Fig. 1. Expedition route – from the Chersky ridge (2) to the Zyryanka village (1). Landmarks: 3 - Omulyovka river, tributary of Yasachnaya river (4), river Kolyma (5). E.S. Chertoprud, a research fellow at the A.N. Severtsov Institute of Ecology and Evolution (IEE RAS), and A.A. Novikov, from Kazan State University (KFU), participated in organizing and conducting a hydrobiological expedition in the Magadan Region and the Verkhnekolymsky District of Yakutia (Fig. 1). For approximately three weeks in July and August 2025, the hydrobiologists rafted on a catamaran and packraft along the Omulyovka and Yasachnaya Rivers (Fig. 2), collecting zooplankton and meiobenthos samples from reservoirs located on river terraces. Fig. 2. Through the Omchikchan midlands – on the way to Kolyma The main goal of the fieldwork was to analyze the diversity of microcrustaceans in the northern spurs of the Chersky Range and the floodplain waters of the upper Kolyma River. The primary targets were copepods (Copepoda) and cladocerans (Cladocera), which are abundant in the waters of the northern taiga. The expedition enjoyed sunny, hot weather, rare in Eastern Siberia. Locals joked that they "managed to experience a short Yakut summer." From the river's upper reaches, the hydrobiologists quickly rafted on the receding floodwaters—the result of heavy rains in early summer. By the time the group reached the rapids, the waters had already subsided, ensuring the safe passage of the route. Fig. 3. Swampy lakes of the northern slopes of the Chersky ridge (altitude > 600 m above sea level) More than 50 natural and oxbow lakes were surveyed, and samples were collected from the substream waters of several streams (Figs. 3, 4). Because the expedition's route followed the river valley flowing from the Chersky Ridge, the studied water bodies varied greatly in elevation. The southernmost lakes were located at approximately 1000 m, while the northernmost oxbow lakes in the Kolyma River floodplain were only 30 m above sea level. Overall, approximately 150 qualitative and quantitative samples of zooplankton and meiobenthos were collected, as well as bottom sediments for paleolimnological analysis. Crustaceans were collected from the water column using plankton nets, benthic organisms were collected using a tube sampler, and samples from the substream waters were obtained using the Karaman-Chapuis method: small holes on the shore were dug, water seeped into them, and then this water was filtered using a net. Fig. 4. Swampy lakes of the northern slopes of the Chersky Ridge (altitude > 600 m above sea level) Some of the copepod material has already been analyzed, revealing a number of species new to the studied areas, as well as several species new to science. The remarkable diversity of the fauna is particularly noteworthy: 29 copepod species were found in 10 samples (Fig. 5). It is noteworthy that many of the discovered species are already known from Central and Eastern Siberia. This may indicate a commonality in the copepod fauna across Siberia, from the Yenisei River to the Kolyma River. Further laboratory work is planned to identify all discovered crustaceans to the highest possible taxonomic level. Morphological character studies and molecular genetic analysis will be performed on a number of taxa with questionable status or potentially new to science. Thus, the expedition's materials will provide an opportunity to fill gaps in our knowledge of the structure and regulation of aquatic communities in northeastern Eurasia. Fig. 5. Some interesting species of Copepoda: A. Acanthodiaptomus pacificus – a typical Far Eastern species; B. Ectocyclops phaleratus – a rare species in cold regions; C. Eucyclops arcanus – a typical Siberian species; D. Diacyclops sp. – possibly new to science; E. Attheyella dentata – a Palearctic species; Bryocamptus sp. – possibly a new species, previously recorded in Central Siberia The expedition was supported by local residents throughout the fieldwork, ensuring the rapid and safe transportation of the hydrobiologists to the start and end points of the route. We wholeheartedly thank Alexander Vladimirovich Kremnev, without whose assistance it would have been impossible to reach the upper reaches of the Omulyovka River with all our expedition equipment. We also extend a special thanks to Sergei Anatolyevich Dolgov, head of the village of Zyryanka, for his assistance in organizing sampling in the floodplains of the Yasachnaya and Kolyma rivers, as well as for transporting the team from Yakutia back to the Magadan Region (Fig. 6). Fig. 6. Expedition members with the head of the village of Zyryanka Future plans include continuing the analysis of aquatic microcrustacean communities in the Magadan Region and the Verkhnekolymsky District of Yakutia. A key focus of this research will be assessing the impact of mineral development on aquatic biodiversity.

