scholarly journals Interactive effects of MnO2, organic matter and pH on abiotic formation of N2O from hydroxylamine in artificial soil mixtures

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Shurong Liu ◽  
Anne E. Berns ◽  
Harry Vereecken ◽  
Di Wu ◽  
Nicolas Brüggemann
Keyword(s):  
Organic Matter ◽  
Interactive Effects ◽  
Artificial Soil ◽  
Soil Mixtures

scholarly journals DOM degradation by light and microbes along the Yukon River-coastal ocean continuum

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Brice K. Grunert ◽  
Maria Tzortziou ◽  
Patrick Neale ◽  
Alana Menendez ◽  
Peter Hernes
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Salinity Gradient ◽  
Coastal Ocean ◽  
Interactive Effects ◽  
The Arctic ◽  
Yukon River ◽  
Spring Freshet ◽  
Dom Composition

AbstractThe Arctic is experiencing rapid warming, resulting in fundamental shifts in hydrologic connectivity and carbon cycling. Dissolved organic matter (DOM) is a significant component of the Arctic and global carbon cycle, and significant perturbations to DOM cycling are expected with Arctic warming. The impact of photochemical and microbial degradation, and their interactive effects, on DOM composition and remineralization have been documented in Arctic soils and rivers. However, the role of microbes, sunlight and their interactions on Arctic DOM alteration and remineralization in the coastal ocean has not been considered, particularly during the spring freshet when DOM loads are high, photoexposure can be quite limited and residence time within river networks is low. Here, we collected DOM samples along a salinity gradient in the Yukon River delta, plume and coastal ocean during peak river discharge immediately after spring freshet and explored the role of UV exposure, microbial transformations and interactive effects on DOM quantity and composition. Our results show: (1) photochemical alteration of DOM significantly shifts processing pathways of terrestrial DOM, including increasing relative humification of DOM by microbes by > 10%; (2) microbes produce humic-like material that is not optically distinguishable from terrestrial humics; and (3) size-fractionation of the microbial community indicates a size-dependent role for DOM remineralization and humification of DOM observed through modeled PARAFAC components of fluorescent DOM, either through direct or community effects. Field observations indicate apparent conservative mixing along the salinity gradient; however, changing photochemical and microbial alteration of DOM with increasing salinity indicate changing DOM composition likely due to microbial activity. Finally, our findings show potential for rapid transformation of DOM in the coastal ocean from photochemical and microbial alteration, with microbes responsible for the majority of dissolved organic matter remineralization.

Research on Some Physicochemical Parameters of Artificially Created Soil Mixtures

2020 ◽  
Vol 24 (9) ◽  
pp. 27-31
Author(s):  
E.A. Pendyurin ◽  
S.Yu. Rybina ◽  
L.M. Smolenskaya ◽  
M.M. Latypova
Keyword(s):  
Industrial Waste ◽  
Cultural Landscapes ◽  
Humus Content ◽  
Harmful Effect ◽  
Artificial Soil ◽  
Plant Residues ◽  
Winter Period ◽  
Natural Soil ◽  
Soil Mixture ◽  
Soil Mixtures

Compositions of artificial soil mixtures, including sand, clay, defecation mud, waste from wet magnetic separation and plant residues in different proportions have been developed. The components were preliminarily comminuted by an auger-drill in order to obtain a homogeneous composition with subsequent granulation, stored in natural conditions in the autumn-winter period, followed by filling in experimental vessels. No any phytotoxic effect for the initial components and for all analyzed samples of the obtained artificial soil mixtures was detected. The chemical composition and some physicochemical properties of artificial soil mixtures, such as density, deposit of moisture and humus content, were determined. It was shown that the samples of the obtained soil mixtures are close to the control (dark gray forest soil of the Belgorod region) and can be recommended for further use in creating cultural landscapes as a substitute for natural soil. The developed type of artificial soil mixtures is suitable for the cultivation of bulbous crops; moreover, a large increase in yield in comparison with the control for some compositions was found. Artificially created soil mixtures reduce the harmful effect on the environment by eliminating the storage of industrial waste such as iron ore and food, plant residues used in the composition of the artificial soil mixture. Artificial soil mixture can be used for remediation of technologically disrupted areas, which will allow restoring disturbed lands and reducing man-caused impact on solid waste landfills. The addition of industrial waste allows them to be re-involved in the technological cycle, which contributes to the development of low-waste and waste-free technologies. The results obtained indicate the possibility of using the studied soil mixtures for cultivation of the decorative bulbous plants. To recommend the developed compositions for the use in agriculture, it is necessary to assess the possibility of impurity translocation from soil samples into cultivated crops.

