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An ecological explanation is proposed for the prevalence of eicosapentaenoic acid (20:5n-3, EPA) in the lipids of primary producers in aquatic ecosystems, such as diatoms, and of alpha-linolenic acid (18:3n-3, ALA) in the lipids of primary producers in terrestrial ecosystems, specifically seed plants. Photosynthetic membranes are unique due to the presence of conical non-bilayer lipids, monogalactosyldiacylglycerols (MGDG), which are absent in both other plant cell membranes and animal cell membranes. The non-bilayer properties - specifically, the ability to form an inverted conical shape - of MGDG molecules are conferred by the acyl chains of polyunsaturated fatty acids (PUFA). When saturated chains are present, these molecules transform into regular cylindrical bilayer lipids. As structural lipids, MGDG determine essential physical and chemical properties of membranes, often collectively referred to as “fluidity”. These properties include molecular rotation rate, diffusion, permeability, free volume, packing defects, lateral pressure, and curvature stress, all of which influence the effectiveness of membrane protein function. The primary ecological feature of diatoms and other marine and freshwater algae of the “red” evolutionary line, which distinguishes them from green plants, is their ability to photosynthesise under rapid changes in light intensity. This occurs both during their circulation in the mixed surface layer of the water column and throughout the tidal cycle in the littoral zone. The common strategies for light adaptation in green plants - such as changes in chloroplast morphology and alterations in the number and structure of light-harvesting complexes and their antennae - are too slow for these dynamic conditions. Instead, light adaptation in diatoms is achieved through the rapid operation of the xanthophyll cycle (XC) and non-photochemical quenching. These processes occur several times faster than their counterparts in members of the “green” evolutionary line. The presence of a sufficient amount of conical non-bilayer structural lipids, specifically MGDG, is crucial for the effective functioning of the XC, as it facilitates the solubilization of xanthophylls and the incorporation of de-epoxidase into the membrane. It is likely that EPA within MGDG in diatoms plays a key role in the rapid operation of the XC by conferring the structural lipid molecules with the necessary inverted conical shape. This shape cannot be fully achieved by the less unsaturated shorter chain of ALA.

In recent decades, many freshwater and coastal marine ecosystems have experienced increased inputs of chromophoric dissolved organic matter (CDOM) of terrestrial origin, primarily humic substances (HS). This phenomenon, commonly referred to in English-language literature as brownification, involves the darkening of water bodies due to elevated concentrations of colored organic compounds. The influx of HS into aquatic systems alters the optical, chemical, and trophic characteristics of the water column. This interdisciplinary review synthesizes current scientific knowledge on the effects of humic substances on phytoplankton primary production, trophic structure, and community composition under conditions of climate change. Key mechanisms are examined, including reduced light penetration, enhanced thermal stratification, nutrient transport, and the involvement of HS in redox processes. Evidence suggests that moderate humification can stimulate productivity through microbial degradation and photodecomposition of allochthonous organic matter, releasing additional nutrients. However, at high HS concentrations, photosynthetic activity declines, phytoplankton shift toward mixotrophy, and biodiversity decreases. Altered light spectra favor groups with accessory pigments and vertical mobility, such as cryptophytes, dinoflagellates, and cyanobacteria, potentially reducing ecosystem trophic efficiency. Ecosystem responses to humification vary with geographic, climatic, and morphometric characteristics of water bodies. Special attention is given to boreal and Arctic regions, where permafrost thaw and increased precipitation intensify HS runoff. Key research directions are identified, including thresholds of abrupt change, the role of mixotrophy in carbon cycling, and the development of region-specific adaptation strategies. The review underscores the importance of an integrated approach to assessing the ecological consequences of aquatic humification.

