Microarthropod communities in anthropogenic urban soils. 1. Structure of microarthropod complexes in soils of roadside lawns

The structure and abundance of microarthropod communities in soils of roadsides in the city of Vilnius were studied. Soil samples were taken from lawns on roadside slopes and in roundabout junctions, at the curb and at a distance of 10 m from it. The abundance of microarthropods closely correlated with the degree of vegetation development: in lawns landscaped 10, 20, and 40 years ago, this parameter averaged 2300, 6500, and 49 000 ind./m², respectively. The abundance of soil microarthropods near the curb was three times lower (for some groups five times lower) than at a distance of 10 m. Oribatid species adapted to alkaline soils in such areas were identified.     

Microarthropod communities in anthropogenic urban soils. 2. Seasonal dynamics of microarthropod abundance in soils at roundabout junctions

The seasonal dynamics of microarthropods in anthropogenic soils was studied in the central lawns of roundabout junctions in the city of Vilnius. The microarthropod communities were found to suffer from the impact of automobile exhausts: their abundance was minimum at the curb and increased significantly at a distance of 10 m from it (at the center of a lawn), but it did not reach the values typical of the soil of the control plot. The dynamics of the microarthropod abundance in anthropogenically disturbed and control soils were similar, with the abundance of microarthropods increasing in the autumn-winter period (October–December). The microarthropod communities formed in the anthropogenic soils were unstable, with a high level of dominance of a few species. Oribatids Scutovertex minutus and Tectocepheus velatus, the gamasid mite Rhodacarus coronatus, and the springtail Brachystomella parvula proved to be well adapted to alkaline soils.     

Quantitative isolation of microbial DNA from the different types of soils of natural and agricultural ecosystems

A novel procedure was developed for direct quantitative isolation of microbial DNA from soil. This technique was used to evaluate microbial DNA pools in soils of contrasting types (chernozems and brown forest soils) under different anthropogenic loads. A strong correlation was found between microbial biomass and DNA contents in soils of different types (R2 = 0.799). The ratio of soil CO2 emission rate to the amount of extractable DNA in the soil was shown to reflect physiological state of the soil microbial community; this ratio can be used as an ecophysiological parameter similarly to the metabolic quotient qCO2.     

The biomass of microbial communities in different types of alluvial soils in the upper reaches of the Selenga River delta

The biomass of several groups of microbial communities occurring in three types of alluvial soils in the upper reaches of the Selenga River delta near the village of Murzino, Kabanskii district, Buryat Republic was studied. The general tendency in the dynamics of the biomass of the dominant groups of microorganisms in drought summer-autumn period of 2005 was revealed. The bacterial complex predominated at the beginning of July; actinomycete and spore-fungal complexes, at the end of August; and spore-fungal and actinomycete complexes, at the beginning of October. In the alluvial sod soil, the actinomycete mycelium biomass was dominant in July, which was caused by more droughty conditions in this facies because it is located at a higher elevation above the river level than other facies.     

Differential responses of marine communities to natural and anthropogenic changes

Responses of ecosystems to environmental changes vary greatly across habitats, organisms and observational scales. The Quaternary fossil record of the Po Basin demonstrates that marine communities of the northern Adriatic re-emerged unchanged following the most recent glaciation, which lasted approximately 100 000 years. The Late Pleistocene and Holocene interglacial ecosystems were both dominated by the same species, species turnover rates approximated predictions of resampling models of a homogeneous system, and comparable bathymetric gradients in species composition, sample-level diversity, dominance and specimen abundance were observed in both time intervals. The interglacial Adriatic ecosystems appear to have been impervious to natural climate change either owing to their persistence during those long-term perturbations or their resilient recovery during interglacial phases of climate oscillations. By contrast, present-day communities of the northern Adriatic differ notably from their Holocene counterparts. The recent ecosystem shift stands in contrast to the long-term endurance of interglacial communities in face of climate-driven environmental changes.     

Priming effect in semi-arid soils of northern Ethiopia under different land use types

Biogeochemistry - Input of organic carbon (C) to the soil stimulates soil microbial activity leading to changes in turnover of soil organic matter, a phenomenon referred to as priming effect (PE)....     

Dissipation of phorate in different types of soils

Summary Studies on the dissipation of phorate in different types of soils of Kerala, India, were carried out. The residues of the insecticide persisted most in the forest soil followed by alluvial, red, laterite and sandy soils in the descending order. The half-life periods of the insecticide estimated by chemical and bioassay methods approximated to one another. Correlations of the persistence of the insecticide with the properties of the soil revealed that organic matter played a dominant role in prolonging the persistence of the insecticide in the soils.Part of Ph.D. thesis of Senior author presented to Kerala Agricultural University, Vellanikkara, Trichur District, Kerala State, India.     

