Phosphate dynamics in a sub-tropical lake ecosystem

2020 ◽  
Author(s):  
Priyanka Singh ◽  
Anil Kumar Haritash ◽  
Himanshu Joshi
Keyword(s):  
Redox Potential ◽  
Inorganic Phosphate ◽  
Extreme Weather ◽  
Organic Phosphate ◽  
Lake Ecosystem ◽  
Post Monsoon ◽  
Physico Chemical ◽  
The World ◽  
Phosphate Fluxes ◽  
Available Phosphate

<p>Lake Ecosystem is a key component of biosphere that supports aquatic life and provide sink to the untreated effluent (domestic, industrial, and agricultural). Due to rapid industrialisation and changing climate, 30-40% of the lakes in the world are now eutrophic. The basic cause of eutrophication is the addition of nutrients (nitrogen and phosphate) into the lake system. Phosphate has been observed to be the limiting nutrient in 80% of the lakes and reservoirs in the world. Unlike other elements, phosphate does not escape from the system but changes from one form to the other depending upon the prevailing physico-chemical conditions. Chemical parameters like pH and redox potential are the major governing factors for phosphate fluxes. Sediments in the benthic zone serves as a sink as well as the source of phosphate for the photic zone. In the present study, a relationship between the physico-chemical properties of water and the fractions of phosphate in the sediments were studied. The study was conducted during three different seasons i.e. post-monsoon, winter, and summer to observe the seasonal variation. The pH, DO, ORP, and available phosphate in the water varied from 8.5, 14.7 mg/l, 39 mV, and 5.8 mg/l, 8.4, 3.5 mg/l, -64 mV, and 8.7 mg/l, and 7.8, 7.3 mg/l, 119 mV, and 10.5 mg/l during post-monsoon, winter, and summer, respectively. Phosphate in sediments was fractionated using SMT protocol. It was categorised under inorganic and organic phosphate classes, and the inorganic phosphate was further categorised as Non apatite inorganic phosphate (NAIP: Fe/Al bound) and Apatite inorganic phosphate (AIP: Ca bound).  The inorganic phosphate in the sediments was observed to be more than organic phosphate during post monsoon and summer, and at the same time the available phosphate in the overlying water was found low in concentration. The growth of phytoplankton is constrained by decreasing bio available phosphate in water. Concentration of NAIP was observed to vary with redox potential and concentration of AIP with pH. The study justified the hypothesis of direct relationship of sediment chemistry with bio availability of phosphate in water. Winter was found to be the extreme weather for phosphate fluxes. The findings point towards need of proper management such as chemical precipitation, sediment dredging etc. during this extreme weather conditions.</p>

Theoretical Exploration of 2,2’-Bipyridines as Electro-Active Compounds in Flow Batteries

2019 ◽  
Author(s):  
Mariano Sánchez-Castellanos ◽  
Martha M. Flores-Leonar ◽  
Zaahel Mata-Pinzón ◽  
Humberto G. Laguna ◽  
Karl García-Ruiz ◽  
...  
Keyword(s):  
Redox Potential ◽  
Active Material ◽  
Chemical Properties ◽  
Small Subset ◽  
Solubility In Water ◽  
Protonation Reaction ◽  
Redox Active ◽  
Physico Chemical ◽  
Pka Value ◽  
Flow Batteries

Compounds from the 2,2’-bipyridine molecular family were investigated for use as redox-active materials in organic flow batteries. For 156 2,2’-bipyridine derivatives reported in the academic literature, we calculated the redox potential, the pKa for the first protonation reaction, and the solubility in aqueous solutions. Using experimental data on a small subset of derivatives, we were able to calibrate our calculations. We find that functionalization with electron-withdrawing groups leads to an increase of the redox potential and to an increase of the molecular acidity (as expressed in a reduction of the pKa value for the first protonation step). Furthermore, calculations of solubility in water indicate that some of the studied derivatives have adequate solubility for flow battery applications. Based on an analysis of the physico-chemical properties of the 156 studied compounds, we down-select five molecules with carbonyl- and nitro-based functional groups, whose parameters are especially promising for potential application as negative redox-active material inorganic flow batteries.

