INFLUENCE OF DRAINAGE REGIME ON THE CHEMISTRY AND MORPHOLOGY OF SOME MANITOBA SOILS: CLAYEY CHERNOZEMIC AND GLEYSOLIC SOILS OF THE RED RIVER PLAIN

1984 ◽  
Vol 64 (4) ◽  
pp. 605-620 ◽  
Author(s):  
W. MICHALYNA ◽  
R. H. RUST
Keyword(s):  
Redox Potential ◽  
Red River ◽  
Morphological Description ◽  
Redox Potentials ◽  
Groundwater Levels ◽  
Exchangeable Ca ◽  
Morphological Criteria ◽  
River Plain ◽  
Extractable Iron

A number of clayey soils of the Red River-Osborne Association that developed under imperfectly to poorly drained conditions on the Red River Plain in Manitoba were studied. These soils, traditionally classified as Gleyed Chernozemic soils and Gleysolic, were characterized by morphological description, chemical and physical analyses. Most of the areas of the Red River Plain are cultivated and have had considerable improvement of surface drainage. Redox potentials, groundwater level and redox potential in the groundwater were determined at selected sites for various periods to a maximum of 2 years. Soils traditionally classified as Gleysols had shallow sola, minimal grumic features, and low chromas and mottles that would meet with present criteria; exchangeable Ca/Mg ratios were commonly near unity in the lower part of the solum. These soils were in an oxidized condition with Ept above 550 mV in the profiles; groundwater levels were below 1.4 m. Oxalate to dithionite extractable iron ratios were greater than 0.45 in the lower part of the solum on the Gleysols and those Gleyed Chernozemic soils with chromas of 2 or less with mottles. Gleyed Chernozemic soils with chromas of 2 or less with mottles would key as Gleysols using the present Canadian criteria; this would result in a change of traditional concepts. Classification of these soils according to the Canadian (taxon) and the U.S. systems are discussed. Key words: Chemical criteria, morphological criteria, water table, soil temperature, redox potential

scholarly journals INFLUENCE OF DRAINAGE REGIME ON THE CHEMISTRY AND MORPHOLOGY OF SOME MANITOBA SOILS: SANDY CHERNOZEMIC AND GLEYSOLIC SOILS OF THE LOWER ASSINIBOINE DELTA

1984 ◽  
Vol 64 (4) ◽  
pp. 587-604 ◽  
Author(s):  
W. MICHALYNA ◽  
R. H. RUST
Keyword(s):  
Redox Potential ◽  
Soil Temperature ◽  
Early Summer ◽  
Near Surface ◽  
Groundwater Levels ◽  
Reducing Conditions ◽  
Exchangeable Ca ◽  
Morphological Criteria ◽  
Water Tables

A number of imperfectly and poorly drained sandy soils from the Almasippi Association of the Lower Assiniboine Delta in Manitoba, traditionally classified as Gleyed Chernozems and Gleysols, were characterized by morhological descriptions, chemical and physical analyses. Soil temperature, groundwater levels, and redox potential of both soil and water were determined at selected sites for various periods to a maximum of 2 years. The upper 30 cm of the soils, traditionally considered as Gleysols, had undergone strong reducing conditions (100 to −200 mV) for at least 2 mo in the spring and early summer; these areas were covered with hydrophytic vegetation and remained saturated at or near surface to July. The subsoil below 45 cm remained in an oxidized state throughout the year. Exchangeable Ca/Mg ratio was near unity in the Gleysols and substantially greater in the Gleyed subgroups. Oxalate to dithionite-extractable iron ratios were greater than 0.45 in the lower part and below the solum of Gleysolic and Gleyed soils. In soils classified as Gleyed subgroups, water tables were below 1.3 m throughout the season and soil profiles were in an oxidized condition. Classification of these soils according to the present Canadian and U.S. system would require a change in concept and approach from the traditional view of Gleysolic soils in Canada. Key words: Redox potential, chemical criteria, morphological criteria, water table, soil temperature

scholarly journals Relationships of Hydrological Seasons in Rivers and Groundwaters in Selected Catchments in Poland

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 250
Author(s):  
Przemysław Tomalski ◽  
Edmund Tomaszewski ◽  
Dariusz Wrzesiński ◽  
Leszek Sobkowiak
Keyword(s):  
River Flow ◽  
Geographical Location ◽  
Base Flow ◽  
Water Shortages ◽  
Groundwater Levels ◽  
Average Value ◽  
Geographical Regions ◽  
New Variables ◽  
Mixed Types

The study applied the method of hydrological season identification in a time series of river total and base flows and in groundwater levels. The analysis covered a series of daily measurements from the period 2008–2017 in nine catchments located in different geographical regions of Poland. The basis of the classification of hydrological seasons, previously applied for river discharges only, was the transformation of the original variables into a series reflecting three statistical features estimated for single-name days of a year from a multiyear: average value, variation coefficient, and autocorrelation coefficient. New variables were standardized and after hierarchical clustering, every day of a year had a defined type, valorizing three features which refer to quantity, variability, and the stochastic nature of total and base river flow as well as groundwater stage. Finally, sequences of days were grouped into basic (homogenous) seasons of different types and transitional seasons including mixed types of days. Analysis indicated determinants of types, length, and frequency of identified hydrological seasons especially related to river regime, hydrogeological and hydrometeorological conditions as well as physiographical background were directly influenced by geographical location. Analysis of the co-occurrence of the same types of hydrological seasons allowed, in some catchments, periods of synchronic alimentation (groundwater and base flow, mainly in the cold half-year) and water shortages (all three components, mainly in the warm half-year) to be identified.

