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Abstract  The organic matter content in the eggs and early larvae of the ctenophores Mnemiopsis leidyi and Beroe ovata from the Black Sea was determined using the adapted microtechnique of dichromate oxidation. The content of organic matter in the eggs of M. leidyi (0.25 μg/indiv.) was 5 times less than in B. ovata (1.28 ± 0.29 μg/indiv.). The somatic content of organic matter was 0.25 ± 0.09 μg/indiv. (25.1 ± 8.3 μg/mg, wet wt) for 2-day-old larvae of M. leidyi (0.2–0.3 mm in body length) and 1.37 ± 0.19 μg/indiv. (67.1 ± 5.7 μg/mg wet wt) for larvae of B. ovata (0.4 mm in body length). The specific organic content of larvae of both species steadily decreased with an increase in ctenophore body size and weight, approaching 3–4 μg/mg of wet weight for 2 mm specimens of M. leidyi and 3–5 μg/mg of wet weight for 6 mm B. ovata. The specific organic content of early larvae was 20–30 times higher than that of adult ctenophores. The results of this investigation could be useful in the evaluation of the energy budget for somatic growth and generative production in these species. Calculations indicate that with specific wet weight growth rates of 0.43/day for M. leidyi larvae and 0.29/day for B. ovata larvae, their true organic increases are respectively 30 and 38% less, i.e., no more than 0.31/day for the former and 0.18/day for the latter species. [ABSTRACT FROM AUTHOR]

Metabolic rates of the ctenophoreBeroe ovatawithin the length range from 0.4 mm (newly hatched larvae) to 60 mm were investigated. At 20°? the respiration rates (Q, µg O2 ind.-1 h-1) of individuals with wet weights (W, mg) less than or greater than 100 mg changed according to the equationsQ=0.093W0.62 andQ=0.016W0.99, respectively. The weight-specific respiration rate of the juvenile ctenophores with wet body weights of 0.021-100 mg diminished approximately 20-fold (from 0.35 to 0.017 µg O2mg-1 h-1, respectively), but did not change within the range from 100 to 30,000 mg. The difference in the slope of the regression lines seems to be attributable to the ontogenetic changes inB.ovatametabolism. For the tested temperature range of 10-28°?, the meanQ10 coefficient was equal to 2.17±0.5. The basal metabolism ofB.ovatanarcotised by chloral hydrate was 4.5±0.9 times lower than total metabolism. Such a metabolic range is considered to be characteristic of aquatic invertebrates with high levels of locomotory activity. [ABSTRACT FROM AUTHOR]

The impact of the introduced ctenophore Beroe ovata on its prey Mnemiopsis leidyi, another invader ctenophore voraciously feeding on mesozooplankton, and consequently on the mesozooplankton community, was evaluated by undertaking both laboratory and field studies in the northern Black Sea. Ingestion and growth rates as well as the gross growth efficiency of B. ovata were estimated from laboratory experiments. The daily ration of ctenophores was related to food abundance within a wide range of prey concentration and never reached saturation. Beroe ovata required high food rations (not less than 20% of body weight per day) for growth. The abundances, biomasses and population structures of these two introduced ctenophore species were also monitored, along with mesozooplankton, in inshore waters of the northern Black Sea (i.e. Sevastopol Bay and adjacent regions) over a period of 3 years (1999-2001) which is after B. ovata's arrival. The annual dynamics of the M. leidyi population were similar for the last 3 years: very low abundances and biomass values were observed during most of the year (unlike the previous years), with a sudden increase in summer-early autumn, but only for about a 2 month period. The B. ovata bloom during the peak M. leidyi biomass resulted in the M. leidyi biomass falling sharply to extremely low values. The predatory impact of M. leidyi on prey zooplankton was found to be reduced during the period of study compared with before. [ABSTRACT FROM AUTHOR]

Focuses on the chemical composition, respiration and feeding rates of alien ctenophore Beroe ovata in the Black Sea. Techniques used for determination of predatory impacts of Beroe ovata on Mnemiopsis leidyi; Role of Beroe ovata in control of dynamics and structure of the planktonic community.

