Measurement of the difference in the geomagnetic induction between the magnetometer pillars of the geomagnetic observatory of the Ukrainian Antarctic Akademik Vernadsky station

The article describes the features of measurements of spatial inhomogeneities of the geomagnetic field between the pillars of magnetometers in the measuring pavilion, which were carried out at the geomagnetic observatory of the Ukrainian Antarctic Akademik Vernadsky station in 2015. Some preliminary results of these measurements are also given. The concept of the timescaled value of the geomagnetic field induction is introduced, which is convenient for compensating for time changes of the real geomagnetic induction and bringing it to one reference level of induction. The differences in geomagnetic induction between pillars are obtained as the differences in time-scaled values of the geomagnetic induction on the pillars. The technique allows comparing long-term series of measurements of field inhomogeneities at important points in space. The main objectives are to increase the accuracy of measurements of local inhomogeneities of the geomagnetic field in the measuring pavilion of the geomagnetic observatory of the Ukrainian Antarctic Akademik Vernadsky station and to determine the differences in the geomagnetic induction between the pillars on which the magnetometer sensors are installed. Obtaining numerical values of the differences in the geomagnetic induction between the pillars as objective criteria needed to assess the accuracy of the data in the final processing of geomagnetic observatory data. The method of comparison of two series of data is used: one obtained by the scalar magnetometer installed in the observatory as a mandatory stationary device, and the other obtained during measurements with a mobile magnetometer at the desired points in space. Compensation of temporal changes of the geomagnetic field by time-scaling the measurement readings of the mobile magnetometer relative to one reference value and thus, bringing them to one selected and fixed time epoch. Special geometric scheme of mobile measurements in the space around the pillars with magnetometer sensors or at important points in space. A rough estimate of method errors. Based on the analysis of the obtained data, the efficiency of the method and its acceptable potential accuracy were confirmed. We obtained approximate numerical values of the differences in the geomagnetic field induction between the pillars on which the magnetometer sensors are installed. Further increase in the accuracy of determining these differences is possible using modern devices of high accuracy and GPS-synchronization of mobile measurements.

Calculation of United Quality Latent Indices of Deschampsia antarctica plants adaptability of different origin grown in vitro

The research was to develop and describe in detail the algorithm for calculating the United Quality Latent Index (UQLI, Iq ) of plant adaptability from the collection of Deschampsia antarctica Ė. Desv. genotypes obtained from seeds collected at different sites in the Argentine Islands region, the maritime Antarctic, and grown in vitro at the laboratory conditions. Genome size and genetic distances by ISSR and IRAP markers according to data from published articles were used as basic indices of initial genetic heterogeneity for analyzed plant genotypes. To assess individual adaptability indices for eleven D. antarctica genotypes, we used measurement of the leaf length morphometric index and determination of the flavonoids content by rutin and the content of photosynthetic pigments. The spectra of reserve and protective proteins in leaves were investigated by polyacrylamide gel electrophoresis. To obtain the United Quality Latent Index of Adaptability (Iqi, UQLI), the method of extreme grouping was used. The estimation of Iqi (UQLI) was performed using pairwise comparisons of indices from differences sets for each pair of genotypes. We developed and described in detail the algorithm for Iqi estimation for eleven D. antarctica genotypes. As an example of application, correlation models of probability relations of the indices are presented. To evaluate the complex adaptability for eleven D. antarctica genotypes grown in vitro we used developed algorithm for the UQLI calculation. The individuality of the adaptive portrait for all studied genotypes under in vitro cultivation conditions was shown. The influence of basic genetic characteristics (genome size and genetic distances) on auxin metabolism-related indices of leaf length and flavonoid content was shown. Such effect may be carried out by genetic characteristics both individually and together, probably via auxin metabolism. Among the eight genotypes researched, we distinguish four different variants by correlation models and two (positive and negative) by the general Iqi value. Thus the Iqi (UQLI) is proposed to describe a large number of source data at different organization levels which characterize sample genotypes by reducing the dimensions to one dimensionless number. This genotypes’ individuality and the peculiarities of their grouping by Iqi should be taken into account when doing experimental studies using these genotypes as model plants, especially in experiments studying the regulation of productivity and the effect of the various exogenous factors, etc.

