Lake Imandra Research Articles

SEISMICITY of the RUSSIAN PART of EAST EUROPEAN PLATFORM and ADJACENT TERRITORIES in 2020

On the Russian territory of the East European Platform, seismic observations were carried out by 47 stationary seismic stations. In 2020, 36 seismic events of tectonic and technogenic-tectonic nature were registered. As before, weak natural and man-made seismicity was recorded on the territory of the Voronezh crystalline massif and the Baltic Shield: in Karelia, border areas with Finland, near the Kandalaksha Bay, within the Khibiny, Kovdor massifs and in the Vite-Guba area of Imandra lake on the Kola Peninsula. A feature of seismicity in 2020 is the occurrence of earthquakes in the paleorift structures of the northeast of the East European Platform: in the Kirov Kazhim and Central Russian aulacogens. The total volume of seismic energy released in 2020 is Е=7.16·109 J, which is 2 times lower than in 2019, but 2 times more than the energy released in 2018.

Biogeochemical Adaptation of Fish Metabolism to the Reduction of Anthropogenic Load on the Subarctic Imandra Lake

Biogeochemical Adaptation of Fish Metabolism to the Reduction of Anthropogenic Load on the Subarctic Imandra Lake

Evidence for postglacial seismicity in lacustrine records in the western Kola Peninsula (north-western Russia)

In this article we describe and interpret disturbances in the sedimentary records of four lakes on the western flank of Lake Imandra (NE Fennoscandia, Kola Peninsula). The research framework comprises sedimentological and textural criteria for a visual description of sedimentary structures sediment core data, chronological (radiocarbon dating) data, and ground-penetrating radar (GPR) data. Disturbances preserved in lake sequences contain a mixture of chaotic fragments of sand, silt, polychromatic gyttja, peat, and wood fragments embedded in the organogenic matrix. The synchronicity of disturbances, fast sediment accumulation in lakes, relationship with Quaternary faults, the observed mass movements in lake sediments are interpreted as potential consequences of the earthquake shaking. A seismic event with a magnitude Mw no less than 4.5–5 and intensity of shaking I0 = IV–VI took place in the Middle Holocene, 6400–6100 cal. yr BP. Our studies show that although this area is not seismically active today, some of the main fault zones experienced short periods of reactivation also in the postglacial time, when glacioisostatic rebound after the ice retreat was already very low.

Assessment of the current state of the Lake Imandra ecosystem (Russia, Murmansk region) using statistical and bioindication methods

The diatom assemblages of surface sediments of the Lake Imandra were studied. Lake Imandra is the largest freshwater reservoir in the Murmansk region. Significant differences in the composition of diatom assemblages were revealed in various parts of the water area, differing in the type and intensity of anthropogenic load. With the help of bioindication and statistical methods, the main factors influencing the development of certain diatom assemblages were identified.

Preliminary results of a diatom analysis of the Imandra lake bottom sediments (Kola region)

Preliminary data of micropaleontological (diatom analysis) study of bottom sediments of Lake Imandra are presented. A total of 485 taxa have been identified. According to changes in the composition of diatom communities, diatom zones were identified, reflecting the development of the lake from a periglacial lake in the Late Glacial period to its present state.

Paleoseismic Events Reflected in Late Pleistocene and Holocene Deposits of the Terraces of Imandra Lake (Kola Region, Fennoscandian Shield)

Paleoseismic Events Reflected in Late Pleistocene and Holocene Deposits of the Terraces of Imandra Lake (Kola Region, Fennoscandian Shield)

ИЗМЕНЕНИЯ КЛИМАТА И ЦВЕТЕНИЕ АРКТИЧЕСКОГО ОЗЕРА ИМАНДРА

Trends of meteorological parameters potentially implicated in harmful algal blooms regularly occurring since early 2000-ies in a major Arctic freshwater basin the lake Imandra have been analyzed. Compared with the preceding period, increases occurred in mean annual and seasonal air temperatures, sunshine duration, and solar radiation, whereas decreases occurred in spring cloudiness and winter precipitates. These changes resulted in altered light regimens in the lake, which were associated with an increased availability of photosynthetically relevant radiation in springtime. In combination with an increased biogenic matter load, this could lead to drastic changes in the structure of phytoplanktonic communities and in their seasonal successions, as well as in biogenic matter dynamics. Based on these considerations and published data, a conceptual model of the emergence and development of regular harmful algal blooms in the lake Imandra is suggested.

