Integrating Resource Heterogeneity and Plant Plasticity: Modelling Nitrate and Phosphate Uptake in a Patchy Soil Environment

1996 ◽  
Vol 84 (6) ◽  
pp. 891 ◽  
Author(s):  
R. B. Jackson ◽  
M. M. Caldwell
Keyword(s):  
Phosphate Uptake ◽  
Resource Heterogeneity ◽  
Soil Environment ◽  
Plant Plasticity

Empirical model approach for the evaluation of pH and conductivity on pollutant diffusion in soil environment

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Mathematical Model ◽  
Quadratic Equation ◽  
Diffusivity Coefficient ◽  
Soil Environment ◽  
Irreversible Reaction ◽  
Chemical Pollutant ◽  
The Mathematical Model ◽  
Coefficient Of Diffusion ◽  
Level Of Agreement ◽  
Model Approach

This work is aimed at developing a mathematical model equation that can be used to predict the fate of contaminant in the soil environment. The mathematical model was developed based on the fundamental laws of conservation and the equation of continuity given asand was resolved to obtain a quadratic equation of the form C(X) = DX2+vX+f. The developed equation was then used to fit the experimental data that were obtained from the Physio-chemical analysis of the soil samples which were obtained at various depths; within the vicinity of the H & H Asphalt plant Company, located at Enito 3 in Ahoada West L.G.A, River State, Nigeria. The Experimental and Model results obtained from the Calculation and Simulation of the developed models were compared numerically and graphically as presented in this work. It was observed that there is reasonable level of agreement between the three results. The polynomial of the curve was established to ascertain the validity of the model; this was done for all the parameters that were analyzed. From the findings the model developed can be used to predict the concentration of a chemical pollutant at various depths. The reliability of the model developed was established giving the fact that through this quadratic equation the diffusivity (coefficient of diffusion), the water velocity and the irreversible reaction decay rate could be determined.

Shrub Size Modulates Resource Heterogeneity in a Sagebrush-Steppe Ecosystem

2020 ◽  
Vol 80 (1) ◽  
pp. 28
Author(s):  
Lin Liu ◽  
Kari E. Veblen ◽  
Thomas A. Monaco
Keyword(s):  
Sagebrush Steppe ◽  
Resource Heterogeneity ◽  
Steppe Ecosystem

Verification of anoxic phosphate uptake as the main biochemical mechanism of the “dephanox” process

1997 ◽  
Vol 35 (10) ◽  
pp. 87-94 ◽  
Author(s):  
R. Sorm ◽  
J. Wanner ◽  
R. Saltarelli ◽  
G. Bortone ◽  
A. Tilche
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Uptake Rate ◽  
Phosphate Uptake ◽  
Biochemical Mechanism ◽  
Batch Experiments ◽  
Batch Tests ◽  
Genetic Probes ◽  
Activated Sludge Systems ◽  
Removal System

The phenomenon of anoxic phosphate uptake with simultaneous denitrification was studied. For this purpose kinetic batch tests have been carried out by using the activated sludge samples from three modifications of nutrient removal activated sludge systems: two based on an anaerobic-anoxic-oxic (A2/O) system and a third on an anaerobic-oxic (A/O) system. The results showed significant differences in anoxic phosphate uptake rate between activated sludge which was alternatively exposed to anoxic conditions and activated sludge from the A/O arrangement. These differences were also accompanied by different denitrification rates. Simultaneously with batch experiments the microscopic observation of activated sludge samples was carried out. Neisser and Gram stained samples showed clear differences in shape, size and distribution of polyphosphate accumulating bacteria between A2/O and A/O Processes. Moreover, experiments performed using genetic probes confirmed the differences in microbiological composition of activated sludge samples from different nutrient removal system arrangements.

Effect of calcium on transport characteristics of cultured proximal renal cells

1985 ◽  
Vol 249 (3) ◽  
pp. F346-F355
Author(s):  
L. M. Sakhrani ◽  
N. Tessitore ◽  
S. G. Massry
Keyword(s):  
Phosphate Uptake ◽  
Cytosolic Calcium ◽  
Ruthenium Red ◽  
Extracellular Calcium ◽  
Transport Processes ◽  
Renal Cells ◽  
Sodium Uptake ◽  
Calcium Loading ◽  
Sodium Dependent ◽  
Acute Changes

