INVESTIGATION OF SOME SOILS DEVELOPED IN HUMMOCKS OF THE CANADIAN SUB-ARCTIC AND SOUTHERN-ARCTIC REGIONS. 2. ANALYTICAL CHARACTERISTICS, GENESIS AND CLASSIFICATION

1975 ◽  
Vol 55 (3) ◽  
pp. 321-330 ◽  
Author(s):  
S. PAWLUK ◽  
R. BREWER
Keyword(s):  
Organic Matter ◽  
Arctic Region ◽  
Low Ph ◽  
Base Saturation ◽  
Freeze Thaw ◽  
Forest Tundra ◽  
Ph Values ◽  
Arctic Regions ◽  
High Level

Soils formed in mineral hummocks of the Forest–Tundra region have analytical characteristics reflecting "podzolic" processes. These soils have upper sola that are moderately to strongly acidic, with low pH values and base saturation; have high contents of organically complexed iron and aluminum; and show "chloritization" of montmorillonite, potassium removal from mica and moderate weathering of feldspars. Soils from the Southern-Arctic region have similar acidic characteristics but lack evidence for chemical and mineralogical weathering. Podzolic processes appear much weaker than in the Forest–Tundra region. However, soils from both regions are similar in morphological and micromorphological characteristics. A moderately high level of organic matter is present in the upper sola and at the permafrost interface. The soils are characterized by structures more closely reflecting freeze–thaw processes and faunal activity than podzolic alteration.

Investigation of Cu(II) adsorption from aqueous solutions by NKF-6 zeolite

2011 ◽  
Vol 63 (3) ◽  
pp. 395-402 ◽  
Author(s):  
H. Zhang ◽  
D. Zhao ◽  
L. Chen ◽  
X. J. Yu
Keyword(s):  
Aqueous Solutions ◽  
Outer Sphere ◽  
Low Ph ◽  
Ambient Conditions ◽  
Temperature Dependent ◽  
Ph Values ◽  
Batch Technique ◽  
Negative Effect ◽  
High Level ◽  
Positive Effect

Adsorption of Cu(II) from aqueous solutions using NKF-6 zeolite was investigated by batch technique under ambient conditions. The adsorption was investigated as a function of pH, ionic strength, fulvic acid (FA), foreign ions and temperature. The results indicated that the adsorption of Cu(II) on NKF-6 zeolite gradually increases from 0 to 90% with increasing pH at pH<6.5, and maintains high level at pH>6.5. Outer-sphere complexation or ion exchange may be the main adsorption mechanism of Cu(II) to NKF-6 zeolite at low pH values, whereas the adsorption of Cu(II) at pH>6.5 is mainly dominated by inner-sphere complexation or precipitation. A positive effect of FA on Cu(II) adsorption onto NKF-6 zeolite is observed at low pH values, while a negative effect of FA is observed at high pH values. The thermodynamic parameters (i.e., ΔH0, ΔS0 and ΔG0) for the adsorption of Cu(II) were determined from the temperature dependent isotherms at 20, 40 and 60°C, respectively, and the results indicated that the adsorption reaction is favoured at low temperature. The results suggested that the adsorption process of Cu(II) on NKF-6 zeolite is spontaneous and exothermic.

scholarly journals Assessment of Empirical and Semi-Analytical Algorithms Using MODIS-Aqua for Representing In-Situ Chromophoric Dissolved Organic Matter (CDOM) in the Bering, Chukchi, and Western Beaufort Seas of the Pacific Arctic Region

2021 ◽  
Vol 13 (18) ◽  
pp. 3673
Author(s):  
Melishia I. Santiago ◽  
Karen E. Frey
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Field Measurements ◽  
Arctic Region ◽  
Chromophoric Dissolved Organic Matter ◽  
Arctic Regions ◽  
The Pacific ◽  
In Situ Conditions ◽  
Latitudinal Transect

