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The paper presents the results of U-Pb isotope dating of zircons extracted from rocks of the southern part of the Baltic Shield (Early Riphean conglomerates and Paleoproterozoic secondary quartzites) and makes a comparison of these results with the ages of crystalline complexes of the East European Platform (EEP). The paper presents the study results on composition of quartzites from the Bol. Tyuters and Gogland islands. There has been discussion about tectonic and paleogeographical features in the period prior to the beginning of Riphean sedimentation in the northeastern part of the EEP. It is concluded that the conglomerates are composed of erosional products of mainly Paleoproterozoic and less frequently Archean crystalline complexes. At the same time, the rocks at the base of the generalized section of Riphean deposits (Gogland group), did not contain any zircons with ages referring to 200 million years prior to the inferred time (1640–1660 Ma) of the beginning of the conglomerate sequence formation. The rocks that compose the Gogland group and their underlying Paleoproterozoic basement rocks have significant differences. We associate these differences with the existence of pre-Riphean sheet-like deposits, comprising rocks of essentially quartz composition, in the southern Baltic Shield, in the upper levels of the peneplenized Paleoproterozoic basement structure. The deposits relics are only found on the Bol. Tyuters Island; in all other places, these deposits were completely eroded or underwent significant structural and material transformations. The absence of detrital zircon grains with ages ranging from 1.87 to 1.65 Ga in the clastic rocks of the Riphean basal horizons implies no noticeable Pre-Riphean and Early Riphean orogenic movements in the northeastern part of the EEP. Tectono-magmatic reactivation in this region occurred only in the middle of the Early Riphean.

The paper covers the results of the civic science project that involved VIR partners – Russian Geographical Society, Russian Schoolchildren’s Movement and the Association of Communicators in Education and Science – as organizers and schoolchildren, students and their parents from different regions of Russia as participants. The project, started in 2020 with observations of a single crop – an apple tree, elicited a positive response from motivated schoolchildren and was continued in 2021–2022 with the inclusion of various fruit and berry crops. In the course of the three years of the project, a phenological database was replenished with 3340 entries made by 670 project participants.

A complex cladistic analysis of molecular and morphological data of the Monimiaceae family is carried out. The hypothetic modes of the family dispersal are reconstructed basing on the data received for the studied representatives of the Monimiaceae family from all parts of the range and available fossils data. The family supposedly originated in Africa and penetrated into South America via the Antarctic way, and through the Arabian Peninsula and Sri-Lanka to South-Eastern Asia, Australia, New Zealand, New Caledonia, and further then to Madagascar.

Gogland Island, located in the Gulf of Finland in the Baltic Sea, was densely populated in the past but has been nearly abandoned since the Second World War. The self-restoration of wildlife takes place there. Recent research on the island aimed to evaluate the conservation value of this process. It was expected that the island would demonstrate a standard for the perfect state of protected areas of the boreal zone of Europe. The island has been overgrown with forests; open areas occupy insignificant parts and tend to shrink. Picturesque landscapes have been formed, but the conservation value of these areas are questionable as the biodiversity is rather low there. They contain "empty forest" that is partly impassable. The island demonstrates that to achieve the maximum effect for biodiversity conservation, the abandonment of land without any management would be insufficient. The fate of the island partly supports the concept of Pleistocene rewilding: a mosaic of forests and meadows, maintained by ungulates, should be considered a normal state of environments. [ABSTRACT FROM AUTHOR]

The volcanoes of Kamchatka are a World Heritage Site. They are of aesthetic, conservation, and scientific value; therefore, they must be protected from negative anthropogenic influences. However, according to the recent assessment by the International Union for Conservation of Nature, this site inspires significant concern. A similar viewpoint was also expressed in the local press. A part of the site, Avachinsky Pass, inspires a particular concern. This is a place between the volcanoes Koryaksky and Avachinsky. An excessive number of visitors was considered the main threat because it resulted in the trampling of soil and the extirpation of threatened animals. We performed a survey of the Avachinsky Pass aiming to estimate its state. Based on aerial pictures and observation we composed a scheme of habitats over the area around Avachinsky Pass revealing the disturbed plots of land. Moreover, we registered vertebrates considering them as biological indicators. It became clear that tourism has a significant impact on the state of the Avachinsky Pass, but the affected area is relatively small. Despite a large number of visitors, the survey revealed high biodiversity. We registered 19 species of birds and 9 species of mammals. Among them, black-capped marmots are especially informative as they have a settled way of life; they do occur on the Pass. The absence of grazing and logging contributes to the conservation of elfin forests and other plant communities on the slopes making the object resistant to anthropogenic impacts. Off-road vehicles pose the biggest threat to bare-ground revegetation.