Based on the results of research conducted by scientists from the A.N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences (Moscow), the I.D. Papanin Institute of Biology of Inland Waters of the Russian Academy of Sciences (Borok), the A.O. Kovalevsky Institute of Biology of the Southern Seas of the Russian Academy of Sciences (Sevastopol), and the Southern Branch of the Joint Russian-Vietnamese Tropical Research and Technology Center (Ho Chi Minh City, Vietnam), a collective monograph, “Biological Diversity and Ecological Status of the Mekong Delta (Vietnam)” (edited by I.N. Marin and A.V. Tiunov), was prepared. Moscow: KMK Scientific Publications Partnership. 2025. 541 p. The Mekong River is the largest in Indochina and one of the most voluminous rivers in the world. In its lower reaches, the river forms a vast delta located in the Socialist Republic of Vietnam. The delta covers approximately 40,000 square kilometers. Over 2.6 million hectares (approximately 65% ​​of the delta's area) are used for agriculture, accounting for approximately a quarter of the country's total cultivated land. Up to 90% of the country's rice exports are grown in these areas. The river's natural branches and a vast network of artificial canals form the largest transportation system in the south of the country. The delta is home to approximately 20 million people; it adjoins the combined deltas of the Dong Nai and Saigon rivers and the vast metropolis of Ho Chi Minh City. Due to its vast size and diverse ecological conditions, the Mekong Delta supports a wide variety of animals, including a number of endemic species, making it a center of biological diversity. However, high anthropogenic load inevitably has a negative impact on the delta's complex and dynamic ecosystems. The natural hydrological regime of the Mekong has been altered by the construction of dams, dikes, and irrigation canals, significantly affecting water flow, the direction of bottom currents, the dynamics of river sediments, and siltation. This disrupts habitats at the confluence of river and sea waters and the migration routes of aquatic animals. Pesticides and fertilizers from fields, antibiotics from coastal fish and shrimp farms, urban runoff, petroleum products, and other toxic substances enter the water; the riverbed and bottom sediments are polluted with solid waste, particularly plastic. Pollution and overfishing reduce the diversity and abundance of aquatic organisms. Human impact is exacerbated by global climate change, which leads to rising sea levels and, consequently, the infiltration of saltwater through channels deep into the delta and soil salinization. Clearly, the delta's biodiversity and ecological well-being are under threat and require close attention. This collective monograph presents the results of comprehensive research conducted primarily between 2020 and 2024 under the Ecolan E-3.4 theme "Mekong River Ecosystem under Global Climate Change and Anthropogenic Impact" of the Joint Russian-Vietnamese Tropical Research and Technology Center. The author's chapters cover a wide range of key characteristics of the delta ecosystem. The first section examines the delta's hydrological conditions and its zoning. The second section describes the current state of the biota, including data on biodiversity and quantitative characteristics of phytoplankton, major zooplankton groups, benthic crustaceans, and fish. The third section examines various aspects of anthropogenic impact, from trawling and plastic pollution of the delta to detailed data on the concentrations of heavy metals, radionuclides, and hydrocarbons in water and bottom sediments. The main text of the chapters is presented in Russian, with abstracts in English. The monograph in PDF format is available for reading and downloading at the link.

