Ukrainian Antarctic Journal

Spatial model of the Trooz Glacier dynamics based on meteorological data from the Akademik Vernadsky station

Kornyliy Tretyak — 2026-07-02

This paper models the dynamics of the Trooz Glacier, Antarctic Peninsula. To integrate remote and meteorological data, we processed ice flow velocities derived from satellite radar imagery, air temperature, and precipitation obtained from the ERA5 reanalysis, and in situ meteorological observations from the Ukrainian Antarctic Akademik Vernadsky station. Glacier surface velocity was estimated using the offset-tracking method applied to Sentinel-1 satellite data for the period 2015–2025, generating 286 ice flow maps. An approach is developed to calculate air temperature over the glacier surface using in situ measurements from the remotely located Akademik Vernadsky station, in the absence of additional data. Spatial models of temperature and glacier velocity were constructed, accounting for additional parameters such as precipitation and glacier surface elevation above sea level. Time series analysis over the past decade indicates contrasting trends: increasing air temperature at the Akademik Vernadsky station (+0.12 °C/year) and decreasing temperatures over the glacier surface (–0.07 to –0.13 °C/year). A Fourier series approximation made it possible to clarify a seasonal pattern in glacier velocity. From the mean velocities, there is a tendency toward 1–4% acceleration in ice flow. Analysis of the model showed that air temperature and surface elevation together explain approximately 54% of the spatial variation in mean velocity, with the remaining variability attributable to other factors, including glacier bed geometry, ice thickness, subglacial drainage conditions, and local ice-flow morphology. The resulting spatial models can be used to further predict climate-driven changes in the glacier system.

Microclimatological variability of incoming solar irradiance and snow cover availability near native vascular plants in the maritime Antarctic

Mykhailo Savenets — 2026-07-02

Incoming solar irradiance is a crucial factor for the survival of native vascular plants in Antarctica, providing the primary energy source for local terrestrial vegetation growth. We analyse the microscale variability of incoming solar irradiance at the surface and evaluate its applicability as a proxy parameter for detecting snow cover availability in remote regions. The study is based on a network of 38 temperature and light sensors deployed within an established monitoring site in the Argentine Islands Kyiv Peninsula region during 2017–2025. At the microscale level, in sites where Colobanthus quitensis and Deschampsia antarctica occur, typical austral-summer irradiance values range from 200 to 500 W ⋅ m^–2, with deviations of up to ±60% driven by local microscale conditions. We analysed the periods with near-zero measured irradiance, indicating stable snow cover that typically occurred from April to October. Being measured at the surface, solar irradiance disappearance can serve as a proxy for snow cover formation. The snow formation timing was relatively consistent, whereas the snowmelt timing varied significantly across sites. At the locations of native vascular plants distribution, the snow-free period varied in the range of 90 to 200 days, being dependent on microclimatological features. No statistically robust differences in the intra-annual irradiance cycle were detected between sites occupied by C. quitensis and D. antarctica; however, irradiance duration suggests a tendency for C. quitensis to preferentially occupy locations with longer irradiated periods. This study emphasises the importance of accounting for incoming solar radiation at the microscale and demonstrates the potential of light sensors as a proxy for assessing snow cover availability in remote Antarctic regions where direct observations are not possible.

Ionospheric response to the weak geomagnetic storm of 1–2 February 2025 in the Weddell Sea Anomaly region: observations from Ukrainian Antarctic Akademik Vernadsky station

Maryna Reznychenko — 2026-07-02

The ionospheric response to the weak geomagnetic storm of 1–2 February 2025 was studied within the Weddell Sea Anomaly region. The behavior of the key ionospheric parameters (N_mF₂ and h_mF₂) was analysed using ionosonde observations from the Ukrainian Antarctic Akademik Vernadsky station and vertical total electron content derived from Global Navigation Satellite System measurements. A pronounced nighttime depletion was observed in both ionosonde F2-layer peak electron density (N_mF₂) and the total electron content values on 1 and 2 February 2025. This indicates the development of the negative phase of the ionospheric storm and a weakening of the Weddell Sea Anomaly under minor geomagnetic disturbances. N_mF₂ decreased by a factor of ~2 on 1 February and by a factor of ~5 on 2 February, while the total electron content was reduced by ~15–20 TECU and ~25 TECU, respectively. The negative phase penetrated farther toward the equator on 1 February, whereas on 2 February it remained restricted to high- and mid-latitude regions. Notably, such a strong depletion in N_mF₂ occurred despite a significant uplift of the F2-layer peak height (h_mF₂) by ~60–70 km. No clear signatures of vertical plasma transport driven by the penetration electric field of magnetospheric origin were found in the observed h_mF₂ variations. The likely reason for such a depletion in ionospheric plasma density is storm-time changes in neutral composition associated with upwelling, reduction in the O/N₂ ratio, and transport of the composition disturbance zone by thermospheric winds from high to low latitudes. These results demonstrate that even minor geomagnetic storms can substantially modify the ionosphere–thermosphere system over Antarctica and significantly impact the Weddell Sea Anomaly.

