scholarly journals Iron-catalysed oxidation and halogenation of organic matter in nature

2015 ◽  
Vol 12 (4) ◽  
pp. 381 ◽  
Author(s):  
Peter Comba ◽  
Marion Kerscher ◽  
Torsten Krause ◽  
Heinz Friedrich Schöler
Keyword(s):  
Organic Matter ◽  
Ozone Depletion ◽  
Terrestrial Ecosystems ◽  
Formation Mechanisms ◽  
Mechanistic Studies ◽  
Biomimetic Chemistry ◽  
Fenton Chemistry ◽  
Volatile Hydrocarbons ◽  
Recent Advances ◽  
Catalysed Oxidation

Environmental context Natural organohalogens produced in and released from soils are of utmost importance for ozone depletion in the stratosphere. Formation mechanisms of natural organohalogens are reviewed with particular attention to recent advances in biomimetic chemistry as well as in radical-based Fenton chemistry. Iron-catalysed oxidation in biotic and abiotic systems converts organic matter in nature to organohalogens. Abstract Natural and anthropogenic organic matter is continuously transformed by abiotic and biotic processes in the biosphere. These reactions include partial and complete oxidation (mineralisation) or reduction of organic matter, depending on the redox milieu. Products of these transformations are, among others, volatile substances with atmospheric relevance, e.g. CO2, alkanes and organohalogens. Natural organohalogens, produced in and released from soils and salt surfaces, are of utmost importance for stratospheric (e.g. CH3Cl, CH3Br for ozone depletion) and tropospheric (e.g. Br2, BrCl, Cl2, HOCl, HOBr, ClNO2, BrNO2 and BrONO2 for the bromine explosion in polar, marine and continental boundary layers, and I2, CH3I, CH2I2 for reactive iodine chemistry, leading to new particle formation) chemistry, and pose a hazard to terrestrial ecosystems (e.g. halogenated carbonic acids such as trichloroacetic acid). Mechanisms for the formation of volatile hydrocarbons and oxygenated as well as halogenated derivatives are reviewed with particular attention paid to recent advances in the field of mechanistic studies of relevant enzymes and biomimetic chemistry as well as radical-based processes.

scholarly journals Linking Genes to Traits in Fungi

2021 ◽  
Author(s):  
A. L. Romero-Olivares ◽  
E. W. Morrison ◽  
A. Pringle ◽  
S. D. Frey
Keyword(s):  
Organic Matter ◽  
Nitrogen Uptake ◽  
Brown Rot ◽  
Terrestrial Ecosystems ◽  
Organic Matter Decomposition ◽  
Gene Frequencies ◽  
Ecological Processes ◽  
Linked Gene ◽  
Carbon Cycles ◽  
Brown Rot Fungi

AbstractFungi are mediators of the nitrogen and carbon cycles in terrestrial ecosystems. Examining how nitrogen uptake and organic matter decomposition potential differs in fungi can provide insight into the underlying mechanisms driving fungal ecological processes and ecosystem functioning. In this study, we assessed the frequency of genes encoding for specific enzymes that facilitate nitrogen uptake and organic matter decomposition in 879 fungal genomes with fungal taxa grouped into trait-based categories. Our linked gene-trait data approach revealed that gene frequencies vary across and within trait-based groups and that trait-based categories differ in trait space. We present two examples of how this linked gene-trait approach can be used to address ecological questions. First, we show that this type of approach can help us better understand, and potentially predict, how fungi will respond to environmental stress. Specifically, we found that trait-based categories with high nitrogen uptake gene frequency increased in relative abundance when exposed to high soil nitrogen enrichment. Second, by comparing frequencies of nitrogen uptake and organic matter decomposition genes, we found that most ectomycorrhizal fungi in our dataset have similar gene frequencies to brown rot fungi. This demonstrates that gene-trait data approaches can shed light on potential evolutionary trajectories of life history traits in fungi. We present a framework for exploring nitrogen uptake and organic matter decomposition gene frequencies in fungal trait-based groups and provide two concise examples on how to use our framework to address ecological questions from a mechanistic perspective.