Scientists from the A.N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences (IEE RAS), co-authored with colleagues from the N.K. Koltsov Institute of Developmental Biology of the Russian Academy of Sciences (IB RAS), presented prioritized data on the multilevel molecular differentiation of the Strand's birch mouse, Sicista strandi, a restricted-range southern European-Caucasian species. To clarify the nature of Sicista strandi differentiation (the appearance of the specimen from the Kursk region is shown above), the authors analyzed the variability of the mitochondrial cytb gene and a fragment of the first exon of the nuclear IRBP gene in several species samples. The obtained results demonstrated the subdivision of S. strandi into two genetically highly separated forms: one (northern - II) includes individuals from the Belgorod (Belogorye) and Kursk regions, and the other (southern - I - A, B) includes samples from populations of the North Caucasus, Saratov, Rostov (R/D), and Luhansk regions. Within the southern form, moderate differences were detected for the first time between Strand's birch mice from the Rostov region and populations of the North Caucasus and Saratov region. One S. strandi specimen from the Belgorod region was noted to have haplotypes of the IRBP gene typical for this population, but also an alien mitotype similar to those of individuals from the Rostov region (Fig. 1). "This result may indicate the present or past existence of a hybrid zone between the northern form and the 'Don' lineage of the southern form," says study co-author Marina Baskevich, PhD, senior researcher. Another co-author of the study from the Institute of Ecology and Evolution of the Russian Academy of Sciences, PhD, senior researcher Lyudmila Khlyap, notes the unique nature of hybridization for the genus Sicista. The practical significance of this study lies in its contribution to the study of biodiversity and the patterns of formation of the Palearctic rodent fauna. The work was published in the journal Animals: Bogdanov, A.S.; Rozhkova, D.N.; Khlyap, L.A.; Baskevich, M.I. Multi-Level Molecular Differentiation of Populations of the Strand's Birch Mouse Sicista strandi (Rodentia, Dipodoidea). Animals 2025, 15, 2605. Presented by Baskevich M.I., Senior Researcher, Microevolution Lab, IEE RAS.

Experts from the Institute of Ecology and Evolution (IEE) of the Russian Academy of Sciences conducted a field study of the fauna of Bobrovy Island in the Nagatinsky Zaton district of Moscow and recommended clearing the island of debris and improving the beavers' living conditions on the island by replenishing the food supply and dredging the seabed along the shore. "Since Soviet times, the island has been an abandoned storage site for building materials, part of the loading and unloading system of the Yuzhny Port. The island is currently in a state of disrepair – there is a lot of trash, including large items (tires, rebar, broken batteries), illegal buildings, and other traces of illegal picnics. The inner lake is particularly polluted," commented Andrey Zaitsev, PhD in Geographical Sciences and head of the IEE RAS Technology Transfer Center. A study by IEE RAS also showed that the beavers' food supply on the island has been depleted. Almost all the aspen trees found on the island, which are the beavers' primary food source, have either already fallen or bear tooth marks and could be felled as early as this winter. Living conditions for beavers on the island will only worsen, so measures must be taken to improve them, including clearing debris, planting the plants most attractive for beavers, and dredging the bottom near the shore to allow the animals to dig additional burrows. "Renewal and development of Bobrovy Island will help preserve the animal population. Leaving the island untouched means losing the animals currently living there: when their food supply is completely exhausted, they will abandon the island, which could even lead to their death. After all, there are no other suitable habitats for them in this part of Moscow, or they are already occupied by other beavers. The only correct solution is to carry out restoration work and further renew the area, taking into account the interests of the animals. This is feasible – there is international experience in ensuring comfortable coexistence between beavers and people in the same area," emphasized Andrey Zaitsev. A study by IEE RAS confirmed that, contrary to popular belief about the island's mass infestation, a single family of up to six animals lives there, with