Традиционные и новые промыслы экостровских саамов при переходе к оседлости в XIX — начале XX вв

The paper reveals the features of traditional and new crafts of the Yokostrov Sami in the 19th and early 20th centuries during transition to settlement. This process coincided with migration of the Yokostrov pogost from the Yokostrov Strait to the bay Belaya Guba of the Lake Imandra. The study is based on materials of Russian and foreign ethnographic and travel essays as well as on archive sources, statistics and toponyms.

Biological responses of whitefish (Coregonus lavaretus L.) to reduced toxic impact: Metal accumulation, haematological, immunological, and histopathological alterations

Bioaccumulation of the main pollutants in the organs of whitefish, as well as their haematological parameters, were examined dynamically over a 40-year period in historically contaminated Lake Imandra. A quantitative histological analysis was performed to assess the physiological state of whitefish and histopathologies of organs, as well as their physiological and biochemical functions in the current period of toxic load decline. Biological reactions of whitefish from the historically contaminated area have been greatly modified in contrast to those of whitefish from the never contaminated area of the lake, and this shift persisted even after approximately 20 years of toxic load decline. First, high antioxidant status supports the body's systems, smoothing over the negative consequences of metal toxicity, phagocytosis and inflammatory reactions. Moreover, the defence mechanism of whitefish from the historically contaminated area actively uses the oxidative systems of nonspecific immunity. Second, the adaptive strategy is aimed at improving gas exchange without compensatory proliferation of gill structure, which increases their functional surface and reduces the distance to the bloodstream, as well as increasing haemoglobin in maturing erythrocytes. Third, the higher efficiency of endo- and phagocytosis was confirmed by detecting increased monocytes and macrophages in the peripheral blood and decreased melano-macrophage centres in the fish kidney. Elevated accumulation of Fe, Cu, and Se may serve a sign of liver pathology, while elevated accumulation of Zn and Co already indicates kidney pathology, which is confirmed by histopathological alterations.

The Role of Trace Elements in the Adaptation of Fish Metabolism under Reduced Pollution: A Case Study of the Subarctic Lake Imandra

The Role of Trace Elements in the Adaptation of Fish Metabolism under Reduced Pollution: A Case Study of the Subarctic Lake Imandra

Spatial and temporal dynamics of diatom assemblages of Lake Imandra (Russia, Murmansk region)

Diatom assemblages of sediments of large arctic reservoir (Lake Imandra), spatial and temporal distribution of the taxonomic composition of diatoms and structure were studied. We identified differences in the current state of the ecosystem in certain areas due to both natural and anthropogenic causes. The periods and causes of changes in the state of the lake ecosystem are determined, and a conclusion about future trends is made.

Paleoecological reconstruction of ecosystem of Lake Imandra (Russia, Murmansk region) based on diatom analysis of sediments

Abstract. This paper provides information about diatom assemblages in sediments of large arctic reservoir (Lake Imandra). The distribution of the taxonomic composition and structure of diatoms for several centuries has been studied. The periods and causes of changes in the state of the lake ecosystem are determined, and a conclusion about future trends is made. The data obtained can be used for monitoring the ecological state of the environment and water bodies.

