Modification of sediment redox potential by three contrasting macrophytes: implications for phosphorus adsorption/desorption

2003 ◽  
Vol 54 (1) ◽  
pp. 87 ◽  
Author(s):  
Kane T. Aldridge ◽  
George G. Ganf
Keyword(s):  
Redox Potential ◽  
Phosphorus Uptake ◽  
Potamogeton Crispus ◽  
Emergent Macrophytes ◽  
Freshwater Macrophytes ◽  
Phosphorus Adsorption ◽  
Bare Sediment ◽  
Organic Debris ◽  
Below Ground ◽  
Adsorption Desorption

Freshwater macrophytes may increase sediment redox potential and the affinity of sediments for phosphorus through radial oxygen loss from their below-ground biomass. This study demonstrated that the ability to alter sediment redox potential differs between macrophytes, according to their capacity to transport oxygen. Of the emergent macrophytes, Typha domingensis increased sediment redox potential (218 mV above bare sediment) to a greater extent than Bolboschoenus caldwellii (41 mV above bare sediment). However, the inhibition of convective flow in T. domingensis reduced its oxidizing ability by 78 mV. In contrast, Potamogeton crispus, a submerged macrophyte, had no influence on sediment redox potential. The presence of T. domingensis also increased phosphorus uptake from the water column by 0.88 mg P m−2 day−1, above that of bare sediments. In addition, inundation predictably decreased sediment redox potential from 175 mV to −176 mV over a 42-day period. Similarly, the addition of cellulose (10 mg L−1) decreased sediment redox potential by 42 mV. Consequently, deposition of organic debris may counteract the oxidizing effects of macrophytes that have a limited capacity to transport oxygen, such as P. crispus. Results suggest that macrophytes play an important role in facilitating the restoration of freshwater systems.

The impact of biomass harvesting on phosphorus uptake by wetland plants

2001 ◽  
Vol 44 (11-12) ◽  
pp. 61-67 ◽  
Author(s):  
S-Y. Kim ◽  
P.M. Geary
Keyword(s):  
Plant Biomass ◽  
Phosphorus Uptake ◽  
P Uptake ◽  
Plant Parts ◽  
Biomass Harvesting ◽  
Below Ground ◽  
The Impact ◽  
Total P ◽  
Better Than ◽  
P Removal

Two species of macrophytes, Baumea articulata and Schoenoplectus mucronatus, were examined for their capacity to remove phosphorus under nutrient-rich conditions. Forty large bucket systems with the two different species growing in two types of substrate received artificial wastewaters for nine months, simulating a constructed wetland (CW) under high loading conditions. Half of the plants growing in the topsoil and gravel substrates were periodically harvested whereas the other half remained intact. Plant tissue and substrate samples were regularly analysed to determine their phosphorus concentrations. With respect to phosphorus uptake and removal, the Schoenoplectus in the topsoil medium performed better than the Baumea. Biomass harvesting enhanced P uptake in the Schoenoplectus, however the effect was not significant enough to make an improvement on the overall P removal, due to the slow recovery of plants and regrowth of biomass after harvesting. From P partitioning, it was found that the topsoil medium was the major P pool, storing most of total P present in the system. Plant parts contributed only minor storage with approximately half of that P stored below ground in the plant roots. The overall net effect of harvesting plant biomass was to only remove less than 5% of total phosphorus present in the system.

scholarly journals An experimental study on the effects of freeze–thaw cycles on phosphorus adsorption–desorption processes in brown soil

RSC Advances ◽  
2017 ◽  
Vol 7 (59) ◽  
pp. 37441-37446 ◽  
Author(s):  
Qingzhi Wang ◽  
Jiankun Liu ◽  
Lingqing Wang
Keyword(s):  
Experimental Study ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Phosphorus Adsorption ◽  
Soil P ◽  
Freeze Thaw ◽  
Chemical Properties Of Soils ◽  
Adsorption Desorption ◽  
Physical And Chemical ◽  
And Chemical Properties

Freeze–thaw cycles (FTCs) can strongly influence the physical and chemical properties of soils in cold regions, which can in turn affect the adsorption–desorption characteristics of phosphorus (P) in the soil.

Classification of Dissolved and Particulate Phosphate Components in Xiangxi River, China

2014 ◽  
Vol 535 ◽  
pp. 293-297
Author(s):  
Wen Jun Yang ◽  
Jian Li ◽  
Zhong Wu Jin
Keyword(s):  
Water Quality ◽  
Suspended Sediment ◽  
Langmuir Equation ◽  
Three Gorges Project ◽  
Phosphorus Adsorption ◽  
The Three Gorges ◽  
Xiangxi River ◽  
The Three Gorges Project ◽  
Adsorption Desorption

These years the water quality deteriorated in Xiangxi River (XXR)---one tributary of Yangtze River in the Three Gorges Project reservoir area. Many components existed in XXR such as nutrients, suspended sediment (SS) and phytoplankton. The nutrients containing phosphorus could be adsorbed to the fine SS, which influenced the water quality components cycling obviously. For calculating the concentrations of different forms of phosphates (mainly the dissolved phosphate and particulate phosphate) more precisely, the formula was deduced based on the Langmuir equation and modified Langmuir equation. Then the field observed data were used to validate the deduced formula, which showed that the deduced formula can calculate the concentrations well. The formula could be applied for the water quality or ecological modeling, and also provide more information for water quality improvement. Keywords: Suspended sediment; Phosphorus; Adsorption-desorption; Xiangxi River

