Ukrainian Antarctic Journal

30 years of Ukraine's polar research in Antarctica and the Ukrainian Antarctic Journal

2024-09-20T16:08:06+02:00

The article briefly presents the history of the Ukrainian Antarctic Akademik Vernadsky station, the beginning and the current state of Antarctic scientific research in Ukraine in the Antarctic Peninsula. It also provides information on the contribution of the scientific publication Ukrainian Antarctic Journal to the dissemination of the results of Antarctic research from the area of the Akademik Vernadsky station.

Snow cover at the Akademik Vernadsky station: response on wind, temperature and precipitation variations

2024-09-20T15:58:00+02:00

We analyze the changes in snow depth at different time scales (from within a day to over many years) and its dependence on the precipitation phases, wind regime, and air temperature. The study employs observational data for snow cover and regular meteorological records of the air temperature (2 m), precipitation, and wind (direction and speed at 10 m) in 2002–2022. The data were processed by classical climatological methods. To compare the data on snow depth with precipitation phases, air temperature, wind speed and direction, we used temporal interpolation. It is shown that solid precipitation occurs most often, when the annual distribution of precipitation is considered. A significant percentage of precipitation in the liquid phase is observed during the Antarctic summer and Antarctic autumn. The portion of the mixed precipitation is the smallest throughout the year. The influence of the precipitation phases on the accumulation/melting of snow has seasonal character. The period from April to November is favorable for snow accumulation. In December, the solid precipitation leads to an increase in snow depth, but the mixed and liquid phases are accompanied the melting of the snow cover. The most significant snow cover grows smaller in January-February due to melting. The emphasis is on the local effect of the snow depth decrease due to strong winds in a setting with the accompanying effect of the thermal factor. Further analysis showed that the parameter most closely associated with snow cover depth reduction was a combination of wind speed and direction. Snow cover depth was reduced the most in January–March due to melting, yet on a daily scale, the reduction’s intensity was not the highest. The highest frequency of cases of intense reduction in snow cover depth by more than 1 cm/3h is seen if the wind is either northerly, northeasterly, or southerly. The most frequent reduction in snow cover depth is seen under the northerly and northeasterly winds and positive temperatures. The north and northeastern air masses’ advection is mostly associated with heat advection, and thus, the snow cover depth is reduced by melting. The eastern, northeastern, and southeasterly winds can be connected to the effect of the foehn winds due to the closeness of the continent. The most frequent occurrence of a significant reduction in the snow cover under the southern wind is noted under a high wind speed and negative air temperature.

Current trends in the zonal distribution and asymmetry of ozone in Antarctica based on satellite measurements

2024-09-20T16:00:25+02:00

The development of the Antarctic ozone hole in late winter and spring (September–November) is the most noticeable phenomenon in the polar stratosphere. It has appeared every season since the early 1980s within the stratospheric polar vortex, preventing air mass from mixing with middle latitudes and affecting the distribution of minor atmospheric constituents, including ozone. The ozone hole strongly depends on dynamic factors, mainly planetary wave propagation from the troposphere to the stratosphere. This study aims to identify the total ozone longitudinal distribution for austral spring and individual months, September, October, and November, and consider the observed trends in detail. We provide an analysis to retrieve trends in total ozone during the development of the ozone hole. Time averaging of the total ozone longitudinal distribution was performed using the three-month ozone means in the austral spring. This procedure eliminates fluctuations and impacts of traveling waves. The latitudinal range of 55–80°S was analyzed to characterize the total ozone distribution in the ozone hole edge and inner regions. Distributions for individual months (September, October, and November) were considered to describe the observed trends in detail. The analysis of the obtained results indicates a close-to-linear negative total ozone trend during the ozone hole intensification (the 1980s–early 1990s). This trend was determined at all the analyzed latitudes, with total ozone decreasing by 150 DU during 15 years in the zonal longitudinal minimum region. However, the analysis of the trends shows that ozone layer recovery is not observed in the Antarctic spring, taking into account low ozone levels in 2020–2023. No clear trends were noted after the period of decline, but the October values in zonal maximum have slightly decreased in the last decade. The zonal minimum has drifted eastward during the decline in total ozone, but the subsequent time range shows large interannual changes without any significant long-term tendency in both maximum and minimum longitudes.

