scholarly journals Dynamic Interception Effect of Internal and External Nitrogen and Phosphorus Migration of Ecological Ditches

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2553
Author(s):  
Yuyang Liu ◽  
Songmin Li ◽  
Xiaoling Wang ◽  
Yuchen An ◽  
Ruonan Wang
Keyword(s):  
Microbial Communities ◽  
Concentration Gradient ◽  
Interstitial Water ◽  
Nitrogen And Phosphorus ◽  
Overlying Water ◽  
Absorption Function ◽  
Effective Measure ◽  
Ammonium N ◽  
The Matrix ◽  
Bottom Mud

The “ecological ditch” (eco-ditch) is an effective measure used to alleviate agricultural non-point-source pollution. However, information is lacking about the continuous transport characteristics of internal and external nitrogen and phosphorus in the interstitial water of the bottom mud of these ditches and overlying water under dynamic continuous inflow conditions. Understanding of the effect of matrix dams and microbial communities inside eco-ditches on the continuous transport characteristics of the N and P therein needs to be improved. To determine the interception effects of eco-ditches on the transfer of endogenous and exogenous N and P, an eco-ditch combining plants and a matrix dam was built to explore the transport distribution characteristics of N and P in the intermittent water and overlying water in the bottom of the eco-ditch and in the bottom of the soil ditch. We compared and analyzed the composition characteristics of the microbiological communities along the ecological and soil ditches. The research results showed that: (1) The concentration gradient between the interstitial water and the overlying water in the soil ditch is the main reason for the transport and diffusion of pollutants. However, in eco-ditches, the absorption function of plant roots and the differences between the structures of the microbial communities destroy the correlation of this concentration gradient diffusion, especially the effect on ammonium N; (2) a large number of mycelia adhere to the surface of the matrix dam in an eco-ditch, and are conducive to the adsorption and purification of pollutants in the water; (3) Proteobacteria, Chloroflexi, Actinomycetes, and Acidobacteria were the main bacterial groups in the ditches. The aquatic plants in the eco-ditch changed the microenvironment of the sediment, and both the microbial diversity and abundance along the eco-ditch were higher than in the soil ditch.

Environmental Dredging to Remove Fine-Grained, Organic-Rich Sediments and Reduce Inputs of Nitrogen and Phosphorus to a Subtropical Estuary

2018 ◽  
Vol 52 (4) ◽  
pp. 42-57 ◽  
Author(s):  
Austin L. Fox ◽  
John H. Trefry
Keyword(s):  
Water Depth ◽  
Interstitial Water ◽  
Indian River Lagoon ◽  
Benthic Fluxes ◽  
Nitrogen And Phosphorus ◽  
Overlying Water ◽  
Fine Grained ◽  
Total Inventory ◽  
Indian River ◽  
Subtropical Estuary

AbstractEnvironmental dredging of fine-grained, organic-rich sediments, locally referred to as Indian River Lagoon (IRL) muck, have been promoted as an integral part of restoring the IRL, Florida, to a healthy ecosystem. In Turkey Creek, a tributary to the IRL, ~300 metric tons of N and ~70 metric tons of P were removed with 160,000 m3 of wet muck and sand via environmental dredging during 2016 and 2017. Within the established dredged area, muck removal efficiency was ~63%; some areas were not dredged deep enough to remove all the muck. An additional 24,000 m3 of muck located outside the dredged area were not removed due to the presence of docks and seawalls. Prior to dredging, benthic fluxes of dissolved N (as ammonium) and P (as phosphate) from sediments to the overlying water, adjusted to 25°C, averaged 11 mg N/m2/h and 2.5 mg P/m2/h, respectively. Where IRL muck was removed to expose the underlying sand or mixed sand and muck, benthic fluxes of N and P were 20- to 30-fold lower after dredging. Subsequent disturbances, including Hurricane Matthew in October 2016, redistributed residual muck, leaving the dredged area 26% muck-free. Where muck was incompletely dredged or reintroduced by slumping, fluxes returned to predredging values within 6 months as equilibrium was reestablished between sediments and interstitial water. Dredging produced a 50% increase in water depth and basin volume with positive increases in salinity and the total inventory of dissolved oxygen. This deeper basin also serves as a sediment trap that will sequester future inputs of muck and mitigate future benthic fluxes of N and P by reducing the transport of muck into the IRL.

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.