Diversity and host specificity of monogeneans in Antarctic fishes: a review

Ivanna Dudliv — 2026-07-02

We compiled and harmonised published records of monogeneans from Antarctic and sub-Antarctic fishes, standardising host names, georeferencing localities, deduplicating records, and excluding ambiguous entries (genuslevel hosts or “not specified” hosts) from specificity metrics. We aggregated occurrences from 49 unique localities spanning the Scotia Arc, Antarctic Peninsula, East Antarctica, Ross Sea, and the Kerguelen–Crozet–Heard–Macquarie region. The dataset comprises 31 species (35 including genus-level records), representing 11 genera in 7 families and two subclasses, drawn from 46 publications; species richness within the Subclass Monopisthocotylea was concentrated in Capsalidae (10 species), Gyrodactylidae (9), and Tetraonchoididae (8), with one species each in Mazocraeidae, Hexabothriidae, and Diclidophoridae within Polyopisthocotylea. We identified 29 species-level taxa with unambiguous hosts; of these, 15 (51.7%) were recorded from a single fish host, 6 (20.7%) from two hosts, and 8 (27.6%) from three or more (median = 1; maximum = 12 for Pseudobenedenia nototheniae). The spatial distribution of records was uneven, with the Kerguelen Plateau and the Ross Sea containing the densest clusters. In contrast, many other records occurred as isolated points, limiting the reliability of inferring species ranges. Overall, our analysis provides a curated baseline of diversity, host associations, and regional coverage for Antarctic monogeneans, highlights gaps caused by underspecified hosts and localities, and supplies standardised counts for future taxonomic and ecological work.

Accuracy of time-lapse camera data and variability in Gentoo penguin breeding phenology on Galindez Island

Svitozar Davydenko — 2026-07-02

The condition and dynamics of penguin populations are among the key indicators for assessing Antarctic marine living resources and developing a krill fishery strategy. The Argentine Islands are the southern border of the range of one of the most numerous penguin species – the Gentoo penguin, Pygoscelis papua. The P. papua colony on Galindez Island (CEMP site GAI), where the Ukrainian Antarctic Akademik Vernadsky station is located, is the second southernmost colony of this species, and one of the largest in the region, with a penguin population of about 7 000 adults in peak season (2025/2026) and growing from year to year. Over the past five years, both parts of the colony, one near the main station building and one on the Penguin Point, have expanded significantly towards each other. The largest of the newly formed areas of the colony is located near the Magnetometers Pavilion of Vernadsky Station. This study aims to assess the accuracy of determining the chronology of the main events of the reproductive cycle of P. papua by comparing time-lapse camera data with visual observations of nests, and to examine phenology in the newly formed part of the colony. It was found that the most accurate determination was made for the date of the crèche formation – the time difference was less than 1 day. The dates of first egg laying and first chick hatching were determined with somewhat lower precision, as visual observations and camera recordings differed by about 2 days for both events. Camera data typically lag behind visual observations of events. A larger number of photos captured at 30-minute intervals throughout the daylight hours will help to significantly increase the accuracy of identifying reproductive cycle events. A study of a new part of the Galindez Island colony near the Magnetometers Pavilion (GMP site) showed that all events of the reproductive cycle in this area occur 6–10 days earlier than in the old parts of the colony. This observation is not related to differences in penguin arrival times across different parts of the island and requires further research.

Reproductive endosymbiotic bacteria of Antarctic springtails: on the verge of new discoveries?

Oleksandra Protsenko — 2026-07-02

Endosymbiotic bacteria infect a vast number of invertebrate representatives from diverse taxa. This study reviews the results of identifying endosymbiotic bacteria (specifically the genera Wolbachia, Cardinium, Rickettsia, Arsenophonus and Spiroplasma) that are capable of potentially influencing the reproductive strategies of the host organism in members of the Collembola fauna of the Antarctic region. Outside Antarctica, these bacteria have an important role in forming the adaptive mechanisms and population structures of arthropods in response to changing environmental conditions. This study analyses the species diversity of Antarctic Collembola and conducts a retrospective search for available data on the infection of species found in and beyond the Antarctic region by endosymbiotic bacteria. It was established that these bacteria infect springtail species, including those that may occur in Antarctica (Folsomia candida, Megalothorax minimus, Mesaphorura macrochaeta, and Parisotoma notabilis). The ecology and physiology of the region’s arthropods have already been extensively studied. However, there is currently no information available in the scientific literature indicating the presence of relevant endosymbiotic associations in Antarctic springtails. The identified lack of data may indicate either the potential isolation of local populations or the existence of environmental conditions in which infection of Antarctic springtails by bacteria of the genera Wolbachia, Cardinium, Rickettsia, Arsenophonus,
and Spiroplasma is not possible for various reasons. At the same time, more extensive molecular genetic screening using modern sequencing technologies is required to provide a definitive answer regarding the possible infection of Antarctic springtail species by endosymbiotic bacteria. The analysis of the published data highlights a promising direction for further studies of symbiotic microorganisms associated with Antarctic organisms, particularly springtails.