Variability of Weddell Sea ionospheric anomaly as deduced from observations at the Akademik Vernadsky station

Ionospheric Weddell Sea anomaly is an inversion of diurnal variation of the electron density in the ionosphere over Antarctic Peninsula, Weddell Sea, and neighbor territories observed during Antarctic summer. This paper aims at analyzing the reaction of the ionosphere during the Weddell Sea anomaly to changes in solar and geomagnetic activity as deduced from the data of vertical sounding of the ionosphere conducted at the Akademik Vernadsky station. The aim is achieved by comparing the monthly median values of the critical frequencies of the ionosphere (foF2) during Weddell Sea anomaly for the years of high and low solar activity; as well as by comparison of median December height-time diagrams (HT-diagrams) of foF2 calculated separately for the time intervals characterized by low or high levels of F10.7 and K indices for the period from 2007 till 2016. It was experimentally demonstrated that the Weddell Sea anomaly depends on the levels of solar ultraviolet flux and local K indices. The biggest nighttime maximum of ionization corresponds to low K indices and high values of F10.7. The most accurate inversion of diurnal variation of electron density in the F region is observed under the low values of K index and low F10.7 flux. The growth of geomagnetic activity decreases the nighttime ionization under both low and high levels of F10.7 fluxes and leads to a blur of the night maximum. Visible virtual heights of maximums increase together with F10.7 independently of the K index level. Blurring of the night maximum can be explained by destruction of the field of thermospheric winds supporting the nighttime anomaly, and/or by increasing role of plasma drifts in comparison with wind impact. The growth of visible virtual height of the nighttime maximum with increasing solar F10.7 flux could be explained by the gain of equatorward thermospheric wind with increasing solar ultraviolet flux that leads to growth of plasma upwelling effect. The Doppler frequency shift of the signals reflected from the ionosphere during nighttime in presence of the Weddell Sea anomaly is close to zero which could be explained by a stable F2 layer formed as a result of dynamic equilibrium between photochemical processes and upward plasma transport.

Ice sheet velocity tracking by Sentinel-1 satellite images at Graham Coast Kyiv Peninsula

The study of Antarctic glaciers and ice sheets velocity is one of the most discussed topics. Such high interest in this topic is primarily because the ice from the Antarctic glaciers, which gets to the ocean, significantly affects the ocean level and the global climate. Development of modern satellite technologies for Earth remote sensing made it possible to elaborate a number of methods for ice sheets’ displacements estimation and calculation of such displacements velocities. This work uses remote sensing data from the satellite system Copernicus Sentinel-1 to estimate the ice cover velocities in the Kyiv Peninsula in the time interval from December 2020 to March 2021. To this end, 10 radar images of the study area from early December to the end of March were used with an interval of 12–14 days. All selected images were analyzed in pairs to establish changes on the surface for the selected time interval. GRD-format images from Copernicus Sentinel-1 satellite, corrected for Earth's ellipsoid shape, were used. Based on the offset tracking operation, we calculated the speeds of ice cover movements within the Kyiv Peninsula for each pair of images with approximately two weeks' time difference. As a result, the speed of ice movements varies considerably and at the glacier mouth can reach 3.5–4 meters per day. Also, the rate of ice displacement in the glacier body changed over time. Thus, the highest ice velocities were in the glacier's mouth. However, short-term time intervals of intensification were recorded for the rear and even the marginal parts of the glaciers in contact with the ice sheet. Thus, the lowest part of the glacier activating sequence leads to the upper part shifting. Notably, this increase in the displacement of ice cover was recorded in February, one of the warmest months in this part of Antarctica.

Population features of Boeckella poppei in Lake Wujka, King George Island

The maritime Antarctic is one of the most interesting regions on planet where climate change can be observed to impact all components of its poor flora. Boeckella poppei is common in the maritime and continental Antarctic species of the copepod. The aim of the study was to check the local trends in the copepod's population density over summer. The samples were collected 23.12.05, 03.01.06 and 10.01.06 at the King George Island from the lake near the Polish Antarctic Station. The population density varied with strongly fluctuating ratios of different juvenile and generative developmental stages. We also analyzed the regularities reported by other authors. The sex structure of the population did not change during the study period with females much more numerous than males. The article discusses possible causes of this phenomenon.

