The Influence of Edaphic and Orographic Factors on Algal Diversity in Biological Soil Crusts on Bare Spots in the Polar and Subpolar Urals

The influence of edaphic and orographic factors on the formation of algal diversity in biological soil crusts was studied in mountain tundras of the Polar and Subpolar Urals. Bare spots developed in the soils on different parent materials and overgrown to different extents were investigated. Overall, 221 algal species from six divisions were identified. Among them, eighty-eight taxa were new for the region studied. The Stigonema minutum, S. ocellatum, Nostoc commune, Gloeocapsopsis magma, Scytonema hofmannii, Leptolyngbya foveolarum, Pseudococcomyxa simplex, Sporotetras polydermatica species and species of the Cylindrocystis, Elliptochloris, Fischerella, Leptosira, Leptolyngbya, Myrmecia, Mesotaenium, Phormidium, Schizothrix genera were permanent components of biological soil crusts. The basis of the algal cenoses in soil crusts was composed of cosmopolitan cyanoprokaryotes, multicellular green algae with thickened covers and abundant mucus. The share of nitrogen fixers was high. The physicochemical properties of primary soils forming under the crusts of spots are described. The more important factors affecting the species composition of algae in the crusts are the elevation gradient, temperature, soil moisture, and the contents of Ca, Mg, mobile phosphorus, and total nitrogen.     

Algological and Mycological Characterization of Soils under Pine and Birch Forests in the Pasvik Reserve

The structure of algological and mycological complexes in Al–Fe-humus podzols (Albic Podzols) under pine and birch forests of the Pasvik Reserve is characterized. The number of micromycetes is higher in more acid soils of the pine forest, while the species diversity is greater under the birch forest. The genus Penicillium includes the largest number of species. The greatest abundance and occurrence frequency are typical for Penicillium spinulosum, P. glabrum, and Trichoderma viride in pine forest and for Umbelopsis isabellina, Mucor sp., Mortierella alpinа, P. glabrum, Aspergillus ustus, Trichoderma viride, and T. koningii in birch forest. Cyanobacteria–algal cenoses of the investigated soils are predominated by green algae. Soils under birch forest are distinguished by a greater diversity of algal groups due to the presence of diatoms and xanthophytes. Species of frequent occurrence are represented by Pseudococcomyxa simplex and Parietochloris alveolaris in soils of the pine forest and by Tetracystis cf. aplanospora, Halochlorella rubescens, Pseudococcomyxa simplex, Fottea stichococcoides, Klebsormidium flaccidum, Hantzschia amphioxys, Microcoleus vaginatus, and Aphanocapsa sp. in soils under birch forest     

Cyanobacterial–algal cenoses in ordinary chernozems under the impact of different phytoameliorants

General ecological and taxonomic characteristics of cyanobacterial–algal cenoses in ordinary chernozems under different ameliorative plants (phytoameliorants) were studied in the Trans-Ural region of the Republic of Bashkortostan. A comparative analysis of the taxa of studied cenoses in the soils under leguminous herbs and grasses was performed. The phytoameliorative effect of different herbs and their relationships with cyanobacterial–algal cenoses were examined. Overall, 134 cyanoprokaryotic and algal species belonging to 70 genera, 36 families, 15 orders, and 9 classes were identified. Cyanobacterial–algal cenoses included the divisions of Chlorophyta, Cyanoprokaryota, Xanthophyta, Bacillariophyta, and Euglenophyta. Representatives of Ch-, X-, CF-, and P-forms were the leading ecobiomorphs in the studied cenoses.     

Forest-growing properties of soils under young Siberian stone pine (<Emphasis Type="Italic">Pinus sibirica</Emphasis>) forests in Western Siberia

The results of studying the forest-growing properties of the iron-illuvial podzols under purposefully formed young Siberian stone pine (Pinus sibirica L.) forests are presented. The sufficient supply of these stands with moisture and the high content of nitrogen in the soils make the soils favorable for the regeneration, growth, and development of dark coniferous forests. The soils of the test objects exposed to sanitary cutting were compared to those under the control stand. The silvicultural procedures were shown to promote more efficient use of the soil resources by Siberian pine trees.     

