Search results for " Organic carbon"
showing 10 items of 291 documents
Novel Autotrophic Organisms Contribute Significantly to the Internal Carbon Cycling Potential of a Boreal Lake
2018
ABSTRACT Oxygen-stratified lakes are typical for the boreal zone and also a major source of greenhouse gas emissions in the region. Due to shallow light penetration, restricting the growth of phototrophic organisms, and large allochthonous organic carbon inputs from the catchment area, the lake metabolism is expected to be dominated by heterotrophic organisms. In this study, we test this assumption and show that the potential for autotrophic carbon fixation and internal carbon cycling is high throughout the water column. Further, we show that during the summer stratification carbon fixation can exceed respiration in a boreal lake even below the euphotic zone. Metagenome-assembled genomes an…
Contribution of aerobic anoxygenic phototrophic bacteria to total organic carbon pool in aquatic system of subtropical karst catchments, Southwest Ch…
2017
Aerobic anoxygenic phototrophic bacteria may play a particular role in carbon cycling of aquatic systems. However, little is known about the interaction between aerobic anoxygenic phototrophic bacteria and hydrochemistry in groundwater-surface water exchange systems of subtropical karst catchments. We carried out a detailed study on the abundance of aerobic anoxygenic phototrophic bacteria and bacterioplankton, hydrochemistry and taxonomy of bacterioplankton in the Maocun watershed, Southwest China, an area with karst geological background. Our results revealed that bacteria are the important contributors to total organic carbon source/sequestration in the groundwater-surface water of this …
Evolution of organic carbon pools and microbial diversity in hyperarid anthropogenic soils
2016
Abstract We investigated the organic carbon pools and the microbial diversity and activity in anthropogenic terraced soils in a desert area of Southern Peru to highlight how the introduction of agriculture influences carbon evolution and storage and genetic and functional diversity of soil microbiota over time. Five sites were selected considering soils cultivated since 5, 15, 20, 35 and 65 years, sampled along the profile depth (0–20 and 20–40 cm layer). Soil and microbial parameters comprised by organic carbon pools, microbial respiration, microbial community physiological profile (CLPP) and microbial diversity (PCR-DGGE) were determined. The results showed that the highest C concentratio…
Influence of Altered Microbes on Soil Organic Carbon Availability in Karst Agricultural Soils Contaminated by Pb-Zn Tailings.
2018
Soil organic carbon (SOC) availability is determined via a complex bio-mediated process, and Pb-Zn tailings are toxic to the soil microbes that are involved in this process. Here, Pb-Zn-tailings- contaminated karst soils with different levels (paddy field > corn field > citrus field > control group) were collected to explore the intrinsic relationship between Pb-Zn tailings and microbes due to the limited microbial abundance in these soils. The SOC concentration in the paddy fields is the highest. However, based on the soil microbial diversity and sole-carbon-source utilization profiles, the rate of SOC availability, McIntosh index, Shannon-Wiener diversity index, Simpson’s diversi…
Influence of environmental pollution with creosote oil or its vapors on biomass and selected physiological groups of microorganisms
2017
Survival of microorganisms in soils from treatment facility and landfill of wooden railway sleepers contaminated with creosote oil as well as in two types of soils with different content of organic carbon, treated with creosote oil vapors, was assessed. Microbiological assays including determination of: the biomass of living microorganisms method and the number of proteolytic, lipolytic and amylolytic microorganisms were carried out under laboratory conditions. Chromatography analysis of the soil extract from railway sleepers treatment facility was performed using GC/MS. The highest biomass and the number of tested microorganisms were determined in soils from wooden railway sleepers landfil…
Organic carbon dynamics in soil particle-size separates of sandy Spodosols when forest is cleared for maize cropping
2003
Summary In southwest France, much of the forest lands on sandy Spodosols has been converted to continuous maize cropping in the last few decades. To evaluate the impacts of such change on the content and properties of the soil organic matter, we compared the amount of organic carbon and 13C natural abundance in soil and particle-size separates at three locations, selected on the basis of different contents of 0–50 μm particles (clay + silt). After three decades of cultivation, the amount of carbon from the forest pools (Cf) decreased by about 60%, attributable mainly to easily degradable material in sand-sized fractions (−70%). However, a recalcitrant residue remained in soil at a constant …
Water-extractable organic matter linked to soil physico-chemistry and microbiology at the regional scale
2015
10 pages; International audience; A better understanding of the links between dissolved organic matter and biogeochemical processes in soil could help in evaluating global soil dynamics. To assess the effects of land cover and parental material on soil biogeochemistry, we studied 120 soil samples collected from various ecosystems in Burgundy, France. The potential solubility and aromaticity of dissolved organic matter was characterised by pressurised hot-water extraction of organic carbon (PH-WEOC). Soil physico-chemical characteristics (pH, texture, soil carbon and nitrogen) were measured, as was the δ13C signature both in soils and in PH-WEOC. We also determined bacterial and fungal abund…
The relationship between copper accumulated in vineyard calcareous soils and soil organic matter and iron
2002
Summary The intensive use for over 100 years of copper sulphate (Bordeaux mixture) to fight mildew in vineyards has led to a substantial accumulation of copper (Cu) in surface soils. To assess the effects of such large concentrations, the surface soils of 10 Burgundy vineyards were sampled and analysed for total organic matter (carbon and nitrogen) and metal (copper and iron) contents. Physical (i.e. size fractionation) and chemical (sequential extraction) methods were used to determine the distribution of these elements. The most Cu-contaminated plots showed the largest accumulation of organic carbon and Cu in the coarse sand and fine sand fractions. Copper was strongly correlated with org…
Tectonic control over large-scale diffuse degassing in eastern Sicily (Italy)
2002
Eastern Sicily (southern Italy) is characterised by the presence of many natural gas emissions (mofettes, mud volcanoes). These gases are mostly carbon dioxide and methane, with minor amounts of helium, hydrogen, carbon monoxide and hydrocarbons. In this study, the extent and orientation of soil gas anomalies (He and CO2) were investigated on a wide area (approximately 110 km2) located just SW of Mt. Etna. From a structural point of view, this area lays on a typical foredeep–foreland system that marks the boundary between the southern part of the Eurasian plate and the northern part of the African plate in the central Mediterranean. No tectonic structure was revealed in this area by surface…
Soil organic carbon stocks under recommended management practices in different soils of semiarid vineyards
2019
The Intergovernmental Panel on Climate Change (IPCC) approach is widely used to estimate the C account through the use of standardized coefficients that are not site specific. For these reasons, the aim of the work was to define specific IPCC coefficient taking into account differences in pedological characteristics that affect soil C steady state. In a vineyard area of Sicily, the effectiveness of 5 years of recommended management practice (RMP) adoption on soil organic carbon (SOC) stock increases was evaluated by considering 100 paired sites distributed over four functional soil groups. Each site consisted of two neighbouring plots. The soil of one plot was managed with cover crops accor…