Contemporary issues in watershed and water quality modeling for eutrophication control

1998 ◽  
Vol 37 (3) ◽  
pp. 93-102
Author(s):  
Robert V. Thomann ◽  
Lewis C. Linker
Keyword(s):  
Coastal Waters ◽  
Water Quality Modeling ◽  
Significant Decline ◽  
Suspension Feeding ◽  
Watershed Model ◽  
Nitrogen And Phosphorus ◽  
Overlying Water ◽  
Chesapeake Bay Watershed ◽  
Eutrophication Control ◽  
Quality Modeling

Three issues are discussed: controllability of nonpoint nutrient loadings using watershed models; the sometimes counter intuitive results from eutrophication models from nutrient controls for coastal waters; and the potential significant interaction of improvement in habitat for suspension feeding bivalves. For the Chesapeake Bay watershed model, and for Limit of Technology (LOT) controls, a 16% and 45% reduction in nitrogen and phosphorus, respectively, is calculated. For the Bay, it is concluded that removal of phosphorus only is less effective than nitrogen in improving bottom water DO because of differential transport of nitrogen downstream. For the Delaware estuary, a significant decline in phytoplankton chlorophyll has been observed in the absence of any nutrient controls but in the presence of improved DO. A simple model is offered that hypothesized an increase in benthic bivalve filtration of overlying water as a result of improvement in DO.

scholarly journals Responses of soil microbial communities and enzyme activities to nitrogen and phosphorus additions in Chinese fir plantations of subtropical China

2015 ◽  
Vol 12 (13) ◽  
pp. 10359-10387 ◽  
Author(s):  
W. Y. Dong ◽  
X. Y. Zhang ◽  
X. Y. Liu ◽  
X. L. Fu ◽  
F. S. Chen ◽  
...  
Keyword(s):  
Microbial Community ◽  
Microbial Communities ◽  
Enzyme Activities ◽  
Microbial Community Composition ◽  
Soil Microbial Communities ◽  
Chinese Fir ◽  
Subtropical China ◽  
Nitrogen And Phosphorus ◽  
Soil Microbial ◽  
Nutrient Additions

Abstract. Nitrogen (N) and phosphorus (P) additions to forest ecosystems are known to influence various above-ground properties, such as plant productivity and composition, and below-ground properties, such as soil nutrient cycling. However, our understanding of how soil microbial communities and their functions respond to nutrient additions in subtropical plantations is still not complete. In this study, we added N and P to Chinese fir plantations in subtropical China to examine how nutrient additions influenced soil microbial community composition and enzyme activities. The results showed that most soil microbial properties were responsive to N and/or P additions, but responses often varied depending on the nutrient added and the quantity added. For instance, there were more than 30 % greater increases in the activities of β-Glucosidase (βG) and N-acetyl-β-D-glucosaminidase (NAG) in the treatments that received nutrient additions compared to the control plot, whereas acid phosphatase (aP) activity was always higher (57 and 71 %, respectively) in the P treatment. N and P additions greatly enhanced the PLFA abundanceespecially in the N2P treatment, the bacterial PLFAs (bacPLFAs), fungal PLFAs (funPLFAs) and actinomycic PLFAs (actPLFAs) were about 2.5, 3 and 4 times higher, respectively, than in the CK. Soil enzyme activities were noticeably higher in November than in July, mainly due to seasonal differences in soil moisture content (SMC). βG or NAG activities were significantly and positively correlated with microbial PLFAs. There were also significant relationships between gram-positive (G+) bacteria and all three soil enzymes. These findings indicate that G+ bacteria is the most important microbial community in C, N, and P transformations in Chinese fir plantations, and that βG and NAG would be useful tools for assessing the biogeochemical transformation and metabolic activity of soil microbes. We recommend combined additions of N and P fertilizer to promote soil fertility and microbial activity in this kind of plantation.

Comparison of the catabolic activity and catabolic profiles of rhizospheric, gravel-associated and interstitial microbial communities in treatment wetlands

2013 ◽  
Vol 67 (4) ◽  
pp. 886-893 ◽  
Author(s):  
Kela P. Weber ◽  
Raymond L. Legge
Keyword(s):  
Microbial Communities ◽  
Organic Contaminants ◽  
Microbial Population ◽  
Interstitial Water ◽  
Critical Role ◽  
Treatment Wetlands ◽  
Vertical Flow ◽  
Catabolic Activity ◽  
General Difference ◽  
Wetland Mesocosms

