Атмосферная циркуляция в индоокеанском секторе Восточной Антарктиды за последние 200 лет по данным изучения химического состава снежно‑фирнового покрова

Spatial and temporal variability of a sea‑salt aerosol (Na+) concentration was investigated in snow‑firn cores and snow pits taken at four sites of the Indian Ocean sector of the East Antarctica (along a profile between stations Progress and Vostok: PV‑10, NVFL‑1, SW‑42, and the Vostok point). In long annually resolved Na+ records, we had revealed the following periodicities: 17 to 95‑year (Vostok) and 29 to 52‑year (NVFL‑1), while the shorter records are characterized by 8‑year periodicity. The Na+ concentrations decrease as the snow accu‑ mulation increases (especially, at the Vostok station), and this is evidence for a presence of «dilution effect» in the sites with the great part of «dry precipitation». The closest relationship was revealed between changes in flows of Na+ at points SW‑42, and PV‑10. Variability of the Na+ fluxes had been linked to the circulation indices (AAO, PDO, SOI, MEI, SPO) and the sea level pressure in the Southern Hemisphere, as well as to occurrence of Elementary Circulation Mechanisms (ECM). The revealed irregularity of the Na+ precipitation over the area under investigation is caused by different atmospheric circulation patterns as well as by influ‑ ence of basic Action Centers of the Atmosphere (ACA) in the Southern Hemisphere. The closest relationship is found to take place with South Pacific ACA (Vostok, 1976–2009) and with the South Indian ACA (SW‑42 and PV‑10). A presence of distant atmospheric relations (including one with El Nino) had been revealed for the inland areas. Changes in features of the atmospheric circulation in the South Indian Ocean over the last 200‑year period have been reconstructed on the basis of summarized Na+ records from the Vostok station area. Distinctive feature of the atmospheric circulation is the 40‑year periodicity with its increasing intensity during the following periods: 1805–1820, 1830–1860, 1890–1900, 1940–1950, and 1980–2000. In addition, we had revealed that changes in the atmospheric circulation in the Indian Ocean (Southern Hemisphere) were synchronous with similar variability of the circulation in the Siberian (Northern Hemisphere) sector.По данным изучения химического состава снежно-фирнового покрова в индоокеанском секторе Восточной Антарктиды установлены пространственно-временные изменения аккумуляции морского аэрозоля (Na+). Исследованы корреляционные связи аккумуляции Na+ с индексами циркуляции и полем давления Южного полушария, а также элементарными циркуляционными механизмами. Впервые выполнена реконструкция интенсивности региональной циркуляции за последние 200 лет

Ice core chemistry database: an Antarctic compilation of sodium and sulfate records spanning the past 2000 years

Changes in sea ice conditions and atmospheric circulation over the Southern Ocean play an important role in modulating Antarctic climate. However, observations of both sea ice and wind conditions are limited in Antarctica and the Southern Ocean, both temporally and spatially, prior to the satellite era (1970 onwards). Ice core chemistry data can be used to reconstruct changes over annual, decadal, and millennial timescales. To facilitate sea ice and wind reconstructions, the CLIVASH2k (CLimate Variability in Antarctica and the Southern Hemisphere over the past 2000 years) working group has compiled a database of two species, sodium [Na+] and sulfate [SO2− 4 ], commonly measured ionic species. The database (https://doi.org/10.5285/9E0ED16E-F2AB4372-8DF3-FDE7E388C9A7; Thomas et al., 2022) comprises records from 105 Antarctic ice cores, containing records with a maximum age duration of 2000 years. An initial filter has been applied, based on evaluation against sea ice concentration, geopotential height (500 hPa), and surface wind fields to identify sites suitable for reconstructing past sea ice conditions, wind strength, or atmospheric circulation

Химический состав приземного атмосферного аэрозоля в Баренцбурге (архипелаг Шпицберген) по результатам многолетних исследований

