Search results for "SOI"
showing 10 items of 4823 documents
Functional diversity of decomposer organisms in relation to primary production
1998
Abstract The term `biodiversity' is claimed to lack connections to a serious scientific background. In this work, we approached the concept of biodiversity from a functional point of view by asking: “At what level of the ecological organization (species, trophic species/feeding guilds, trophic levels etc.) should reduction in biodiversity matter to bring about visible changes in ecosystem performance?” We investigate the concepts of `functional diversity' and `ecosystem performance' in relation to feeding habits (such as fungivory, detritivory etc.) of soil fauna and plant growth. After analysing the results of a number of microcosm studies, we came into the following conclusions: (i) troph…
Plant litter decomposition and microbial characteristics in volcanic soils (Mt Etna, Sicily) at different stages of development
2006
Soils at different developmental stages were sampled from eight sites on the slopes of Mt Etna, Sicily (Italy) and characterized for total C, microbial biomass and microbial respiration. The values of these parameters were greatest for the most developed soils, but differences in recent management and site characteristics limited analysis of trends with soil development across the eight sites. The decomposition kinetics of both intact leaf litter and the water-insoluble fraction of leaf litter from three common species on Etna [Etnean broom (Genista aetnensis), European chestnut (Castanea sativa), and Corsican pine (Pinus nigra)] were determined in four of the soils (the two with the smalle…
Surface soil moisture retrieval using L-band SMAP SAR data and its validation
2016
Surface soil moisture was retrieved globally by systematically correcting for the effects of vegetation and soil surface roughness. The retrieval is enabled by employing physical-models of radar forward scattering for individual vegetation types to account for vegetation scattering and absorption, and by constraining the surface roughness effect using time-series observations. The L-band SMAP multi-polarized (HH/VV/HV) σ° data acquired globally every three days were used from mid-April to early July, 2015. Assessment was conducted over 13 rigorously-chosen core validation sites covering a wide range of biomass types, biomass amount, and soil conditions. The soil moisture retrieval reached a…
Compartmentalization of gypsum and halite associated with cyanobacteria in saline soil crusts
2016
The interface between biological and geochemical components in surface crust of a saline soil was investigated using X-Ray Diffraction (XRD), and variable pressure scanning electron microscopy (SEM) in combination with Energy Dispersive X-ray Spectrometry (EDS). Mineral compounds such as halite and gypsum were identified crystallized around filaments of cyanobacteria. A total of 92 genera were identified from the bacterial community based on 16S gene pyrosequencing analysis. The occurrence of the gypsum crystals, their shapes and compartmentalization suggested that they separated NaCl from the immediate microenvironment of the cyanobacteria, and that some cyanobacteria and communities of su…
Evaluation in microcosm of biostimulation and bioaugmentation efficacy on diesel-contaminated soil
2021
Bioremediation is a promising technology for the treatment of hydrocarbon (HC) contaminated soils that is based on the biodegradation capacities of native or introduced microbial populations. Biotractability tests are essential for choosing the optimal bioremediation treatment. For this purpose, multiple microcosm tests, based on biostimulation by landfarming or bioventing and addition of nutrients, were conducted for 120 days on a soil contaminated by diesel, after assessing its intrinsic catabolic potential. An additional bioaugmentation treatment was performed for further 60 days by inoculating selected HC degrading bacteria. HC (C10-C40) concentration was monitored by GC-FID analysis an…
Analysis of emerging contaminants and nanomaterials in plant materials following uptake from soils
2017
The reuse of treated wastewater or wastewater-impacted river water is growing, particularly in arid areas, due to the climate change. As well, the disposal of sludges, biosolids or biochar as soil amendments to improve agricultural output is widely implemented in the EU. These practices can be a source of emerging contaminants and engineering nanomaterials (ENMs) to the environment and condition their incorporation to food chain that could affect human beings. This review covers current analytical techniques, instruments and methodologies used to determine emerging contaminants and ENMs from irrigation water and/or soil amendments in plants. Trends regarding sample treatment, separation and…
Long-term impact of 19 years' farmyard manure or sewage sludge application on the structure, diversity and density of the protocatechuate-degrading b…
2012
International audience; Impact of long-term biosolids application on soil-living micro-organisms key players of ecosystemic services is scarcely reported. Here, the impact of the 19 year-long application of farmyard manure (FM) and sewage sludge (SS) organic fertilisation regimes on the protocatechuate-degrading bacterial (pca) community was estimated by comparison to a mineral fertilisation regime (U). The structure, diversity and density of the pca community were determined using pcaH, a gene encoding the protocatechuate 3,4-dioxygenase. Ten years after the last application, the structure of the pca community in soils amended with 55100 (100 t/ha/2 years) and to a lesser extent with FM (1…
Spatial patterns of bacterial taxa in nature reflect ecological traits of deep branches of the 16S rRNA bacterial tree
2009
International audience; Whether bacteria display spatial patterns of distribution and at which level of taxonomic organization such patterns can be observed are central questions in microbial ecology. Here we investigated how the total and relative abundances of eight bacterial taxa at the phylum or class level were spatially distributed in a pasture by using quantitative PCR and geostatistical modelling. The distributions of the relative abundance of most taxa varied by a factor of 2.5–6.5 and displayed strong spatial patterns at the field scale. These spatial patterns were taxon-specific and correlated to soil properties, which indicates that members of a bacterial clade defined at high t…
A multiproxy record of palaeoenvironmental conditions at the Middle Palaeolithic site of Abric del Pastor (Eastern Iberia)
2019
This paper presents a multiproxy palaeoenvironmental study from Abric del Pastor (Alcoy, Spain), a rock shelter which has yielded evidence for Middle Palaeolithic human occupation. The sedimentary sequence has been analysed for lipid biomarker n-alkane abundances (ACL, CPI), compound specific leaf wax δH and δC, and bulk organic geochemistry (TOC, %N, %S), providing a record of past climate and local vegetation dynamics. Site formation processes have been reconstructed through the application of soil micromorphology. Analyses of anthracological, microvertebrate and macrofaunal assemblages from selected subunits are also presented here. Our data indicates that a variable climate marked by pr…
Soil microbial activity and functional diversity in primeval beech forests
2015
Virgin forests are unique ecosystems, which can be used as etalon for basic biocoenotic investigation. Soil microorganisms are very sensitive reagents on influence of biotical factors, and at the same time are the active producers of phytotoxic and phytostimulating exometabolites. Studies of soil microbiota were conducted in virgin beech forests of Shyrokoluzhansky massif of the Carpathian Biosphere Reserve. It was found the ratio and the number of different ecological-trophic groups of soil microorganisms changes with altitude. So the number of ammonificators with increasing of altitude above sea level was reduced. The soil at altitude of 1,100 meters above sea level was characterized by m…