Transformation of Water-Soluble Organic Substances in Litters of Podzols in the Background and Technogenic Areas of the Kola Peninsula

Mineralization of water-soluble organic substances in forest litters of different compositions under conditions of their pollution with heavy metals from aerogenic emissions is considered. Water-soluble organic substances of the pine forest litters are shown to be less stable than that under the spruce forests irrespective of their pollution; the portion of mineralized at 20°C carbon for a month reached 40%. In the spruce litters, mineralizable amounts of carbon are related to their pollution: in the technogenic areas, compared to the background ones, carbon losses from the litters are twice greater. In the course of decomposition, in the spruce and pine litters, phenol compounds accumulate among the water-soluble organic compounds, and this process is more intense in the contaminated areas. After the decomposition of all the litters, irrespectively of their composition and the distance from the pollution sources, the water-soluble organic substances are characterized by higher indices of humification (HIX), more intense fluorescence, and greater coefficients of specific extinction (E₂₆₀). In the ultraviolet spectra, bands appear in the region of aromatic amines absorption. These changes indicate the transformation of water-soluble organic substances: the degrees of their condensation and aromaticity increase and nitrogen-containing aromatic compounds are formed.     

Soils of Mountainous Forests and Their Transformation under the Impact of Fires in Baikal Region

Data on postpyrogenic dynamics of soils under mountainous taiga cedar (Pinus sibirica) and pine (Pinus sylvestris) forests and subtaiga–forest-steppe pine (Pinus sylvestris) forests in the Baikal region are analyzed. Ground litter–humus fires predominating in this region transform the upper diagnostic organic soil horizons and lead to the formation of new pyrogenic organic horizons (Opir). Adverse effects of ground fires on the stock, fractional composition, and water-physical properties of forest litters are shown. Some quantitative parameters of the liquid and solid surface runoff in burnt areas related to the slope gradient, fire intensity, and the time passed after the fire are presented. Pyrogenic destruction of forest ecosystems inevitably induces the degradation of mountainous soils, whose restoration after fires takes tens of years. The products of soil erosion from the burnt out areas complicate the current situation with the pollution of coastal waters of Lake Baikal.     

Soil pH and plant diversity drive co-occurrence patterns of ammonia and nitrite oxidizer in soils from forest ecosystems

In this study, we investigated how co-occurrence patters of ammonia and nitrite oxidizers, which drive autotrophic nitrification, are influenced by tree species composition as well as soil pH in different forest soils. We expected that a decline of ammonia oxidizers in coniferous forests, as a result of excreted nitrification inhibitors and at acidic sites with low availability of ammonia, would reduce the abundance of nitrite-oxidizing bacteria (NOB). To detect shifts in co-occurrence patterns, the abundance of key players was measured at 50 forest plots with coniferous respectively deciduous vegetation and different soil pH levels in the region Schwäbische Alb (Germany). We found ammonia-oxidizing archaea (AOA) and Nitrospira-like NOB (NS) to be dominating in numbers over their counterparts across all forest types. AOA co-occurred mostly with NS, while bacterial ammonia oxidizers (AOB) were correlated with Nitrobacter-like NOB (NB). Co-occurrence patterns changed from tight significant relationships of all ammonia and nitrite oxidizers in deciduous forests to a significant relationship of AOB and NB in coniferous forests, where AOA abundance was reduced. Surprisingly, no co-occurrence structures between ammonia and nitrite oxidizers could be determined at acidic sites, although abundances were correlated to the respective nitrogen pools. This raises the question whether interactions with heterotrophic nitrifiers may occur, which needs to be addressed in future studies.     

Soil actinomycetes in the National Forest Park in northeastern China

The taxonomic and functional structure of actinomycete complexes in the litters and upper horizons of the soils under an artificial coniferous–broad-leaved forest located around the town of Chanchun (Tszilin province, PRС). The complex of actinomycetes included representatives of the Streptomyces, Micromonospora, Streptosporangium, and Streptoverticillium genera and oligosporous forms. In the actinomycete complexes, streptomycetes prevailed in the abundance (61–95%) and frequency of occurrence (100%). In the parcels of Korean pine (Pinus koraiensis) and Mongolian oak (Quercus mongolica), streptomycetes of 19 species from 8 series and 4 sections were isolated. The most representative, as in European forest biomes, was the Cinereus Achromogenes series. A distinguishing feature of the streptomycete complex in the biomes studied was the high participation of species from the Imperfectus series. The verification of the functional activity of natural isolates made it possible to reveal strains with high antagonistic and cellulolytic abilities. A high similarity of actinomycete complexes was found in Eurasian forest ecosystems remote from each other, probably due to the similarity of plant polymers decomposable by actinomycetes.     