The chemical composition (ions, elements, polycyclic aromatic hydrocarbons) of aerosol and gaseous impurities (SO2, HNO3, HCl, NH3) in the surface layer of the atmosphere in Barentsburg, located on the Western Svalbard island (Svalbard archipelago), is analyzed. Atmospheric aerosol and gaseous impurities brought to the Arctic from middle latitudes and deposited on snow and ice not only interact with various natural objects, but also spread to long distances with melting dirty snow and ice. Air sampling was carried out following to methodology adopted by the international networks of the atmospheric monitoring programs in South-East Asia (EANET) and Europe (EMEP). In 2011-2015, the observations of the chemical composition of the atmospheric ground layer were performed daily during the light season (April–September), and monthly from April 2016 to 2018. The largest total ion concentrations were observed in 2011–2012. Seasonal variability of ion concentrations in the aerosol was characterized by high values in the cold period (October–February) and low values in the warm one (May–June). High values of the coefficient of correlation between ions Na+ and Cl− (r = 0,93) as well as between Mg2+ and Cl−  (r = 0,81) throughout the year show that the main source of the aerosol is the sea surface. The significant correlation between ions K+, NO3-, NH4+, SO42−, K+, SO42− in the polar night point to the influence of local sources: coal mining at the mine and its3 combustion at thermal power plants. Emission of polycyclic aromatic hydrocarbons and the gaseous impurities (SO2, HNO3) into the atmosphere, especially during the polar night, is also influenced by local sources. Among the elements the maximum enrichment of the aerosol was revealed for As, Cr, Zn, Mo, Cd, Sn, Sb, W, and Pb with a low content of Cd, Sn, Sb, W, and Pb in the coal, sludge and on the underlying surface. On the basis of the elemental composition of the aerosol and the back-trajectory analysis, it was shown that the air masses enriched in heavy metals come to the area of the Barentsburg settlement from middle latitudes.Прослежена межгодовая (2011–2017 гг.) и сезонная (2016–2018 гг.) изменчивость компонентов химического состава (ионы, элементы, полициклические ароматические углеводороды) атмосферного аэрозоля и газообразных примесей (SO2, HNO3, HCl, NH3) в приземной атмосфере западной части Российской Арктики (пос. Баренцбург на Шпицбергене)

Химический состав атмосферного аэрозоля арктических районов в летний период 2021 года

Atmospheric aerosol is an important characteristic of the state of the atmospheric air, therefore, in the summer of 2021, atmospheric aerosol samples were collected in the expeditions of the Shirshov Institute of Oceanology of the Russian Academy of Sciences to study the chemical composition (ions, trace elements, polyaromatic hydrocarbons) of aerosols in the Arctic atmosphere. The expeditions were carried out on the research ship (RS) Akademik Mstislav Keldysh in the Kara Sea (83rd cruise, June 18 - July 8, 2021), in the Barents Sea and the Norwegian-Greenland Basin (84th cruise, July 24 - August 26, 2021). It is established that the average total concentration of ions in the aerosol of the Kara Sea is 5.4±1.9 µg/m3, which corresponds to the average data obtained in previous years. In the aerosol of the Barents Sea and the Norwegian-Greenland basin, the average value of 5.0±2.1 μg/m3 was considered as potentially possible for the studied region. Concentrations of such ions as Na+, NH4 + and Cl-dominated in the aerosol composition of all regions. The average total concentration of trace elements in the composition of the aerosol of the Barents Sea and the Norwegian-Greenland basin is 1,5 times higher than in the aerosol of the Kara Sea. The predominant concentrations of trace elements in the aerosol of both study areas were Cr, Zn, Al, Fe. Mo, Sr, Ba, Mn, Sn, Ti, Pb, Cu, Ni. As a result of the calculation of the ranking of trace elements by atmospheric pollution in the aerosol of the Kara Sea, Fe, Cu, Ni, Pb are prioritized, and in the aerosol of the Barents Sea and the Norwegian-Greenland basin - Fe, Cu, Sn, Pb. The level of air pollution with trace elements in both areas is low. 13 compounds of polyaromatic hydrocarbons with an average total concentration of 0.65 ng/m3 in aerosol collected in 83 cruise, and 0.75 ng/m3 in 84 one were identified. Compounds of polyaromatic hydrocarbons with two and three benzene rings (naphthalene, phenanthrene and their homologues) coming from petrogenic sources accounted for 92 and 80% of the total amount of polyaromatic hydrocarbons, respectively. Atmospheric aerosol sampling for the study of chemical composition was carried out under conditions of fog of various densities, with precipitation and destruction of seasonal ice.Выявлены различия и сходство химического состава (ионы, микроэлементы, ПАУ) приводного атмосферного аэрозоля, собранного в летний период 2021 г. по маршрутам экспедиций НИС«Академик Мстислав Келдыш» в районе Карского моря (второй этап 83-го рейса, 18 июня - 8 июля 2021 г.), в Баренцевом море и Норвежско-Гренландском бассейне (84-й рейс, 24 июля - 26 августа 2021 г.)

