The mycological properties of medieval culture layers as a form of soil ‘biological memory’ about urbanization

Background, aim, and scope  The mycological properties of soil can offer information about ancient human–landscape interaction, including urbanization. This preposition has been confirmed in our study of the habitation deposits in the medieval Russian settlements (eighth to fourteenth centuries A.D.). Materials and methods  The mycobiota of profiles of anthropogenically transformed soil of excavated medieval settlements were examined in different climate conditions in the European part of Russia. The fungal biomass and biomass structure were evaluated using luminescent microscopy. The isolation and enumeration of microfungi were performed using the method of serial dilutions of soil samples and plating them out on the number of solid media. The isolation of keratinolytic microfungi was performed by hear-bite technique. Results  It was established that in ancient urban soils, the mycobiota may have properties different from those of zone fungal communities. The examined cultural layers of ancient settlements differ from the horizons of the surrounding natural soils because of a bigger rate of fungal spores in fungal biomass, more mosaic distribution of microfungal communities, different species composition and dominant microfungal species, increased incidence of some ecological, and trophic fungal groups (for example, keratinophilic, potentially pathogenic microfungi). Discussion  The mycological characteristics of anthropogenic deposits in the excavated medieval settlements were found to be mainly similar to mycological properties of modern urban soils. Conclusions  These properties of habitation deposits can be interpreted as a kind of “soil mycological memory” of the ancient urban impact. Recommendations and perspectives  Soil mycological characteristics could be used in paleoecological reconstructions and biomonitoring of urban impacts     

Mycological characteristics of the cultural layer of a medieval settlement on soddy calcareous soils

The difference between fungal communities in the cultural layer of a medieval settlement and in the background soddy calcareous soil is shown. In the cultural layer, the portion of spores, especially large spores (d > 6 μm), in the total fungal biomass is increased, whereas the portion of mycelium, especially with a thickness of > 4 μm, is decreased. The species composition of micromycetes in the cultural layer is also transformed; species from the Aspergillus and Fusarium genera predominate. The frequency and diversity of Penicillium representatives decreases, whereas the fungal species from the Phoma, Doratomyces, Geomyces, and Verticillium genera, which are not typical of the background soil horizons, increases. The diversity of the minor fungal species also increases in the cultural layer. An increased content of keratin-decomposing soil fungi is found in the cultural layer. It is argued that the use of the entire set of these characteristics makes it possible to perform mycological indication of the parts of the cultural layer that served different purposes (ancient streets, house floors, backing of the walls, etc.) within the settlement.     

Principles of selecting reference soils for the Red Data Book of Russian Soils

The meaning of the term “etalon” (reference, standard) in natural sciences and, particularly, in soil science is discussed. The need to preserve natural landscapes and soils as reference objects for comparison with their anthropogenically transformed analogues and as a basis for sustaining the natural diversity of plants and animals is demonstrated. The principles and criteria for the choice of reference soils for the Red Data Book of Russian Soils are suggested. The choice of reference soils should be made with due account for the provinces of the soil-geographical (or soil-ecological) zonation as territories characterized by similar environmental conditions and typical soil cover patterns.     

Communities of microscopic fungi in contaminated and reference Al-Fe-humus podzols and their influence on copper mobility

The transformation of microscopic fungi communities under the impact of contamination, the influence of environmental conditions (soil temperature and moisture) on the development of fungal communities in the course of model successions and on the copper mobility in soil, and the most favorable conditions for copper mobilization were studied in Al-Fe-humus podzols of the Kola peninsula contaminated with heavy metals (Cu and Ni). The long-term aerotechnogenic contamination affects the structure of the microbial communities; the species diversity of the communities can somewhat increase at the expense of the increasing diversity of rare, atypical, and “weed” species and decreasing numbers of dominants. The dynamics of fungal communities are less expressed in the contaminated soils as compared with the reference soils. The conditions of rather low temperature (5°C) and an increased moisture content (120% of the field water capacity) are the most favorable for mycelium growth and copper mobilization. Such conditions are typical of the soils in the studied region. Hence, there is a possibility for the soil self-purification due to gradual mobilization of the copper and its subsequent leaching.     