scholarly journals Soil Pollution vs. Soil Collembola as a Bioindicator: A review

2010 ◽  
Vol 2 (5) ◽  
pp. 1-11
Author(s):  
Atreyee Sahana
Keyword(s):  
Organic Matter ◽  
Soil Health ◽  
Soil Formation ◽  
Terrestrial Ecosystems ◽  
Soil Types ◽  
Natural Soil ◽  
Natural Health ◽  
Arthropod Fauna ◽  
Mineral Components ◽  
Inorganic Mineral

Soil is the foundation of all life activities in terrestrial ecosystems. Soil micro arthropod groups (less than 2 mm in size) like Acari and Collembola comprise more than 90% of arthropod fauna in most soil types. They majorly help in soil formation by breaking up the organic matter and mixing it up with inorganic mineral components. Among them, various species of Collembola have been proved to be effective bioindicator tool to measure soil health either it is polluted or not by its several characteristics in temperate countries. Therefore, in today’s world where pollution in soil by various agents is a baffling issue like other environmental pollutions, these natural soil inhabitants can make a hope to measure the natural health of soil.

Kinetic and mechanistic studies of Rh(III)-catalysed oxidation of D-xylose and L-sorbose by N-bromoacetamide in perchloric acid medium

2011 ◽  
Vol 8 (3) ◽  
pp. 622-635
Author(s):  
A. K. Singh ◽  
S. Yadav ◽  
J. Srivastava ◽  
S. Rahmani ◽  
R. K. Singh ◽  
...  
Keyword(s):  
Acid Medium ◽  
Perchloric Acid ◽  
Mechanistic Studies ◽  
Catalysed Oxidation

scholarly journals Compositional and chemical characteristics of dissolved organic matter in various types of cropped and natural Chinese soils

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Songyan Li ◽  
Meng Li ◽  
Guoxi Wang ◽  
Xiaolei Sun ◽  
Beidou Xi ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Soil Type ◽  
Spectral Characteristics ◽  
Terrestrial Ecosystems ◽  
Soil Types ◽  
Chemical Characteristics ◽  
Natural Soils ◽  
Red Soils ◽  
Chernozem Soils

Abstract Background Exploration of composition and chemical characteristics of soil dissolved organic matter (DOM) is significant to understand its biogeochemical role in terrestrial ecosystems. A total of 43 cropped and 16 natural soils (0–20 cm) under four soil types (cinnamon, chernozem, red and paddy soils) across China were collected to investigate the spectral characteristics of DOM using UV–Vis and 3D-EEM spectroscopy. Results The chernozem soils exhibited the highest aromaticity and humification degree among the four soil types. Ranges of biological index (BIX, 0.53–1.17) and fluorescence index (FI, 1.55–2.10) were found in the investigated DOM, showing joint contribution from allochthonous and autochthonous sources. Higher BIX and FI in the DOM of the paddy and red soils indicated a greater reliance on autochthonous sources for these two soil types. The cropped soils showed no significant differences in chemical characteristics and sources from the natural soils for the cinnamon, chernozem and red soils. UVA (16.2–47.9%) and UVC fulvic-like substances (15.4–40.5%) were the prevailing DOM components, which were highest in the chernozem soils. Additionally, the cropped soils had a higher proportion of humic-like substances than the natural soils in the DOM. Conclusions Both soil type and land-use strongly affected the chemical characteristics of soil DOM, but only soil type had an impact on the DOM composition for the collected soils. These findings may contribute to the prediction of the biochemical behavior of soil DOM under different soil types and land-uses in terrestrial ecosystems.

scholarly journals Stratospheric ozone depletion during the 1995–1996 Arctic winter: 3-D simulations on the potential role of different PSC types

