Ukrainian Antarctic Journal

Temporal stability of induction vectors from Antarctic Peninsula, AIA INTERMAGNET observatory

S. Sanaka — 2023-08-16

Induction vectors represent geomagnetic transfer functions used in magnetotellurics and related passive electromagnetic sounding methods in geophysics. They are obtained from the measurements of geomagnetic variation and carry information on the distribution of local and regional electric resistivity in the subsurface, which can be interpreted in terms of geology and tectonics. The underlying concept of their interpretation works properly if the so-called far-field condition is fulfilled, i.e., if certain assumptions on the geometry of utilized natural electromagnetic source fields are met. The magnetotelluric practitioner expects problems in the regions where the electromagnetic variations originate to a high extent from ionospheric currents as sources. Due to the polar (or auroral) electrojets, this skepticism towards the electromagnetic far-field methods clearly applies to the high latitudes, polar regions, and auroral zones. In the present study, the investigation focuses on the extent to which problems typical for the auroral electrojet sources occur in the geomagnetic variation data from the Argentine Islands INTERMAGNET observatory (AIA) located at the Ukrainian Antarctic Akademik Vernadsky station. Induction vectors from one month of AIA variation data measured in the normal framework of the INTERMAGNET observatory are analysed for their stability over both period and time, where a time resolution of one day allows for the detection of changes originating from the source signals instead of from subsurface resistivity distribution. The outcomes from AIA are compared to the corresponding ones of two northern hemisphere stations which belong to the International Monitor for Auroral Geomagnetic Effects (IMAGE) network, located in Finland and Poland. Results show that AIA induction vectors do not exhibit the problems expected in the high latitudes; their time stability is very similar to that of stations at a comparable but opposite geomagnetic latitude of 50 degrees, which corresponds geographically to mid-latitudes in Europe. A further outcome of this study is that some slight, occasional changes in induction vectors can be attributed to increased geomagnetic activity because they are correlated to the planetary diurnal Ap index.

Tectonic plates moment of inertia and angular momentum determination: the case of the Antarctic plate

I. Savchyn — 2023-08-16

The main goal of this study is to develop and test an algorithm for determining the moment of inertia and angular momentum of a tectonic plate based on the processing of time series of daily solutions of continuous GNSS (Global Navigation Satellite System) stations. The proposed algorithm consists of four consecutive stages: reformatting data to the internal format; dividing the plate into cells and determining their masses; determining the rotation poles and distances from cells to the poles; calculating the plate’s moment of inertia and angular momentum. The algorithm uses freely available time series of daily solutions
from continuous GNSS stations or any other data prepared in a similar format. The algorithm is tested for determining the moment of inertia and angular momentum of the Antarctic plate based on the processing of time series of daily solutions of continuous GNSS stations for the period 1995–2021. It is confirmed that the Antarctic Plate’s rotation poles, moment of inertia, and angular momentum are dynamic parameters. However, additional calculations and in-depth comprehensive analysis are required to determine the causes of such dynamics. As a result of comparing, the dynamics of changes in the Antarctic Plate’s rotation poles partially compensate for the unevenness of the Earth's rotation to keep the angular momentum of the Earth constant.

Modeling the Trooz Glacier’s movement using air temperature data and satellite SAR observations in 2015‒2022

K. Tretyak — 2023-08-16

The aim of this study is modeling the dependence of maximum velocity of the Trooz Glacier (Kyiv Peninsula, West Antarctica) on air temperature. For this purpose, we processed a time series of meteorological observations at the Akademik Vernadsky station and the ice flow velocity of the Trooz Glacier. The ice velocities were determined from the synthetic aperture radar images, acquired by the Sentinel-1 satellite, for the period from May 2015 to November 2022. The SAR images were processed in the SNAP (Sentinel Application Platform) program using the Offset Tracking method. As a result, 219 ice flow velocity
maps were obtained. During the studied period, the maximum velocities varied from 2.64 m/day (August 19, 2015) to 4.05 m/day (April 18, 2020). A functional dependence between the temperature data from the Akademik Vernadsky station and the remotesensing data on the air temperature above the glacier’s surface was established. We combined the three parameters (time series of the maximum velocities of the glacial flow, remote temperature measurements above the glacier, and direct temperature measurements at the Akademik Vernadsky station) in a linear model. In order to increase the accuracy of the modeling, an a posteriori optimization was carried out. As a result, the average error in determining the maximum velocity of the glacier reduced from 23 cm/day to 17 cm/day.