The influence of <Emphasis Type="Italic">Aster x salignus</Emphasis> Willd. Invasion on the diversity of soil yeast communities

The annual dynamics of yeast communities were studied in the soddy-podzolic soil under the thickets of Aster x salignus Willd., one of the widespread invasive plant species in central Russia. Yeast groups in the soils under continuous aster thickets were found to differ greatly from the yeast communities in the soils under the adjacent indigenous meadow vegetation. In both biotopes the same species (Candida vartiovaarae, Candida sake, and Cryptococcus terreus) are dominants. However, in the soils under indigenous grasses, eurybiontic yeasts Rhodotorula mucilaginosa, which almost never occur in the soil under aster, are widespread. In the soil under aster, the shares of other typical epiphytic and pedobiontic yeast fungi (ascomycetic species Wickerhamomyces aniomalus, Barnettozyma californica and basidiomycetic species Cystofilobasidium macerans, Guehomyces pullulans) significantly increase. Thus, the invasion of Aster x salignus has a clear effect on soil yeast complexes reducing their taxonomic and ecological diversity.     

Blue-green algae in soils of specially protected natural territories in the Cis-Ural and Southern Ural regions

Blue-green algae (Òyanobacteria) have been studied in soils of specially protected natural territories of the Cis-Ural and Southern Ural regions. The species composition of the algae has been determined in water and dish cultures with fouling glasses. The investigated soils are characterized by the rich flora of bluegreen algae comprising 79 species and intraspecies taxa. Recreation loads on the territory have resulted in a drop in the species diversity and numbers of algae; their taxonomic structure is becoming simplified. Active development of algae from the Oscillatoriales order assigned to the P-form and to the typical xerophytes (species of the Oscillatoria, Phormidium, and Plectonema genera) has been registered in some anthropogenically disturbed areas.     

Different plant covers change soil respiration and its sources in subtropics

Heterotrophic soil respiration (R _H) and autotrophic soil respiration (R _A) by a trenching method were monitored in four vegetation types in subtropical China from November 2011 to October 2012. The four vegetation types included a shrubland, a mixed-conifer, a mixed-legume, and a mixed-native species. The average R _H was significantly greater in soils under the mixed-legume and the mixed-native species than in the shrubland and the mixed-conifer soils, and it affected the pattern of soil total respiration (R _S) of the four soils. The change in R _H was closely related to the variations of soil organic C, total N and P content, and microbial biomass C. The R _A and the percentage of R _S respired as R _A were only significantly increased by the mixed-native species after reforestation. Probably, this depended on the highest fine root biomass of mixed-native species than the other vegetation types. Soil respiration sources were differently influenced by the reforestation due to different changes in soil chemical and biological properties and root biomass.     

Effect of aerotechnogenic emissions on the content of heavy metals in herbaceous plants of the Lower Don region

The effect of soil properties and distance from the source of technogenic emission on the input of Pb, Zn, Cd, Cu, Mn, Cr, and Ni into daisy family plants (Asteraceae) has been studied. It has been found that the high level of anthropogenic load related to the atmospheric emissions from the Novocherkassk power plant (NPP) favors the accumulation of heavy metals (HMs) in herbaceous plants. Contamination with Pb, Cd, Cr, and Ni is revealed in plants growing near the NPP. The main factors affecting the distribution of HMs in the above- and underground organs of plants include individual physiological features of plant species controlling the barrier functions of different plant organs. Ambrosia artemisiifolia L., Artemisia austriaca Pall. ex. Wild. Jack., and Tanacetum vulgare L. are accumulators of HMs. The resistance of herbaceous plants to pollution has been determined from the acropetal coefficient and actual biogeochemical mobility of HMs. Ambrosia artemisiifolia L. is most resistant to contamination with Mn; Achillea nobilis L. is most resistant to Pb, Ni, and Cd; Cichorium intybus L. is most resistant to Zn and Cu.     