2001 ◽  
Vol 19 (9) ◽  
pp. 1163-1181 ◽  
Author(s):  
J. Hendricks ◽  
F. Baier ◽  
G. Günther ◽  
B. C. Krüger ◽  
A. Ebel
Keyword(s):  
Ozone Depletion ◽  
Middle Atmosphere ◽  
Spatial Scales ◽  
Stratospheric Ozone ◽  
Three Dimensional ◽  
Particle Growth ◽  
Atmospheric Composition ◽  
Formation Mechanisms ◽  
Three Dimensional Model ◽  
Type Ia

Abstract. The sensitivity of modelled ozone depletion in the winter Arctic stratosphere to different assumptions of prevalent PSC types and PSC formation mechanisms is investigated. Three-dimensional simulations of the winter 1995/96 are performed with the COlogne Model of the Middle Atmosphere (COMMA) by applying different PSC microphysical schemes. Model runs are carried out considering either liquid or solid PSC particles or a combined microphysical scheme. These simulations are then compared to a model run which only takes into account binary sulfate aerosols. The results obtained with the three-dimensional model agree with trajectory-box simulations performed in previous studies. The simulations suggest that conditions appropriate for type Ia PSC existence (T < TNAT ) occur over longer periods and cover larger areas when compared to conditions of potential type Ib PSC existence. Significant differences in chlorine activation and ozone depletion occur between the simulations including only either liquid or solid PSC particles. The largest differences, occurring over large spatial scales and during prolonged time periods, are modelled first, when the stratospheric temperatures stay below TNAT , but above the threshold of effective liquid particle growth and second, in the case of the stratospheric temperatures remaining below this threshold, but not falling below the ice frost point. It can be generally concluded from the present study that differences in PSC microphysical schemes can cause significant fluctuations in ozone depletion modelled for the winter Arctic stratosphere.Key words. Atmospheric composition and structure (aerosols and particles; cloud physics and chemistry; middle atmosphere composition and chemistry)

scholarly journals Large-scale genome sequencing of mycorrhizal fungi provides insights into the early evolution of symbiotic traits

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Shingo Miyauchi ◽  
Enikő Kiss ◽  
Alan Kuo ◽  
Elodie Drula ◽  
Annegret Kohler ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Transposable Elements ◽  
Genome Sequencing ◽  
Mycorrhizal Fungi ◽  
Large Scale ◽  
Terrestrial Ecosystems ◽  
Pathogenic Species ◽  
Fungal Genomes ◽  
Induced Genes

Abstract Mycorrhizal fungi are mutualists that play crucial roles in nutrient acquisition in terrestrial ecosystems. Mycorrhizal symbioses arose repeatedly across multiple lineages of Mucoromycotina, Ascomycota, and Basidiomycota. Considerable variation exists in the capacity of mycorrhizal fungi to acquire carbon from soil organic matter. Here, we present a combined analysis of 135 fungal genomes from 73 saprotrophic, endophytic and pathogenic species, and 62 mycorrhizal species, including 29 new mycorrhizal genomes. This study samples ecologically dominant fungal guilds for which there were previously no symbiotic genomes available, including ectomycorrhizal Russulales, Thelephorales and Cantharellales. Our analyses show that transitions from saprotrophy to symbiosis involve (1) widespread losses of degrading enzymes acting on lignin and cellulose, (2) co-option of genes present in saprotrophic ancestors to fulfill new symbiotic functions, (3) diversification of novel, lineage-specific symbiosis-induced genes, (4) proliferation of transposable elements and (5) divergent genetic innovations underlying the convergent origins of the ectomycorrhizal guild.

scholarly journals Strong warming of subarctic forest soil deteriorated soil structure via carbon loss – Indications from organic matter fractionation

2019 ◽  
Author(s):  
Christopher Poeplau ◽  
Páll Sigurðsson ◽  
Bjarni D. Sigurðsson
Keyword(s):  
Organic Matter ◽  
Forest Soil ◽  
Soil Structure ◽  
Terrestrial Ecosystems ◽  
Soil Mass ◽  
Soil Warming ◽  
Ecosystem Responses ◽  
Structure Changes ◽  
Northern Latitudes ◽  
Fraction Distribution

