Population number, viability, and taxonomic composition of the bacterial nanoforms in iron-manganic concretions

It is shown for the first time that a significant part of the bacteria (up to 40%) in the iron-manganic concretions of soddy-podzolic and soddy meadow soils are represented by nanoforms; their number reaches 600–700 million cells/g. Judging from the specific luminescent coloration, the fraction of viable cells among the bacterial nanoforms is very high in the concretions and amounts up to 88–99%. For the first time, the following phyla were identified among the bacterial nanoforms in the concretions with the use of the FISH method: Alphaproteobacteria, Betaproteobacteria, Gammaproteobateria, Deltaproteobacteria, Acidobacteria, and Planctomycetes. The Gammaproteobacteria phylum predominated in the concretions from the soddy-podzolic soil, and the Deltaproteobacteria phylum predominated in the concretions from the soddy meadow soil. In the alluvial meadow soil, the Alphaproteobacteria, Betaproteobacteria, and Acidobacteria phyla were found. The significant number and portion of bacterial nanoforms in the concretions, their high vitality, and their taxonomic diversity allow us to conclude that the bacterial nanoforms play an important role in the processes taking place in the concretions.     

Bacterial nanoforms of some soil concretions

For the first time ever, it is shown that, in iron-manganese concretions from sod podzolic and sod meadow soils, a significant percentage of bacteria (up to 40%) is represented by nanoforms, the quantity of which reaches 0.6–0.7 billion cells/g. The proportion of cells with undisturbed membranes is 98% higher among nanoform bacteria than in the accommodating layer. Among nanoforms of bacteria from concretions, mycoplasm-like organisms were observed using the electron microscopy method. The high proportion of bacterial nanoforms in concretions allows us to assume that they play a significant role in the process of concretion formation.     

Nitrogen Isotopes in Soils and Plants of Tundra Ecosystems in the Khibiny Mountains

Eurasian Soil Science - The isotopic composition of nitrogen in soils and plants may be an indicator of transformation of its compounds and sources of N nutrition of plants. Natural 15N abundance...     

15N Natural Abundance of Soil Microbial Biomass in Alpine and Tundra Ecosystems

Eurasian Soil Science - Isotopic composition of nitrogen in soil microbial biomass (δ15Nmicr) is connected with the transformation of nitrogen compounds and with the balance of carbon and...     

Emission of CO2 by soils in the impact zone of the Severonikel smelter in the Kola subarctic region

The intensity of the in situ soil respiration in the background northern taiga spruce forests of the Kola subarctic region reaches 120–290 mg C-CO₂/m² per h. In the impact zone of the Severonikel smelter, it decreases to 90–140, 30, and 15–30 mg C-CO₂/m² per h at the stages of spruce defoliation, spruce-birch woodland, and technogenic barrens of the technogenic succession, respectively. For the first time, the impact of the industrial pollution on root respiration has been assessed, and the dependences of the CO₂ emission, the contribution of mineral soil horizons to this process, the microbial biomass, and root respiration on the concentrations of available nickel and copper compounds have been determined. The efficiency of two remediation technologies applied to technogenic barrens near the smelter has been evaluated on the basis of four parameters of the soil biological activity. The results indicate that remediation with the creation of a new filled soil layer is more efficient than chemical and phytoremediation methods.     

The emission of carbon dioxide from soils of the Pasvik nature reserve in the Kola Subarctic

The emission of carbon dioxide (CO₂) from podzols (Albic Podzols (Arenic)) and the factors controlling its spatiotemporal variability in the forest ecosystems of the Pasvik Reserve in the Kola Subarctic are characterized. Relatively favorable climatic conditions beyond the polar circle in summer are responsible for intensive soil respiration. The type of forest affects the emission of CO₂ from the soil surface. The lowest rate of the CO₂ emission is typical of the soils under lichen pine forest (105–220 mg C/(m² h) or 180 g C/m² during the summertime). Higher rates are observed for the soils under green moss pine (170–385 mg C/(m² h) or 360 g C/m² during the summertime) and birch (190–410 mg C/(m² h) or 470 g C/m² during the summertime) forests. This may related to a higher contribution of root respiration (44, 88, and 67%, respectively). Soil respiration and the contribution of root respiration to it increase with an increase in the canopy density; mass of small roots; microbial biomass; depth of the stony layer; soil moistening; and the contents of available carbon, nitrogen, phosphorus, and potassium compounds. At the same time, they decrease with an increase in the portion of lichens in the ground cover. The seasonal dynamics are characterized by the CO₂ emission maximums in the summer and fall and minimum in the spring. The daily dynamics are smoothed under conditions of the polar day.     

Spatial Variability of Carbon Dioxide Emission by Soils in the Main Types of Forest Ecosystems at the Zvenigorod Biological Station of Moscow State University

Carbon dioxide (CO₂) emission from the soil surface in forest biogeocenoses of the Zvenigorod Biological Station of Moscow State University in summer varies on average from 120 to 350 mg C–CO₂/(m² h) and depends on the hydrothermal conditions (soil moisture and temperature) and the type of phytocenosis. The intensity of CO₂ emission in the biogeocenosis does not depend on its parcel structure and varies with respect to plant microgroups: it is maximum in oxalis pine–spruce and maple–lime forests and bracken spruce–birch forests and minimum in areas of forest fall without vegetation. The upper (from 0 to 20 cm thick) soil layer provides up to 50% of the total soil CO₂ emission. The role of microbial respiration in the total CO₂ emission from soils is determined by weather conditions and varies from 9–33% in a dry summer to 55–75% in a summer with favorable temperature and moisture.     

Transformation of Nitrogen Compounds in Soils of Mountain Tundra Ecosystems in the Khibiny

Eurasian Soil Science - The content of nitrogen compounds and processes of nitrogen mineralization and nitrification were studied in the soils of four tundra ecosystems in the Khibiny Mountains....     

Application of humic substances in the remediation of heavy-metal-polluted soils of the Subarctic Zone of the Kola Peninsula

The effect of humic substances of various origin on the behavior of heavy metals was investigated in a field model experiment on remediation of technogenic wastelands near the mining-metallurgical compplex Severonickel in the Subarctic Zone of the Kola Peninsula. Two distinct types of humates, coal and peat, were applied to the experimental sites in various doses and combinations with NPK fertilizer and lime. The combination of peat humates with lime proved the most effective for stabilizing heavy metals in a sixweek experiment. The application of coal humates in conditions of prolonged contamination, accompanied by suppression of vegetation and biota, is effective in small doses (0.5%) and, conversely, causes the mobilization of metals with an increase in humate concentration (1%).     

Dependence of Soil Properties under Alpine Lichen Heath Community on the Soil Water Content and the Presence of Vaccinium vitis-idaea

Eurasian Soil Science - An increasing participation of dwarf shrubs and shrubs in plant communities of alpine meadows and a tendency to a decrease in summer precipitation in mountain regions...