two or three additional individuals occasionally visiting. "This means that the permanent inhabitants of Bobrovy Island, after which it was named, can be counted on the fingers of two hands," noted Ivan Bashinsky, a senior researcher at the Institute of Ecology and Evolution of the Russian Academy of Sciences and a PhD in Biology. To preserve the existing beaver population on the island, it will be necessary to allocate a separate area for them, providing improved living conditions and food supplies. The remaining territory, where beavers' presence is undesirable and unsafe for the animals themselves, must be protected from their invasion, including by planting plant species unattractive to them. Related materials: News.Mail:  "The Institute of Ecology and Evolution of the Russian Academy of Sciences has called for the planting of willows and water lilies to preserve beavers on Bobrovy Island" Science.Mail: "Beavers may disappear from Moscow's Bobrovy Island" SkyTechNews: "Scientists are calling for the conservation of beavers in Moscow: researchers have already found a solution to the problem"

Video recordings of all online lectures in the "World of Wetland Ecosystems: From Basics to Innovations" series have been published publicly. They have been compiled into thematic playlists on the following platforms: VKontakte Youtube From January to May 2025, scientists from the RITM Carbon Consortium, together with invited experts, conducted 19 online lectures aimed at popularizing modern scientific knowledge about the structure and functioning of wetland ecosystems. A total of 2,674 people registered for the lectures, including representatives of the scientific and educational communities, school and university students, business and government representatives, and creative professionals. During and after the online lectures, we saw great interest from attendees, receiving many expressions of gratitude and requests to make the lecture recordings publicly available. You asked, and we heard you! All lecture recordings are now publicly available – enjoy! Lecture List: Marsh Science: A Science of the Past, Present, and Future. E.D. Lapshina, Yugra University;Methods for Studying the Structure and Dynamics of Marsh Ecosystems. O.L. Kuznetsov, S.A. Kutenkov, Karelian Research Center of the Russian Academy of Sciences;Life and Adaptations of Plants in Marshes. N.P. Mironycheva-Tokareva, N.P. Kosykh, E.K. Vishnyakova, Institute of Soil Science and Agrochemistry RAS (ISSA RAS);Main Soil Types in Marsh Ecosystems. S.V. Loyko, Tomsk State University;Who Lives in Marshes? Part 1. The Role of Marshes in Maintaining the Annual Cycles of Western Siberian Birds. E.G. Strelnikov, Yugansky Nature Reserve;Who Lives in Marshes? Part 2. Mammals, Reptiles, and Amphibians of Marshes. N.V. Nakonechny, Surgut State University;Geography of Marshes Worldwide and in Russia and the Coverage of Its Territories by the Russian Climate Monitoring System. Yu.V. Kupriyanova, Yugra University ;The Role of Coastal Wetlands in Climate Change Mitigation: A Review of Research Trends. N.E. Ryazanova, MGIMO;Tall-grass Spruce Forests in Lowland Bogs – Refugia of Biological Diversity. A.V. Gornov, CEPF RAS;The Role of Bogs in Climate Regulation: Why Methane Emissions Cannot Be Ignored and How Should They Be Accounted for? A.F. Sabrekov, Yugra University;Carbon Stocks and Fluxes in Soil and Biomass of Main Bog Types. E.E. Veretennikova, E.A. Dyukarev, Institute of Monitoring of Climatic and Ecological Systems, Yugra University;The Potential of Bog Ecosystems for Greenhouse Gas Absorption, Carbon Accumulation, and Sequestration: Applied Aspects. A.A. Kaverin, Yugra University;Use of Unmanned Aerial Vehicles (UAVs) in Bog Ecosystem Studies: Automation of Ground-Based Measurements. D.V. Ilyasov, Yugra University;Dynamics of Vegetation and Carbon Stocks in Swamp Forests Under the Effects of Drainage. A.A. Egorov, Institute of Forest Science of the Russian Academy of Sciences;Rewetting of Drained Swamps as a Method of Protection from Peat Fires. M.A. Medvedeva, Institute of Forest Science of the Russian Academy of Sciences;The Role of Swamps in the Livelihoods of Indigenous Minority Peoples. S.V. Onina, Yugra University;Phyto-Purification Systems – Constructed Wetlands. N.M. Shchegolkova, Faculty of Soil Science, Moscow State University;Inorganic Carbon in Swamp Ecosystems. E.A. Soldatova, Institute of Forest Science of the Russian Academy of Sciences;Mathematical Modeling in Swamp Science. M.V. Glagolev, Faculty of Soil Science, Moscow State University.