Ionospheric response to the February 27, 2023 intense geomagnetic storm over Kharkiv and the Akademik Vernadsky station

2024-09-23T07:44:56+02:00

This study aims to investigate ionospheric responses to the February 27, 2023 intense geomagnetic storm over Kharkiv and the Akademik Vernadsky (hereinafter – Vernadsky) station using ionosondes. The behavior of the key ionospheric parameters (h_mF2 and N_mF2) before, during, and after the geomagnetic storm was investigated. The observational F2-layer peak electron density and height were compared with those derived by the International Reference Ionosphere (IRI-2016) model. Significant negative ionospheric storms were identified over Kharkiv during all the nights after the geomagnetic storm beginning (up to ~70% decrease of the N_m_F2). At the same time, during the daytime hours of February 27, a moderate positive ionospheric storm (up to ~40% increase of the N_m_F2) was registered. Over Vernadsky Station, during the main phase of the geomagnetic storm, a very strong negative ionospheric storm (up to a factor of ~4 reduction of the N_m_F2) was observed both during daytime and night-time. We offer hypotheses of the possible physical mechanisms (electrodynamics, changes in the neutral composition, partial depletion of the plasmasphere, and a shift of the ionospheric trough) responsible for the observed ionospheric effects. Further investigations with physical models of the coupled atmosphere, ionosphere, and plasmasphere are necessary to identify the dominant drivers in each case. Comparison of the observed ionospheric parameters with the predictions of IRI F2-layer peak sub-models shows that neither h_m_F2 (AMTB-2013 and SHU-2015), and N_m_F2 (URSI and CCIR) sub-models can qualitatively reproduce strong storm-induced ionospheric variations over Kharkiv. Over Vernadsky Station, both h_m_F2 sub-models underestimate the observed h_m_F2 during the storm period, whereas the NmF2 sub-models are more sensitive to the changes in geomagnetic activity. Under geomagnetically quiet conditions, the qualitative agreement between observations and the model is satisfactory, but further improvements of the empirical models are required to reach acceptable accuracy of quantitative predictions.

Exploring an antioxidant and hemostasis activity of peptides from Antarctic krill Euphausia superba

2024-09-12T14:47:32+02:00

The goal of the study was to obtain the fractions of endogenous and hydrolytic peptides from the hydrobiont Euphausia superba and evaluate their antioxidant potential and possible activity against certain hemostasis factors. The fraction of endogenous peptides was isolated by stepwise precipitation of proteins with perchloric acid and ethanol. Peptides with a molecular weight up to 5 kDa were isolated by by ultrafiltration. Hydrolysis with trypsin was used to obtain hydrolytic peptides. The purity of peptide fractions was confirmed by SDS-polyacrylamide gel electrophoresis. Antioxidant activity was assessed by analyzing the peptides’ reducing power, 2,2-diphenyl-1-picrylhydrazyl, and nitric oxide radical scavenging activity. To assess the effect of peptides on the amidolytic activity of thrombin, active thrombin was preincubated with peptide fractions, and further thrombin activity was determined using the chromogenic substrate S2238. The ability of the peptides to influence ADP-induced platelet aggregation was tested in platelet-rich plasma. The results showed that endogenous and hydrolytic peptides exhibit moderate antioxidant activity; however, endogenous peptides were more potent antioxidants than peptides produced by trypsin hydrolysis. The influence of E. superba peptides on some hemostasis factors has been established. Inhibition of ADP-induced platelet aggregation by hydrolytic peptides (by 1.76 times) was found, while endogenous peptides possess the opposite effect. The differences in the activity and effectiveness of the peptides indicate that the fractions contain molecules that differ in amino acid composition. Considering the data, E. superba can be a source for peptides with moderate antioxidant activity and peptides that can affect the activity of key hemostasis factors.

Plant growth-promoting potential of bacterial isolates from the rhizosphere of Deschampsia antarctica

2024-09-20T16:05:05+02:00

Plants’ adaptations, in combination with the rhizosphere and endosphere microbiome, ensure their survival in the extreme conditions of the Antarctic. The work aimed to quantify the culturable microorganisms of different groups and establish the plant growth-promoting potential of bacterial isolates from the rhizosphere of Deschampsia antarctica. Standard microbiological methods (enumeration of microorganisms and study of the properties of isolates, in particular, the cell wall organization by Gram staining, motility, endospore formation, growth at different temperatures, halotolerance, need for oxygen, ability to assimilate some organic carbon sources) and biochemical methods to determine the properties of isolates (oxidase, catalase activities, tests for the ability to reduce nitrate, produce amylases, lipases, proteases). The ability of the isolates to produce siderophores was determined using a medium with chromazurol S and hexadecyltrimethylammonium bromide, to solubilize insoluble phosphate-containing compounds using Pikowska’s medium with Ca₃(PO4)₂ and Menkina’s medium with egg lecithin. The content of auxin-like substances in the medium was determined by the Salkowski method. The effect of the isolates on wheat growth was determined by the germination of wheat seeds treated with the isolates, the length of shoots and roots of plants, and chlorophyll content in leaves. The isolates were identified using phylogenetic analysis of the 16S rRNA gene. The most abundant groups of microorganisms in the rhizosphere of D. antarctica were oligotrophic, oligonitrophilic, and cellulose-degrading microorganisms. Among 120 isolates of the rhizosphere zone of D. antarctica, 7 oligonitrophilic isolates (RE1, RE3, RE4, RE8, RP8, RO4, RT1) were selected, which solubilized insoluble phosphate-containing compounds, synthesized lipases, amylases, auxin-like substances, and siderophores. Isolate RT1 (Bacillus sp. RT1 by physiological and biochemical properties and the 16S rRNA gene) showed the best plant growth-promoting properties. Treatment of wheat seeds with this isolate increased germination by 25%, shoot and root length by 15%, leaf area 3 times, and chlorophyll content 1.6 times.

