No abstract

The formation of biolayers of various taxonomic and biochemical composition occurs on the rock surfaces under various environmental conditions. The composition of metabolites in various types of biolayers on the marble surface in natural outcrops and urban environment was studied. Metabolome profiling was fulfilled by GC-MS. It was found that communities in urban environment are much less biochemically diverse than in a quarry. The seasonal differences in metabolite network between samples dominate over taxonomic ones in biolayers with predomination of algae and cyanobacteria and in biolayers with predomination of fungi. The biolayers of different stage of soil formation are less susceptible to seasonal variability.

Humification is considered to be a global process that is implemented in soils and organic sediments and also in natural water and air. e term "suspended soils" has become increasingly common in recent years. Suspended soils are defined as the part of the organic matter that has not undergone the full decomposition process and has not turned into the humus of terrestrial soils. Suspended soils were shown to contain higher total nitrogen, phosphorus, and potassium contents than the forest soil, but the moisture content in suspended soils was significantly lower. Our study of the structural composition of humic substances in suspended soils was conducted with an aim of evaluating the humification rates and structural composition of humic acids in the suspended soil in tropical forests of South Vietnam. Soil samples from three selected areas were investigated: the soil under phorophytes (mineral soil presented by samples of topsoil of the typical dry savanna landscape) and two soils from epiphytous formations. Samples were collected from savanna-type sparse communities, located on oligotrophous plains in Phú Quốc Island (South Vietnam) in 2015. General properties of the soil and the elemental composition of suspended soils were determined, and the humic substance chemical composition was evaluated using solid state 13 C-NMR. Data obtained showed that the pH of the soils under phorophytes was higher than in the suspended soils; basal respiration did not tend to change indices between soils under phorophytes and suspended soils, but the suspended soil was less enriched by nitrogen than the soil under phorophytes.is can be related to the total amount of organic matter exposed to humification in various soils and to the presence of an essential portion of mineral particles in the soil under phorophytes. Data on elemental composition of the humic acids (HAs) indicated that one method of humification is implemented in all three soils that were investigated. e humic acids of the phorophyte soil showed the same content of aromatic fraction as the suspended soil. e most comparable soil type in terms of humic substance composition is Cambisols from humid forests of subboreal and subtropical zones. e humification process implemented in suspended soils showed the absence of mineral compounds or mineral fine earth, which indicated that humification in conditions of pure organic substrates can result in formation of deep humified organic matter, as shown by humic acids with an essential aromatic fraction content.

Due to a significant increase in mining activity and subsequent ecosystem disturbances, it is becoming increasingly important to understand how degraded, unproductive quarries can be converted into new, self-sustaining communities that develop into natural environments. Former limestone quarry was investigated with aim to determine the best reclamation practice for surfaces of former lime rock quarries. Effects of spontaneous succession and forestry reclamation restoration approaches on vegetation and soil features were studied. The study was conducted in one of the largest limestone quarries of the Leningrad region, south taiga region. Species composition and vegetation cover were estimated for different plant communities within each ecotype of the quarry. Also soil characteristics were evaluated at each plot. We found that the main differences between plots were due to their position in the landscape; the most similar communities colonize similar ecotypes. On flat landforms, biodiversity is reduced under biological reclamation. At the sites under spontaneous succession, the level of biodiversity increases. In terms of biodiversity conservation and economic benefit, spontaneous succession is preferable to forestry reclamation for the restoration of carbonate substrates. After examining CO2 emissions from the quarry as a result of weathering of carbonates and soil respiration, as well as the level of CO2 sequestration from the atmosphere, we show that the establishment of certain landscape forms within former quarries can help to reduce atmospheric CO2.

This work presents data obtained as a result of studying the composition of cyanobacteria in lithobiotic communities on various substrates (Ruskeala marble, rapakivi-granite, granite gneiss) in different light conditions on the territory of the Karelian Isthmus: Leningrad Oblast, Republic of Karelia, and South Finland. The species composition of cyanobacteria was revealed, and the species composition on certain types of substrates was analyzed. A total of 49 species of cyanobacteria were noted for the Republic of Karelia (13 of which were not previously recorded in this territory). The detailed taxonomic and environmental characteristics of species are given. Changes in the species diversity of cyanobacteria in connection with specific habitats are shown. The type of substrate, the degree of moisture, and illumination are noted as the main factors determining the diversity of cyanobacteria in lithobiotic communities.