The influence of spruce on acidity and nutrient content in soils of Northern Taiga dwarf shrub–green moss spruce forests

Presently, among the works considering the influence of forest trees on soil properties, the idea that spruce (Picea abies) promotes the acidification of soils predominates. The aim of this work is to assess the effects of spruce trees of different ages and Kraft classes on the acidity and content of available nutrient compounds in the soils under boreal dwarf shrub–green moss spruce forests by the example of forest soils in the Kola Peninsula. The soils are typical iron-illuvial podzols (Albic Rustic Podzols (Arenic)). Three probable ways of developing soils under spruce forests with the moss–dwarf shrub ground cover are considered. The soils under windfall–soil complexes of flat mesodepressions present the initial status. The acidity of organic soil horizons from the initial stage of mesodepression overgrowth to the formation of adult trees changed nonlinearly: the soil acidity reached its maximum under the 30–40-year-old trees and decreased under the trees older than 100 years. The contents of nitrogen and available nutrients increased. The acidity of the mineral soil horizons under the trees at the ages of 110–135 and 190–220 years was comparable, but higher than that under the 30–40-year-old trees. The differences in the strength and trends of the trees’ effect on the soils are explained by the age of spruce trees and their belonging to different Kraft classes.     

Heavy metal content and toxicity of mine and quarry soils

Purpose

Soils formed in metallic mines and serpentinite quarries, among other unfavourable features, have high levels of heavy metals. They can release into the environment causing surface and subsurface water contamination, uptake by plants, their accumulation in the food chain and adverse effects on living organisms. In this work, we studied the magnitude of the soils’ toxic effects not only on spontaneous plants but also on two species with phytoremediation potential.

Materials and methods

Several soils from two different exploitations were selected: a lead and zinc mine and a serpentinite quarry. Soils were characterized, and the pseudo-total and extractable contents of Co, Cr and Ni in soils from a serpentinite quarry were determined. The Cd, Pb and Zn pseudo-total and extractable contents were determined in soils developed in the Pb/Zn abandoned mine. Using a biotest, the chronic toxicity of the soil samples on higher plants was determined. Festuca ovina L., Cytisus scoparius (L.) Link., Sinapis alba L. and Brassica juncea L. were selected, the first two because they are spontaneous plants in the study areas and the last two because they have heavy metal phytoremediation potential.

Results and discussion

Pseudo-total contents of Co, Cr and Ni in the serpentinite quarry soils and of Zn, Pb and Cd in the Zn/Pb mine soils exceed generic reference levels. CaCl₂ is the reactant that extracts the highest proportion of Co, Cr and Ni in the quarry soils and EDTA the largest proportion of Pb Zn and Cd content in the mine soils. The germination index values based on seed germination and root elongation bioassays revealed increasing plant sensitivity to the mine soils in the following order: B. juncea?<?S. alba?<?F. ovina?<?C. scoparius. The wide range of GI values indicates that the response of test plants to soil heavy metals depended on their concentrations and soil characteristics, especially pH and organic matter content.

Conclusions

The pollution index indicates severe Cd, Pb and Zn contamination in the mine soils, as well as high Cr and Ni and moderate Co contamination in the serpentinite quarry soils. The performed biotests were suitable for identifying toxic soils and showed that the studied soils are toxic to the spontaneous plants, more to C. scoparius than to F. ovina. They also indicate that the mine soils are more toxic than the quarry soils for both species.

     

Response of <Emphasis Type="Italic">Piptatherum miliaceum</Emphasis> to co-culture with a legume species for the phytostabilisation of trace elements contaminated soils

Purpose

The presence of high concentrations of trace elements (TEs) in mine soils like those in the Sierra Minera of La Unión-Cartagena (SE Spain) limits the development of a vegetation cover on such sites, and pollution dispersion by water and wind erosion represents a serious risk for the surrounding ecosystems. The aim of this study was to evaluate different phytostabilisation procedures based on the co-culture of a legume (Bituminaria bituminosa) and a high-biomass (Piptatherum miliaceum) species for this type of soils.

