Diatom Complexes Research Articles

Distribution, taxonomic diversity and ecology of paleogene <i>Bacillariophyta</i> in Ukraine

The geographic distribution, level of taxonomic diversity, and ecological preferences of Bacillariophyta complexes extracted from Paleogene deposits in various regions of Ukraine are characterized. The stratigraphic sequence of diatom assemblages, the relationship of the conditions of their formation to paleoceanological events in sedimentation basins, and the biostratigraphic significance are traced. The most taxonomically diverse (up to 250 species) associations of marine diatoms and silicoflagellates are found in the Middle to Upper Eocene deposits of the northeast margin of the Dnieper-Donetsk Depression, the northwest margins of the Donbas, and the slopes of the Voronezh Uplift. In Eocene-Oligocene deposits of the Ukrainian Shield, diatom complexes consist of over 60 marine and brackish taxa. Early Oligocene marine associations, widespread in the Sambir Carpathians and the eastern part of the Azov region, include over 130 species-level taxa. Changes in the proportion of ecological groups of diatom algae indicate their formation under different facies conditions and the transition from marine warm to more cold-water coastal-marine environments during the Eocene, with episodes of freshwater input in the Oligocene.

Environmental evolution of the south shore of Kandalaksha Bay, as indicated by the study of bottom sediments from small lakes

Environmental changes on the south shore of Kandalaksha Bay in Holocene time were reconstructed by analyzing the data obtained by palynological and 14C methods. Diatom complexes of marine, freshwater and transition facies are described. The possible application of pollen indicators for a better understanding of the genesis of sediments is discussed.

Diatom Complexes in Modern Bottom Sediments of Lakes of the Central Tunguska Plateau, Evenkia

Diatom Complexes in Modern Bottom Sediments of Lakes of the Central Tunguska Plateau, Evenkia

The Early-Middle Pleistocene Environmental Changes on the Diatom Proxies at the South Kunashir Island (Kurile Islands)

The article considers diatom biostratigraphy and ecological factors of the formation of diatom complexes that characterize the Pleistocene volcanic-sedimentary facies of shelf deposits of the Golovnin Formation. Dividing the Golovnin Formation is proposed according to diatom complexes into three biostratigraphic zones: Zone <i>Eupyxidicula zabelinae,</i> Zone <i>Thalassiosira antiqua</i>, Zone <i>Proboscia Proboscima barboi</i>. Three transgressive phases of formation of the Golovnin deposits were established under the paleoecological analysis of diatom associations. Early Pleistocene transgressions are named Kunashir I (2.12-2.0 Ma) and Kunashiri II (1.95-1.77 Ma). The Late Golovnin transgressions during 0.424-0.374 Ma and 0.337-0.300 Ma are correlated to the Marine Isotopic Stages 11 and 9 respectively.

Assessment of the ecological situation long-term transformations in the Ivankovo reservoir

The work is devoted to the evaluation of the new concept of integrated monitoring practical application results. The theoretical novelty of the concept consists in the joint analysis of diatom complexes from columns of bottom sediments and modern phytoplankton complexes. The work confirms that there are no processes of redeposition during precipitation formation in all analyzed columns. The results of the water quality assessment by two indexes are considered: the saprobity index (S) and the integral quality index (QI). Comparison and spatial- temporal analysis of the obtained results were carried out. Within the framework of the new concept, the results of chemical analysis of water and sediment samples were used for reference. The main objective of the work was to demonstrate the effectiveness of the new concept of integrated monitoring in assessing long-term transformations occurring in reservoir.

Diatom complexes from bottom sediments of Lake Semenovskoe (Murmansk)

For the first time, the composition of diatom complexes of the bottom sediments of Lake Semenovskoe was studied, located within the city of Murmansk. In the core 44 cm thick, 117 species and intraspecific taxa of diatoms were found. Significant rearrangements in the taxonomic composition and structure in the direction from the lower layers to the upper ones were revealed. In the lower layers of the core are benthic acidophilic forms of Frustulia rhomboides (Ehrb.) De Toni (32%), Brachysira serians (Bréb.) Round & Mann (8,5%), Semiorbis hemicyclus (Ehrb.) Patrick (6,1%). In modern layers, the dominant steel species are: planktonic alkalibiont Aulacoseira subarctica (Müll.) Haworth (46%), planktonic-benthic alkaliphile Cyclotella meneghiniana Kütz. (10%). The benthic acidophilic species S. hemicyclus and Oxyneis binalis (Ehrb.) Round completely disappeared.

