9 research outputs found

    Tab. 1: Chupa Inlet, Kandalaksha Bay of the White Sea. Population density of the dominant boreal copepod species and daily pellet carbon flux

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    Data on the zooplankton community structure, gut evacuation rate and carbon content of zooplankton faecal pellets were used for assessing the contribution of zooplankton to vertical carbon fluxes in the White and Kara Seas. The results revealed strong regional and seasonal variations of pellet carbon input related to differences in structure and dynamics of the zooplankton communities in the regions studied. In the deep regions of the White Sea, maximum daily pellet carbon flux from the 0-50 m layer was observed in the spring. It reached 98 mg Corg m-2 day-1 and coincided with a strong predominance of the large arctic herbivorous copepod Calanus glacialis in the surface layers. In summer and fall, it decreased by 1 to 2 orders of magnitude due to migration of this copepod to its overwintering depths. In contrast, in the shallow coastal regions, the pellet production was low in spring, gradually increased during summer and reached its maximum of 138 mg Corg m-2 day-1 by late summer to beginning of autumn. Such a seasonal pattern was in accordance with the seasonal variation of abundance of major pellet producers, the small boreal copepods Acartia bifilosa, Centropages hamatus, and Temora longicornis. In the estuarine zone of the Kara Sea, the pellet flux was mostly formed by pellets of brackish-water omnivorous copepods. It varied from 35 mg Corg m-2 day-1 in 1997 to 96 mg Corg m-2 day-1 in 1999. In the central Kara Sea with its typical marine community, the daily flux reached 125 mg Corg m-2 day-1 in summer. The results of our calculations indicate that both in the White and Kara seas zooplankton pellet carbon contributes up to 30 % to the total carbon flux during particular seasons

    Films Based on a Blend of PVC with Copolymer of 3-Hydroxybutyrate with 3-Hydroxyhexanoate

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    Polymeric packaging materials are one of the factors of environmental pollution. Reducing the environmental burden is possible by increasing the environmental friendliness of packaging materials. In this work, we study polymer films based on polyvinyl chloride (PVC) with a copolymer of 3-hydroxybutyrate with 3-hydroxyhexanoate P (3-GB) (3-GG) with different component ratios. The process of processing blends in the process of obtaining a packaging film is considered. The optical characteristics of the obtained films are determined. Thermal analysis of the obtained films was carried out using the differential scanning calorimetry (DSC), TGA, and thermomechanical analysis (TMA) methods. The degree of gelling of the resulting mixture was determined. It is shown that PHB has miscibility with PVC

    (Table 1) Temperature, salinity, and micronutrient concentrations in the surface water layer of the White Sea on August 17-28, 2004

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    Species composition, cell concentration (N), and biomass (B) of phytoplankton, as well as chlorophyll a (Chl a) concentration, primary production (PP), and concentrations of dissolved inorganic micronutrients (phosphorus, silica, nitrogen as nitrite) were estimated for the Kandalaksha Bay (KB), the Dvina Bay (DB), and the basin (Bas) of the White Sea in August of 2004. Micronutrient concentrations were lower compared to the average long-term values for the summer period. Chl a concentration varies from 0.9 to 2.0 mg/m**3 for most of the studied areas, reaching up to 7.5 mg/m**3 in the Northern Dvina River estuary. The surface water layer of the DB was the most productive area, where PP reached up to 270-375 mg C/m**3/day. Phytoplankton biomass varied from 11 to 205 mg C/m**3 with the highest values observed in the Bas and DB. Three groups of stations were defined during the analysis of phytoplankton species composition similarity. Dinoflagellates Dinophysis norvegica and Ceratium fusus were particular to phytoplankton assemblages in the KB; diatom Ditylum brightwellii was particular to the upper and central parts of the DB. These three phytoplankton species were less abundant in the Bas

    Association Mapping of Fertility Restorer Gene for CMS PET1 in Sunflower

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    The phenomenon of cytoplasmic male sterility (CMS), consisting in the inability to produce functional pollen due to mutations in mitochondrial genome, has been described in more than 150 plant species. With the discovery of nuclear fertility restorer (Rf) genes capable of suppressing the CMS phenotype, it became possible to use the CMS-Rf genetic systems as the basis for practical utilization of heterosis effect in various crops. Seed production of sunflower hybrids all over the world is based on the extensive use of the PET1 CMS combined with the Rf1 gene. At the same time, data on Rf1 localization, sequence, and molecular basis for the CMS PET1 type restoration of fertility remain unknown. Searching for candidate genes of the Rf1 gene has great fundamental and practical value. Therefore, in this study, association mapping of fertility restorer gene for CMS PET1 in sunflower was performed. The genome-wide association study (GWAS) results made it possible to isolate a segment 7.72 Mb in length on chromosome 13, in which 21 candidates for Rf1 fertility restorer gene were identified, including 20 pentatricopeptide repeat (PPR)family genes and one Probable aldehyde dehydrogenase gene. The results will serve as a basis for further study of the genetic nature and molecular mechanisms of pollen fertility restoration in sunflower, as well as for further intensification of sunflower breeding
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