On the performance of CARISMA – Akademik Vernadsky station Schumann resonance monitoring

O. Koloskov — 2023-08-16

The main objective of this study is to evaluate the effectiveness of the CARISMA (Canadian Array for Realtime Investigations of Magnetic Activity) – Akademik Vernadsky station (65.25°S 64.25°W, Vernadsky) Extremely Low Frequency (ELF) induction magnetometer network as a planetary monitoring system for thunderstorm activity, with observation sites located in the Arctic and Antarctic regions, respectively. To achieve this, daily ELF records from Vernadsky and Fort Churchill (FCHU, 58.76°N 94.08°W) collected in January 2022 were processed and analyzed. For CARISMA, data from the FCHU site were used due to the better signal-to-noise ratio. The horizontal magnetic components of Schumann signals obtained at Vernadsky and FCHU underwent spectral and polarization processing. ELF transients were identified, and subsequent geolocation was performed as well. Both regular (quiet) thunderstorm activity periods and an unprecedented local amplification of lightning activity near the Hunga Tonga-Hunga Ha'apai volcano during its eruption on January 15, 2022, were studied. Throughout the quiet periods, ELF signal processing yielded similar characteristics of integral lightning activity derived from CARISMA and Vernadsky records, consistent with findings in the literature and previous investigations at the Vernadsky site. On the other hand, the analysis of Schumann spectra and ELF transients during the Tonga volcano eruption confirmed that most thunderstorms were concentrated within a relatively small area around the epicenter, validating the point source model for the global lightning center. This paper demonstrates that the CARISMA and Vernadsky magnetometer network is well-suited for establishing a global lightning activity monitoring and
intense lightning geolocation system. Such a system can be employed to assess and study global temperature trends, monitor the growth of lightning activity in high latitudes, and detect terrestrial, atmospheric, and geospace disaster phenomena.

Records of Boeckella poppei (Mrazek, 1901) (Calanoida: Centropagidae) obtained during Ukrainian Antarctic Expeditions

M. Nabokin — 2023-08-16

The copepod Boeckella poppei (Mrazek, 1901) (Calanoida: Centropagidae) is one of the Maritime Antarctic’s most common freshwater zooplankton species. It was first discovered in 1961–1962 on Signy Island (South Orkney Islands). Nowadays, it is found on many other islands in the region. The copepod is also found on Western Subantarctic islands, in the eastern part of the continent, and South America. However, in the Wilhelm Archipelago, there have been only a few disjointed findings of the species so far: it has been noted as numerous both north and south of the Ukrainian Antarctic Akademik Vernadsky station, yet for the
archipelago, there are only two brief records which do not describe its distribution in this region. Our data are based on 114 specimens collected in 2005–2023 during Ukrainian Antarctic Expeditions. Boeckella poppei was found in 51 samples from 23 lakes on eight islands: Uruguay, Irizar, Berthelot, Galindez, Roca, and Eight (Wilhelm Archipelago), Nelson, King George (South Shetland Islands). Live specimens were recorded during the ice-free period and significantly after the surface was frozen. In many samples, adults and copepodid stages were found, while nauplii were not found.

Adaptations of the antarctic bacterium Paenibacillus tundrae IMV B-7915 to copper (II) chloride exposure

S. Komplikevych — 2023-08-16

Heavy metals are common in Antarctic habitats. However, the adaptations of Antarctic microorganisms to heavy metals are poorly understood. One of the mechanisms of toxicity of transition metals is the formation of free radicals which damage the cell macromolecules. In 2020, we isolated the bacteria Paenibacillus tundrae IMV B-7915 from a sample containing moss, soil, and underground parts of Deschampsia antarctica (Berthelot Islands, Maritime Antarctic). The aim of the study was to investigate the influence of copper (II) chloride on the specific growth rate, the content of products of free radical damage to lipids and proteins, the activity of antioxidant defense system enzymes, and the synthesis of extracellular polymeric substances in P. tundrae IMV B-7915. The bacteria were incubated for an hour in Tris-HCl buffer with 2–8 mM copper (II) chloride, then washed and inoculated into the tryptic soy broth. The bacteria were cultured for 72 hours. The content of copper in the cells was determined by atomic absorption spectrometry. The content of indicators of lipid peroxidation (diene conjugates, lipid hydroperoxides, thiobarbituric acid-reactive substances), oxidative modification of proteins (carbonyl groups in proteins), the activity of the antioxidant defense system enzymes (catalase, superoxide dismutase, glutathione peroxidase, glutathione S-transferase, glutathione reductase), total thiols, exopolymeric compounds (exopolysaccharides and proteins) were determined photometrically. Within an hour, cells accumulate 1.5–3.4 mg Cu/g of biomass, leading to a decrease in biomass accumulation and specific growth rate within 24 hours. In cells, copper ions induce free radical reactions of damage to cell macromolecules, reflected in the increase in the content of primary lipid peroxidation products and carbonyl groups in proteins. Cell division is inhibited. In response, P. tundrae IMV B-7915 cells activate efflux systems, as evidenced by a significant decrease in copper content during prolonged cultivation, and enzymes of antioxidant defense and synthesis of exopolysaccharides. The complex of the studied adaptation reactions ensures the detoxification of copper accumulated in cells, reflected in the restoration of the specific growth rate.