An araphid diatoms from marine Miocene deposits of the Fisher Massif (Prince Charles Mountains, East Antarctica)

The Late Cenozoic history of Antarctica is reflected in the few ice-free ground deposits of the continental marginal zone. While the planktonic diatom flora of the Cenozoic Antarctic, which has dominated the biocenoses of the Southern Ocean since the Eocene, has been fairly well studied based on Deep-Sea Drilling, the benthic diatoms found in sediments have been studied extremely poorly. In the materials collected during the 52nd and 53rd Russian Antarctic expeditions in 2006–2008 from deposits of the Fisher Massif (central part of the Prince Charles Mountains), a rich fossil diatom complexes were found, including more than 80 mainly benthic taxa. Of these, 13 species of araphid diatoms have been studied and described.

A new algorithm for integral sedimentation zones identification on the example of the Ivankovo and Rybinsk reservoirs

The work is devoted to the new concept of integrated monitoring practical application and evaluation it’s results. The theoretical novelty of the concept consists in the joint analysis of diatom complexes from bottom sediments columns and modern phytoplankton complexes. The Ivankovo and Rybinsk reservoirs were chosen as the objects of research. This decision was made due to their advanced age, the power of accumulated deposits and the degree of study. The bottom sediment columns sampling points optimal locations in the Rybinsk and Ivankovo reservoirs was established as a result of the conducted research. During the creation of reservoirs, the lakes on their territory were flooded. The resulting morphometric bottom relief determined those relict lakes locations as zones of stable sedimentation. According to the comprehensive studies results, long-term negative processes caused by anthropogenic load have been confirmed in the investigated reservoirs.

Late holocene diatom complexes paleoecological reconstructions (problems, possibilities, solutions)

The paper discusses the latest deposits distinctive features and the problems of their analysis. The main difficulties in paleoecological and paleoclimatic reconstructions are listed. A summary of the methodological techniques developed over the past decades based on diatom analysis is given. New methods of reservoir ecosystems long-term changes reconstruction using paleolimnology methodological techniques are described.

ОЦЕНКА ИНФОРМАТИВНОСТИ НОВОЙ КОНЦЕПЦИИ КОМПЛЕКСНОГО МОНИТОРИНГА НА ПРИМЕРЕ ИВАНЬКОВСКОГО ВОДОХРАНИЛИЩА

The paper presents results of one of the stages of integrated monitoring new concept testing. The novelty of the concept implies a joint analysis of diatom complexes from bottom sediment columns and modern phytoplankton complexes. The Ivankovo reservoir was chosen as the object of research. The results of the water quality assessment by the saprobity index (S) are considered. Biomonitoring did not reveal significant changes in the saprobity index (S). In the analysis of diatom complexes from columns of bottom sediments, the differentiation between the coastal zone and the open areas of the reservoir was established. In the coastal zone, an increase in the numerical values of S was registered. Saprobization of the coastal sections of the reservoir is presumably determined by a combination of factors: unauthorized construction, overgrowth of coastal zones, etc. The main objective of the work was to demonstrate the informative value of the new concept of integrated monitoring in assessing long-term transformations occurring in the reservoir.

Relative sea-level variations indicated by micropaleontological data from small lake bottom sediments (Kandalaksha Bay, NW Russia)

Abstract. The results of the micro-paleontological study of bottom sediments from a small lake on the Kandalaksha Bay shore of the White Sea are reported. Three stages in the evolution of the lake basin: marine, transitional and lacustrine were recognized. The characteristics of their diatom complexes and palynological spectra were revealed. Marine-facies sediments were shown to be dominated by poly- and mesohalobes, their share in the transition facies is twice as small, and freshwater diatom complexes contain up to 10% halophiles. Facies were shown to be reliably identified, using the pollen and spores of distinctive species indicative of certain ecological conditions. Non-pollen palynomorphs (algae Pediastrum, Botryococcus and sponge spicules) can be used for identifying various facies. These data will be used later to more reliably and objectively reconstruct variations in relative sea level and the sea shoreline migration in the Holocene. A decrease in sea level was established at the turn of 7200 cal. years and the isolation of the lake from the sea occurred about 6700 cal. years ago.