Abstract. Net loss of soil organic carbon (SOC) from terrestrial ecosystems is a likely consequence of global warming and this may affect key soil functions. Strongest changes in temperature are expected to occur at high northern latitudes, with boreal forest and tundra as prevailing land-cover types. However, specific ecosystem responses to warming are understudied. We used a natural geothermal soil warming gradient in an Icelandic spruce forest (0–17.5 °C warming intensity) to assess changes in SOC content in 0–10 cm (topsoil) and 20–30 cm (subsoil) after 10 years of soil warming. Five different SOC fractions were isolated and the amount of stable aggregates (63–2000 µm) was assessed to link SOC to soil structure changes. Results were compared to an adjacent, previously investigated warmed grassland. Soil warming had depleted SOC in the forest soil by −2.7 g kg−1 °C−1 (−3.6 % °C−1) in the topsoil and −1.6 g kg−1 °C−1 (−4.5 % °C−1) in the subsoil. Distribution of SOC in different fractions was significantly altered, with particulate organic matter and SOC in sand and stable aggregates being relatively depleted and SOC attached to silt and clay being relatively enriched in warmed soils. The major reason for this shift was aggregate break-down: topsoil aggregate mass proportion was reduced from 60.7 ± 2.2 % in the unwarmed reference to 28.9 ± 4.6 % in the most warmed soil. Across both depths, loss of one unit SOC caused a depletion of 4.5 units aggregated soil, which strongly affected bulk density (R2 = 0.91 when correlated to SOC and R2 = 0.51 when correlated to soil mass in stable aggregates). The proportion of water extractable carbon increased with decreasing aggregation, indicating an indirect SOC protective effect of aggregates > 63 µm. Topsoil changes in total SOC and fraction distribution were more pronounced in the forest than in the adjacent warmed grassland soils, due to higher and more labile initial SOC. However, no ecosystem effect was observed in the response of subsoil SOC and fraction distribution. Whole profile differences across ecosystems might thus be small. Changes in soil structure upon warming should be studied more deeply and taken into consideration when interpreting or modelling biotic responses to warming.

Estimating soilpCO2using paleosol carbonates: implications for the relationship between primary productivity and faunal richness in ancient terrestrial ecosystems

Paleobiology ◽  
2012 ◽  
Vol 38 (4) ◽  
pp. 585-604 ◽  
Author(s):  
Timothy S. Myers ◽  
Neil J. Tabor ◽  
Louis L. Jacobs ◽  
Octávio Mateus
Keyword(s):  
Organic Matter ◽  
Primary Productivity ◽  
Western Europe ◽  
Central Africa ◽  
Terrestrial Ecosystems ◽  
Upper Jurassic ◽  
Morrison Formation ◽  
Positive Correlation ◽  
Terrestrial Environments ◽  
Ancient Ecosystems

In this paper we present a method for estimating soilpCO2in ancient environments using the measured carbon-isotope values of pedogenic carbonates and plant-derived organic matter. The validity of soilpCO2estimates proves to be highly dependent on the organic δ13C values used in the calculations. Organic matter should be sourced from the same paleosol profiles as sampled carbonates to yield the most reliable estimates of soilpCO2. In order to demonstrate the potential use of soilpCO2estimates in paleoecological and paleoenvironmental studies, we compare samples from three Upper Jurassic localities. SoilpCO2estimates, interpreted as a qualitative indicator of primary paleoproductivity, are used to rank the Late Jurassic terrestrial environments represented by the Morrison Formation in western North America, the informally named Lourinhã formation in Western Europe, and the Stanleyville Group in Central Africa. Because modern terrestrial environments show a positive correlation between primary productivity and faunal richness, a similar relationship is expected in ancient ecosystems. When the relative paleoproductivity levels inferred for each study area are compared with estimates of dinosaur generic richness, a positive correlation emerges. Both the Morrison and Lourinhã formations have high inferred productivity levels and high estimated faunal richness. In contrast, the Stanleyville Group appears to have had low primary productivity and low faunal richness. Paleoclimatic data available for each study area indicate that both productivity and faunal richness are positively linked to water availability, as observed in modern terrestrial ecosystems.

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