We analyzed a variety of satellite-based ocean color products derived using MODIS-Aqua to investigate the most accurate empirical and semi-analytical algorithms for representing in-situ chromophoric dissolved organic matter (CDOM) across a large latitudinal transect in the Bering, Chukchi, and western Beaufort Seas of the Pacific Arctic region. In particular, we compared the performance of empirical (CDOM index) and several semi-analytical algorithms (quasi-analytical algorithm (QAA), Carder, Garver-Siegel-Maritorena (GSM), and GSM-A) with field measurements of CDOM absorption (aCDOM) at 412 nanometers (nm) and 443 nm. These algorithms were compared with in-situ CDOM measurements collected on cruises during July 2011, 2013, 2014, 2015, 2016, and 2017. Our findings show that the QAA a443 and GSM-A a443 algorithms are the most accurate and robust representation of in-situ conditions, and that the GSM-A a443 algorithm is the most accurate algorithm when considering all statistical metrics utilized here. Our further assessments indicate that geographic variables (distance to coast, latitude, and sampling transects) did not obviously relate to algorithm accuracy. In general, none of the algorithms investigated showed a statistically significant agreement with field measurements beyond an approximately ± 60 h offset, likely owing to the highly variable environmental conditions found across the Pacific Arctic region. As such, we suggest that satellite observations of CDOM in these Arctic regions should not be used to represent in-situ conditions beyond a ± 60 h timeframe.

REORGANIZATION OF SOIL MATERIALS IN THE GENESIS OF AN ACID LUVISOLIC SOIL OF THE PEACE RIVER REGION, ALBERTA

1978 ◽  
Vol 58 (2) ◽  
pp. 209-220 ◽  
Author(s):  
S. PAWLUK ◽  
M. DUDAS
Keyword(s):  
Iron Oxides ◽  
Low Ph ◽  
Parent Material ◽  
Acidic Condition ◽  
Base Saturation ◽  
Biological Processes ◽  
Freeze Thaw ◽  
Peace River ◽  
River Region ◽  
Microscopic Investigations

The Boundary soil is described as a "podzolic complex" developed from acidic parent material derived from shale of Cretaceous age. The soil has low pH and base saturation values that result from the formation of sulfates, primarily natrojarosite, and its subsequent alteration in the soil solum to various forms of hydrated iron oxides. The iron oxides impart to the B horizon reddish hues of high chroma. The acidic condition has resulted in weathering of clay-sized mica to vermiculite, especially in the upper part of the solum. Results from micromorphological and analytical studies also show that considerable clay and, to a much lesser extent, organically combined iron and aluminum have been leached from the upper solum and deposited throughout the lower solum and C horizon. Reorganization of clay through illuviation appears to extend well into the C horizon. Microscopic investigations show strong reorganization of materials in the upper solum to a granic–granoidic fabric by biological processes and in the middle solum to granoidic and metafragmic fabrics, probably through coalescence of granic units by freeze–thaw processes.

scholarly journals Morphological features, productivity and pollution state of abandoned agricultural soils in the Russian Arctic (Yamal Region)

One Ecosystem ◽  
2021 ◽  
Vol 6 ◽  
Author(s):  
Timur Nizamutdinov ◽  
Evgeny Abakumov ◽  
Evgeniya Morgun
Keyword(s):  
Organic Matter ◽  
Food Security ◽  
Trace Metals ◽  
Agricultural Soils ◽  
Morphological Features ◽  
The Arctic ◽  
Arctic Regions ◽  
Northern Regions ◽  
Essential Contribution ◽  
High Level

Recently, questions about the return of the concept of Arctic agriculture in order to promote sustainable development of the northern regions and ensure food security have been raised more often. The re-involvement of previously-used and abandoned soils into agricultural usage can provide an essential contribution for the development of the Arctic regions. We conducted a comprehensive research of soils with different levels of abandonment in the central part of the Yamal Region (Russia) and compared their morphological features, chemical and physical properties, fertile qualities and the level of contamination with heavy and trace metals to background soils of the region. It has been noted that there are no evident features of cryoturbation processes in the profiles of abandoned agricultucal soils and regular changes in the redox regime, as a consequence of the presence of reductimorphic spots in the soil profiles, have been recorded. Soil organic matter (SOM) stock in the topsoil of abandoned soils is estimated as medium and has a similar level to the stocks of total organic matter in the agricultural soils of the Arctic circumpolar region (Norway, Sweden, and Finland). Statistically significant differences in the content of nutrients between abandoned and background soils were recorded which indicates stability of the soil nutritional state during different abandoned states. Particularly notable are the differences between the content of available forms of phosphorus. The results of the study revealed significant differences between soils of various periods of abandonment and the background soils of the Yamal Region. Abandoned soils can be used for ground and greenhouse agriculture, these soils having a high level of fertility and are not limited for use in agriculture by the level of contamination with heavy and trace metals. According to the character of trace metal contamination, abandoned and background soils are evaluated as uncontaminated on the base of Zc and Igeo indices values. Reuse of the previously abandoned soils can undoubtedly become the basis for increasing agricultural production and ensuring food security in the Yamal Region.