Algological and mycological assessments of the soil state in the impact zone of the Kirovo-Chepetsk Chemical Plant

The chemical and microbiological (on the basis of algae and micromycetes) analysis of the soils was carried out in the region of the Kirovo-Chepetsk Chemical Plant. It has been shown that the complex soil contamination resulted in essential changes in the algal-mycological complexes: the species diversity of the phototrophs decreased, nitrogen-fixing cyanobacteria practically disappeared from the algocenoses, and melanic forms of fungi dominated in the structure of the micromycetal communities. The higher sensitivity of the mycological indication method to the soil contamination was found in comparison with the methods of biotesting on the basis of protozoa and coliform bacteria.     

Humus Horizons of Soils in Urban Ecosystems

The origin, structure, composition, and properties of soil humus horizons in functional zones of St. Petersburg have been studied. The radiocarbon age of organic matter in the humus horizons varies from 500 to 2700 years, which attests to the natural origin of humus. The structure of microbiomes in the humus horizons of soils under different plant communities has its specific features. The taxonomic structure of microbial communities at the phylum level reflects both genetic features of natural soils and the impact of anthropogenic factors, including alkalization typical of the studied urban soils. Tomographic studies have shown that the transporting system of humus horizons is less developed in the anthropogenically transformed soils in comparison with the natural soils. It can be supposed that the intensity of water and gas exchange in the anthropogenic soils is much lower than that in the natural soils. The fractional and group composition of humus in the urban soils is specified by the long-term pedogenesis, on one hand, and by the impact of metabolic products of the city and the factors of soil formation in the megalopolis, on the other hand. Bulk density of the humus horizon in the urban soils is higher than that in the natural soils; the portion of overcompacted humus horizons in the urban soils reaches 44%. Humus horizons of the lawns along highways are most contaminated with heavy metals: Pb, Zn, and Cu. There are no definite regularities in the distribution of major nutrients (NPK) in the humus horizons of anthropogenic soils.     

Dwarf mistletoe effects on soil basidiomycete community structure, soil fungal functional diversity, and soil enzyme function: Implications for climate change

We used a combination of molecular, culture and biochemical methods to test the hypothesis that severe infection of pine by dwarf mistletoe (genus Arceuthobium) has significant effects on structure and function of soil fungal communities, and on carbon cycling in soils. PCR and DNA sequencing of the basidiomycete communities in paired blocks of uninfected and infected trees revealed: (1) that the top, organic soil layer in this system is inhabited almost exclusively by ectomycorrhizal fungi; (2) no difference in species richness (6 species core⁻¹ in both) or Shannon-Wiener evenness (0.740 and 0.747 in uninfected and infected blocks respectively), however Shannon-Wiener diversity was significantly greater in infected blocks (1.19 vs 1.94 in uninfected and infected blocks respectively, P < 0.05); (3) significant differences in basidiomycete species composition, with nearly complete absence of two system co-dominant Russula species in infected blocks, and replacement of one co-dominant Piloderma species with another in infected plots, indicating physiological variability within the genus. Soil fungal physiological diversity measured using the Fungilog system was significantly greater in terms of both number of carbon substrates used by culturable soil fungi (both ascomycetes and basidiomycetes) in infected blocks, and the rate at which these substrates were used. Soil enzyme assays revealed greater laccase, peroxidase, and cellulase activities in soils associated with infected trees. Thus, event cascades associated with severe dwarf mistletoe infection not only significantly affected soil fungal species composition and increased species diversity, but also impacted on carbon-related function and functional diversity. Given the geographic range of this pathogen, and forecasts that epidemics of this disease will increase in range in severity with global climate change, these effects have the potential to significantly impact local and global carbon budgets.     

Soil carbon content drives the biogeographical distribution of fungal communities in the black soil zone of northeast China

Black soils (Mollisols) are one of the most important soil resources for maintaining food security in China, and they are mainly distributed in northeast China. A previous comprehensive study revealed the biogeographical distribution patterns of bacterial communities in the black soil zone. In this study, we used the same soil samples and analyzed the 454 pyrosequencing data for the nuclear ribosomal internal transcribed spacer (ITS) region to examine the fungal communities in these black soils. A total of 220,812 fungal ITS sequences were obtained from 26 soil samples that were collected across the black soil zone. These sequences were classified into at least 5 phyla, 20 classes, greater than 70 orders and over 350 genera, suggesting a high fungal diversity across the black soils. The diversity of fungal communities and distribution of several abundant fungal taxa were significantly related to the soil carbon content. Non-metric multidimensional scaling and canonical correspondence analysis plots indicated that the fungal community composition was most strongly affected by the soil carbon content followed by soil pH. This finding differs from the bacterial community results, which indicated that soil pH was the most important edaphic factor in determining the bacterial community composition of these black soils. A variance partitioning analysis indicated that the geographic distance contributed 20% of the fungal community variation and soil environmental factors that were characterized explained approximately 35%. A pairwise analysis revealed that the diversity of the fungal community was relatively higher at lower latitudes, which is similar to the findings for the bacterial communities in the same region and suggests that a latitudinal gradient of microbial community diversity might occur in the black soil zone. By incorporating our previous findings on the bacterial communities, we can conclude that contemporary factors of soil characteristics are more important than historical factor of geographic distance in shaping the microbial community in the black soil zone of northeast China.     

