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Room-temperature cavity ring-down spectra (CRDS) of hydrogen sulfide were recorded at three pressures of 10, 20, and 30 Torr in the 12950-13300 cm^-1 range with a sensitivity on the order of 3 × 10^-11 cm^-1 in terms of the absorption coefficient and analyzed. The line positions and intensities are derived from these spectra. The theoretical simulation of these spectra was performed within the method of effective operators. The measured line positions and intensities are compared with the variational calculated values. Considerable difference between calculated ( Azzam A.A.A., Yurchenko S.N., Tennyson J., Naumenko O.V. Exomol line lists XVI: A hot line list for H₂S // Mon. Not. R. Astron. Soc. 2016. V. 460. P. 4063-4074) and observed line positions and intensities is found.

For the first time with high spectral resolution (0,00016 cm^-1) and threshold sensitivity (~ 1E-26 cm/molec.), the absorption spectrum of the H₂S molecule was recorded in the spectral ranges 6227.506-6236.844 and 6244.188-6245.348 cm^-1 at room temperature and pressures of 0.001-0.06 atm. The measurements were carried out at the Institute of General Physics on a high-sensitivity high-resolution diode laser spectrometer with a signal-to-noise ratio of more than 10000. Line center shift coefficients Δ₀/ P and collisional widths Г₂/ P have been estimated for the first time; new spectral lines have been recorded. The estimates of the experimental values of the positions of the line centers determined in this work differ from the calculated positions of the centers in the HITRAN database by the value Dν = (ν_H - ν_exp) × 10³ cm^-1 ≈ 0.001-0.01 cm^-1. The intensity estimates coincide much worse, the relative differences 100% × ( S_H - S _exp)/ S_H amount to tens of percent, the intensities of five lines differ by hundreds of percent or more.

Transit observations of exoplanets make it possible to measure temperature and relative abundance of various elements in their atmospheres. The infrared line of metastable helium HeI 10830 Å is widely used to study the atmospheres of exoplanets by the transit absorption method. The emission spectra of stars have a significant impact on the physical and chemical parameters of the upper layers of the atmospheres. In this paper, we consider the features of absorption in the helium line for stars of different spectral classes by numerical simulation. The results show the key role of the star's emission spectrum in the formation of the upper atmosphere and in the amplitude of transit absorption of exoplanets in the HeI 10830 Å line.

Based on the multiyear expedition studies in the Kara Sea basin (11 expeditions in 2007-2022), we presented for the first time a statistical generalization of the atmospheric aerosol characteristics: the volume contents of submicron and coarse aerosol ( V_f и V_с ), the black carbon concentrations (еВС) and the spectral aerosol optical depth (AOD) of the atmosphere. Increased content of submicron and absorbing (eBC) aerosol was clearly manifested in the average spatial distribution in the southwestern part of the Kara Sea and minimal content in the northern part. The difference in the average concentrations V_f and еВС between these regions is 30-60%. The average aerosol characteristics for the entire Kara Sea had been: the atmospheric AOD (0.5 mm) was 0.043 at the Ångström exponent 0.8; the concentrations еВС were 22.8 ng/m³; and the particle volumes V_f and V_с were 0.26 and 1.39 μm³/cm³ respectively. The average concentrations V_f and еВС over the Kara Sea are shown to be intermediate between the data from the “Cape Baranov” and the Barents Sea.

Seasonal variability of the vertical distribution of chlorophyll a concentration, coefficients of spectral light absorption by optically active components of water and, spectral downwelling irradiance has been investigated in coastal waters of the Black Sea near Sevastopol in 2022-2023. Concentration of phlorophyll a in euphotic zone was minimal in winter (0.66 mg/m³) and maximal in spring (3.57 mg/m³). It has been revealed that colored dissolved organic matter was dominated in absorption at 438 nm in all the seasons. It was noted that the relative contribution of phytoplankton to the total non-water light absorption by all optically active components at 438 nm was the highest in summer. It has been shown that an increase in the total light absorption by suspended and dissolved organic matters led to a narrowing of the euphotic zone and a change in the spectral features of downwelling irradiance. Vertical distribution of Tchl- a and optically active components was associated with hydrophysical characteristics of waters.