Phosphorus dynamics in Australian lowland rivers

2001 ◽  
Vol 52 (1) ◽  
pp. 127 ◽  
Author(s):  
Ian T. Webster ◽  
Phillip W. Ford ◽  
Gary Hancock
Keyword(s):  
Water Column ◽  
Time Scale ◽  
Molecular Diffusion ◽  
Phosphorus Uptake ◽  
Transport Processes ◽  
Phosphorus Concentration ◽  
Uptake Capacity ◽  
Treated Sewage ◽  
Uptake Rates ◽  
Adsorption Desorption

In freshwater systems, phosphorus is adsorbed predominantly to clay within the sediments. Assuming a linear adsorption/desorption isotherm, rapid equilibrium adsorption, and transport by molecular diffusion, estimates are derived for (a) the rates of exchange between the adsorbed phosphorus pool in the sediments and the dissolved pool in the water column and (b) time scales to re-establish equilibrium after a step change in the water column phosphorus concentration. For oxic sediments, the time scale is of the order of tens of days. Anoxic release is much faster;the time scale is tens of minutes. The release of treated sewage at Narrabri abruptly raises the phosphorus concentration in the Namoi River. The concentration only returns to its original level 10–20 km downstream. A sediment adsorptive-uptake model underestimates the downstream phosphorus uptake rates. An alternative model, based on biotic uptake by Cladophora , describes reality better. It treats phosphorus transfer as controlled by physical transport processes and by the phosphorus uptake capacity of the biota. We show also that carp resuspension is faster than diffusion (6 v. 28 days) in restoring phosphorus concentrations in the water column after perturbation by rapid algal drawdown.

scholarly journals Sponge effect of aerated concrete on phosphorus adsorption-desorption from agricultural drainage water in rainfall

2020 ◽  
Vol 15 (No. 4) ◽  
pp. 220-227
Author(s):  
Jinquan Zhang ◽  
Weiguo Fu
Keyword(s):  
Drainage Water ◽  
Agricultural Drainage ◽  
Phosphorus Adsorption ◽  
P Adsorption ◽  
Initial Stage ◽  
Aerated Concrete ◽  
Initial Adsorption ◽  
Adsorption Desorption ◽  
The Relationship ◽  
Peak Value

In the initial stage of the rainfall, the nutrient element phosphorus (P) in the farmland, one of the most important factors causing agricultural non-point source pollution, flows into agriculture drainage ditches rapidly, and an instantaneous phosphorus peak value in the ditch water often occurs. Aerated concrete with high P adsorption properties was chosen as the experiment material in the laboratory to reduce the instantaneous P peak value in the drainage water in the initial stage of the rainfall. The three total P (TP) concentrations of the simulated drainage water (1.0, 2.0, and 3.0 mg/L) stood for three treatments were designed in the adsorption experiment; the same three TP concentrations of the simulated drainage water and the three TP concentrations of the simulated natural water (0.2, 0.3, and 0.4 mg/L) stood for nine treatments in the desorption experiment. The sponge effect of the aerated concrete on the P adsorption-desorption was explored by studying the dynamics of the P adsorption-desorption of the aerated concrete with an increase in the experiment’s time. The results showed the following details: (1) Both the adsorption rate and desorption rate of the aerated concrete decrease with an increase in the experiment’s time. The initial adsorption is dominant during the entire adsorption, as with the initial desorption during the entire desorption. (2) The adsorption capacity of the aerated concrete slightly decreases with the increase in the re-adsorption, whereas the desorption capacity of the aerated concrete significantly decreases with the increase in the re-desorption. Thus, the aerated concrete can be introduced into the agricultural drainage ditch to reduce the instantaneous P peak value in the drainage water in the initial stage of the rainfall, and potential further studies should explore the relationship between the different drainage water loads and the amount of the aerated concrete.

scholarly journals Phosphorus adsorption/desorption kinetics of bioretention

2020 ◽  
Vol 24 (4) ◽  
pp. 2401-2410
Author(s):  
Ying Mei ◽  
Xiao-Han Zhu ◽  
Long Gao ◽  
Hang Zhou ◽  
Ya-Jun Xiang ◽  
...  
Keyword(s):  
Iron Powder ◽  
Aluminum Powder ◽  
Adsorption Properties ◽  
Desorption Kinetics ◽  
Considerable Influence ◽  
Phosphorus Adsorption ◽  
Monolayer Adsorption ◽  
Effects Of Ph ◽  
Adsorption Desorption ◽  
Kinetics Of

A bioretention medium has considerable influence on the removal of pollutants, especially phosphorus pollutants. In this paper, the phosphorus adsorption properties of three bioretention media (sand, iron powder, and aluminum powder) are studied, and the effects of pH and ionic strength on the phosphorus adsorption are analyzed. Results show that the phosphorus adsorption isotherm can be well modeled by the Langmuir equation. The experimental results show the monolayer adsorption capacity of sand is the highest, while the iron powder the lowest. The pH of the solution has a considerable influence on the phosphorus adsorption of sand and iron powder, but has a minimal effect on aluminum powder.

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