DNA barcoding and morphological observations of three lichenized fungal species from James Ross Island (Antarctic Peninsula)

Antarctica seems to many people to be a very remote, isolated, and mysterious place at the end of the world, and its name is hardly mentioned in normal life and conversation. However, considering that it plays a key role in the rapidly warming global climate system and its contribution to the continuing sea-level rise, its importance today is increasing day by day and it can be seen that it is of vital importance for humanity. There is increasing interest in the distribution of terrestrial organisms in Antarctica because of the potential use of biodiversity as a predictor or indicator of climate change. Lichenized fungi cover large areas of Antarctica that are not covered by ice and form precursor organisms that thrive in harsh environments. They are the largest contributors to biomass and diversity. The characteristic features of these organisms can be counted as developing certain protective mechanisms, adapting to temperature and radiation, and surviving even when the amount of water in their body is minimized. On the other hand, lichenized fungi are the most dominant components of Antarctic terrestrial vegetation, and their adaptation to extreme conditions; growth forms, reproduction, adaptation to environmental conditions can also be explained through mechanisms. Because of the lichens, dominant organisms of Antarctica, studying lichen biodiversity is very important. Although around 500 species of lichens were reported from Antarctica, the lichen biodiversity of the continent is far from being fully known; as in the last 5 years of our studies on Antarctic lichens, we and other scientists reported a significant number of undescribed or unreported species. So the lichen biodiversity of Antarctica is not fully known as there are still many undescribed or unreported species on the continent. In this paper, we deal with three lichenized fungal species: Arthonia glebosa Tuck., Lecanora atromarginata (H. Magn.) Hertel & Rambold and Lecidea tessellata Flörke which are common in James Ross Island, using nrITS, mtSSU, and RPB1 sequences. The lichen samples are studied by morphological and anatomical characters. In addition, to determine the phylogenetic positions of the species, we provide nrITS and mtSSU of these 3 species from Antarctica and additionally RPB1 sequences of Lecidea tessellata.

Precipitation phase transition in austral summer over the Antarctic Peninsula

Investigating precipitation phase transitions is crucial for improving our understanding of precipitation formation processes and impacts, particularly in Polar Regions. This study uses observational data and numerical modelling to investigate precipitation phase transitions in the western and northern Antarctic Peninsula (AP) during austral summer. The analysis is based on the ERA5 reanalysis product, dynamically downscaled using the Polar-WRF (Polar Weather Research and Forecasting) model, evaluated using regular meteorological observations and additional measurements made during the Year of Polar Prediction special observing period. We analyse three cases of extra-tropical cyclones bringing precipitation with phase transitions, observed at the Chilean station Professor Julio Escudero (King George Island, north of the AP) and the Ukrainian Antarctic Akademik Vernadsky station (western side of the AP) during the first week of December 2018. We use observed and modelled near-surface air temperature and pressure, precipitation amount and type, and vertical temperature profiles. Our results show that precipitation type (snow or rain) is well-represented by ERA5 and Polar-WRF, but both overestimate the total amount of precipitation. The ERA5 daily variability and vertical air temperature profile are close to the observed, while Polar-WRF underestimates temperature in the lower troposphere. However, ERA5 underestimates the temperature inversion, which is present during the atmospheric river event, while Polar-WRF represents that inversion well. The average weekly temperature, simulated with Polar-WRF, is lower compared to ERA5. The Polar-WRF fraction of snow in the total precipitation amount is higher than for ERA5; nevertheless, Polar-WRF represents the precipitation phase transition better than ERA5 during the event, associated with an atmospheric river. These case studies demonstrated a relationship between specific synoptic conditions and precipitation phase transitions at the AP, evaluated the ability of the state-of-the-art reanalysis and regional climate model to represent these events, and demonstrated the added value of combined analysis of observations from the western and northern AP, particularly for characterizing precipitation during synoptic events affecting the entire AP.

Deep structure and new experimental data of the Bransfield Strait volcanoes (West Antarctica)