Photo 1: Participants of one of the first expeditions to study the octachlorodibenzo-p-dioxin anomaly in the Hoang Lien Nature Reserve. Researchers from the A.N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences (IEE RAS), together with colleagues from the Department of Chemistry and Environment of the Joint Russian-Vietnamese Tropical Science and Technology Center, conducted a study of soils from various regions of Vietnam and discovered over thirty structural groups of previously undescribed highly chlorinated organic compounds, presumably of natural origin. Back in the mid-2000s, researchers recorded abnormally high levels of one dioxin, octachlorodibenzo-p-dioxin, in Hoang Lien National Park in northern Vietnam, along with a distribution pattern of other dioxins atypical for industrial processes. Interestingly, elevated levels of this substance with a similar distribution pattern were also observed in Australia, including in nature reserves unaffected by human activity. These observations led scientists to ask: could such compounds be of natural origin and what other organochlorines are present in these soils? And whether similar processes are occurring in other regions of Vietnam. To answer these questions, a modern method, high-precision mass spectrometry (HRAM MS), was used. Photo 2: Soil profile at the site with the highest octachlorodibenzo-p-dioxin content in Vietnam, Hoang Lien Nature Reserve. The analysis revealed more than two hundred individual highly chlorinated compounds, most of which had not previously been encountered in the scientific literature. Some compounds were structurally similar to natural antibiotics. "The wide variety of structures with a limited number of isomers and the absence of obvious anthropogenic precursors indicate the existence of a number of natural, likely biogenic, processes leading to their formation and serve as further confirmation of the hypothesis of the natural origin of octachlorodibenzo-p-dioxin," notes Andrey Shelepchikov, leading researcher at the Laboratory of Analytical Ecotoxicology at IEE RAS. To date, more than eight thousand natural halogen-containing compounds are known, but most contain only a small number of chlorine atoms. The discovery of large quantities of highly and even perchlorinated compounds in background soils significantly expands our understanding of natural chlorination processes. Scientists have yet to determine the biological and chemical processes that lead to the formation of these compounds and their role in ecosystem functioning. Based on their structural similarity, some of them may possess antibiotic properties, opening up prospects for the search for compounds to combat pathogens resistant to known antibiotics. The work was published in the journal Chemosphere: Andrey A. Shelepchikov, Anastasia D. Kudryavtseva, Truong X. Nghiem. Naturally occurring highly chlorinated organic compounds in soils with elevated OCDD concentrations, Chemosphere, Volume 391, 2025, 144723.

Fig.1: A specimen of the marbled crayfish Procambarus fallax (Hagen, 1870) from the Alma River (Crimea) and its coloration during life Research conducted by the scientists from the A.N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences (Moscow) and the A.O. Kovalevsky Institute of Southern Sea Biology of the Russian Academy of Sciences (Sevastopol) in 2022–2024 revealed the presence of the invasive marbled crayfish Procambarus fallax (Hagen, 1870) (Decapoda: Cambaridae) in western Crimea, in the lower reaches of the Alma and Belbek rivers. The presence of this species was also reported at the mouth of the Chernaya River. "This is the first reliable evidence, based on a comprehensive morphological and molecular genetic analysis, of the presence of this highly invasive species on the Crimean Peninsula and yet another discovery of an invasive species in the fauna of Russia. Phylogenetic analysis showed that the Crimean specimens share the same haplotype as the invasive subpopulation currently recorded in the waters of Europe (Sweden), Japan, and Madagascar," notes Ivan Marin, PhD in Biology and Senior Researcher at IEE RAS. The studied individuals of the European subpopulation, also designated Procambarus virginalis Lyko, 2017, possess a single haplotype, indicating a relatively recent introduction of the species. Research by American scientists has shown that both parental haplotypes of P. virginalis were inherited from the original subpopulation of P. fallax, a sexually reproducing species native to the Everglades (southern Florida, USA), where triploid individuals of this species have also been identified. The European (invasive) subpopulation is represented exclusively by triploid parthenogenetic individuals (females)—the only known example among decapod crustaceans that reproduce