Interactive effects of iron oxides and organic matter on charge properties of red soils in Thailand

Soil Research ◽  
2013 ◽  
Vol 51 (3) ◽  
pp. 222 ◽  
Author(s):  
D. Ketrot ◽  
A. Suddhiprakarn ◽  
I. Kheoruenromne ◽  
B. Singh
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Clay Fraction ◽  
Interactive Effects ◽  
Soil Conditions ◽  
Oxide Surfaces ◽  
Fe Oxide ◽  
Fe Oxides ◽  
Red Soils ◽  
Variable Surface

Iron (Fe) oxides and organic matter (OM) play important roles in maintaining the fertility of highly weathered soils. The main objective of this study was to investigate the interactive effects of variable surface charge minerals, particularly Fe oxide minerals, and OM on the charge properties of red soils from Thailand. We also evaluated the effect of the 5 m NaOH procedure, used to concentrate Fe oxides from soils, on the charge characteristics of Fe oxide concentrates. Fourteen clay fractions (untreated and OM-free clay fractions), and Fe oxide concentrates of these clays, were used in the study. Cation exchange capacity (CEC) and electrophoretic mobility (EM) were measured for the soil clays, artificial mixtures, and goethite adsorbed with humic acid (HA) and phosphate (P). Kaolinite and Fe oxides (predominantly a mixture of hematite and goethite) were the main minerals in the clay fraction. Results indicated that OM or metal–OM complexes may have blocked or neutralised negatively charged sites on clay minerals. After OM removal these sites became accessible, inducing an increase in CEC and shifting the EM values towards more negative values and the isoelectric point (IEP) towards lower pH for many samples. The CEC values of Fe oxide concentrates prepared by 5 m NaOH treatment were overestimated and their EM and IEP shifted towards more negative values. It is possible that the amorphous phase from clay dissolution was still present in the Fe oxide concentrates, or the adsorption of silicate ions modified the surfaces of Fe oxides concentrates. Humic acid and P adsorbed on Fe oxide surfaces caused the IEP to shift to lower values. In natural soil conditions, a variety of anions can be adsorbed on Fe oxide surfaces, which might lead to higher values of negative charge and lower IEP than observed for pure synthetic minerals.

scholarly journals Characterization of the interactive effects of labile and recalcitrant organic matter on microbial growth and metabolism

2019 ◽  
Author(s):  
Lauren N. M. Quigley ◽  
Abigail Edwards ◽  
Andrew D. Steen ◽  
Alison Buchan
Keyword(s):  
Organic Matter ◽  
Marine Bacteria ◽  
Interactive Effects ◽  
Specific Substrate ◽  
Growth Responses ◽  
Metabolic Potential ◽  
Labile Organic Matter ◽  
Casamino Acids ◽  
Geochemical Models ◽  
Species Specific

AbstractGeochemical models typically represent organic matter (OM) as consisting of multiple, independent pools of compounds, each accessed by microorganisms at different rates. However, recent findings indicate that organic compounds can interact within microbial metabolisms. The relevance of interactive effects within marine systems is debated and a mechanistic understanding of its complexities, including microbe-substrate relationships, is lacking. As a first step toward uncovering mediating processes, the interactive effects of distinct pools of OM on the growth and respiration of marine bacteria, individual strains and a simple, constructed community of Roseobacter lineage members were tested. Isolates were provided with natural organic matter (NOM) and different concentrations (1, 4, 40, 400 μM-C) and forms of labile organic matter (acetate, casamino acids, tryptone, coumarate). The microbial response to the mixed substrate regimes was assessed using viable counts and respiration in two separate experiments. Two marine bacteria and a six-member constructed community were assayed with these experiments. Both synergistic and antagonistic growth responses were evident for all strains, but all were transient. The specific substrate conditions promoting a response, and the direction of that response, varied amongst species. These findings indicate that the substrate conditions that result in OM interactive effects are both transient and species-specific and thus influenced by both the composition and metabolic potential of a microbial community.