Long-term transformations analysis of the structure of diatom complexes and phytoplanctonassociactions from Rybinsk and Ivankovsky reservoirs

The paper discusses the prospects of applying the new concept of integrated monitoring (NCIM) on the example of the Rybinsk and Ivankovo reservoirs. NCIM implies a joint study of phytoplankton, which is traditionally carried out in the water area of reservoirs during biomonitoring and layer-by-layer analysis of diatom complexes from accumulated bottom sediments. When comparing the structure of phytoplankton and diatom complexes, the work presents the results of the graphical analysis method application. The end result of the application of the NCIM should be more objective and complete data about long-term geoecological changes occurring in reservoirs.

Preliminary results of diatom analysis of bottom sediments from Lake Maloe Miassovo (Cheluabinsk Region, Russia)

Abstract. In this study the diatom results of analysis a 510 cm long continuous sediments core from Lake Maloe Miassovo (South Urals, Russia) are presented. The core was collected in July 2018 from central part of the lake from a depth of 7 m. Diatom analysis of samples revealed 38 taxa, belonging to 29 genera and 18 family. The analysis of the ecological structure of the diatom flora of the sediment core sample from the lake under study shows that it is dominated by the Holarctic representatives of benthic and fouling organisms giving preference to the alkaline environmental conditions, which is due to the shallowness of the lake. The prevalence of Staurosira construens Ehrenberg diatom in sediments have been established. Diatom diagram has been divided into two diatom zones on the basis on changing diatom abundances and taxa composition Diatoms were found in low concentrations, or were absent in the lower part of the core of bottom sediments, which could be due to a lack of organic substances, as well as low air and water temperatures. The composition of diatom complexes almost unchanged in the upper part, but their concentration increases significantly.

Paleolimnological changes in the composition of diatom complexes in the context of the Holocene Baltic Sea transgressions (Lake Zaychikhinskoye)

Abstract. The study examines the issues of changes in the level of the Baltic Sea over the past 10 thousand years. According to the data of domestic and foreign authors on time, there is no unambiguous data on the duration and level of littorina transgression, which is considered the largest during the Holocene period. By the research, with the financial support of the RFBR grant-graduate students No. 20-35-90089, studies of bottom sediments of lakes Goluboye, Bolshoye Molochnoye and Zaychikhinskoye are being carried out. The report presents the results of the diatom analysis of Lake Zaychikhinskoye. The main stages of the lake s development are determined, it is established that in the early Holocene its development was determined by the transgressive-regressive stages of the Baltic. At the initial stage, the reservoir was part of a deep oligotrophic Ancylus lake. During the littorina transgression, the Baltic Sea level most likely did not rise to lake level in this area.

Review of the longstanding research results using the author's method of graphical analysis

The work is devoted to the analysis of long-term studies by the method of graphical analysis. Initially, the method was developed in the study of diatom complexes from modern lake sediments of the European part of Russia. Three initial types of taxonomic proportions of diatom complexes and three scenarios of their transformation have been established. Later, the method was successfully applied in the study of diatom complexes from Late Holocene deposits. The basic concepts and solving information tasks were formulated. Later, this made it possible to successfully analyze long-term transformations in river phytoplankton communities (biomonitoring). A similar model of fluctuations in the number of microorganisms in water has been established. The informative value of the method was demonstrated when analyzing transformations in complex systems that do not belong to the category of living: in rivers and reservoirs.