Theoretical Exploration of 2,2’-Bipyridines as Electro-Active Compounds in Flow Batteries

2019 ◽  
Author(s):  
Mariano Sánchez-Castellanos ◽  
Martha M. Flores-Leonar ◽  
Zaahel Mata-Pinzón ◽  
Humberto G. Laguna ◽  
Karl García-Ruiz ◽  
...  
Keyword(s):  
Redox Potential ◽  
Active Material ◽  
Chemical Properties ◽  
Small Subset ◽  
Solubility In Water ◽  
Protonation Reaction ◽  
Redox Active ◽  
Physico Chemical ◽  
Pka Value ◽  
Flow Batteries

Compounds from the 2,2’-bipyridine molecular family were investigated for use as redox-active materials in organic flow batteries. For 156 2,2’-bipyridine derivatives reported in the academic literature, we calculated the redox potential, the pKa for the first protonation reaction, and the solubility in aqueous solutions. Using experimental data on a small subset of derivatives, we were able to calibrate our calculations. We find that functionalization with electron-withdrawing groups leads to an increase of the redox potential and to an increase of the molecular acidity (as expressed in a reduction of the pKa value for the first protonation step). Furthermore, calculations of solubility in water indicate that some of the studied derivatives have adequate solubility for flow battery applications. Based on an analysis of the physico-chemical properties of the 156 studied compounds, we down-select five molecules with carbonyl- and nitro-based functional groups, whose parameters are especially promising for potential application as negative redox-active material inorganic flow batteries.

The current state of the question of the "reaction" of fluids of the human body

2021 ◽  
Vol 20 (4) ◽  
pp. 411-420
Author(s):  
L. B. Wagner
Keyword(s):  
Human Body ◽  
Current State ◽  
Physico Chemical ◽  
The World ◽  
Diagnostics And Therapy

The question of the "reaction" of the fluids of the human body is not entirely new, but only in the last few years, mainly during the war years, it has attracted the general attention of biologists, physiologists and doctors around the world. Only now are more or less broad prospects emerging, which the development of this question promises for physiology, diagnostics, and therapy. Therefore, I ask the reader to arm yourself with patience in order to overcome the preliminary physico-chemical part of this review.

HYDROLYSIS OF LECITHIN BY PLANT PLASTID ENZYMES

1955 ◽  
Vol 33 (1) ◽  
pp. 575-589 ◽  
Author(s):  
Morris Kates
Keyword(s):  
Phosphatidic Acid ◽  
Inorganic Phosphate ◽  
Organic Phosphate ◽  
Water Soluble ◽  
Lag Phase ◽  
Carrot Root ◽  
First Order ◽  
Spinach Chloroplasts ◽  
Egg Lecithin ◽  
Hydrolysis Of

Enzymatic liberation of choline from egg lecithin by plastid fractions from sugar beet, spinach, and cabbage leaves and from carrot root was a rapid, first order reaction (up to 70% hydrolysis), and was not preceded by a lag phase. None of the choline-containing products of lecithin degradation (lysolecithin, glycerylphosphorylcholine, or phosphorylcholine) lost choline on incubation with spinach chloroplasts. Inorganic phosphate liberation from lecithin by the plastids was preceded by a lag phase and was much slower than choline liberation. Spinach chloroplasts catalyzed the liberation of inorganic phosphate from L-α-phosphatidic acid and from L-α-glycerophosphate. The water-soluble organic phosphate liberated from lecithin by spinach chloroplasts was identified chromatographically as phosphorylcholine. The ether-soluble organic phosphate produced during the hydrolysis of egg lecithin by carrot plastids was isolated and identified as L-α-phosphatidic acid. These observations suggest that the enzymatic hydrolysis of lecithin by plant plastids involves the following reactions: (1) lecithin → L-α-phosphatidic acid + choline; (2) L-α-phosphatidic acid → inorganic phosphate + diglyceride and/or (3) L-α-phosphatidic acid → glycerophosphate + fatty acids and (4) glycerophosphate → inorganic phosphate + glycerol; and (5) lecithin → phosphorylcholine + diglyceride. The L-α-structure for egg lecithin was confirmed.

scholarly journals Physico-Chemical Properties of Deep-Lying Oils

2021 ◽  
Vol 134 (3) ◽  
pp. 11-17
Author(s):  
I. G. Yashchenko ◽  
◽  
Y. M. Polishchuk ◽  
Keyword(s):  
Spatial Distribution ◽  
Physicochemical Properties ◽  
Chemical Properties ◽  
Oil Production ◽  
Urgent Problem ◽  
Physico Chemical ◽  
The World ◽  
Oil Gas