Plant growth promoting properties of an antarctic strain Amycolatopsis sp. Cq 72-27

I. Roman — 2023-08-16

Unique biotopes can be a source of new plant growth promotion (PGP) bacteria with rare properties. The Antarctic habitat is an attractive location for research, as it is characterized by many stress factors, and the local microbiota is under permanent selective pressure. We believe that the rhizosphere bacteria of this habitat may have important PGP properties that can be used in agriculture. A variety of research methods were used in this work: the molecular genetic technique to establish the gene sequence, chemical to test the ability to produce nitrite, ammonia, and indole acetic acid, microbiological to investigate the cultured properties of the strain, as well as antagonistic and PGP activities. We found that the strain belongs to the genus Amycolatopsis. It showed antagonistic activity against phytopathogenic bacteria (Xanthomonas campestris pv. campestris IMB8003 and Bacillus subtilis ATCC 31324) and fungi (Alternaria alternata DSM 1102, Fusarium oxysporum ІМВ 54201, Aspergillus niger ІМВ 16706), and also demonstrated some PGP properties (solubilization of phosphorus and zinc and production of nitrite and ammonia). Inoculation of wheat seeds with spores of this strain promoted germination and growth of seedlings. The strain has demonstrated properties that make it a promising basis for developing biofertilizers that can be used in agriculture.

Bioactive substances of Colobanthus quitensis (Kunth) Bartl. from the Darboux and Lagotellerie Islands, western coast of Antarctic Peninsula

R. Ivannikov — 2023-08-31

The study aimed to investigate a wide spectrum of biologically active substances of an aboriginal Antarctic plant (Colobanthus quitensis) from the central and southern parts of its Antarctic part of general spread collected in 2020–2022. For 17 plants from 2 populations, we obtained extracts and analyzed them using high-throughput chromatography (HPLC). This was the first biochemical screening of plants from previously not investigated parts of this species’ range (Graham Coast and Marguerite Bay in the maritime Antarctic). The HPLC method characterized the overall metabolite pools and their separate components which could potentially have high biological activity. The most numerous groups of compounds included phenols and benzoic acids, hydroxybenzoic acids, hydroxycinnamic acids, flavonoids, apigenin glycosides, luteolin glycosides, tricin glycosides, flavonoid conjugates of the hydroxycinnamic acids, chlorophyll catabolites, carotenoids, terpenoids, and sterols. The quantitative content of the pearlwort’s metabolites depended on the population, probably due to the differences in the microhabitats. Meanwhile, such variability offers a wide selection of possible targets for biochemical screening. The Antarctic pearlwort is richer in some conjugates (such as flavonoid conjugates with the hydroxybenzoic acids) than the other Antarctic aboriginal plant – Antarctic hairgrass (Deschampsia antarctica). The determined substances might potentially be of great practical significance.

Review of ‘Contributions to understanding climate interactions: stratospheric ozone’ by Gennadi Milinevsky, Asen Grytsai, Oleksandr Evtushevsky, and Andrew Klekociuk. (2022)

S. Krakovska — 2023-08-31

Review of ‘Contributions to understanding climate interactions: stratospheric ozone’ by Gennadi Milinevsky, Asen Grytsai, Oleksandr Evtushevsky, and Andrew Klekociuk. (2022). Kyiv, Akademperiodyka, 252 pp. ISBN: 978-966-360-471-8.

Investigations of atmospheric ozone have been fast developing in the last two centuries. Their importance became more evident after the ozone hole discovery in the mid-1980s. Today, it is clear that stratospheric ozone is essential for the Earth’s biosphere, and its content (which conditionally may be named ‘ozone layer thickness’) varies and is determined by different chemical and dynamical processes. In this book, a team of authors considers mainly the physical, particularly dynamic processes influencing ozone in the Earth’s atmosphere. The monograph has seven chapters. It studies the ozone layer, primarily focusing on the middle and high latitudes. Ukrainian researchers wrote the book in co-authorship and long-term cooperation with their Australian colleague, famous atmospheric researcher, Dr. Andrew Klekociuk. The authors are experts in atmospheric physics and present their own results and a review of the current state of the ozone-climate interaction problems. The book includes many references to the recent scientific publications that direct readers to more detailed information to understand the topic better.