via apomictic parthenogenesis. This characteristic provides the population with exceptional dispersal capacity—colonizing new bodies of water is possible even with the introduction of a single juvenile individual. The invasive subpopulation also exhibits high ecological plasticity, including tolerance to low oxygen levels and short-term temperature drops below 8°C. In Crimea, in December 2022, this species was discovered in bodies of water that periodically freeze over during the winter. However, at the time of sampling on December 12, 2022, the overnight air temperature dropped to 0°C, and the water temperature in the Belbek River (Sevastopol) was approximately 6–8°C. The authors of the study hypothesize that the spread of the marbled crayfish in the lower reaches of the Alma and Belbek Rivers may be related to the activity of migratory birds (e.g., mute swans and ducks), which are capable of transporting juvenile crayfish or their eggs on their feet, plants, or feathers. This hypothesis is supported by the disjunctive (discontinuous) nature of the finds' range, which does not correspond to a gradual spread along the riverbeds. Notably, the marbled crayfish coexists at the mouth of the Belbek River with the epigean amphipod Niphargus potamophilus Birštein, 1954 (Amphipoda: Niphargidae), for which this locality remains the only known occurrence in Crimea. It has previously been suggested that this species is most likely carried from one body of water to another by migratory birds. New data show that marbled crayfish can survive at average annual temperatures of approximately 12°C (typical for Sevastopol). This suggests the possibility of this species appearing, or being discovered soon, in other regions with similar climatic conditions—Anapa (12.4°C), Tuapse (12.4°C), Krasnodar (12.7°C), Sochi (14.4°C), as well as in cooler areas, such as Rostov-on-Don (11°C). In conclusion, the data obtained convincingly demonstrate the ongoing eastern expansion of this tropical invasive species. However, there is currently no evidence of its significant negative impact on local ecosystems. Unlike many other invasive organisms, the marbled crayfish does not form dense aggregations due to its relatively small size (50–60 mm in adults) and serves as a prey item for a number of predators, including large fish and larger native crayfish species. Significant predation pressure likely limits population sizes and reduces potential impacts on ecosystems of the Crimean Peninsula, where crayfish are currently found only occasionally. However, this species can transmit certain diseases, particularly crayfish plague, a mycotic (fungal) disease that causes widespread mortality in European crayfish. The work was published in the journal Arthropoda Selecta: Marin I.N., Statkevich S.V. 2025. The first discovery of the invasive marbled crayfish Procambarus fallax (Hagen, 1870) in Crimea // Arthropoda Selecta. Vol. 34. No. 3: 359–364. This study is the first to mention the presence of invasive crayfish in the Chernaya River. Related materials: AiF: "Oceanologist Tavrichesky assessed the danger of marbled crayfish appearing in Crimea" RBC: "Dangerous marbled crayfish discovered for the first time in the rivers of the Crimean Peninsula" Kuban24: "New species of marbled crayfish from Crimea capable of colonizing the rivers of Krasnodar Krai" SevKor: "Dangerous crayfish discovered in Sevastopol rivers" Rostovskaya Gazeta: "Blue slime and marbled crayfish: scientists report threat to Rostov Oblast" Realnoe Vremya: "Marbled crayfish discovered in Crimean rivers" Gorod24: "Dangerous marbled crayfish discovered for the first time in Crimean rivers" MK: "New species of crayfish discovered in Crimean rivers" ForPost: "Dangerous foreigner trying to enter Russia through Sevastopol" KIA: "Marbled crayfish have appeared in Crimean rivers" Crimea News Feed: "A dangerous invasive crayfish has been found in Crimean rivers." AiF: "An uninvited guest. What threat does the marbled crayfish from the US pose to the Russian ecosystem?"   AiF Zen: "Tavrichesky explained how plague-carrying marbled crayfish arrived in Crimea." SmolNarod: "A dangerous crayfish has arrived in Crimea through unknown means, potentially damaging the local ecosystem." Amik: "Plague carriers. What danger do the marbled crayfish that have appeared in Crimean waters pose?" Science.Mail: "Marbled crayfish discovered in Crimean rivers for the first time" Komsomolskaya Pravda: "A new species for Russia: marbled crayfish discovered in Crimean rivers" Crimea News: "Marbled crayfish discovered in Crimean rivers" News.Mail: "A new species of crayfish for Russia may appear in Rostov" Komsomolskaya Pravda:  "A new species of crayfish for Russia may appear in Rostov" Sevastopol News:  "A dangerous foreigner is trying to enter Russia through Sevastopol" Realnoe Vremya: "An invasive marbled crayfish has been discovered in Crimea" RIA Novosti Crimea: "A dangerous invasive crayfish has been found in Crimean rivers" Informer: "A new species of crayfish for Russia has been discovered in Crimean rivers" NewsSpot: "A new plague on our ecosystems – marbled crayfish have taken over the waterways of the Crimean Peninsula"