The article analyzes retrospective literature data and the results of our own research on ichthyoplankton in the coastal waters of southeastern Crimea (the waters of the Karadag Nature Reserve) over the period 1950-2024. Samples were collected in the coastal zone using vertical and horizontal surface fishing methods. Information on taxonomic composition, structure, and abundance dynamics of ichthyoplankton are presented. During a 70-year research period, eggs and larvae of 66 fish species from 33 families were identified. The recovery of ichthyoplankton abundance and species composition after the collapse of the Black Sea ecosystem in the 1990s occurred against the background of climatic changes that significantly impacted the hydrological regime and thermohaline structure of waters in the Azov-Black Sea Basin. In recent years, there has been an increase in the number of species, including due to the introduction of Mediterranean species, and a change in the dominance and sub-dominance of species has occurred.

Structural and functional characteristics of plankton communities are widely used as ecological indicators of global ocean warming. In terms of long-term variability, they indicate the existence of monotonous negative, positive and “zero” trends, i. e. their absence. The latter can be considered as phenomena of regional resilience of plankton communities to global warming. Based on the materials of regional sampling and international databases, an analysis of the interannual variability of zooplankton biomass and indices of its species diversity in the Arabian, Mediterranean and Black seas (from 2000 to 2023) was carried out. For comparison, data on biomass measurements in five other regions of the Atlantic and Pacific Oceans were used. It is shown that the duration of the existence of phenomena of regional stability of plankton communities ranges from several to tens of years, in a wide range of species diversity and biological productivity of waters. In most of the studied regions, the absence of interannual trends in zooplankton biomass corresponded to their absence in the interannual variability of chlorophyll a concentration as an indicator of phytoplankton biomass. Such a correspondence indirectly indicates a trophic basis for the interannual stability of zooplankton biomass.

The accidental diesel fuel spill near the city of Norilsk in 2020 served as the basis for studying the behavior of hydrocarbons in Far Northern soils, which are characterized by a low rate of natural self-purification. The objective of this study is to determine the direction of transformation in the composition of diesel fuel hydrocarbons in various soil types, which is important for optimizing remediation measures for petroleum pollution in the Arctic zone of Russia. Using gas chromatography-mass spectrometry, the distribution of diesel fuel components - including normal and isoprenoid alkanes, alkylcyclohexanes, bicyclic naphthenes, alkyl-substituted benzene derivatives of normal and isoprenoid structures, naphthalenes, and phenanthrenes - was analyzed in Arctic soils differentiated by distance from the spill site and time elapsed since the accident. Differences in hydrocarbon composition in the vertical soil profile were identified, reflecting the pathways of contamination and the specific soil types. In sandy and waterlogged alluvial-gley soils near the spill site, downward percolation of diesel fuel led to an increased proportion of high-molecular-weight and branched hydrocarbons, attributed to exclusion chromatography effects during filtration through the soil. Transport of diesel fuel along the watercourse resulted in the loss of low-molecular-weight members across all homologous hydrocarbon series due to leaching and evaporation during aquatic migration. The deposition of residual diesel components in floodplain sod-alluvial-gley soils was accompanied by mixing in the upper soil layers, while the lower profile showed accumulation of isoprenoid alkanes, alkylbenzenes, bicyclic naphthenes, naphthalenes, and phenanthrenes with a higher content of low-molecular-weight fractions. One year after the diesel fuel entered the watercourse, redistribution of contaminants was observed in the floodplain sod-alluvial-gley soil profile under the influence of seasonal hydrodynamic processes, including the influx of a new portion of pollutants during spring floods. Traces of the initial contamination persisted only in the deeper soil layers.

As a result of studying the collections of Herbariums ABG, LE, MW, MHA, NSK, NS, TK, ALTB, as well as their own expedition collections, information about the species composition of the genus <i>Geranium</i> L. in the flora of the Republic of Kazakhstan has been clarified. For the first time, the species <i>G. transbaicalicum</i> Serg was identified in the flora of Kazakhstan. The ranges of <i>G. affine , G. asiaticum , G. collinum , G. divaricatum , G. pratense , G. sergievskajae , G. pseudosibiricum, G. pusillum , G. robertianum , G. schrenkianum , G. sibiricum , G. sylvaticum , G. transversale , and G. turczaninovii</i> species in Kazakhstan have been supplemented. The lectotype of <i>G. regelii</i> Nevski is designated. A key has been compiled to identify the species.