The aim of the study is to determine the existence of a complex magma-gas-fluid system of the West Antarctica northern volcanic branch in the Bransfield Strait. It consists of several different-level deep magma chambers with magmas raised directly from the mantle or the accumulation zone located at a depth of about 25–30 km. Research methods are based on the known idea that the Earth can be considered a spherical capacitor formed by various layers from its core to the surface with different parameters — thickness, permittivity, density, contact potential difference. Our experimental data show that there is a molten zone at 195–225 km where considerable part of volcanic roots is located. Certain structural patterns for land and submarine volcanic structures are revealed, and the first data on the deep migration channels of fluids in the Bransfield Strait are obtained. Volcanic channels are filled with different basic, ultramafic rocks, and sedimentary rocks too. The deep roots of volcanic structures' presence can be associated with the pulsed functioning of a gas-fluid channel with low viscosity. The gas-saturated melts form some zones of intermediate crystallization in the crust due to this channel. These studies showed that multiphase pulsed volcanic activity mainly through the vertical migration channels of deep fluids from the melting zone played a significant role in forming the tectonic diversity and the evolution of the Antarctic continental margin region structures. The results of modified methods of processing and decoding satellite images and photographs allow supplementing the understanding of the West Antarctica structures’ formation. These results of the Bransfield Strait magmatic systems studying indicate the need for further research to understand the mechanism of formation and evolution of structures and deep geospheres in different regions of the Earth.

Isolation and characterization of culturable actinobacteria associated with Polytrichum strictum (Galindez Island, the maritime Antarctic)

The main objective of the study is the evaluation of the diversity of actinobacteria associated with Polytrichum strictum — dominant species of widespread Antarctic Тall moss turf subformation and their characteristics as the producers of biologically active compounds. The actinobacterial isolates were isolated by direct inoculation, phenol pretreatment, and heated treatment. The cultural properties of the isolates were evaluated using diagnostic media. The antimicrobial activity of the isolates was determined by the point inoculations method. The phylogenetic analysis was based on sequence analysis of the 16S rRNA gene. The biosynthetic genes screening was performed using polymerase chain reaction. A total of 23 actinobacterial isolates associated with P. strictum were isolated, the four identified genera being Streptomyces (7 isolates), Micromonospora (14 isolates), Kribbella (1 isolate), and Micrococcus (1 isolate). Eight psychrotrophic strains of all identified genera were identified. The optimal pH values for all isolates were in the range 6–10. Four isolates grew on the medium with 7.5% NaCl. A significant number of the isolates showed a wide range of enzymatic activities. Antagonists of a wide range of pathogenic microorganisms were found, including against multidrug-resistant strain of Candida albicans and Methicillin-resistant Staphylococcus aureus. Some strains were active against phytopathogenic bacteria, namely three strains against Erwinia amylovora, one strain against Agrobacterium tumefaciens, and one strain against Pectobacterium carotovorum. More than half of the isolates showed antifungal activity against Fusarium oxysporum and Aspergillus niger. The biosynthetic genes involved in synthesizing a wide range of bioactive compounds were found in more than 80% of isolates. Antarctic actinobacteria isolated in this study demonstrate potential as the producers of a wide range of biologically active compounds. Further studies of these actinobacteria may lead to the identification of previously unknown biologically active compounds.

Minimizing tourist impact on the Argentine Islands ecosystem, Antarctic Peninsula, using visitor site guidelines approach

There has been an ongoing increase in tourist visits to the Antarctic since 2010. These visits primarily concentrate on a small number of sites, increasing the possible environmental impact. One of the tourism hotspots is the central Argentine Islands in Wilhelm Archipelago. These islands, being one of the top 20 most visited Antarctic sites, consist of Galindez Island, Winter Island, and Skua Island. They are known for wildlife, rich vegetation (old moss banks, rich bryophyte and lichen communities, Antarctic pearlwort Colobanthus quitensis and hairgrass Deschampsia antarctica populations), spectacular views. They include one of the oldest Antarctic research stations: the Ukrainian Antarctic Akademik Vernadsky station. Previously no measures have been developed to minimize the impact of tourism on this region. Thus, the Visitor Site Guidelines (VSG) approach and the numerous studies in the region were used to determine the central values of this site and to identify those key features that can be opened for tourists. In addition to the most frequently mentioned values, such as seabirds and mammals, we considered it necessary to mention the vegetation. We assessed threats to these values, distinguishing known and potential impacts. We have also analyzed and developed landing requirements for the studied area, including the most critical requirement to be considered, namely the number of visitors. We think that the maximum number of visitors should be 36 at any time and 270 per day, not counting passengers of yachts. This is the first time that the Visitor Site Guidelines were modified to limit the number of yachts visiting the site to three yachts per day. To reduce the tourist load at the station itself and at the same time to concentrate tourists in the studied region, we proposed two tourist trails: one for Galindez Island, the other — the existing trail for Winter Island. The prepared draft of Visitor Site Guidelines is given in Appendix 2.