Response of ectomycorrhizal communities to past Roman occupation in an oak forest

The impact of past Roman occupation on the composition of ectomycorrhizal (ECM) communities was analysed in 12 Roman settlements in an oak forest in Central France. At each Roman settlement, soils and ECM roots were sampled from two plots (600 m² each), one plot close to the remains of the buildings (<100 m), supposed to be impacted by ancient Roman agriculture, and the second plot 250-500 m away from the remains of the buildings, supposed to be less intensively influenced by previous cultivation. Soils were analysed and ECM fungal taxa were identified by morphotyping and sequencing the rDNA ITS region. The soil properties were significantly affected by the past Roman occupation, in terms of nutrient availability, especially for P, N and Mg. The enhancement of soil nutrient levels by past Roman land-use had significantly modified alpha diversity and species composition of ECM communities. Among the 67 determined ECM morphotypes, 40 were shared by the occupied and non-occupied plots, 17 were found only in the occupied plots and 10 only in the non-occupied plots. Six morphotypes were significantly more frequent near the antique remnants. Our study showed, for the first time, that ectomycorrhizal communities are impacted by previous Roman land-use, even after nearly two thousand years of forest state.     

Physical properties of soils in Rostov agglomeration

Physical properties of natural and anthropogenically transformed soils of Rostov agglomeration were examined. The data obtained by conventional methods and new approaches to the study of soil physical properties (in particular, tomographic study of soil monoliths) were used for comparing the soils of different functional zones of the urban area. For urban territories in the steppe zone, a comparison of humus-accumulative horizons (А, Asod, Ap, and buried [A] horizons) made it possible to trace tendencies of changes in surface soils under different anthropogenic impacts and in the buried and sealed soils. The microtomographic study demonstrated differences in the bulk density and aggregation of urban soils from different functional zones. The A horizon in the forest-park zone is characterized by good aggregation and high porosity, whereas buried humus-accumulative horizons of anthropogenically transformed soils are characterized by poor aggregation and low porosity. The traditional parameters of soil structure and texture also proved to be informative for the identification of urban pedogenesis.     

The number and biomass of microorganisms in ancient buried and recent chernozems under different land uses

The size, number, and biomass of bacteria and microscopic fungi were studied in chernozems of different land uses (forest, fallow, pasture, and cropland), in paleosols under mounds of different ages in the territories adjacent to the background recent chernozems; and in the cultural layer of an ancient settlement of the Bronze Age, Early Iron Age, and Early Middle Age (4100–1050 years ago). The method of cascade filtration revealed that bacterial cells had a diameter from 0.1 to 1.85 μm; their average volume varied from 0.2 to 1.1 μm³. Large bacterial cells predominated in the soils of natural biocenoses; fine cells were dominants in the arable soils and their ancient analogues. The bacterial biomass counted by the method of cascade filtration was first found to be 10–380 times greater than that determined by luminescence microscopy. The maximal bacterial biomass (350–700 μg/g) was found in the soils of the birch forest edge (~80-year-old) and under the 80-year-old fallow. In the soils of the 15–20 year-old fallows and pastures, the bacterial biomass was 110–180 μg/g; in the arable soils and soils under the mounds, it was 80–130 and 30–130 μg/g, respectively. The same sequence was recorded in soils for the content of fungal mycelium and spores, which predominated over the bacterial mass. With the increasing age of the buried paleosols from 1100 to 3900 years, the share of the biomass of fungal spores increased in the total fungal and total microbial biomasses. In the cultural layer of the Berezovaya Luka (Altai region) settlement that had been functioning about 4000 years ago, the maximal biomass and number of fungal spores and the average biomass of bacteria and fungal mycelium comparable to that in the studied soils were revealed. In this cultural layer, the organic matter content was low (Corg, 0.4%), and the content of available phosphorus was high (P₂O₅, 17 mg/g). These facts attest to the significant saturation of this layer with microbial cenoses 4000 years ago and to their partial preservation up to now owing to the high concentration of ancient human wastes there.     