Prielbrusye National Park is one of the most popular tourist destinations in Russia. In recent years internal tourism development, stimulated by restrictive measures (due to the COVID pandemic and geopolitical situation), resulted in significant growth of tourist flow to the national park’s territory. A surge in anthropogenic load on the park’s geosystems might degrade them and lead to environmental pollution. This research involved chemical studies of natural waters and snow from the south slope of the Elbrus and audit of the most popular tourist trails. The results have shown that in the snow alongside mountain hiking pistes to the Elbrus all the way up to 4,720 m above sea level (a.s.l.) oil stains concentration is up to 38 times higher than maximum acceptable concentration (MAC). Content analysis of heavy metals in snow cover on the Elbrus slopes and in the river Baksan has shown a significant rise in lead load over the period of 2015–2021 from the trace levels to 1.5 MAC, which is the result of increased anthropogenic load on the south slope of the Elbrus mountain. Ground observation of tourist trails has brought to light numerous patches of vegetation trampling, width extension and branching of the main trail, as well as campfire sites. The research results can be used as a rationale to take measures to reduce recreational load, to improve local geosystems’ condition and to develop a plan of action on nature conservation within the park’s territory.

A new naviculoid diatom genus, Gandhia gen. nov., was described based on a detailed morphological investigation using light and scanning electron microscopy. Gandhia obtecta (Jüttner and Cox) Kulikovskiy, Glushchenko, Iurmanov, M.Thacker, B.Karthick and Kociolek comb. nov. was previously described as a member of the genus Navicula Bory sensu lato. This species differs from other species in the genus Navicula s.l. by the presence of an internal siliceous lamina covering the alveoli and forming the image of longitudinal lines on either side of the axial area, visible in LM. The presence of this siliceous lamina is similar to laminae in genera such as Pinnularia and Gomphoneis. This unusual morphology is not typical for Navicula sensu stricto, as previously noted by other scientists. Additional investigation of Gandhia obtecta comb. nov. and Gandhia ramosissimoides (H.P. Gandhi) Kulikovskiy, Glushchenko, M.Thacker, B.Karthick and Kociolek comb. nov. from waterbodies of the Western Ghats and the Himalayan region was conducted. Comparison with other species with the same morphological features included two additional species in the genus, namely, Gandhia jakovljevicii (Hustedt) Kulikovskiy, Glushchenko, M.Thacker, B.Karthick, and Kociolek comb. nov. and Gandhia lucida (Pantocsek) Kulikovskiy, Glushchenko, M.Thacker, B.Karthick and Kociolek comb. nov. We discuss the biogeographic patterns of the species, including disjuncts between Europe and Asia.

Gogland Island, located in the Gulf of Finland in the Baltic Sea, was densely populated in the past but has been nearly abandoned since the Second World War. The self-restoration of wildlife takes place there. Recent research on the island aimed to evaluate the conservation value of this process. It was expected that the island would demonstrate a standard for the perfect state of protected areas of the boreal zone of Europe. The island has been overgrown with forests; open areas occupy insignificant parts and tend to shrink. Picturesque landscapes have been formed, but the conservation value of these areas are questionable as the biodiversity is rather low there. They contain “empty forest” that is partly impassable. The island demonstrates that to achieve the maximum effect for biodiversity conservation, the abandonment of land without any management would be insufficient. The fate of the island partly supports the concept of Pleistocene rewilding: a mosaic of forests and meadows, maintained by ungulates, should be considered a normal state of environments.

Introduction. The resolution of the problem of radio polarimetry in multiposition microwave screening systems (MMSS) with aperture synthesis requires the use of antennas with a high level of cross-polarization discrimination (XPD) in a wide spatial angle. The radio images are reconstructed in MMSS at distances commensurate with the aperture of the antenna structures. Therefore, the value of the spatial angle, at which high XPD is required, can reach 30°. This leads to a new problem of creating an antenna configuration of the X and Ku band, the application of which in MMSS will resolve the problem of constructing a radio image of depolarized microwave radiation scattered on the human body in the form of hidden dangerous objects.Aim. To develop a double-ridged receiving antenna for long-term operation in MMSS with an XPD level of 28 dB at a spatial angle of 30° and operating frequencies of 8…20 GHz.Materials and methods. The requirements for the receiving antenna in MMSS were determined. Theoretical justifications were proposed for the choice of antenna design. Aperture synthesis was used to construct microwave images in MMSS. The stages and results of modelling broadband double-ridge antennas were presented using the CST Studio software broadly applied for three-dimensional electro-magnetic field modelling. The results of modelling pyramidal and conical double-ridged antennas, as well as those in circular and elliptical waveguides, were analyzed. The designed antenna was tested in an anechoic chamber. The measurement results were compared with those obtained during simulation.Results. An elliptical double-ridged horn antenna with a VSWR of no more than 2 and cross-polarization discrimination in a spatial angle of 30° of no less than 28 dB for the frequency range that covers an octave was designed and constructed.Conclusion. The developed antenna can be used in MMSS for the purpose of detecting the effect of micro-wave radiation depolarization as hidden dangerous objects on a human body. Such characteristics of the antenna as its high XPD value in a wide spatial angle will allow the future introduction of microwave polarimetry in MMSS.