Temporal changes in therophytic communities across the boundary of disturbed-intact ecosystems

External control processes cause continual compositional and structural readjustments of Mediterranean pasture ecosystems. Such control processes include herbivore grazing, meteorological fluctuations and traditional management activities, which determine the stable environment where the succession occurs. Traditional management in this ecosystem frequently involves periodic ploughing or controlled fires.Experimental disturbances were applied to pastures of different maturity. Recovery was studied by relating information gathered for each disturbed system to successional age. The boundary between original systems of differing ages and the newly created systems was studied to compare the space-time evolution of therophytic communities. Permanent transects perpendicular to the disturbance boundaries and containing many small plots were sampled during consecutive years.Sampling plots located on both sides of the boundaries were classified into communities, in order to detect the space-time pasture evolution in successive years. Annual conditional probabilities were calculated for transitions between the recognised communities. During succession different strategies were detected in response to meteorological variations. In pioneer successional stages, substitutions of one community by another in the same space seem to be random. However, greater determinism was detected in more mature pastures, where, in addition, communities' abundance does not respond to meteorological change.Nomenclature follows T. G. Tutin et al. 1964–1980. Flora Europaea. Cambridge University Press, Cambridge.     

A preliminary study on the effect of Cu,Pb and Zn contamination of soils on community structure and certain life-history traits of oribatids from urban areas

The effect of pollution of urban soils by traffic exhausts on oribatid mites was studied along a traffic gradient of the city of Thessaloniki. Although the population density of the main orbatid species appeared increased in polluted areas, the total orbatid numbers were reduced due to the reduction in species richness. The highest species diversity was recorded in moderately polluted areas. The morphometric characteristics as well as certain life-history traits did no correlate with the level of traffic influence. Nevertheless, these characteristics were considered important for the understanding of the pollution impact on life in soils. Moderate body size, sexual reproduction, increased reproductive effort and wide habitat preferences characterize species in urban sites. Scheloribates latipes and Tectocepheus sarekensis can be used as bioindicators for Pb and Zn pollution of soils, respectively.     

Arbuscular mycorrhizal symbiosis on serpentine soils: the effect of native fungal communities on different Knautia arvensis ecotypes

Serpentine soils represent a unique environment that imposes multiple stresses on vegetation (low Ca/Mg ratios, macronutrient deficiencies, elevated heavy metal concentrations and drought). Under these conditions, a substantial role of arbuscular mycorrhizal (AM) symbiosis can be anticipated due to its importance for plant nutrition and stress alleviation. We tested whether serpentine and non-serpentine populations of Knautia arvensis (Dipsacaceae) differ in the benefits derived from native AM fungal communities. Four serpentine and four non-serpentine populations were characterised in terms of mycorrhizal colonisation and soil characteristics. The serpentine populations showed significantly lower mycorrhizal colonisation than their non-serpentine counterparts. The mycorrhizal colonisation positively correlated with soil pH, Ca and K concentrations and Ca/Mg ratio. Seedlings from each population were then grown for 3 months in their sterilised native substrates, either uninoculated or reinoculated with native AM fungi. Two serpentine and two non-serpentine populations responded positively to mycorrhizal inoculation, while no significant change in plant growth was observed in the remaining populations. Contrary to our hypothesis, serpentine populations of K. arvensis did not show higher mycorrhizal growth dependence than non-serpentine populations when grown in their native soils and inoculated with native AM fungi.     

Tricholoma matsutake dominates diverse microbial communities in different forest soils

Fungal and actinobacterial communities were analyzed together with soil chemistry and enzyme activities in order to profile the microbial diversity associated with the economically important mushroom Tricholoma matsutake. Samples of mycelium-soil aggregation (shiro) were collected from three experimental sites where sporocarps naturally formed. PCR was used to confirm the presence and absence of matsutake in soil samples. PCR-denaturing gradient gel electrophoresis (DGGE) fingerprinting and direct sequencing were used to identify fungi and actinobacteria in the mineral and organic soil layers separately. Soil enzyme activities and hemicellulotic carbohydrates were analyzed in a productive experimental site. Soil chemistry was investigated in both organic and mineral soil layers at all three experimental sites. Matsutake dominated in the shiro but also coexisted with a high diversity of fungi and actinobacteria. Tomentollopsis sp. in the organic layer above the shiro and Piloderma sp. in the shiro correlated positively with the presence of T. matsutake in all experimental sites. A Thermomonosporaceae bacterium and Nocardia sp. correlated positively with the presence of T. matsutake, and Streptomyces sp. was a common cohabitant in the shiro, although these operational taxonomic units (OTUs) did not occur at all sites. Significantly higher enzyme activity levels were detected in shiro soil. These enzymes are involved in the mobilization of carbon from organic matter decomposition. Matsutake was not associated with a particular soil chemistry compared to that of nearby sites where the fungus does not occur. The presence of a significant hemicellulose pool and the enzymes to degrade it indicates the potential for obtaining carbon from the soil rather than tree roots.     