The article is devoted to the urgent problem of studying the features of the properties of poorly studied oils at great depths (more than 4,500 m), the need for development of which is caused by the continuing decline in oil production in traditional oil producing provinces. The analysis of the spatial distribution of reserves across the continents and countries of deep-seated oils and changes in their physico-chemical properties and the occurrence conditions, which made it possible to identify their main features. The studies used information on 21067 oil samples from 167 oil-bearing basins of the world, obtained from the database on the physicochemical properties of oils. The features of the physicochemical properties of deep-seated oils have been established, which are manifested in a decrease in the density and viscosity of oils, in a decrease in the content of sulfur and asphalt-resinous substances, and in an increase in the content of light fractions and oil gas in comparison with oils of small and medium depths.

scholarly journals The Comparison of Electrodialysis and Nanofiltration in Nitrate Removal from Groundwater

2021 ◽  
Vol 6 (1) ◽  
pp. 17-30
Author(s):  
J Touir ◽  
S Kitanou ◽  
M Zait ◽  
S Belhamidi ◽  
M Belfaquir ◽  
...  
Keyword(s):  
Produced Water ◽  
Nitrate Removal ◽  
World Health ◽  
Quality Of Water ◽  
Physico Chemical ◽  
Major Interest ◽  
The World ◽  
Health Organization ◽  
Agricultural Regions

Nitrate groundwater contamination is of major interest all over the world. This problem arises in agricultural regions across Morocco. An excess amount of nitrate causes a serious problem in urban water networks and human health. Because of these health risks, considerable attention has been paid to find effective treatment processes to reduce nitrate concentrations to safe levels. The World Health Organization has set an acceptable level for nitrate in drinking water at 50 mg/L. The aim of this study is to reduce the nitrate concentration from groundwater using two membrane processes: Electrodialysis (ED) and Nanofiltration (NF). Efficiencies of these two technologies are compared in respect to nitrate ions removal, cost process and final quality of water. The results of technologies show that, for electrodialysis standards level can be achieved for a demineralization rate of 15% and the physico-chemical quality of the produced water is satisfactory. For nanofiltration we obtain a nitrate removal of 90% but the produced water is very de-mineralized and must be remineralized.

scholarly journals Water Water Everywhere

2000 ◽  
Vol 1 ◽  
pp. 17-19
Author(s):  
Jean Levy
Keyword(s):  
Global Warming ◽  
20Th Century ◽  
Extreme Weather ◽  
The World

During the last decade of the 20th century the world was exposed to increasing episodes of extreme weather. Figures reveal a 0.6°C rise in average temperatures since records began in 1860, with the 1990s being the warmest decade and 1998 the warmest year. Experts believe that these rising temperatures, or global warming, are in part due to human influences.

Metabolic Acidosis is a Potent Stimulus for Cellular Inorganic Phosphate Generation in Uraemia

1995 ◽  
Vol 88 (4) ◽  
pp. 405-412 ◽  
Author(s):  
Alan Bevington ◽  
Dennis Brough ◽  
Frease E. Baker ◽  
Jane Hattersley ◽  
John Walls
Keyword(s):  
Steady State ◽  
Metabolic Acidosis ◽  
Inorganic Phosphate ◽  
Lactate Production ◽  
Extracellular Fluid ◽  
Low Ph ◽  
Organic Phosphate ◽  
Glycolytic Flux ◽  
Before And After

1. During metabolic acidosis, significant fluxes of inorganic phosphate (Pi) may occur from cellular to extracellular fluid. In this study Pi was measured in erythrocytes of uraemic patients before and after haemodialysis and was related to their plasma pH (acidosis), plasma Pi (hyperphosphataemia) and cellular organic phosphate concentrations. 2. Before dialysis, the ratio of cellular to extracellular Pi concentration correlated inversely with plasma pH, increasing 2.5-fold as pH fell from 7.4 to 7.2. 3. An increase in cellular Pi similar to that seen in the patients was observed within 90 min of adding acid to normal erythrocytes in vitro. 4. The total Pi content of the cell suspension increased 25% on decreasing plasma pH from 7.4 to 7.2, largely as a result of generation of Pi from 2,3-bisphosphoglycerate in the cells. This was accompanied by net efflux of Pi into plasma. 5. In addition, the increase in the steady-state cellular Pi concentration on adding a constant extracellular Pi load was 50% greater at pH 7.2 than at 7.4, implying that alterations in the regulation of the transmembrane Pi gradient also contribute to the rise in cellular Pi observed at low pH. 6. At normal plasma Pi concentration (1 mM), glycolytic flux (lactate production) was inhibited by 20% when pH was lowered from 7.4 to 7.2. However, this inhibition was blocked when cellular Pi was increased by adding Pi to the plasma in vitro. 7. Metabolic acidosis is therefore a potent stimulus for Pi generation in erythrocytes, and this Pi may serve to stimulate glycolysis which is normally inhibited by low pH.

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