The A.N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences will participate in the All-Russian Winter Scientific School of the Floating University, which will be held from February 9 to 11, 2026. The School will be held in Moscow, St. Petersburg, Kaliningrad, Murmansk, Sevastopol, Rostov-on-Don, Arkhangelsk, Listvyanka (Lake Baikal), Vladivostok, and Yuzhno-Sakhalinsk. The Winter School program includes lectures, workshops, excursions, and introductions to research teams in laboratories. The School will help junior students choose a research field and become familiar with modern marine science. Senior students, graduate students, and young scientists will find a supervisor and expand their professional network. The School will also include one-day research sessions for high school students. The Winter School program includes 50 tracks in the following scientific areas: - Ocean and Atmospheric Physics - Marine Biology - Geology and Geophysics - Data Analysis, Methods, and Instrumentation - Interdisciplinary Research The IEE RAS track is "Marine Biodiversity: Methods and Trends in Marine Mammal and Bird Studies." Detailed information can be found at the link. The school is designed for undergraduate and graduate students majoring in Earth sciences, as well as related fields such as physics, mathematics, computer science, biology, and chemistry. Participants of the Winter School will be eligible for a competitive selection for the Floating University expeditions during the 2026 field season and will also have access to an aggregator of internships and job openings from program partners. To participate in the Winter School, please complete an application form on the website pu-ocean.ru. Space is limited; a competitive selection process will be conducted based on the applications received. Deadline: November 14, 2025! The school will be held in Russian. Participation in the Winter School is free. Participants will receive information on our Telegram channel. The Winter School is the first stage of the All-Russian scientific and educational program "Floating University". The program is implemented within the framework of the UN Decade of Ocean Science and is part of the "Science of Victory" initiative of the Decade of Science and Technology of the Russian Federation, and is supported by the Ministry of Science and Higher Education. The overall organization is carried out by the Floating University Coordination Center at the Moscow Institute of Physics and Technology. The Winter School helps disseminate knowledge about the ocean, provide professional guidance to talented young people, and thereby address the personnel shortage in the field of Earth sciences in Russia.

Fig. 1. Examples of pigment patterns of African cichlids (left) and Neotropical cichlids (right) (photo: Denis Prazdnikov) Cichlids are one of the most species-rich families of bony fishes and exhibit an exceptional diversity of color patterns, often rivaling those of coral reef dwellers in their brightness and combination of pattern elements (Fig. 1). The role of endocrine regulatory mechanisms underlying the observed diversity of pigment patterns remains poorly understood. Thyroid hormones are a vital part of the endocrine system and can regulate many growth and development processes, including pigmentation, in vertebrates and humans. Fig. 2. Examples of pigment pattern variability in Amatitlania nigrofasciata females (a) raised under different hormonal conditions: euthyroid (Eu-), hyperthyroid (Hyper-) and hypothyroid (Hypo-). (b) An example of pigment cells involved in the formation of yellow-orange xanthophoric elements on the body (iridophores (i), melanophores (m) and xanthophores (x)). In this study, a researcher at the A.N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences (IEE RAS) analyzed the results of long-term experimental studies on the influence of thyroid hormones on the development of pigment patterns in cichlids. Specifically, the study demonstrated the important role of hormones in regulating various types of pigment cells (melanophores, iridophores, xanthophores, and erythrophores) and the formation of adult pattern elements (Fig. 2). The data obtained indicate that thyroid hormones may participate in the evolution of cichlid coloration through various mechanisms. "Thyroid hormones could be a valuable tool for future research, particularly in assessing the role of variability