Abstract: A study of the fluorescence characteristics of phytoplankton in the coastal regions off the Crimean coasts of the Black Sea showed that the seasonal dynamics of the activity of the phytoplankton photosynthetic apparatus is identical both in Sevastopol Bay and inshore waters. The mean monthly values of the photochemical efficiency of photosystem II over 1 year vary within narrow limits and are close to the values of Diatoms and Dynophycea grown under optimal conditions. Phytoplankton in Black Sea coastal regions is provided with nutrients, and its developmental conditions are close to optimal. The light intensity that saturates the electron transport rate increases sevenfold from winter to summer. In summer, it coincides with the results of the phytoplankton photosynthesis rate measurements, and in winter it varies up to fivefold. [ABSTRACT FROM AUTHOR]

The N 2 − N 2 and N 2 − Ar continuum absorption spectra are calculated using the classical trajectory-based simulation (CTS). The spectra obtained are validated by new measurements in the subTHz spectral range along with the previously reported data in the far infrared. A novelty of our approach consists in the use of the CTS method to simulate both the fundamental nitrogen absorption band and the rototranslational band in N 2 − Ar , i.e., we succeeded to step beyond the conventionally used approximation of the only rigid monomers. This extension of the theory made it possible, in particular, to demonstrate the validity of the rigid monomer assumption for the CTS simulation of the rototranslational N 2 − Ar band. The broadband spectra within 77–354 GHz were measured using the resonator spectrometer at temperatures of 278–333 K and pressures of 900–1600 Torr. A minor underestimation of the calculated absorption by 3.7% and 5% is shown for the N 2 − N 2 and N 2 − Ar system, respectively. On the basis of the obtained data, a new analytical model is developed for the N 2 − N 2 absorption in the subTHz range, which can be used in radiation propagation codes for the Earth, Titan, or other nitrogen-rich atmospheres. The advantage of the model proposed here over those previously published is discussed. • Bimolecular spectra of N 2 N 2 and N 2 Ar are obtained using the classical trajectory-based simulation. • Theoretical spectra are validated by an extensive set of broad-band experimental spectra. • Proved deviation of the observed N 2 N 2 mm-wave continuum from quadratic dependence on frequency. • The fundamental N 2 CIA band in N 2 Ar is simulated beyond the rigid monomer approximation. • A new analytical model is developed for the N 2 N 2 continuum in the subTHz range. [ABSTRACT FROM AUTHOR]

Aim: Invasive species are of increasing global concern. Nevertheless, the mechanisms driving further distribution after the initial establishment of non-native species remain largely unresolved, especially in marine systems. Ocean currents can be a major driver governing range occupancy, but this has not been accounted for in most invasion ecology studies so far. We investigate how well initial establishment areas are interconnected to later occupancy regions to test for the potential role of ocean currents driving secondary spread dynamics in order to infer invasion corridors and the source-sink dynamics of a non-native holoplanktonic biological probe species on a continental scale. Location: Western Eurasia. Time period: 1980s-2016. Major taxa studied: 'Comb jelly' Mnemiopsis leidyi. Methods: Based on 12,400 geo-referenced occurrence data, we reconstruct the invasion history of M. leidyi in western Eurasia. We model ocean currents and calculate their stability to match the temporal and spatial spread dynamics with large-scale connectivity patterns via ocean currents. Additionally, genetic markers are used to test the predicted connectivity between subpopulations. Results: Ocean currents can explain secondary spread dynamics, matching observed range expansions and the timing of first occurrence of our holoplanktonic non-native biological probe species, leading to invasion corridors in western Eurasia. In northern Europe, regional extinctions after cold winters were followed by rapid recolonizations at a speed of up to 2,000 km per season. Source areas hosting year-round populations in highly interconnected regions can re-seed genotypes over large distances after local extinctions. Main conclusions: Although the release of ballast water from container ships may contribute to the dispersal of non-native species, our results highlight the importance of ocean currents driving secondary spread dynamics. Highly interconnected areas hosting invasive species are crucial for secondary spread dynamics on a continental scale. Invasion risk assessments should consider large-scale connectivity patterns and the potential source regions of non-native marine species. [ABSTRACT FROM AUTHOR]