Interaction of minerals, organic matter, and microorganisms during biogeochemical interface formation as shown by a series of artificial soil experiments

2016 ◽  
Vol 53 (1) ◽  
pp. 9-22 ◽  
Author(s):  
Geertje J. Pronk ◽  
Katja Heister ◽  
Cordula Vogel ◽  
Doreen Babin ◽  
Jörg Bachmann ◽  
...  
Keyword(s):  
Organic Matter ◽  
Artificial Soil ◽  
Interface Formation

scholarly journals The Regulation by Phenolic Compounds of Soil Organic Matter Dynamics under a Changing Environment

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Kyungjin Min ◽  
Chris Freeman ◽  
Hojeong Kang ◽  
Sung-Uk Choi
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Environmental Changes ◽  
N Deposition ◽  
Interactive Effects ◽  
Plant Metabolites ◽  
Regulatory Effects ◽  
Dynamics Models ◽  
The Relationship

Phenolics are the most abundant plant metabolites and are believed to decompose slowly in soils compared to other soil organic matter (SOM). Thus, they have often been considered as a slow carbon (C) pool in soil dynamics models. Here, however, we review changes in our concept about the turnover rate of phenolics and quantification of different types of phenolics in soils. Also, we synthesize current research on the degradation of phenolics and their regulatory effects on decomposition. Environmental changes, such as elevated CO2, warming, nitrogen (N) deposition, and drought, could influence the production and form of phenolics, leading to a change in SOM dynamics, and thus we also review the fate of phenolics under environmental disturbances. Finally, we propose the use of phenolics as a tool to control rates of SOM decomposition to stabilize organic carbon in ecosystems. Further studies to clarify the role of phenolics in SOM dynamics should include improving quantification methods, elucidating the relationship between phenolics and soil microorganisms, and determining the interactive effects of combinations of environmental changes on the phenolics production and degradation and subsequent impact on SOM processing.

scholarly journals Physicochemical changes in pyrogenic organic matter (biochar) after 15 months of field aging

Solid Earth ◽  
2014 ◽  
Vol 5 (2) ◽  
pp. 693-704 ◽  
Author(s):  
A. Mukherjee ◽  
A. R. Zimmerman ◽  
R. Hamdan ◽  
W. T. Cooper
Keyword(s):  
Organic Matter ◽  
Crop Yields ◽  
Physicochemical Characteristics ◽  
Exchange Capacity ◽  
Interactive Effects ◽  
Sem Images ◽  
Physicochemical Changes ◽  
13C Nuclear Magnetic Resonance ◽  
Pyrogenic Organic Matter ◽  
Over Time

Abstract. Predicting the effects of pyrogenic organic matter (OM) addition (either natural or intentional as in the case of biochar amendment) on soil chemistry and crop yields has been hampered by a lack of understanding of how pyrogenic OM evolves in the environment over time. This work compared the physicochemical characteristics of newly made and 15-month-field-aged biochars and biochar–soil mixtures. After aging, biochars made by pyrolysis of wood and grass at 250, 400 and 650 °C exhibited 5-fold increases in cation exchange capacity (CEC), on average; appearance of anion exchange capacity (AEC); and significant decreases in pH, ash content and nanopore surface area. Cross polarization 13C nuclear magnetic resonance (NMR) analyses indicated relative increases in O-containing functional groups, including substituted aryl, carboxyl and carbonyl C, and losses of O-alkyl groups. Similar chemical trends were observed for soil–biochar mixtures, suggesting the same biochar aging processes occurred in the soil environment. However, there was evidence for a role of soil OM–microbe–biochar interaction during aging. Field aging of soil with biochar resulted in large increases in C and N content (up to 124 and 143%, respectively) and exchange capacity (up to 43%) beyond that calculated by the weighted addition of the properties of biochar and soil aged separately. These beneficial interactive effects varied with soil and biochar type. Scanning electronic microscopy (SEM) images of biochar particles aged with soil showed colonization by microbes and widespread OM coatings. Thus, sorption of both microbially produced and soil OM are likely processes that enhanced biochar aging. Thus, biochar's full beneficial effects on soil properties likely increase over time, and proper assignment of C sequestration credits to biochar users will require consideration of soil–biochar interactions.

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