Особливості сезонної сукцесії фітопланктону в прибережній зоні Криму (Чорне море) у різні за кліматичними умовами роки (2009–2014)

Under conditions of climatic changes, it is of great interest to study the dynamics of various functional complexes of phytoplankton species. The long-term influence of previous cold winters on the course of the seasonal succession of phytoplankton, as well as the intensity of blooms in the open waters of the Black Sea, were shown earlier. In the coastal zone, this relationship has not yet been sufficiently studied. Based on regular monitoring studies in the coastal area of Sevastopol from 2009–2014, features of the course of seasonal succession of phytoplankton in years with different climatic conditions were revealed: the “cold” years differed from the “warm” ones by a longer dominance of diatom complexes in terms of cell abundance, especially of small-celled species, which characterize the initial stage of seasonal succession of phytoplankton. The level of development of both diatoms and dinoflagellates was minimal compared to other years, with a shift in the periods of maxima to later months. In contrast, the "warm" years were characterized by the predominance of dinoflagellates for most of the study period, with a shift in timing of the maxima to earlier months. Both diatoms and dinoflagellates reached their maximal development in “warm” years in spring and autumn. In the “moderate” years, phytoplankton development proceeded either by analogy with the “cold” (2009) or “warm” (2011) years. The seasonal succession described above is typical for the northwestern Black Sea, in particular, the Sevastopol coastal area, and differs from the average pattern for the northwestern part described earlier for 1992–1993. The difference consisted of an increase in the proportion of stages I and III due to a decrease in stage II compared to 1992–1993.

Assessment of long-term changes in the trophic status of two reservoirs

The studies were carried out with the integrated monitoring of the Ivankovo and Rybinsk reservoirs. The work is devoted to the assessment of long-term changes in the trophic status of water bodies under the influence of natural and anthropogenic influence. The studies combined two traditional methods of analysis. A layer-by-layer study of diatom complexes in bottom sediments and the determination of the taxonomic composition of phytoplankton in reservoirs were carried out. The saprobity index (S) was calculated for diatom complexes from sediments. A comparison was made with similar calculations for the species structure of phytoplankton complexes. Spatial and temporal heterogeneity of saprobization processes in reservoirs was confirmed.

Upper Pliocene Diatom Complexes and its Significance for Establishing the Lower Boundary of Quarter (South of the Far East)

Upper Pliocene Diatom Complexes and its Significance for Establishing the Lower Boundary of Quarter (South of the Far East)

Paleogeographic reconstructions of the Northwest Karelia region evolution in the holocene based on the study of small lake sediments

The results of a study of bottom sediments from two small nameless lakes located on the proximal side of Salpausselkä II (Kalevala) glacial deposits at various elevations within glacial-lacustrine and morainic plains are reported. Using a set of methods, including spore-pollen, diatom and radiocarbon (C14) analyses, new data were obtained on the onset of the formation of the lakes, stages of their development, sedimentation of organic sediments and the effect of local geomorphological conditions on the composition of spore-pollen spectra and diatom complexes in different paleoclimatic periods in the Holocene. Evidence shows that the lakes began to form virtually simultaneously with glacial retreat. Terrigenous sediments accumulated in the lakes in Preboreal time. They were replaced by organic sediments about 9140 ± 220 (C14) B. P., i. e. 200–450 years later than in the eastern and southeastern parts of Kalevala marginal deposits. A hiatus was revealed in the deposition of bottom sediments in one of the lakes lying at a higher absolute elevation. The hiatus was due to a drop in the water level in Boreal time caused by a change to a more xeric climate and a glacioisostatic uplift of the crystalline Fennoscandian Shield. Vegetation dynamics from Preboreal time to the present day was reconstructed.

Таксономическое разнообразие диатомовых комплексов голоценовых донных отложений малых водоемов депрессии озера Имандра

Исследования таксономического разнообразия диатомовых водорослей в голоценовых донных отложениях двух малых водоемов на западном побережье оз. Бабинская Имандра (Мурманская область) продемонстрировало исторические трансформации видового состава и структуры диатомовых комплексов в ответ на меняющиеся условия окружающей среды в голоцене. Изученные водоемы характеризовались доминированием бентосных форм и обрастателей в составе палеосообществ на протяжении всего голоцена. Наиболее резкие изменения в диатомовых комплексах были вызваны тектоническим событием в зоне Имандровской депрессии.