Suspended matter and its components in the western Black Sea

Distribution and composition of suspended matter in the western Black Sea is examined in relation to influence of river run-off and eutrophication. Changes in suspended matter concentration and composition within the studied area are shown to be caused principally by intensity of production processes associated with different levels of eutrophication of coastal waters. Data on suspended matter obtained aboard or by remote control from space satellites are analyzed as a basis for evaluation of eutrophication scales and monitoring for evolution of marine production processes

Seasonal and Long-Term Variability of Coccolithophores in the Black Sea According to Remote Sensing Data and the Results of Field Investigations

Based on satellite data from the SeaWiFS, MODIS-Aqua, and MODIS-Terra scanners, the long-term dynamics of coccolithophores in the Black Sea and their large-scale heterogeneity have been studied. During the twenty years in May and June, mass development of coccolithophores population of different intensities was recorded annually. Summer blooms of coccolithophores reached peak levels in 2006, 2012, and 2017, after abnormally cold winters. It was noted that in conditions of low summer temperatures, the blooming of coccolithophores could be significantly reduced or acquire a local character (2004). In the anomalous cold summer of 2001, coccolithophore blooms was replaced by the mass growth of diatoms. Over twenty years, numerous signs of coccolithophores mass development in the cold season have been revealed. Winter blooms develop mainly in warm winters with periods of low wind activity. The formation of a thermocline and the surface layer’s stability are essential factors for initiating winter blooms of coccolithophores. It was noted that after the winter blooms of coccolithophores, their summer growth was poorly expressed. It is shown that during periods of rapid growth, the bulk of coccolithophores is concentrated in the upper mixed layer and thermocline. During the blooming period, the share of coccolithophores in phytoplankton biomass constituted 70–85%. The intensity of coccolithophore’s blooms is associated with the previous diatoms’ growth level. The effect of eddies circulation on the distribution and growth of coccolithophores is considered

Seasonal and Long-Term Variability of Coccolithophores in the Black Sea According to Remote Sensing Data and the Results of Field Investigations

Based on satellite data from the SeaWiFS, MODIS-Aqua, and MODIS-Terra scanners, the long-term dynamics of coccolithophores in the Black Sea and their large-scale heterogeneity have been studied. During the twenty years in May and June, mass development of coccolithophores population of different intensities was recorded annually. Summer blooms of coccolithophores reached peak levels in 2006, 2012, and 2017, after abnormally cold winters. It was noted that in conditions of low summer temperatures, the blooming of coccolithophores could be significantly reduced or acquire a local character (2004). In the anomalous cold summer of 2001, coccolithophore blooms was replaced by the mass growth of diatoms. Over twenty years, numerous signs of coccolithophores mass development in the cold season have been revealed. Winter blooms develop mainly in warm winters with periods of low wind activity. The formation of a thermocline and the surface layer’s stability are essential factors for initiating winter blooms of coccolithophores. It was noted that after the winter blooms of coccolithophores, their summer growth was poorly expressed. It is shown that during periods of rapid growth, the bulk of coccolithophores is concentrated in the upper mixed layer and thermocline. During the blooming period, the share of coccolithophores in phytoplankton biomass constituted 70–85%. The intensity of coccolithophore’s blooms is associated with the previous diatoms’ growth level. The effect of eddies circulation on the distribution and growth of coccolithophores is considered

Abundance and size composition of ctenophore Mnemiopsis leidyi population in the Caspian Sea on 2001-06-24 to 2001-07-01

Abundance and size distribution of ctenophore Mnemiopsis leidyi in different parts of the Caspian Sea were studied in summer 2001 in relation to environmental conditions. In general, principal differences were found in M. leidyi abundance and population reproduction activity in northern-, middle- and southern Caspian waters. Ctenophore was practically absent in the northern Caspian. In the west of the middle Caspian Sea it penetrated far to the north demonstrating low reproduction activity. In the east the first single comb jellies were pointed out only in the most south of the region. In the warmest and most productive southern part of the Caspian Sea several zones of M. leidyi active breeding were found with total abundance exceeding 6000 #/m**2. Breeding activity and abundance of ctenophores increased here from the east to the west exceeding maximum values along the western coast of the southern Caspian Sea in regions of intensive sprat catching. Dependence of M. leidyi population development on temperature conditions was mentioned. On the base of remote sensed surface temperature, chlorophyll, and suspended mater distribution analysis possible ctenophore settling mechanisms by mesoscale dynamic structures were examined. Practical applications of obtained results are discussed for using effective biological methods to prevent catastrophic consequences of M. leidyi invasion to the Caspian Sea

DEVELOPMENT OF LOCAL COMMUNITIES ON THE BASIS OF EXPERIMENTAL BOTTOM STATIONS IN DIFFERENT ZONES OF THE NORTH-CASPIAN SHELF

Aim. On the basis of four experimental bottom stations installed at various depths of the North Caspian shelf, the local communities of marine organisms were formed, on various constructions and in close proximity to them were investigated. The aim of the work is to study the features of community development on the basis of bottom biological stations, to measure their quantitative characteristics, to assess the informative character of the structural and functional characteristics of local communities for analyzing the state of the marine environment. Methods. Experimental bottom stations were installed in various regions of the North Caspian shelf using diving equipment to study their impact on the environment. Control over the development of associated fauna was carried out with the help of traps and the method of direct accounting for the materials of photo-video surveys. Sampling of fouling was carried out by the method of registration sites. Based on the number of species of flora and fauna of local communities, a ballroom information system has been suggested, that can be used for monitoring. Results. Research materials indicate a significant difference in the species composition, biomass and the structure of communities of local cenoses formed at the bottom stations with the same design and ecological capacity at various depths of the North Caspian shelf. In the shallow shelf zone at depths of 6-8 m in the local community of the bottom station, the vegetation component is dominant. At great depths, the total biomass increases in local cenoses and animal communities, including filter-feeders, make significant contribution to the self-purification of the marine environment. Conclusions. The results indicate the possibility of using complex observations of the structure and functional characteristics of local communities formed on the base of bottom stations, as well as the development of species of indicators and objects of accumulation of toxicants for assessing the state of the marine environment. The development of this approach involves the experiments with different station costructioons and materials and use of biotechnology implantation of test organisms on the design of bottom stations