Oribatid mites (Acariformes: Sarcoptiformes) in Sub-Antarctic Islands and Antarctica: a track analysis

2024-09-20T16:06:34+02:00

Southern non-marine mites are widely distributed in the continents that developed out of the macrocontinent Gondwana, with similar groups found in Australia, New Zealand, Sub-Antarctic Islands, and southern South America. In the present study, we conducted a literature analysis of non-marine oribatid (moss) mite species (Acariformes: Sarcoptiformes) studies at the Sub-Antarctic Islands and Antarctic continent, an applied a track analysis. The purpose of the study is to identify sites potentially inhabited by ancestor species and understand the biogeographical patterns of their dispersion to new sites where current species have arisen through speciation processes. The results of the track analysis revealed the existence of species that inhabit three main zones: the first track includes South Georgia and the Sub-Antarctic Islands of the South Atlantic, the southern Indian Ocean and southern Australia and New Zealand. The second track includes South Georgia Island and the Antarctic Peninsula; and the third track includes South Georgia Island and the Falkland Islands. All these tracks intersect in South Georgia Island, suggesting that this island would be the zone from which the species reported spread to the other sites mentioned, colonizing Antarctica, the Falkland Islands, and probably southern South America.

Polar research infrastructure network: the Ukrainian input

2024-10-16T09:52:39+02:00

The polar regions play a crucial role in the Earth’s system. They are essential for our climate and are sentinels of climate change and human expansion. The polar research community needs access to world-class research infrastructure operating on-site to understand and predict essential processes in the polar regions and provide evidence-based information. To address that, a consortium of the European Union and international polar research operators is joining their efforts in the Polar Research Infrastructure Network (POLARIN) project. POLARIN is an international network of polar research infrastructure and services, aiming to address the polar regions' scientific challenges. The network includes various complementary and interdisciplinary top-level research infrastructure: Arctic and Antarctic research stations, ice-capable research vessels, observatories, data bases, and ice core and sediment repositories. This article aims to highlight Ukraine's role in the global effort to study and understand the polar regions, focusing on its participation in POLARIN project and the significance of its potential contributions. It is argued that Ukraine has played a role in shaping policies for creating an international network of polar infrastructure issues by sharing research facilities, contributing data and insights to global discussions on environmental conservation, climate change mitigation, and sustainable development in the polar regions.

Monitoring indicators of vegetative and energy supply of activity in the process of human adaptation to long-term extreme living conditions

2024-09-15T14:09:57+02:00

The study was designed to trace winterers' parameters of vegetative and energetic activity supply over time, arbitrary regulation of mental processes, and evaluation of sleep quality. It also aims to identify a complex of informative criteria for human adaptation to harsh living conditions. To this effect, we created an original model that allows to optimize diagnostics of people's functional state and its dynamics given a variety of factors. We examined ten winterers (seven men and three women) whose mean age was 35.4 ± 2.0 years, and 18–28 records per participant were obtained for everyone. Three options for specific changes of adaptive and compensatory reactions in the participants of the long-term Antarctic expedition were observed. The first included pronounced vasomotor responses of the hypertonic type with preserved functions of the somnogenic mechanisms. In the second option, measured parameters remained almost always within the norm. For the third option, typical were vasomotor responses following the dystonic type, sleep disturbances of varying degrees, and unstable evaluations of health, activity, and mood, with a tendency to decrease. Under unfavorable changes in the vasomotor responses during the wintering season, the signs of maladaptive changes in the brain's functional state were clearer. A relatively higher proportion of insufficiently adaptive productivity changes as a result of decreasing functional state was seen in the winterers with the first variety of adaptation dynamics. In the people with the second variety, a sufficient level of adaptation is often reached by a compensatory reaction type. As for the third variety, the subjects had the least representation of the stable reaction type and significant compensatory and exhaustive types. Thus, the results allow us to identify a complex of informative parameters that permits evaluating the quality and dynamics of human adaptation to long-term extreme life conditions. The data have to be considered to forecast work productivity in extreme conditions, study the quality and duration of adaptation, and plan measures to prevent the disruption of adaptive-compensatory mechanisms in the wintering team.