Siberian iris Iris sibirica L. (Iridaceae) is known as a species included in many regional Red Books and has valuable ornamental and medicinal properties. The lack of a unified approach to overcoming dormancy, which is characteristic to varying degrees of mature seeds of many iris species, usually complicates their micropropagation. This study allowed us to determine the conditions that facilitate the germination of both mature and immature seeds of I. sibiricain vitro culture. The effect of 6-benzylaminopurine (6-BAP) on the morphogenetic potential of I. sibirica was assessed, which made it possible to create a protocol for effective microclonal propagation of the species. Data were obtained on the stimulation of I. sibirica seed germination in order to obtain adventitious shoot formation by direct organogenesis without callus formation. It was found that the use of cytokinin 6-BAP at a concentration of 1 mM is most effective for obtaining, on average, 3-4 adventitious shoots in seedlings obtained from immature seeds, as well as for increasing the energy of seed germination regardless of their maturity. At a low concentration of cytokinin, no violation of the ability of adventitious shoots to rhizogenesis was noted, which made it possible to obtain microclones with a well-developed root system when transplanted to a hormone-free medium. The deposition of microclones for 2 months at a low temperature allowed increasing the survival rate of regenerated plants to 86.5 % when they were subsequently transferred to ex vitro conditions. The plants developed at an accelerated rate, which allowed most seedlings to bloom in the second year after transplantation to the introduction site. This work is relevant for obtaining a large amount of plant material, both for further study and for preserving the species in vitro and ex situ , given that the habitats of I. sibirica are subject to anthropogenic impact and some populations listed in the Red Books have not been found again.

New syntaxa are described, validation of alliance is carried out. New data on the distribution of plant communities, their ecology and composition are given. Alliance Carici supinae-Stipion zalesskii Korolyuk all. nov. Holotypus - ass. асс. Artemisio austriacae-Stipetum capillatae Schubert, Jager et Mahn ex Korolyuk 2014. Diagnostic species (D. s.): Artemisia austriaca , Carex supina , Festuca valesiaca , Potentilla humifusa , Seseli ledebourii , Stipa capillata , S. zalesskii. The alliance unites bunchgrass typical steppes of the steppe zone of the Trans-Volga-Kazakhstan steppe province (Lavrenko et al., 1991). It is characterized by prevalence of widespread steppe xerophytes, including bunchgrasses. Three associations within the alliance have been described. Ass. Artemisio austriacae-Stipetum capillatae Schubert, Jager et Mahn ex Korolyuk 2014 - bunchgrass typical steppes of Western Siberia, the Urals, the Southern Urals, the Trans-Urals, and Northern Kazakhstan. D. s.: Artemisia austriaca , Carex supina , Festuca valesiaca , Potentilla humifusa , Seseli ledebourii , Stipa capillata , S. zalesskii . Ass. Artemisio nitrosae-Festucetum valesiacae Zolotareva, Korolyuk et Makunina 2023 - steppes on sandy soils. D. s.: Artemisia nitrosa , Camphorosma monspeliaca , Kochia prostrata . Ass. Gypsophilo paniculatae-Artemisietum glaucae Korolyuk 2014 Zolotareva, Korolyuk et Makunina 2023 - steppes on sandy soils. D. s.: Artemisia frigida , A. marschalliana , Cleistogenes squarrosa , Gypsophila paniculata , Helichrysum arenarium , Silene borysthenica , S. borysthenica . A new association is described in the class Salicetea herbaceae Br.-Bl. 1948, the order Salicetalia herbaceae Br.-Bl. in Br.-Bl. et Jenny 1926 and the alliance Saxifrago stellaris-Oxyrion digynae Gjaerevoll 1950. Ass. Hymenolomo crispuli-Salicetum polaris Sinelnikova ass. nov. (Suppl., Table 2) - snowbed communities of the class Salicetea herbaceae Br.-Bl. 1948 in the highlands of the south-eastern spurs of the Chersky ridge (Magadan Region). D. s.: Anthelia juratzkana , Bistorta elliptica , Carex podocarpa , Hymenoloma crispulum , Lagotis minor , Salix polaris. The association includes two subassociations - typicum (Suppl., Table 1, rel. 1-24) and rhodioletosum quadrifidae (Suppl., Table 1, rel. 24-37). A new association is described in the class Festucetea vaginatae Soό 1957, the order Festucetalia vaginatae Soό 1957 and the alliance Sileno borysthenicae-Cleistogenion squarrosaeKorolyuk 2017. Ass. Kitagawio baicalensis-Festucetum beckeri Chupina ass. nov. (Suppl., Table 3) - psammophytic steppes on the terraces of the right bank of the Ob river. D. s.: Kitagawia baicalensis , Melilotus albus , Vicia amoena , Vincetoxicum sibiricum , Hippophae rhamnoides. The article presents new data on the distribution of the associations from the class Therosalicornietea Tx. in Tx. et Oberd. 1958: Salicornietum perennantis (Soó ex Wendelberger 1943) Soó 1964 nom. corr. (Suppl., Table 3, 4), Salicornio perennantis-Suaedetum salsae Freitag, Golub et Yuritsina 2001 (Suppl., Table 5), Suaedetum kulundensis Korolyuk 2010 (Suppl., Table 6), Suaedetum salsae Golub et Tchorbadze in Golub 1995 (Suppl., Table 7), Artemisio nitrosae-Camphorosmetum songoricae Korolyuk 1999 (Suppl., Table 8), Suaedetum corniculatae Burtseva in Mirkin et al. 1992 (Suppl., Table 9), Suaedo corniculatae-Camphorosmetum songoricae Korolyuk 1999 (Suppl., Table 10).