• The HITRAN2020 molecular spectroscopic database and its validations are presented. • Extended line-by-line coverage to 55 molecules, with new isotopologues included. • Increased spectral and dynamic ranges for multiple molecules. • Quality and amount of spectral parameters (including sophisticated line shapes) is increased. • Updates to cross sections, CIA, software tools & auxiliary data also described. The HITRAN database is a compilation of molecular spectroscopic parameters. It was established in the early 1970s and is used by various computer codes to predict and simulate the transmission and emission of light in gaseous media (with an emphasis on terrestrial and planetary atmospheres). The HITRAN compilation is composed of five major components: the line-by-line spectroscopic parameters required for high-resolution radiative-transfer codes, experimental infrared absorption cross-sections (for molecules where it is not yet feasible for representation in a line-by-line form), collision-induced absorption data, aerosol indices of refraction, and general tables (including partition sums) that apply globally to the data. This paper describes the contents of the 2020 quadrennial edition of HITRAN. The HITRAN2020 edition takes advantage of recent experimental and theoretical data that were meticulously validated, in particular, against laboratory and atmospheric spectra. The new edition replaces the previous HITRAN edition of 2016 (including its updates during the intervening years). All five components of HITRAN have undergone major updates. In particular, the extent of the updates in the HITRAN2020 edition range from updating a few lines of specific molecules to complete replacements of the lists, and also the introduction of additional isotopologues and new (to HITRAN) molecules: SO, CH 3 F, GeH 4 , CS 2 , CH 3 I and NF 3. Many new vibrational bands were added, extending the spectral coverage and completeness of the line lists. Also, the accuracy of the parameters for major atmospheric absorbers has been increased substantially, often featuring sub-percent uncertainties. Broadening parameters associated with the ambient pressure of water vapor were introduced to HITRAN for the first time and are now available for several molecules. The HITRAN2020 edition continues to take advantage of the relational structure and efficient interface available at www.hitran.org and the HITRAN Application Programming Interface (HAPI). The functionality of both tools has been extended for the new edition. [ABSTRACT FROM AUTHOR]

• Measurements of the broad mm-wave continuum absorption of pure CO 2 and CO 2 -Ar mixtures. • Two independent semiclassical trajectory-based calculations of the absorption are compared to measurements. • Significant contribution from true bound dimers is revealed. • The formula describing both frequency and temperature dependence of the continuum is suggested for atmospheric applications. Broadband spectra of the continuum absorption in pure CO 2 gas and its mixture with Ar are studied at room temperature using a resonator spectrometer within 105–240 GHz. The expected pressure and frequency dependence is observed. The obtained data are validated by two independent calculations of the interaction-induced absorption using a semiclassical trajectory-based method. The observed continuum is interpreted in terms of bimolecular absorption, including a significant contribution from true bound dimers. A simplified formula describing both frequency and temperature dependency of the CO 2 –Ar continuum within a frequency range from 60 GHz to 450 GHz at temperatures from 200 K to 400 K is suggested for use in atmospheric studies. [ABSTRACT FROM AUTHOR]

• Nitrogen continuum spectrum is experimentally and theoretically studied under close to atmospheric conditions. • Obtained spectra validate previous experimental data and theoretical models. • We demonstrate negligible contribution of N 2 -N 2 bound dimer to the total absorption. • Refined set of empirical parameters is derived for the mm-submm radiation propagation models. We report the results of experimental study for the N 2 absorption in the millimeter wavelength range at pressure and temperature ranging, respectively, from 750 to 1500 Torr and from 265 to 310 K. The obtained data are shown to be in a good agreement with the previously published experimental results, as well as with the predictions issued from available empirical models of nonresonant absorption and from the simulation of the N 2 –N 2 rototranslational collision-induced absorption performed recently using the classical trajectories method relying on complete ab initio potential and induced dipole surfaces. Analysis of the first spectral moments leads to a conclusion that the role of true bound (N 2) 2 dimer absorption is negligible at least in the range of atmospheric temperatures. New experimental data reported in this paper are supported by our theoretical modelling being however somewhat in excess of the data presented in the HITRAN/CIA database for the same spectral range. We consider our data as an update of the previously available so-called "dry" atmospheric continuum which is conventionally employed nowadays in the mm-waves propagation models. [ABSTRACT FROM AUTHOR]