Biological potential of cultivated microbiota of bryophytes from the different biotopes of the maritime Antarctic

Olha Maslovska — 2026-07-02

Antarctic substrates are inhabited by microorganisms resistant to environmental factors. Since large areas of soil worldwide are saline and contaminated with metals, which limit plant growth, it is important to isolate plant growth-promoting bacteria that are resistant to environmental factors. The aim of this study was to isolate copiotrophic, oligotrophic, oligonitrophilic, phosphate-, and zinc-solubilising bacteria, and to determine their properties, including enzymatic activity, the ability to produce auxins and siderophores, and growth under the influence of heavy metals and NaCl. The research material consisted of samples of short moss turf and cushion subformation with Andreaea depressinervis or Andreaea regularis, bryophyte carpet and mat subformation dominated by Ceratodon purpureus or Sanionia georgicouncinata and tall moss turf subformation (moss bank) fragments dominated by Polytrichum strictum or Chorisodontium aciphyllum, collected from biotopes of the maritime Antarctic. The cultivated microbiota of bryophytes of short moss turf and cushion subformation, bryophyte carpet and mat subformation, and tall moss turf subformation (moss banks) differed in the number of detected microbial groups and their enumeration. Copiotrophs and oligotrophs dominated the bacterial community structure of most samples, but oligonitrophyles prevailed in the short moss turf and cushion subformation fragments with An. depressinervis. Bacteria isolated from samples of bryophyte carpet and mat subformation with dominance of San. georgicouncinata are characterised by a wider range of properties – amylase, protease, cellulase, and lipase activities, and the ability to solubilise ZnO and Ca₃(PO₄)₂. All bacterial isolates synthesised auxin-like compounds (up to 11.8 μg ⋅ ml^–1). Most of them produced siderophores. The isolated bacteria possess a range of adaptive properties, including the ability to grow over a wide temperature range (+4…+42 °C), high salt tolerance (up to 10.0% NaCl), and resistance to heavy metals (Mn²⁺, Fe²⁺, Cu²⁺, Cd²⁺, Co²⁺, and Cr₂O₇ ^2–). Based on 16S rRNA gene sequencing, Bacillus sp. Sg840, Pseudomonas sp. S135, and Sporosarcina sp. S371 were identified. The identified properties and tolerance to environmental factors characterise the plant growthpromoting potential of bacteria isolated from Antarctic bryophyte subformations.

Sex-specific features of neuroendocrine and immune responses in women and men during the Ukrainian Antarctic Expedition

Oleksandr Chernov — 2026-07-02

We investigated sex-specific features of neuroendocrine, cardiovascular, and immune responses in participants of the Ukrainian Antarctic expeditions during prolonged isolation, as well as in response to acute physical exercise, with a comparative evaluation in women and men. The study included 22 men and 9 women who spent one year at the Ukrainian Antarctic Akademik Vernadsky station, as well as control groups residing in Kyiv. Blood samples were collected before the expedition, quarterly during the stay at the station, and after returning to Kyiv. Serum cortisol, testosterone, and growth hormone levels were measured using enzyme-linked immunosorbent assay (ELISA), while lymphocyte subpopulations were analysed by flow cytometry. A modified Cooper test was used as a model of acute physical exercise to assess physiological responses among expedition candidates. The results showed that cortisol levels increased already in the first quarter of the expedition in participants of both sexes, suggesting activation of the hypothalamic–pituitary–adrenal axis during adaptation to Antarctic conditions. In men, peak cortisol levels were observed at the early stages of the expedition, whereas in women, a more gradual increase was noted, with peak values occurring later in the mission. Testosterone levels increased in both sexes during the expedition; however, after returning to normal conditions, they tended to normalise primarily in men. In women, the increase in heart rate was less pronounced, and recovery of hemodynamic parameters was faster after exertion. The immune response to physical stress also showed sex-related differences: in men, a statistically significant increase in the absolute number of NK cells was observed after exercise, whereas in women these changes were less pronounced; no significant changes in the absolute number of T helper cells were detected in either group. The obtained results indicate that neuroendocrine adaptation to prolonged Antarctic isolation exhibits sex-specific characteristics, but is not associated with evidence of poorer clinical tolerance in women.