Ecologo-geographical differentiation and dynamics of spring migration of water and semiaquatic birds of the Putorana Plateau are analyzed. In 1988-2007 on an area of 250000 kmІ, 8 points were surveyed in the northern, southern, western and eastern parts of the region. The method of route accounting was used. The water and semiaquatic avifauna of the Putorana Plateau in the spring migration period includes 68 species. The most significant in its formation are tundra species (53 %) from among the Anseriformes and Charadriiformes, totaling 94 %. Birds fly in north, east and west directions. They make stops at the early areas of river deltas that are freed from snow and ice. There are species that are distributed in stopping places everywhere (38 %), locally (22 %), pointwise (40 %). Bird population density at stops 15-227, on average ( n = 8) 94 ind./1 km of coastline. The population of birds on lakes is always much poorer than on adjacent river sections. The vast majority of individuals of almost all migratory species are united in monospecific, rarely polyspecific flocks. The entire spring migration of water and semiaquatic birds on the Putorana Plateau takes place from May 19 to June 27 and lasts an average ( n = 10) 23 days. The main passage runs from May 25 to June 17 and lasts an average of ( n = 8) 7 days. Spring migration is most intense in the west of the Putorana, where at least 20000-30000 individuals of woter and semiaquatic birds fly through the surveyed points. The span is much weaker in the center and, especially, in the east of the region. There are 19 species among the dominants of water and semiaquatic habitats, incl. Eurasian Wigeon, Common Teal, Grey-taild Tattler, Northern Pintail, Little Stint.

Participating in the circulation of nutrients epilithic biofilms play an important role in water bodies. Denitrification actively proceeds in the epilithon of water bodies. However, the information on environmental factors that affect the process in biofilms is still limited. The object of study in this article involves the number of cultivated denitrifying bacteria in biofilms formed on the stony substrates in different parts of Lake Baikal littoral zone. It has been found out that the main factors explaining the differences in the number of cultivated bacteria who perform complete denitrification were the temperature and the concentration of total nitrogen in shallow water. The article shows that lower amount of denitrifiers is a typical for biofilms experiencing nitrogen deficiency as indicated by the low stoichiometric N: P ratio in biofilms. An uneven distribution of heavy metals in the biomass of epilithic biofilms has been determined. It also may potentially impact denitrification in the epilithon of Lake Baikal.

The hydrochemical and microelement composition of water and bot tom sediments was determined in the Kuchiger thermal spring (Baikal rift zone). The entry of chemicals with groundwater and high temperatures create favorable and specific conditions for the development of microorganisms. The taxonomic diversity of the microbial community of water and bottom sediments was studied using the analysis of 16S rRNA gene aplicons. 107619 nucleotide sequences assigned to 211 OTUs were analyzed. In the studied samples of water and bottom sediments, bacteria dominated, representatives of archaea accounted for 0.2-3.1 %. The phylum Proteobacteria dominated in microbial communities. The subdominants in the studied samples were the phyla Firmicutes, Chloroflexi, Nitrospirae, Acetothermia, and Actinobacteria, where their ratio varied depending on the biotope. A characteristic feature of the microbial community in the Kuchiger thermal spring is the dominance of chemolithotrophic bacteria.

In 2015-2019 catching of young bluethroats was carried out in order to determine the parameters of their migration stop in the taiga zone in the east of the Russian Plain. A total of 272 birds were analyzed, of which 186 were males and 86 were females. The average duration of the migration stop for young bluethroats was 1.45 days. Transient individuals have fat reserves that allow them to make migratory throws lasting an average of 4.39 ± 0.20 hours. Bluethroats with an average stopping time have a fat accumulation rate of 0.04 ± 0.36 g per day and by the time of departure are able to make non-stop flights lasting an average of 3.89 ± 0.58 hours. Individuals that make the decision to stop lose little of their fat reserves, reducing their ability to fly non-stop until the next stop. The significance of the river valleys in the east of the Russian Plain for a successful stopover remains open, and it has not been fully clarified whether these places have the necessary ecological conditions for the successful stopover of small birds.

The climate change is well pronounced in high latitudes. The quick westward expansion of the Sandhill Crane breeding range in Eurasia requires an analysis of the species impact on the Arctic ecosystems. We employ the data about 223 Sandhill Crane nests in the Chaun-Delta, West Chukotka. Weinvestigated date of clutch onset, clutch sizes, egg sizes, nesting density and nesting success. We tested above parameters vs climatic characteristics of the site in order the learn their effect on the reproductive potential of the species. The most important climatic characteristics that determine the increase in nesting density, clutch and egg sizes, earlier clutch onset and higher nesting success included the First frost free day, the integrated characteristic of May (cold or warm according to the sum of positive temperatures) and the sum of average daily temperatures in the second half of May. The maximum reproductive potential Sandhill crane is realized in conditions of warm and early spring.