Anthropogenic transformation of soils in the Pokrovskoe-Streshnevo Park (Moscow) and adjacent residential areas

The diversity of soils within the specially protected natural territory of Pokrovskoe-Streshnevo in Moscow is discussed. The soils of this large park are not affected by the modern construction activities that delete the features inherited from the early stages of the anthropogenic transformation of soils in Moscow. They are characterized by the book-like type of soil memory, which makes it possible to trace several sequences of the anthropogenic soil transformation. The background natural soils-rzhavozems (Chromic Cambisols)—have been transformed into agrogenic soils (agrosols) and postagrogenic soils (postagrosols) under abandoned plowlands, into urbo-soils and urbanozems in the areas of former or modern settlements, and into techno-soils in the areas of active excavation works and engineering reclamation. The change in the character of the land use without the accumulation of osediments on the surface leads to the development of polygenetic soil horizons.     

The biomass of fungal mycelium in buried paleosols and surface soils of the steppe zone

The contents of fungal mycelium have been studied in paleosols of ancient archeological monuments and in surface soils within the steppe, dry steppe, and desert zones of European Russia, on the Stavropol, Privolzhskaya, and Ergeni uplands. The buried paleosols date back to the Bronze Age (4600–4500 and 4000–3900 BP), the Early Iron Age (1900–1800 BP), and the early 18th century (1719–1721). The fungal mycelium has been found in all these paleosols. The biomass of fungal mycelium varies from 2 to 124 μg/g of soil. The distribution patterns of fungal mycelium in the profiles of buried paleosols and surface soils have been identified. It is shown that the dark-colored mycelium is typical of the ancient paleosols. In some cases, the content of the dark-colored mycelium in them may reach 100% of the total mycelium biomass.     

The importance of mycological studies for soil quality control

Published and original data obtained in the course of long-term studies of mycobiota of several soil types in regions with different pollution levels and composition of the pollutants (Tver, Moscow, and Samara oblasts; West Siberia; and the Komi Republic) are analyzed. The expediency of using mycological characteristics for soil quality control and estimation of the toxic impact on the environment is discussed. The most pollutant-sensitive mycological characteristics were determined for the following soils: oligotrophic peat gley, eutrophic peat, whitish podzolic, Al-Fe-humus podzol, soddy pale podzolic, soddy-podzolic, and brown forest soils. These are (a) the structure of the fungal biomass, (b) the taxonomic diversity of the fungi, and (c) the percentage of melanized forms of micromycetes. At the same time, the total number of fungi (in colony-forming units) and the indices of the richness of individual species and genera proved to be poorly informative for assessing the ecological status of the soils. Criteria for the choice of mycobiotic parameters suitable for scaling the soil ecological quality are suggested.     

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.     

十种湿生植物根际真菌群落参数和土壤肥力的比较

【目的】利用人工湿地是目前我国进行点源污水处理的一项重要技术,人工湿地的湿生植物及其根际微生物对污水处理有重要影响。目前人们普遍关注的是湿生植物根际细菌的群落结构和功能,而对根际真菌群落结构的信息较少。本文主要研究10种湿生植物根际的土壤肥力、真菌数量、生物量和真菌的碳代谢,目的在于筛选出根际土壤真菌生物量和活性均较大的植物种类,为今后人工湿地的建设提供参考依据。【方法】采用"向后抛石法"随机选取采样点,收集10种湿生植物根际土壤。采用常规方法测定土壤有机碳、全氮和全磷含量;真菌数量采用稀释平板法,真菌生物量(麦角固醇含量)采用高效液相色谱法(HPLC)测定;真菌碳代谢指纹采用FF板进行分析。【结果】银边石菖蒲、花叶香蒲和黄菖蒲根际土壤分别有较高的有机碳、全氮和全磷含量(P0.05)。黄菖蒲根际土壤真菌数量和生物量最大(P0.05)。相关分析表明,土壤全磷与真菌数量和生物量有极显著的正相关关系(P0.05),是制约土壤真菌分布的重要因素。碳代谢指纹分析表明,水生美人蕉土壤真菌对95种碳源的平均利用活性以及对6种碳源群的利用强度均大于其它植物,土壤全氮显著地影响了真菌群落对碳水化合物的利用(P0.05)。【结论】10种湿生植物根际土壤肥力和真菌群落有显著性差异,因而土壤肥力和真菌群落可以作为筛选人工湿地植物的重要依据,但这一结论还有待从分子生物学的角度进一步验证。     