Decolorisation of natural organic matter by Phanerochaete chrysosporium: the effect of environmental conditions

2004 ◽  
Vol 4 (4) ◽  
pp. 175-182 ◽  
Author(s):  
K. Rojek ◽  
F.A. Roddick ◽  
A. Parkinson
Keyword(s):  
Organic Matter ◽  
Ionic Strength ◽  
Natural Organic Matter ◽  
Phanerochaete Chrysosporium ◽  
Fungal Growth ◽  
Low Ph ◽  
Colour Removal ◽  
Humic Material ◽  
Carbon And Nitrogen ◽  
Carbon And Nitrogen Content

Phanerochaete chrysosporium was shown to rapidly decolorise a solution of natural organic matter (NOM). The effect of various parameters such as carbon and nitrogen content, pH, ionic strength, NOM concentration and addition of Mn2+ on the colour removal process was investigated. The rapid decolorisation was related to fungal growth and biosorption rather than biodegradation as neither carbon nor nitrogen limitation, nor Mn2+ addition, triggered the decolorisation process. Low pH (pH 3) and increased ionic strength (up to 50 g L‒1 added NaCl) led to greater specific removal (NOM/unit biomass), probably due to increased electrostatic bonding between the humic material and the biomass. Adsorption of NOM with viable and inactivated (autoclaved or by sodium azide) fungal pellets occurred within 24 hours and the colour removal depended on the viability, method of inactivation and pH. Colour removal by viable pellets was higher under the same conditions, and this, combined with desorption data, confirmed that fungal metabolic activity was important in the decolorisation process. Overall, removals of up to 40–50% NOM from solution were obtained. Of this, removal by adsorption was estimated as 60–70%, half of which was physicochemical, the other half metabolically-dependent biosorption and bioaccumulation. The remainder was considered to be removed by biodegradation, although some of this may be ascribed to bioaccumulation and metabolically-dependent biosorption.

scholarly journals Adaptation of Lactobacillus plantarum IMDO 130201, a Wheat Sourdough Isolate, to Growth in Wheat Sourdough Simulation Medium at Different pH Values through Differential Gene Expression

2011 ◽  
Vol 77 (10) ◽  
pp. 3406-3412 ◽  
Author(s):  
Gino Vrancken ◽  
Luc De Vuyst ◽  
Tom Rimaux ◽  
Joke Allemeersch ◽  
Stefan Weckx
Keyword(s):  
Gene Expression ◽  
Lactobacillus Plantarum ◽  
Differential Gene Expression ◽  
Lipoteichoic Acid ◽  
Low Ph ◽  
Exponential Growth Phase ◽  
Cellular Mechanisms ◽  
Content Type ◽  
Ph Values ◽  
Differential Gene

ABSTRACTSourdough is a very competitive and challenging environment for microorganisms. Usually, a stable microbiota composed of lactic acid bacteria (LAB) and yeasts dominates this ecosystem. Although sourdough is rich in carbohydrates, thus providing an ideal environment for microorganisms to grow, its low pH presents a particular challenge. The nature of the adaptation to this low pH was investigated forLactobacillus plantarumIMDO 130201, an isolate from a laboratory wheat sourdough fermentation. Batch fermentations were carried out in wheat sourdough simulation medium, and total RNA was isolated from mid-exponential-growth-phase cultures, followed by differential gene expression analysis using a LAB functional gene microarray. At low pH values, an increased expression of genes involved in peptide and amino acid metabolism was found as well as that of genes involved in plantaricin production and lipoteichoic acid biosynthesis. The results highlight cellular mechanisms that allowL. plantarumto function at a low environmental pH.

scholarly journals Mechanism of Coagulation of Humic Acid in Presence of Metal Ion Coagulants at Low pH Values

1970 ◽  
Vol 73 (5) ◽  
pp. 874-878 ◽  
Author(s):  
Takao YOTSUYANAGI ◽  
Katsumi GOTO ◽  
Masaichi NAGAYAMA
Keyword(s):  
Humic Acid ◽  
Metal Ion ◽  
Low Ph ◽  
Ph Values
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