scholarly journals Role of redox-inactive metals in controlling the redox potential of heterometallic manganese–oxido clusters

2021 ◽  
Author(s):  
Keisuke Saito ◽  
Minesato Nakagawa ◽  
Manoj Mandal ◽  
Hiroshi Ishikita
Keyword(s):  
Photosystem Ii ◽  
Redox Potential ◽  
Quantum Chemical Calculations ◽  
Catalytic Reaction ◽  
Quantum Chemical ◽  
Ionic Radius ◽  
Redox Potentials ◽  
Oxygen Evolving ◽  
Highest Occupied Molecular Orbitals

AbstractPhotosystem II (PSII) contains Ca2+, which is essential to the oxygen-evolving activity of the catalytic Mn4CaO5 complex. Replacement of Ca2+ with other redox-inactive metals results in a loss/decrease of oxygen-evolving activity. To investigate the role of Ca2+ in this catalytic reaction, we investigate artificial Mn3[M]O2 clusters redox-inactive metals  [M] ([M]  = Mg2+, Ca2+, Zn2+, Sr2+, and Y3+), which were synthesized by Tsui et al. (Nat Chem 5:293, 2013). The experimentally measured redox potentials (Em) of these clusters are best described by the energy of their highest occupied molecular orbitals. Quantum chemical calculations showed that the valence of metals predominantly affects Em(MnIII/IV), whereas the ionic radius of metals affects Em(MnIII/IV) only slightly.

scholarly journals Detecting Redox Potentials Using Porous Boron Nitride/ATP-DNA Aptamer/Methylene Blue Biosensor to Monitor Microbial Activities

Micromachines ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 83
Author(s):  
Kai Guo ◽  
Zirui Song ◽  
Gaoxing Wang ◽  
Chengchun Tang
Keyword(s):  
Methylene Blue ◽  
Microbial Community ◽  
Boron Nitride ◽  
Redox Potential ◽  
Microbial Activity ◽  
Potential Change ◽  
Dna Aptamer ◽  
Redox Potentials ◽  
Microplate Reader

Microbial activity has gained attention because of its impact on the environment and the quality of people’s lives. Most of today’s methods, which include genome sequencing and electrochemistry, are costly and difficult to manage. Our group proposed a method using the redox potential change to detect microbial activity, which is rooted in the concept that metabolic activity can change the redox potential of a microbial community. The redox potential change was captured by a biosensor consisting of porous boron nitride, ATP-DNA aptamer, and methylene blue as the fluorophore. This assembly can switch on or off when there is a redox potential change, and this change leads to a fluorescence change that can be examined using a multipurpose microplate reader. The results show that this biosensor can detect microbial community changes when its composition is changed or toxic metals are ingested.

scholarly journals Temperature-induced diurnal redox potential in soil

2021 ◽  
Author(s):  
Kristof Dorau ◽  
Bianca Bohn ◽  
Lutz Weihermüller ◽  
Tim Mansfeldt
Keyword(s):  
Redox Potential ◽  
Temporal Resolution ◽  
High Temporal Resolution ◽  
Redox Potentials ◽  
Soils And Sediments

With the capabilities to measure redox potentials (EH) at a high temporal resolution, scientists have observed diurnal EH that occur in a distinct periodicity in soils and sediments. These patterns...

A LABORATORY STUDY OF GLEYING

1965 ◽  
Vol 45 (2) ◽  
pp. 199-206 ◽  
Author(s):  
J. A. McKeague
Keyword(s):  
Organic Matter ◽  
Acetic Acid ◽  
Room Temperature ◽  
Rate Of Change ◽  
Redox Potentials ◽  
Soil Columns ◽  
Flooded Soils ◽  
Soil Material ◽  
Effects Of Temperature ◽  
Extractable Iron

Columns of different soil materials with ground leaves at the surface were maintained for 18 months with the water table continuously above the surface, or fluctuating between the surface and 15 cm. Redox potentials, colors, and extractable iron were determined. The effects of temperature and of organic matter on the rate of change of Eh were studied with flooded soils in test tubes.The rate and degree of development of dull colors and mottling in the soil columns was influenced greatly by the nature of the soil material. Reduction effected marked increases in acetic acid extractable iron from all of the soil materials. Low redox potentials developed rapidly at room temperature in flooded soils containing appreciable amounts of organic matter. Eh values below 0 mv developed slowly in soils at 1 °C and at room temperature in some soils that were almost devoid of organic matter. Release of Fe+2 from ferrous minerals was thought to account for these low Eh values.

scholarly journals Site-directed mutations in fungal laccase: effect on redox potential, activity and pH profile