in the activity of the hypothalamic-pituitary-thyroid axis in the adaptive evolution of various taxonomic groups of fish," said Denis Prazdnikov, PhD, researcher at the Laboratory of Problems of Evolutionary Morphology at the Institute of Ecology and Evolution of the Russian Academy of Sciences. The article was published published in the journal Hydrobiologia (JCR Q1). Prazdnikov, D.V. (2025), "Thyroid hormone signaling in the evolution of pigment patterns in cichlids: results and research prospects." Hydrobiologia 852 (15), 3819–3830. Related materials: RAS: "Thyroid hormones play an important role in the formation of pigment pattern diversity in cichlid fish" Science.Mail: "Russian scientists have uncovered the secret of the vibrant coloration of tropical fish" Pravda: "Underwater alchemy: Experiments with hormones reveal the secrets of the vibrant coloration of tropical fish"

Fig.1: The northern mole vole is a member of the Arvicolinae subfamily of voles. They spend most of their lives underground and rarely emerge to the surface. Subterranean rodents are of particular interest for population genetic studies. They are characterized by natural habitat fragmentation, limited dispersal, relatively low fecundity, and low population density. Researchers from St. Petersburg University, the Institute of Animal Taxonomy and Ecology of the Siberian Branch of the Russian Academy of Sciences (IAET SB RAS), and the A.N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences (IEE RAS) studied genetic diversity in two populations of the northern mole vole (Ellobius talpinus). One population was located in the center of the species' range in the Saratov Region, and the other was on the eastern periphery of its range in the Novosibirsk Region. Fig.2: The range of the northern mole vole and the geographic location of the two studied populations. Analysis of both nuclear and mitochondrial markers revealed that all genetic diversity parameters were significantly lower at the periphery of the range. The polymorphism of the more genetically diverse Saratov population at microsatellite loci was close to the average for mammals as a whole, lower than that of the vast majority of non-subterranean vole species, and comparable to that of the other two subterranean vole species. Overall, this is consistent with the hypothesis of accelerated loss of genetic diversity in rodents with this ecological specialization. At the same time, genetic diversity of the mitochondrial marker in the Saratov population was quite high. This could be a consequence of secondary contact between several highly divergent subpopulations. Thus, these data clearly illustrate the pattern according to which the indices of mitochondrial haplotype diversity of terrestrial mammals have a U-shaped distribution: a large number of species with very low values ​​(the result of long-term isolation) and a large number with high values ​​(the result of mixing of mitochondrial subpopulations and/or immigration of males). Such a tendency towards a dichotomy of genetic diversity may be particularly characteristic of subterranean mammals. Fig.3: The network of mitochondrial D-loop haplotypes in the northern mole vole Ellobius talpinus, where shading along the lines indicates the number of mutations between haplotypes, and black circles between haplotypes correspond to intermediate haplotypes. S – Saratov, N – Novosibirsk As expected for a subterranean species with limited dispersal capabilities, a high level of genetic differentiation was detected even over distances of several kilometers. Within-population genetic structure reflects dispersal strategies. Sexual differences in dispersal lead to differences in the structure and dynamics of nuclear and mitochondrial genes. In most mammalian species (including the vast majority of vole species and subterranean representatives from other taxa), the dispersing sex is male. "The mole voles of the Novosibirsk population retain a typical vole dispersal pattern, whereas no sex differences in dispersal were detected in the Saratov population. This could be due to landscape and ecological features and different reproductive systems, such as the monopolization of reproduction by a single female within a family group in the Saratov region and polygynous reproduction in the Novosibirsk region," explained Elena Volodina, PhD, senior researcher at the Institute of Ecology and Evolution of the Russian Academy of Sciences. The results of the study were published in the Q1 journal Mammalian Biology: Rudyk A.I., Kuprina K., Bergaliev A.M., Galkina S.A., Romanovich A.E., Novikov E.A., Volodina E.V., Smorkatcheva A.V. Genetic diversity and population structure of the subterranean rodent, northern mole vole (Ellobius talpinus). Mammalian Biology, 2025, v. 105, N 5, pp. 571-588.