model to near-bottom water-column profiles of 224Ra activity in order to yield vertical eddy diffusivities (KZ), based upon which we assess the diffusive exchange of dissolved inorganic carbon (DIC), nutrients and oxygen (O2), across the sediment-water interface in a coastal inlet, Bedford Basin, Nova Scotia, Canada. Numerical model results are consistent with the assumptions regarding a constant, single benthic source of 224Ra, the lack of mixing by advective processes, and a predominantly benthic source and sink of DIC and O2, respectively, with minimal water-column respiration in the deep waters of Bedford Basin. Near-bottom observations of DIC, O2 and nutrients provide flux ratios similar to Redfield values, suggesting that benthic respiration of primarily marine organic matter is the dominant driver. Furthermore, a relative deficit of nitrate in the observed flux ratios indicates that denitrification also plays a role in the oxidation of organic matter, although its occurrence was not strong enough to allow us to detect the corresponding AT fluxes out of the sediment. Finally, comparison with other carbon sources reveal the observed benthic DIC release as a significant contributor to the Bedford Basin carbon system.

Dissolved Inorganic Nitrogen Fluxes at Sediment-Water Interface in Yangtze Estuarine Tidal Flat

2013 ◽  
Vol 726-731 ◽  
pp. 288-295 ◽  
Author(s):  
Huan Guang Deng ◽  
Dong Qi Wang ◽  
Zhen Lou Chen
Keyword(s):  
Tidal Flat ◽  
Environmental Gradients ◽  
Inorganic Nitrogen ◽  
Yangtze Estuary ◽  
Water Interface ◽  
Dissolved Inorganic Nitrogen ◽  
Overlying Water ◽  
Spatial Differences ◽  
Estuary Sediment ◽  
Temporal And Spatial

Yangtze estuary data, collected over three years, indicates that the temporal and spatial distributions of the environmental gradients reflect complicated seasonal changes and spatial differences in the exchange flux of the dissolved inorganic nitrogen (DIN= NH4++ NO3-+ NO2-) across the sediment-water interface. Overall in northern sites of Yangtze estuary, sediment was a source of ammonium (NH4+) (-3.67~10.65 mmol·m-2·d-1) probably because of higher salinities. Sediment was a sink for NH4+ in southern sites (-18.45~3.33 mmol·m-2·d-1) during most years. The exchange behavior of nitrate (NO3-) showed temporal and spatial variation from the upper to lower estuary and ranged from-32.8 mmol·m-2·d-1 to 35.8 mmol·m-2·d-1. The interface exchange direction of ammonium was affected by NH4+ concentration, but the relationship between NO3- concentration and the direction of flux was not obvious. The concentration of nitrite (NO2-) was very low and its interface flux was not related to DIN concentration. Overall, the sediment of Yangtze Estuarine tidal flat was a source of DIN to overlying water in the spring, but a sink for DIN during the other three seasons of the year.

Response of diffusive equilibrium in thin films (DET) and diffusive gradients in thin films (DGT) trace metal profiles in sediments to phytodetritus mineralisation

2012 ◽  
Vol 9 (1) ◽  
pp. 41 ◽  
Author(s):  
Yue Gao ◽  
Martine Leermakers ◽  
Annelies Pede ◽  
Aurelie Magnier ◽  
Koen Sabbe ◽  
...  
Keyword(s):  
Thin Films ◽  
Trace Metals ◽  
Trace Metal ◽  
Phytoplankton Bloom ◽  
Marine Ecosystem ◽  
Trace Metal Concentration ◽  
Water Interface ◽  
Overlying Water ◽  
Study Laboratory ◽  
Diffusive Gradients

Environmental contextContaminated sediments can have a large and lasting effect on marine ecosystems. It was discovered that significant amounts of pollutants, especially arsenic, were released from contaminated sediments during a phytoplankton bloom in the Belgian Continental Zone. Once released to the water column, these pollutants can accumulate up marine food chains and be a source of contaminants to humans. AbstractField data from the Belgian Continental Zone showed elevated trace metal concentrations at the sediment–water interface after the occurrence of a phytoplankton bloom. In the present study, laboratory incubation experiments were used to investigate the effect of the phytodetritus remineralisation process on the release of trace metals from contaminated muddy sediments. This remineralisation process was followed by the measurement of chlorophyll-a and dissolved organic carbon levels in the top sediment layers. Two gel techniques, diffusive equilibrium in thin films (DET) and diffusive gradients in thin films (DGT), were used to assess vertical metal profiles in the sediment pore waters and to calculate the metal effluxes. These metal effluxes compared very well with the trace metal concentration variations in the overlying water of the sediment. Much higher effluxes of Mn, Co and As were observed after 2 days of incubation in the microcosms which received additions of phytodetritus. This trend gradually decreased after 7 days of incubation, suggesting that the elevated efflux of trace metals was proportional to the quantity of phytodetritus mineralised at the sediment–water interface. The release of large amounts of toxic elements from the sediments after phytoplankton blooms can therefore potentially affect the marine ecosystem in the Belgian Continental Zone.

An Overview of Dynamics and Biotoxicity of Metals in the Freshwater Environment

1993 ◽  
Vol 28 (1) ◽  
pp. 1-6 ◽  
Author(s):  
P.M. Huang
Keyword(s):  
Water Column ◽  
Interstitial Water ◽  
Dynamic Equilibrium ◽  
Kinetic Studies ◽  
Integrated Approach ◽  
Freshwater Ecosystem ◽  
Overlying Water ◽  
Freshwater Environment ◽  
Particulate Materials ◽  
The Impact

Abstract The toxic metals, including metalloids, in the freshwater ecosystem are largely associated with surficial sediments and suspended particulate materials. These metals are in dynamic equilibrium with interstitial water and the overlying water column. The bioavailability and toxicity of metals in the freshwater environment are influenced by their speciation and dynamics. Our current understanding of the nature of metal partitioning in particulate materials, interstitial water and the overlying water column is quite limited because of the limitations of the metal fractionation methods and difficulties in obtaining thermodynamic information which approaches the realities in streams, rivers and lakes. Little is known about the in situ metal dynamics. Kinetic studies of metal reactions, thus, warrant in-depth research for years to come. Besides inorganic and organic colloids, microbes contribute to metal transformations. The impact of the interactions of microbes with minerals and organic components on the dynamics and biotoxicity of metals merits attention. Over the last decade, there has been much research on the development of hydrochemical models for better understanding and predicting metal transport in the freshwater system, yet little research has been focused on how well they describe field data. The supply of biologically available metals in the freshwater environment is governed by a series of physical, physicochemical, biochemical and biological processes. To date, there are very few studies on the subject in which an integrated approach has been taken. The roles of these interacting processes in affecting metal dynamics and their impacts on freshwater toxicology deserve increasing attention.

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