The freshwater benthic alga Hydrurus foetidus (Villars) Trevisan was first found in the Iy-Khem River in the Todzha Basin of the Tyva Republic. Geographically, the species is widespread, but it usually grows only in cold waters. The recorded occurrence of H. foetidus in waters with a temperature of 20-21 °C significantly expands our understanding of the ecological distribution of this species. The first discovery of the species in the waters of the Todzha Basin adds to our knowledge of the diversity of algae in the Tyva Republic.

The flora of Omsk Region remains insufficiently and unevenly studied. This is confirmed by numerous findings made during floristic research, which determines the relevance of continuing flora inventory work. The article presents the results of studies of the vascular plant flora of the region for the period 2013-2024. The work was carried out within the framework of the “Flora of Asiatic Russia 2.0” project and is based on field data and verified observations from the iNaturalist platform. For the first time in the region, 28 species and 5 hybrids have been identified, of which 12 species and 4 hybrids are native, while 16 species and 1 hybrid are adventive. Among adventive species, ergasiophygophytes (11 species) predominate, while by degree of naturalization, epecophytes (6 species), ephemerophytes (4 species), colonophytes and ephemerophyte-epecophytes (3 species each) are distinguished. Additional studies are required on the distribution of Sorbus aucuparia L. and Leucanthemum ircutianum DC. in the region. Widely cultivated species ( Cucurbita maxima Duchesne, C. pepo L., Solanum lycopersicum L., S. tuberosum L.) occasionally become wild and persist for a short time near cultivation sites (garden plots, individual residential areas) and landfills. Four rare species have been proposed for inclusion in the Red Book of Omsk Region: Dianthus krylovianus Juz., Astragalus lagobromus Knjaz. & Kulikov, Bupleurum aureum Fisch. and Eremogone koriniana (Fisch. ex Fenzl) Ikonn . The study results significantly expand the known vascular plants flora of Omsk Region, this is of great importance for biodiversity conservation and planning of environmental protection measures.