Materials and methods

A pot experiment was carried out where B. bituminosa was tested as a soil pre-treatment strategy. Five different procedures were followed to study the growth stimulation or competition of both species in a contaminated soil from the Sierra Minera: (i) sowing of P. miliaceum without B. bituminosa (control treatment), (ii) sowing of P. miliaceum for co-cultivation of both species, (iii) sowing of P. miliaceum and co-cultivation of both species in soil with compost, (iv) harvesting and elimination of the aerial part of the plants before sowing of P. miliaceum and (v) harvesting and incorporation to the soil of the aerial part of B. bituminosa before sowing of P. miliaceum.

Results and discussion

The results showed that the co-culture of both species favoured the growth of P. miliaceum, whilst incorporating the aerial part of the legume to the soil increased nitrogen concentration in P. miliaceum but reduced its growth. The use of compost improved both the growth and N uptake of P. miliaceum and did not inhibit nodulation in B. bituminosa. TE extractability in the soils and accumulation in the plants were rather low and very little affected by the addition of the amendments or by co-culture of species.

Conclusions

Nitrogen availability plays an important role in P. miliaceum growth in TE-contaminated mine soils. The addition of compost together with legume cultivation is proposed as an effective combination for the cultivation of P. miliaceum in these soils, as both plant growth and soil conditions were improved following this procedure.

     

Assessment of Soil Water Composition in the Northern Taiga Coniferous Forests of Background Territories in the Industrially Developed Region

The composition of soil water under coniferous forests of Murmansk oblast—an industrially developed region of northern Russia—was investigated. The studied objects were dwarf-shrub–green-moss spruce forests and dwarf-shrub–lichen pine forests on Al-Fe-humus podzols (Albic Rustic Podzols) that are widespread in the boreal zone. The concentrations and removal of organic carbon performing the most important biogeochemical and pedogenic functions were estimated. The results proved significant intra- and inter-biogeocenotic variability in the composition of atmospheric depositions and soil water. Carbon removal with soil water from organic and mineral horizons within elementary biogeoareas (EBGA) under tree crowns was 2–5 and 2–3 times (in some cases, up to 10 times) greater than that in the intercrown areas, respectively. The lowest critical level of mineral nitrogen (0.2 mg/L) was, as a rule, exceeded in tree EBGAs contrary to intercrown areas. Concentrations of sulfates and heavy metals in water of tree EBGA were 3–5 times greater than those in inter-crown areas. Significant inter-biogeocenotic variations related to differences in the height of trees and tree stand density were found. It is argued that adequate characterization of biochemical cycles and assessment of critical levels of components in soil water of forest ecosystems should be performed with due account for the intra- and inter-biogeocenotic variability.     

Comparative Analysis of the Number and Structure of the Complexes of Microscopic Fungi in Tundra and Taiga Soils in the North of the Kola Peninsula

The number, biomass, length of fungal mycelium, and species diversity of microscopic fungi have been studied in soils of the tundra and taiga zones in the northern part of the Kola Peninsula: Al-Fe-humus podzols (Albic Podzols), podburs (Entic Podzols), dry peaty soils (Folic Histosols), low-moor peat soils (Sapric Histosols), and soils of frost bare spots (Cryosols). The number of cultivated microscopic fungi in tundra soils varied from 8 to 328 thousand CFU/g, their biomass averaged 1.81 ± 0.19 mg/g, and the length of fungal mycelium averaged 245 ± 25 m/g. The number of micromycetes in taiga soils varied from 80 to 350 thousand CFU/g, the number of fungal propagules in some years reached 600 thousand CFU/g; the fungal biomass varied from 0.23 to 6.2 mg/g, and the length of fungal mycelium varied from 32 to 3900 m/g. Overall, 36 species of fungi belonging to 16 genera, 13 families, and 8 orders were isolated from tundra soils. The species diversity of microscopic fungi in taiga soils was significantly higher: 87 species belonging to 31 genera, 21 families, and 11 orders. Fungi from the Penicillium genus predominated in both natural zones and constituted 38–50% of the total number of isolated species. The soils of tundra and taiga zones were characterized by their own complexes of micromycetes; the similarity of their species composition was about 40%. In soils of the tundra zone, Mortierella longicollis, Penicillium melinii, P. raistrickii, and P. simplicissimum predominated; dominant fungal species in soils of the taiga zone were represented by M. longicollis, P. decumbens, P. implicatum, and Umbelopsis isabellina.     