1998 ◽  
Vol 334 (1) ◽  
pp. 63-70 ◽  
Author(s):  
Feng XU ◽  
Randy M. BERKA ◽  
Jill A. WAHLEITHNER ◽  
Beth A. NELSON ◽  
Jeffrey R. SHUSTER ◽  
...  
Keyword(s):  
Redox Potential ◽  
Phenol Oxidase ◽  
Ascorbate Oxidase ◽  
Single Mutation ◽  
Redox Potentials ◽  
Wild Type ◽  
Ph Optimum ◽  
Ph Profile ◽  
Potential Activity

A Myceliophthora thermophila laccase and a Rhizoctonia solani laccase were mutated on a pentapeptide segment believed to be near the type-1 Cu site. The mutation L513F in Myceliophthora laccase and the mutation L470F in Rhizoctonia laccase took place at a position corresponding to the type-1 Cu axial methionine (M517) ligand in Zucchini ascorbate oxidase. The triple mutations V509L,S510E,G511A in Myceliophthora laccase and L466V,E467S,A468G in Rhizoctonia laccase involved a sequence segment whose homologue in ascorbate oxidase is flanked by the M517 and a type-1 Cu-ligating histidine (H512). The single mutation did not yield significant changes in the enzymic properties (including any significant increase in the redox potential of the type-1 Cu). In contrast, the triple mutation resulted in several significant changes. In comparison with the wild type, the Rhizoctonia and Myceliophthora laccase triple mutants had a phenol-oxidase activity whose pH optimum shifted 1 unit lower and higher, respectively. Although the redox potentials were not significantly altered, the Km, kcat and fluoride inhibition of the laccases were greatly changed by the mutations. The observed effects are interpreted as possible mutation-induced structural perturbations on the molecular recognition between the reducing substrate and laccase and on the electron transfer from the substrate to the type-1 Cu centre.

scholarly journals Contributions of Microbial “Contact Leaching” to Pyrite Oxidation under Different Controlled Redox Potentials

Minerals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 856
Author(s):  
Bingxu Dong ◽  
Yan Jia ◽  
Qiaoyi Tan ◽  
Heyun Sun ◽  
Renman Ruan
Keyword(s):  
Redox Potential ◽  
Dissolution Rate ◽  
Elemental Sulfur ◽  
Microbial Consortium ◽  
Pyrite Oxidation ◽  
Microbial Consortia ◽  
Redox Potentials ◽  
Sulfur Passivation ◽  
Sulfur Oxidizing ◽  
Contact Oxidation

The function of microbial contact leaching to pyrite oxidation was investigated by analyzing the differences of residue morphologies, leaching rates, surface products, and microbial consortia under different conditions in this study. This was achieved by novel equipment that can control the redox potential of the solution and isolate pyrite from microbial contact oxidation. The morphology of residues showed that the corrosions were a little bit severer in the presence of attached microbes under 750 mV and 850 mV (vs. SHE). At 650 mV, the oxidation of pyrite was undetectable even in the presence of attached microbes. The pyrite dissolution rate was higher with attached microbes than that without attached microbes at 750 mV and 850 mV. The elemental sulfur on the surface of pyrite residues with sessile microorganisms was much less than that without attached microbes at 750 mV and 850 mV, showing that sessile acidophiles may accelerate pyrite leaching by reducing the elemental sulfur inhibition. Many more sulfur-oxidizers were found in the sessile microbial consortium which also supported the idea. The results suggest that the microbial “contact leaching” to pyrite oxidation is limited and relies on the elimination of elemental sulfur passivation by attached sulfur-oxidizing microbes rather than the contact oxidation by EPS-Fe.

scholarly journals Morphological Description and Classification of Wheat Kernels Based on Geometric Models

Agronomy ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 399 ◽  
Author(s):  
Martín-Gómez ◽  
Rewicz ◽  
Goriewa-Duba ◽  
Wiwart ◽  
Tocino ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Morphological Type ◽  
Morphological Description ◽  
Geometric Figure ◽  
Ploidy Levels ◽  
Geometric Models ◽  
Circularity Index ◽  
Length Width ◽  
Wheat Kernels

Modern automated and semi-automated methods of shape analysis depart from the coordinates of the points in the outline of a figure and obtain, based on artificial vision algorithms, descriptive parameters (i.e., the length, width, area, and circularity index). These methods omit an important factor: the resemblance of the examined images to a geometric figure. We have described a method based on the comparison of the outline of seed images with geometric figures. The J index is the percentage of similarity between a seed image and a geometric figure used as a model. This allows the description and classification of wheat kernels based on their similarity to geometric models. The figures used are the ellipse and the lens of different major/minor axis ratios. Kernels of different species, subspecies and varieties of wheat adjust to different figures. A relationship is found between their ploidy levels and morphological type. Kernels of diploid einkorn and ancient tetraploid emmer varieties adjust to the lens and have curvature values in their poles superior to modern “bread” varieties. Kernels of modern varieties (hexaploid common wheat) adjust to an ellipse of aspect ratio = 1.6, while varieties of tetraploid durum and Polish wheat and hexaploid spelt adjust to an ellipse of aspect ratio = 2.4.

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