Sedimentological records of atastrophic mass movements in the lake bottom-sediments of north-western Kola Peninsula and possible scenarios to explain the seismogenic trigger

Abstract. In this present article, we describe disturbances in the sedimentary records of lakes on the western flank of Lake Imandra (NE Fennoscandia, Kola Peninsula). The research framework comprises sedimentological and textural criteria for a visual description of sedimentary structures, borehole drilling data, chronological (radiocarbon dating) data, and ground-penetrating radar (GPR) data. Synchronicity specific features and fast spontaneous sediment accumulation in lakes, as well as traces of strong prehistoric and historical earthquakes and geomorphic setting in the studied area suggest that the observed mass movements in lake sediments are potentially generated by earthquake shaking.

Holocene environments on the west‐central Kola Peninsula (north‐west Russia): lithology, chronology and biostratigraphy records from Lake Tikozero and a neighbouring bog

ABSTRACTThe paper studies sediments from Lake Tikozero that have accumulated successively in the littoral of Lake pre‐Imandra, Imandra lagoon, and an open lake isolated from a parental freshwater body. The ‘Apatity’ bog was concurrently formed on the Lake Imandra coast. Lithological, 14C, pollen and diatom data and findings of previous investigations provide the regional Holocene stratigraphy, which is subdivided into the early (c. 11 550–8200 cal a bp), middle (c. 8200–4000 cal a bp) and late (last 4000 cal a bp) Holocene sub‐stages. In the early Holocene, environments became favourable for diatoms after c. 9700 cal a bp. Birch phytocoenoses and pine forests with birch flourished in the area. In the middle Holocene, the west‐central Kola Peninsula was covered by a pine‐birch forest with alders. Lake Tikozero became shallow and desiccated in a warm and dry climate between c. 6300 and 4000 cal a bp; and a Sphagnum raised bog developed in the adjacent area, provoked by lowering of the water table. Spruce appeared in a pine‐birch forest and indicates a colder and wetter climate in the late Holocene. The flooding of Lake Imandra created a number of new small lakes; and fens occurred along the wet shores.

Current aspects of freshwater quality protection in the Arctic zone of the Russian Federation

The state of freshwater reservoirs is a component of the complex conceptual space of the Arctic zone. On the example of the largest reservoir of the Arctic zone of the Russian Federation Lake Imandra, the article describes the current trends in water quality changes due to the massive development of potentially toxic cyanobacteria, which is not typical of high latitudes. “Blooming” of waters deteriorates water quality, causes deaths of valuable fish species, deteriorates the recreational attractiveness of water bodies. As a result of complex long-term observations, the main reasons for these phenomena were established. These are a change in the hydrochemical parameters of water along with the Arctic climate system. A decrease in the intake of toxic heavy metals and a high level of biogenic elements have created favorable conditions for the development of phytoplankton, including cyanoprokaryotes. To prevent the environmental risks of water quality deterioration and justify the adoption of strategic decisions for drinking and fishery water bodies in the urbanized regions of the Arctic, it is recommended to control the concentration of nutrients and the ratio of ammonium nitrogen to nitrate nitrogen.

Долговременные изменения химических параметров и цветение вредоносных водорослей в арктическом озере Имандра

The large arctic Imandra Lake is located in the industrial Murmansk region, Russia. Since the 2000s it has regular Harmful Algal Blooms. Significant changes in hydrochemical indices were recorded in 1985—2017. The ratio of the main ions has changed, the pH and alkalinity have increased. The indicators of water salinity, the total content of P and N, and their mineral forms have decreased. The concentrations of Zn, Cu, Ni и SO42– have decreased as well. The decrease trends in the content of macronutrients in waters contradict traditional concepts and the role of mineral P and N in the development of HAB. This indicates more complex mechanisms of flowering in this arctic reservoir, which are being discussed.