Physical properties of park soils of the objects of landscape architecture

Here the comparative characteristics of the physical properties of park soils, viz., anthropogenically transformed and engineered soils of the objects of landscape architecture, are given. The mechanical strength of aggregates, density, and aggregate physical properties to characterize the soil and agro-physical and environmental condition of soil objects of landscape architecture and establish the similarities or differences of engineered soil objects with zonal soils are described. We studied the physical properties of soils of different structural and functional elements of the landscape and the regular area of the Arkhangelskoe memorial estate. The structural state of the park soils is characterized as good. The engineered soils of the regular area of the park appear to have excessively high water resistance, while the postagrigenic sod-podzolic soils of the landscape area of the park are absolutely water resistant.     

Soils of the Botanical Garden on Bolshoi Solovetsky Island

Soils of the Botanical Garden on Bolshoi Solovetsky Island are considered. The regularities of distribution, structural characteristics, and properties of anthropogenically transformed soils are studied in comparison with the natural ones formed in the analogous lithological geomorphological conditions.     

福建典型茶园土壤真菌群落特征对不同活性有机碳组分的影响

选择福鼎市白琳镇、磻溪镇、管阳镇、太姥山镇和点头镇5个乡镇典型茶园土壤作为研究对象,分析茶园土壤中真菌群落特征及其对不同活性有机碳组分的影响。结果表明：①茶园土壤中易氧化态有机碳(EOC)、微生物生物量碳(MBC)、可溶性有机碳(DOC)含量均值分别为6.11 mg/g、200.85 mg/kg和68.27 mg/kg,EOC/SOC、MBC/SOC、DOC/SOC占比均值分别为34.05%、1.14%、0.42%;②茶园土壤真菌群落OTU数为点头镇>白琳镇>管阳镇>太姥山镇>磻溪镇,其中优势菌门为子囊菌门(Ascomycota)和担子菌门(Basidiomycota),优势菌属为原隐球菌属(Saitozyma)、被孢霉属(Mortierella)和Pleuroascus,不同茶园土壤中的真菌群落组成结构相似,但真菌多样性指数差异显著(P<0.05);③真菌群落多样性特征方面,EOC、DOC含量与真菌群落多样性存在显著相关性(P<0.05);在真菌群落组成结构方面,Pleuroascus、Cpronia、Chloridum、Cladophialophora相对丰度与DOC、MBC含量呈显著正相关(P<0.05),Moritierella、Westerdykella相对丰度与DOC、MBC含量呈显著负相关(P<0.05);在真菌群落功能预测方面,腐生营养型真菌对土壤不同活性有机碳组分的积累影响显著。     

Mycological complexes in Holocene and Late Pleistocene paleohorizons and in fragments of paleosols

Fragments of buried Late Pleistocene (30000-year-old) and Early Holocene (10000-year-old) paleosols contained viable complexes of microscopic fungi. The mycobiota of these paleosols represents a pool of fungal spores that is lower in number and species diversity as compared to that in the recent humus horizons and higher than that in the inclosing layers. The central part of the paleosol profiles is greatly enriched in microscopic fungi. In the intact humus horizons of the Late Holocene (1000–1200 years) paleosols, actively functioning fungal complexes are present. These horizons are characterized by their higher level of CO₂ emission. The buried horizons, as compared to the recent mineral ones, contain a greater fungal biomass (by several times) and have a higher species diversity of microscopic fungi (including fungi that are not isolated from the recent horizons). Nonsporulating forms are also present there as sterile mycelium. The seasonal dynamics of the species composition and biomass of the fungal complexes were more prominent and differed from those inherent to the surface soil horizons. In the buried humus horizons, the dynamics of the fungal biomass were mainly due to the changes in the content of spores. The data on the composition of the fungal complexes in the buried soils confirm (due to the presence of stenotopic species) the results of paleobotanic analyses of the past phytocenoses or do not contradict them.