Evaluation of the state of soil microbial communities in two types of Siberian forest ecosystems

Microbial respiration and biomass were evaluated in soils of the Ermak Tree Nursery and Pogorel’skii Forest under different coniferous species. The degree of disturbance of each biocenosis was determined from the metabolic coefficient (qCO₂). The microbial investigation demonstrated a lower resistance to ecological factors of the tree nursery biocenosis as compared to those of the Pogorel’skii Forest.     

Reconstruction of the historical changes in mycorrhizal fungal communities under anthropogenic nitrogen deposition.

Archived soil samples (1937-1999) and historic air quality data from the Los Angeles Basin were used for reconstructing the record of change between atmospheric NO(x) loads, soil delta(15)N values and the diversity of arbuscular mycorrhizae (AM), which are ubiquitous plant-fungus mutualists that control plant community productivity. A tripling of atmospheric NO(x) loads between 1937 and the 1970s was paralleled by soil nitrogen enrichment (delta(15)N = 3.18). From 1975 onwards, atmospheric NO(x) declined, but soils became nitrogen saturated (delta(15) N = -4 and NO(3)-nitrogen = 171mgkg(-1)). The shifts in the AM community followed 28 years of atmospheric nitrogen enrichment and coincided with the onset of soil nitrogen saturation. Such changes were manifest in the loss of AM productivity, species richness (one species per year), three genera (Acaulospora, Scutellospora and Gigaspora) in the spore community and Gigaspora within the roots. Nitrogen enrichment also enhanced the proliferation of potentially less mutualistic species of Glomus. Autoregressive models implied that such patterns will persist and be driven by soil nitrogen cycling patterns. Chronic nitrogen enrichment from air pollution thus alters the diversity and mutualistic functioning of AM communities, which, in turn, may influence the plant community.     

Predicting pre-Columbian anthropogenic soils in Amazonia

The extent and intensity of pre-Columbian impacts on lowland Amazonia have remained uncertain and controversial. Various indicators can be used to gauge the impact of pre-Columbian societies, but the formation of nutrient-enriched terra preta soils has been widely accepted as an indication of long-term settlement and site fidelity. Using known and newly discovered terra preta sites and maximum entropy algorithms (Maxent), we determined the influence of regional environmental conditions on the likelihood that terra pretas would have been formed at any given location in lowland Amazonia. Terra pretas were most frequently found in central and eastern Amazonia along the lower courses of the major Amazonian rivers. Terrain, hydrologic and soil characteristics were more important predictors of terra preta distributions than climatic conditions. Our modelling efforts indicated that terra pretas are likely to be found throughout ca 154 063 km² or 3.2% of the forest. We also predict that terra preta formation was limited in most of western Amazonia. Model results suggested that the distribution of terra preta was highly predictable based on environmental parameters. We provided targets for future archaeological surveys under the vast forest canopy and also highlighted how few of the long-term forest inventory sites in Amazonia are able to capture the effects of historical disturbance.     

三江平原不同土地利用生境步甲多样性

2007年6—9月,对三江平原地区6种不同土地利用生境下步甲群落结构进行调查,共采集步甲标本34种871号,其中淡足青步甲、暗青步甲和圆角梨须步甲分别占总数的19.4%、19.3%和13.2%,共同构成本研究区的优势类群。通过对物种丰富度、多样性指数、均匀度指数等多样性指标进行分析,丰富度在杨树林最高,白桦-蒙古栎林最低;多样性指数和均匀度指数在大豆田最高,杨树林最低。土地利用方式对步甲数量有显著影响(F=2.987,P<0.05),杨树林步甲数量最多,松树林最少;采样时间对步甲数量显著影响(F=8.172,P<0.05),9月步甲数量最多,7月最少。但土地利用方式和采样时间对步甲丰富度,多样性,均匀度没有显著影响。     