Long-Term Eutrophication and Dynamics of Bloom-Forming Microbial Communities during Summer HAB in Large Arctic Lake

Harmful algal blooms (HABs) in arctic lakes are recent phenomena. In our study, we performed a long-term analysis (1990–2017) of the eutrophication of Lake Imandra, a large subarctic lake, and explored the biodiversity of bloom-forming microorganisms of a 2017 summer HAB. We performed a 16Sr rRNA metabarcoding study of microbial communities, analysed the associations between N, P, C, and chlorophyll concentrations in the lake water, and developed models for the prediction of HABs based on total P concentration. We have demonstrated that blooms in Lake Imandra occur outside of optimal Redfield ratios and have a nonlinear association with P concentrations. We found that recent summer HABs in a lake occur as simultaneous blooms of a diatom Aulacoseira sp. and cyanobacteria Dolichospermum sp. We have studied the temporal dynamics of microbial communities during the bloom and performed an analysis of the publicly available Dolichospermum genomes to outline potential genetic mechanisms beneath simultaneous blooming. We found genetic traits requisite for diatom-diazotroph associations, which may lay beneath the simultaneous blooming of Aulacoseira sp. and Dolichospermum sp. in Lake Imandra. Both groups of organisms have the ability to store nutrients and form a dormant stage. All of these factors will ensure the further development of the HABs in Lake Imandra and the dispersal of these bloom-forming species to neighboring lakes.

Highly variable sediment deposition in Lake Imandra, NW Russia, since the Late Pleistocene

Highly variable sediment deposition in Lake Imandra, NW Russia, since the Late Pleistocene

The Distribution of Chemical Elements between Ecosystem Components in Belaya Bay, Lake Imandra, Murmansk Oblast

The effect of a large mining complex of Apatit JSC on the aquatic ecosystem of Lake Imandra is discussed. Hydrochemical data are given to characterize the pollution zone, and the distribution and accumulation of chemical elements between abiotic and biotic ecosystem components, including water, bottom sediments, seston, and fish, are described. It is proved that the polluted subarctic lake has acquired eutrophic status; the concentrations of Al, Sr, and Mn have increased 2–3 times and those of Cu and Ni, 4–6 times relative to their conventionally background concentrations. Estimates are given to the biogenic and mineral contributions to the formation of bottom sediments and the bioavailability of accumulation of metals to aquatic organisms.

ФОРМЫ МИГРАЦИИ НИКЕЛЯ И МЕДИ В УЛЬТРАПРЕСНЫХ ВОДАХ ЦЕНТРАЛЬНОЙ ЧАСТИ КОЛЬСКОГО РЕГИОНА

The article presents the waters study results, the composition of which is formed in various hydrogeochemical and ecological conditions. All investigated waters are ultrafresh: TDS of streams and springs does not exceed 30 mg/l, water of Lake Imandra at sampling points is 40 and 73 mg/l. All waters are calcium bicarbonate, but the lake’s waters have an increased content of sulfate ion, chloride ion, and especially sodium. This composition is due to the influence of wastewater from the Kola MMC. It is shown that the 7 km stream is mainly groundwater discharge; however, judging by the concentrations of heavy metals and aluminum, the lateral soil water runoff also takes part in the formation of the stream’s water composition. For all studied waters, the gross concentrations of Ni and Cu hardly change after filtration through a membrane filter with a pore size of 0.45 μm, that is, these metals migrate in a dissolved form (a combination of colloidal and truly dissolved forms). The similarity of the results of determining the migratory forms of Ni and Cu in ultra-fresh waters by experimental and calculation methods is shown. Therefore, according to the assessment of the ratio of suspended, colloidal and truly dissolved forms of copper and nickel based on the results of an experiment using filtration and equilibrium dialysis, in the waters under consideration, the truly dissolved form of migration of Ni and Cu is predominant. The application of physicochemical modeling using the HydroGeo software package made it possible to show that nickel migrates mainly in the form of the Ni2+ ion, and copper in combination with the organic ligands Cu(FА) and Cu(FА2)2-. In addition, it was found that with an increase in the pH value of waters, the proportion of complex compounds increases and the amount of simple ions Ni2+ and Cu2+ decreases