Input and behavior of polycyclic aromatic hydrocarbons in arable,fallow, and forest soils of the taiga zone (Tver oblast)

Contents of 11 most prevalent polycyclic aromatic hydrocarbons (PAHs) in snow and soils of arable, fallow, and forest areas significantly remote from impact technogenic sources of polyarenes have been examined in the Torzhok district of Tver oblast. From the analysis of snow samples, the volumes and composition of PAHs coming from the atmosphere onto the areas of different land use have been determined. Light hydrocarbons prevail in PAHs. They make up 65–70% of total PAHs; their share in soils reaches almost 95%. An increase in the content of PAHs is revealed in fallow soils compared to arable and afforested areas. A direct relationship is revealed between the lateral distribution of total PAHs and the content of organic carbon. The distribution of total PAHs is surface-accumulative in forest soils, mainly uniform in arable soils, and deepaccumulative in fallow soils. PAH groups characterized by similar radial distributions and ratios between their reserves in snow and soils are distinguished: (1) fluorene and phenanthrene, (2) biphenyl and naphthalene, (3) benzo(a)anthracene, chrysene, perylene, and benzo[a]pyrene, and (4) anthracene and benzo[ghi]pyrene.     

Chemical properties and edaphic nutrients content in natural stands of <Emphasis Type="Italic">Quercus pyrenaica</Emphasis> Willd. in Galicia,Spain

The soils where natural stands of “rebollo” oak (Quercus pyrenaica Willd.) occur in Galicia (NW Spain) were characterized in an inventory of 40 stands; the main properties of the soils were also determined by analyzing a total of 30 edaphic parameters. The substrates are principally siliceous, with schists and quartzites predominating; the dominant textural composition is sandy-loam with a scarce presence of clayey-loam and sandy textures, and the soils are basically Umbric Regosol-type. The values of the parameters that reflect the chemical properties of the soil, i.e., the pH, organic matter, nitrogen, and C/N ratio, are similar to those reported as optimal for Quercus spp. forests in the study area. However, the concentrations of macronutrients, except for phosphorous, were higher than in soils under Quercus robur L. with notably high concentrations of the micronutrient iron.     

Natural and Anthropogenic Changes in the Soils and Environment of the Moskva River Floodplain in the Holocene: Pedogenic,Palynological, and Anthracological Evidences

Several series of well-developed paleosols of different ages have been examined on the Moskva River floodplain. In the beginning of the Holocene, forest-steppe biomes were widespread in this area, and dark-humus (Black) soils with stable humate humus and without features of textural differentiation predominated on the floodplain. The presence of meadow-steppe vegetation communities during this period is confirmed by the results of palynological and anthracological analyses. The lower paleosol in section RANIS 2 is represented by the deep humus horizon with ¹⁴C dates from 5500 to 8400 BP and the carbonate-accumulative horizon; it also contains large and deep tunnels of burrowing animals typical of chernozems. Wood charcoal is absent, and pollen of Artemisia and Chenopodium species predominates. Paleosols of the second half of the Holocene are represented by gray-humus and soddy-podzolic soils (Luvisols). In these soils and in the alluvial sediments, beginning from the Subboreal period, pollen of trees predominates; there are abundant charcoal of spruce and burnt spruce needles. In that time, forest-steppe and broadleaved forest biomes on the floodplain were replaced by southern taiga biomes. The second half of the Holocene is also specified by the human impacts on the local landscapes. Palynological and anthracological data attest to the large-scale burning of forests for pastures in the Bronze Age and, later, for cropland. The paleosol of the Iron Age is enriched in humus. It contains tunnels of burrowing animals related to the stage of anthropogenic meadows. It also contains pyrogenic calcite. The recent centuries have been characterized by extremely high floods triggered by the human activity; they have been accompanied by the fast accumulation of coarse-textured alluvial sediments and the formation of weakly developed alluvial soils.