Adaptation of pineal expressed teleost exo-rod opsin to non-image forming photoreception through enhanced Meta II decay

Photoreception by vertebrates enables both image-forming vision and non-image-forming responses such as circadian photoentrainment. Over the recent years, distinct non-rod non-cone photopigments have been found to support circadian photoreception in diverse species. By allowing specialization to this sensory task a selective advantage is implied, but the nature of that specialization remains elusive. We have used the presence of distinct rod opsin genes specialized to either image-forming (retinal rod opsin) or non-image-forming (pineal exo-rod opsin) photoreception in ray-finned fish (Actinopterygii) to gain a unique insight into this problem. A comparison of biochemical features for these paralogous opsins in two model teleosts, Fugu pufferfish (Takifugu rubripes) and zebrafish (Danio rerio), reveals striking differences. While spectral sensitivity is largely unaltered by specialization to the pineal environment, in other aspects exo-rod opsins exhibit a behavior that is quite distinct from the cardinal features of the rod opsin family. While they display a similar thermal stability, they show a greater than tenfold reduction in the lifetime of the signaling active Meta II photoproduct. We show that these features reflect structural changes in retinal association domains of helices 3 and 5 but, interestingly, not at either of the two residues known to define these characteristics in cone opsins. Our findings suggest that the requirements of non-image-forming photoreception have lead exo-rod opsin to adopt a characteristic that seemingly favors efficient bleach recovery but not at the expense of absolute sensitivity

Химический состав аэрозоля в приземном слое прибрежной зоны Восточной Антарктиды

Chemical composition of aerosol in the ground layer of the coastal zone in East Antarctica is analyzed in the article. The aerosol samples were taken in 2006–2015 during seasonal works of the Russian Antarctic Expeditions (RAE), namely, these were 52nd–53rd, 55th, and 58th–60th expeditions. Samples were taken in the 200‑km band of the sea-shore zone along routes of the research vessels (REV) «Akademik Fedorov» and «Akademik Treshnikov» as well as on territories of the Russian stations Molodezhnaya and Mirny. Although the results obtained did show the wide range of the aerosol concentrations and a certain variability of their chemical composition, some common features of the variability were revealed. Thus, during the period from 2006 to 2014 a decrease of average values of the sums were noted. Spatially, a tendency of decreasing of the ion concentrations was found in the direction from the station Novolazarevskaya to the Molodezhnaya one, but the concentrations increased from the Molodezhnaya to the station Mirny. The sum of ions of the aerosol in the above mentioned coastal zone was, on the average, equal to 2.44 μg/m3, and it was larger than that on the territory of the Antarctic stations Molodezhnaya (0,29 μg/m3) and Mirny (0,50 ág / m3). The main part to the sum of the aerosol ions on the Antarctic stations was contributed by Na+, Ca2+, Cl−, SO4 2−. The main ions in aerosol composition in the coastal zone are ions Na+ and Cl−. The dominant contribution of the sea salt and SO4 2− can be traced in not only the composition of atmospheric aerosols, but also in the chemical composition of the fresh snow in the coastal areas of East Antarctica: at the Indian station Maitri, on the Larsemann Hills, and in a boring located in 55.3 km from the station Progress (K = 1.4÷6.1). It was noted that values of the coefficient of enrichment K of these ions decreases as someone moves from a shore to inland. Estimation of contributions of the continental and maritime factors to formation of the aerosol chemical composition revealed higher enrichment ratios for K+, Ca2+, SO4 2− (K = 3.6÷13.0). This reflects not only influence of the natural sources, but the intensity of human activities on the Antarctic continent as well. The elemental composition of solid aerosols was also analyzed. The largest concentrations were determined for Zn, Al and Fe. The ratio of concentration of the elements in both the soluble and insoluble phases of the aerosol showed that 84.1% of the total amount of the elements was contained in a water-insoluble state. Fractional relation between the element concentrations changed in different phases from 16 to 98%. High enrichment of the aerosol particles by Zn, Cu, Cr, Ba, Pb, Ni,Se, As, Cd (the enrichment factors = 27÷26 445) had been revealed. The content of dominant chemical components (Na+, Cl−, Zn, Fe), factors and coefficients of the element enrichment in the aerosols as well as in fresh snow of the coastal zone of East Antarctica are indicative of the identity of sources where their composition is formed.Рассмотрена временнáя и пространственная изменчивость химического состава атмосферного аэрозоля, отобранного в период сезонных работ 52, 53, 55, 58–60‑й РАЭ по маршруту следования НЭС «Академик Федоров» и «Академик Трешников» от станции Новолазаревская до станции Мирный. Заметное снижение суммы ионов в аэрозоле в 2007–2008 гг. хорошо согласуется с исследованиями в районе Восточной Атлантики и связано с гидрологическими процессами в Атлантическом океане. Установлено высокое обогащение аэрозольных частиц Zn, Cu, Cr, Ba, Pb, Se, As, Ni, Cd. Содержание преобладающих химических компонентов (Na+, Cl−, Zn, Fe), факторы и коэффициенты обогащения элементов (ФО = 27÷26 445) и ионов (K = 3,6÷13,0) в аэрозоле в поверхностном и свежевыпавшем снеге (K = 1,4÷6,1) прибрежной части Восточной Антарктиды свидетельствуют об идентичности источников формирования их состава