We examined the effects of acute changes in extracellular and intracellular calcium on transport processes in primary culture of proximal rabbit renal cells. A change in extracellular calcium from 0 to 3 mM inhibited amiloride-sensitive sodium uptake by 30%, and this effect was maximal at 1 mM calcium. Other polyvalent cations (Mn2+, Mg2+, La3+, and Ba2+) produced quantitatively similar inhibition of amiloride-sensitive sodium uptake compared with calcium. An increase in cytosolic calcium produced by calcium loading (20 mM) or by A23187 (20 microM) resulted in an inhibition of 25-40% of amiloride-sensitive sodium uptake. Moreover, quinidine (10(-4)M) and ruthenium red (3 microM), agents presumed to increase cytosolic calcium, inhibited amiloride-sensitive sodium uptake by 20-60%. Both these agents also inhibited sodium-dependent phosphate uptake by 20% but had no effect on ouabain-sensitive 86Rb+ uptake or on sodium-dependent alpha-methylglucoside uptake. Our data indicate that increases in extracellular calcium inhibit amiloride-sensitive sodium uptake and increases in cytosolic calcium inhibit sodium-dependent phosphate and amiloride-sensitive sodium uptakes. The effect of extracellular calcium may be due to charge screening and/or binding to the negatively charged plasma membrane or due to alterations in membrane fluidity.

scholarly journals The Role of Biochar in Regulating the Carbon, Phosphorus, and Nitrogen Cycles Exemplified by Soil Systems

2021 ◽  
Vol 13 (10) ◽  
pp. 5612
Author(s):  
Shu-Yuan Pan ◽  
Cheng-Di Dong ◽  
Jenn-Feng Su ◽  
Po-Yen Wang ◽  
Chiu-Wen Chen ◽  
...  
Keyword(s):  
Environmental Sustainability ◽  
Soil Amendment ◽  
Environmental Control ◽  
Current Knowledge ◽  
Soil Environment ◽  
Nitrogen And Phosphorus ◽  
Soil Systems ◽  
P Mineralization ◽  
Rich Material ◽  
Pyrolysis Of Biomass

Biochar is a carbon-rich material prepared from the pyrolysis of biomass under various conditions. Recently, biochar drew great attention due to its promising potential in climate change mitigation, soil amendment, and environmental control. Obviously, biochar can be a beneficial soil amendment in several ways including preventing nutrients loss due to leaching, increasing N and P mineralization, and enabling the microbial mediation of N2O and CO2 emissions. However, there are also conflicting reports on biochar effects, such as water logging and weathering induced change of surface properties that ultimately affects microbial growth and soil fertility. Despite the voluminous reports on soil and biochar properties, few studies have systematically addressed the effects of biochar on the sequestration of carbon, nitrogen, and phosphorus in soils. Information on microbially-mediated transformation of carbon (C), nitrogen (N), and phosphorus (P) species in the soil environment remains relatively uncertain. A systematic documentation of how biochar influences the fate and transport of carbon, phosphorus, and nitrogen in soil is crucial to promoting biochar applications toward environmental sustainability. This report first provides an overview on the adsorption of carbon, phosphorus, and nitrogen species on biochar, particularly in soil systems. Then, the biochar-mediated transformation of organic species, and the transport of carbon, nitrogen, and phosphorus in soil systems are discussed. This review also reports on the weathering process of biochar and implications in the soil environment. Lastly, the current knowledge gaps and priority research directions for the biochar-amended systems in the future are assessed. This review focuses on literatures published in the past decade (2009–2021) on the adsorption, degradation, transport, weathering, and transformation of C, N, and P species in soil systems with respect to biochar applications.

scholarly journals A Dieldrin Case Study: Another Evidence of an Obsolete Substance in the European Soil Environment

Agriculture ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 314
Author(s):  
Petros Tsiantas ◽  
Evangelia N. Tzanetou ◽  
Helen Karasali ◽  
Konstantinos M. Kasiotis
Keyword(s):  
Active Substance ◽  
Anthropogenic Activities ◽  
Carcinogenic Risk ◽  
The European Union ◽  
Soil Environment ◽  
Single Application ◽  
Environmental Concentration ◽  
Tandem Mass Spectrometric ◽  
Potential Use

Soil constitutes a central environmental compartment that, due to natural and anthropogenic activities, is a recipient of several contaminants. Among them, organochlorine pesticides are of major concern, even though they have been banned decades ago in the European Union, due to their persistence and the health effects they can elicit. In the presented work, a gas chromatographic tandem mass spectrometric (GC-MS/MS) developed method was applied to soil samples after the suspected and potential use of formulations containing organochlorine active substance. One soil sample was positive to dieldrin at 0.018 mg kg−1. Predicted environmental concentration in soil (PECsoil) considering a single application of this active substance potentially attributed the finding in its past use. The subsequent health risk assessment showed negligible non-carcinogenic risk and tolerable carcinogenic risk. The latter signifies that repetitive and prolonged sampling can unveil the pragmatic projection of persistent chemicals’ residues in the soil.

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