Colonization and early succession on anthropogenic soils

Abstract. This paper reports on vegetation development on permanent experimental plots during five years of succession. Nine (1 m²) plots were filled with three typical substrates from man-made habitats of urban and industrial areas in the region of Berlin. The three substrates (a commercial ‘topsoil’, a ruderal ‘landfill’ soil and a sandy soil), differ in organic matter and nutrient contents. Relevés of species composition and percent cover of each species present were made monthly during the growing season from the start of vegetation development. This paper describes the different successional pathways on topsoil and ruderal soil and the colonization process on sandy soil. On topsoil, ruderal annuals are dominant in the first year and are replaced by short-lived perennials from the second year. Those species were replaced by long-lived perennial herbs (Ballota nigra or Urtica dioica) from the third year of succession onwards. On the ruderal land-fill soil the early successional stages are less sharp and the perennial Solidago canadensis is able to dominate within one year after the succession was initiated. On sandy soil there is still an ongoing colonization process, where pioneer tree species like Betula pendula and Populus nigra play a main role. The importance of ‘initial floristic composition’, the role of substrate for community structure and the peculiarities of successional sequences on anthropogenic soils in the context of primary and secondary successions are discussed.     

Adaptation of soil bacterial communities to prevailing pH in different soils

Abstract: The bacterial community response to pH was studied for 16 soils with pH(H₂O) ranging between 4 and 8 by measuring thymidine incorporation into bacteria extracted from the soil into a solution using homogenization-centrifugation. The pH of the bacterial solution was altered to six different values with dilute sulfuric acid or different buffers before measuring incorporation. The resulting pH response curve for thymidine incorporation was used to compare bacterial communities from the different soils. There was a correlation between optimum pH for thymidine incorporation and the soil pH(H₂O). Even bacterial communities from acid soils had optima corresponding to the soil pH, indicating that they were adapted to these conditions. Thymidine incorporation was also compared with leucine incorporation for some soils. The leucine to thymidine incorporation ratio was constant over the tested pH interval when incorporation values were adjusted for isotope dilution. A good correlation was found between the scores along the first component (explaining 80% of the variation) and soil pH ( r ² = 0.85), if principal component analysis of the pH response curves for thymidine incorporation was used. The pH response curves differed most for the extreme pH values used, and a linear relationship was found between the logarithm of the ratio of thymidine incorporation at pH 4.3 to incorporation at pH 8.2 and the soil pH ( r ² = 0.86). Thus, a simplified technique using only two pH values, when measuring the thymidine incorporation, could be used to compare the response to pH of bacterial communities.     

Impacts of anthropogenic stress on rocky intertidal communities

Rocky shores provide a harsh environment for marine organisms andwe briefly discuss natural sources of variation in community structure beforeconsidering anthropogenic impacts in detail. We review impacts caused by (a) acutedisturbances: oil spills, toxic algal blooms and (b) chronic disturbances: nutrient pollution,oil, heavy metals, pesticides, antifouling paints, collecting, trampling/habitatdegradation, siltation and introduced species. Community level effects are emphasisedthroughout and illustrative examples are drawn from field-based case studies. Particularattention is given to the lessons learned from oil spills and the effect of chronicpollution by tributyltin on dogwhelks, the impacts of which ranged from the biochemical tocommunity levels of organisation. Impacts are placed in a global and historicalperspective and the potential for the recovery of shores under appropriate management isdiscussed. Finally we consider the relative merits of the multivariate and univariateapproaches to studying impacted communities and suggest priorities for future research.     

The peculiarities of cytogenetic changes in different types of myelodysplastic syndrome

A cytogenetic study of bone marrow aspirate from 32 patients with different types of myelodysplastic syndrome (MDS) has been carried out. The patients were from eight regions of Ukraine. Chromosome deletions prevailed in the spectrum of karyotype changes. The largest number of chromosome abnormalities was revealed in patients with a refractory anemia with an excess of blasts (66.6% of cases). Chromosomal changes that involved three or more chromosomes occurred among 27% of all karyotype changes examined by us. Transformation of myelodysplastic syndrome to acute myeloid leukemia (AML) was found in 5 patients (45.4% of the cases) among 11 patients with abnormal karyotypes. We propose that cytogenetic confirmation of increased apoptosis in the bone marrow from the myelodysplastic syndrome patients is a phenomenon of chromosome fragmentation. The risk of transformation of myelodysplastic syndrome to acute myeloid leukemia was measured with the use of a new international score system, IPSS.