Microbial communities play a critical role in degrading organic contaminants in treatment wetlands; however, an understanding of the different roles played by rhizospheric, gravel-associated and interstitial microbial communities is deficient due to a lack of data directly comparing these microbial communities. Community level physiological profiling (CLPP) was used to compare the catabolic capabilities of rhizospheric, gravel-associated and interstitial microbial communities in vertical-flow planted and unplanted wetland mesocosms. Wetland mesocosms were decommissioned to gather microbial community samples associated with the roots and gravel bed media taken from the top (10 cm depth), middle (30 cm depth) and bottom (60 cm depth). The catabolic capabilities of the rhizospheric microbial communities were seen to be much greater than those of the gravel-associated communities. A decrease in catabolic capability was seen with increasing depth, suggesting that communities near the surface play a larger role in the degradation of carbon-based compounds. A general difference in catabolic profiles based on plant presence/absence was observed for the interstitial water and all gravel-associated samples at all depths, suggesting that the presence of roots within part of the mesocosm not only has a localized effect on the attached microbial population, but also on gravel-associated microbial communities throughout the mesocosms.

scholarly journals In Situ Nutrient Removal from Rural Runoff by A New Type Aerobic/Anaerobic/Aerobic Water Spinach Wetlands

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 1100 ◽  
Author(s):  
Ya-Wen Wang ◽  
Hua Li ◽  
You Wu ◽  
Yun Cai ◽  
Hai-Liang Song ◽  
...  
Keyword(s):  
Nitrogen Removal ◽  
Constructed Wetland ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Ammonium Nitrogen ◽  
Water Spinach ◽  
Nitrogen And Phosphorus ◽  
The Matrix ◽  
New Type ◽  
Nitrification And Denitrification

Rural runoff with abundant nutrients has become a great threat to aquatic environment. Hence, more and more attention has been focused on nutrients removal. In this study, an improved aerobic/anaerobic/aerobic three-stage water spinach constructed wetland (O-A-O-CW) was used to improve the removal of nitrogen and phosphorus of rural runoff. The removal rate of the target pollutants in O-A-O-CW was compared with the common matrix flow wetland as well as the no-plant wetland. The results showed that the O-A-O-CW significantly increased the chemical oxygen demand, total phosphorus, ammonium-nitrogen, nitrate, and total nitrogen removal rate, and the corresponding removal rate was 55.85%, 81.70%, 76.64%, 89.78%, and 67.68%, respectively. Moreover, the best hydraulic condition of the wetland, including hydraulic retention time and hydraulic loading, was determined, which were 2 days and 0.45 m3·m−2·day−1, respectively. Furthermore, the removal mechanism of the constructed wetland was thoroughly studied, which included the adsorption of nitrogen and phosphorus by the matrix and water spinach, and the nitrification and denitrification by the bacteria. The results demonstrated that the mechanisms of nitrogen removal in the new type wetland were principally by the nitrification and denitrification process. Additionally, adsorption and precipitation by the matrix are mainly responsible for phosphorus removal. These results suggested that the new O-A-O-CW can efficiently removal nutrients and enhance the water quality of the rural runoff.

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.

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 Adsorption and migration of heavy metals between sediments and overlying water in the Xinhe River in central China

2021 ◽  
Author(s):  
Yanqi Zhao ◽  
Ying Yang ◽  
Rongkun Dai ◽  
Sobkowiak Leszek ◽  
Xinyi Wang ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Anthropogenic Activities ◽  
Great Influence ◽  
Central China ◽  
Overlying Water ◽  
Riverbed Sediments ◽  
Static Water ◽  
Bottom Mud ◽  
And Migration ◽  
The Impact

Abstract Long-term polluted rivers often lead to the accumulation of heavy metals in sediments. Anthropogenic activities or biological disturbances break the adsorption balance, causing them to return from the bottom mud to the overlying water and change the aquatic environment. In order to understand the variation of heavy metals between sediments and river water, we collected the riverbed sediments in the polluted Xinhe River and carried out static continuous infiltration and dynamic uninterrupted disturbance experiments. The leaching experiment shows that the absorbability of Cd and Pb is stronger than Cr in the sediment; at the same time, the properties of the medium have a great influence on the adsorption of heavy metals. The disturbance can prompt heavy metals in the sediment to resuspend into the overlying water. The impact is the greatest during the first 12 h, and the influence degree is stronger in the relatively static water than in the moving river. In addition, pH and other factors have different degrees of influence on the desorption of heavy metals.

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