Ice core chemistry database: an Antarctic compilation of sodium and sulfate records spanning the past 2000 years

Changes in sea ice conditions and atmospheric circulation over the Southern Ocean play an important role in modulating Antarctic climate. However, observations of both sea ice and wind conditions are limited in Antarctica and the Southern Ocean, both temporally and spatially, prior to the satellite era (1970 onwards). Ice core chemistry data can be used to reconstruct changes over annual, decadal, and millennial timescales. To facilitate sea ice and wind reconstructions, the CLIVASH2k (CLimate Variability in Antarctica and the Southern Hemisphere over the past 2000 years) working group has compiled a database of two species, sodium [Na+] and sulfate [SO2− 4 ], commonly measured ionic species. The database (https://doi.org/10.5285/9E0ED16E-F2AB4372-8DF3-FDE7E388C9A7; Thomas et al., 2022) comprises records from 105 Antarctic ice cores, containing records with a maximum age duration of 2000 years. An initial filter has been applied, based on evaluation against sea ice concentration, geopotential height (500 hPa), and surface wind fields to identify sites suitable for reconstructing past sea ice conditions, wind strength, or atmospheric circulation

ASSESSMENT OF THE CURRENT STATE OF SOUTH SYGYKTINSKY GLACIER – ONE OF THE LARGEST GLACIERS OF KODAR RANGE

In this paper we present some results of studies of Southern Sygyktinsky Glacier, the largest glacier of Kodar Ridge. The glacier is located at altitude 2340–2690 m, its area is 0.48 km2 and length 1.26 km. Firn line at the end of August was 2485±35 m. Since the end of Little Ice Age the glacier tongue retreated by 800 m and its area decreased by 0.44 km2 (by 48%). Ice surface is asymmetric due to snow redistribution in local topography conditions. There are two ice formation zones on the glacier: firn-ice zone and superimposed ice zone. Snow cover on the glacier surface is thin and its chemical (ion) composition reflects atmospheric aerosol features and intensity of percolation processes. Air temperature measured over ice surface from 9.07 to 21.08 (every hour) varies from −1.5 to +18.0 ºC with mean value of 2.9 ºC. Summer balance in 2009 was estimated by value of 980 mm w.e. with positive-degree-day factor 5.1 mm ºC-1day-1

Atmospheric circulation in the Indian Ocean sector of East Antarctica over the last 200 years according to chemical studies of snow‑firn cover

Spatial and temporal variability of a sea‑salt aerosol (Na+) concentration was investigated in snow‑firn cores and snow pits taken at four sites of the Indian Ocean sector of the East Antarctica (along a profile between stations Progress and Vostok: PV‑10, NVFL‑1, SW‑42, and the Vostok point). In long annually resolved Na+ records, we had revealed the following periodicities: 17 to 95‑year (Vostok) and 29 to 52‑year (NVFL‑1), while the shorter records are characterized by 8‑year periodicity. The Na+ concentrations decrease as the snow accu‑ mulation increases (especially, at the Vostok station), and this is evidence for a presence of «dilution effect» in the sites with the great part of «dry precipitation». The closest relationship was revealed between changes in flows of Na+ at points SW‑42, and PV‑10. Variability of the Na+ fluxes had been linked to the circulation indices (AAO, PDO, SOI, MEI, SPO) and the sea level pressure in the Southern Hemisphere, as well as to occurrence of Elementary Circulation Mechanisms (ECM). The revealed irregularity of the Na+ precipitation over the area under investigation is caused by different atmospheric circulation patterns as well as by influ‑ ence of basic Action Centers of the Atmosphere (ACA) in the Southern Hemisphere. The closest relationship is found to take place with South Pacific ACA (Vostok, 1976–2009) and with the South Indian ACA (SW‑42 and PV‑10). A presence of distant atmospheric relations (including one with El Nino) had been revealed for the inland areas. Changes in features of the atmospheric circulation in the South Indian Ocean over the last 200‑year period have been reconstructed on the basis of summarized Na+ records from the Vostok station area. Distinctive feature of the atmospheric circulation is the 40‑year periodicity with its increasing intensity during the following periods: 1805–1820, 1830–1860, 1890–1900, 1940–1950, and 1980–2000. In addition, we had revealed that changes in the atmospheric circulation in the Indian Ocean (Southern Hemisphere) were synchronous with similar variability of the circulation in the Siberian (Northern Hemisphere) sector