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Water discharges, suspended load and hydrochemistry for 35 inflows of largest Caucasian Lake Sevan were measured 3 times in different hydrological seasons during 2024 and 2025. During summer most of small streams dried out while in winter a number of rivers were frozen into the bottom. The water discharges varied from 0.01 in summer to 8.02 m3/sec in spring. Large natural inflows are Argichi, Dzknaget, Gavaraget, Masrik rivers with water discharges in spring 8.0, 6.3, 4.5, 2.8 m3/sec correspondingly. By the end of...

This study provides a characterization of the Holocene sedimentary processes in Lake Urasar (Lori plateau, Armenia). Lake Urasar is less than 0.1 sq. km with 8.5 m max. depth. 2 m -long sediment core was retrieved by using peat corer in the deepest part of the lake during summer 2023. Obtained core was a subject for detailed lithological description and XRF-scanning. Three lithological units are identified in the sediment sequence reflecting different sedimentation patterns. Unit I (200 - 164 cm) characterized by ...

During summer-autumn 2023 hydrophysical, hydrochemical, and hydrobiological measurements had been done on six small upland Armenian lakes. For the first time colored dissolved organic matter (CDOM) and methane (CH4) - emission were observed. Studied lakes are on 1479-3312 m a.s., has maximal depth up to 12 m with groundwater springs input. Anoxic conditions were noticed on the lake bottom in August but changed to oxygen in October. Conductivity range was 0-231 ?S cm-1, TDS - 3-102 mg l-1, pH - 6.4-9.4 for surfaces...

Water ecosystems of Arctic region are most vulnerable to modern climatic changes, since global biogeochemical processes mostly occur on territories of permafrost zone. This work gives new insights into fundamental research question of how fast organic matter of thawing permafrost can be converted to greenhouse gases which are emitted into the atmosphere (for example, CH4). We aimed to identify microbial response and associated release of CH4 from Arctic lakes in response to temperature increase. We investigated la...

The Yamal Peninsula is one of the most important strategic oil and gas-bearing regions of Russia. Active development of the Far North territories threatens to have negative consequences for the delicate balance of Northern ecosystems, therefore their monitoring and comprehensive research are particularly relevant. In 2012-2013 during the expeditions on the Yamal, Yavay and Gyda peninsulas bottom sediments of the Unnamed lake (57.5 cm; 1300 cal yr BP), located in the catchment area of the Pyasedayakha river, were s...

Zooplankton organisms are widely used as indicators of ecosystem changes (Adrian et al., 2009, Nigamatzyanova G., Frolova L., 2017). Both zooplankton and nutrients play an important role in monitoring and assessing water quality by greatly contributing to biological productivity (Vinberg,1960). In the current study, we examined water quality of different types of water bodies of Ob and Erkuta river basins, based on the analysis of zooplankton communities and the concentration of nutrients. 72 species of zooplankto...

Aquatic ecosystems of the Arctic are very sensitive to the climate change. Thermic processes inside and around water objects (lakes, rivers, wetlands) affected by endo- and exogenous factors and lead to talik formation and geoprocesses interaction and turnover. Hydrological and geophysical investigation in the Lena River delta have been carried out in spring and summer 2016-2018. Sublake and subriver taliks georadar and electrical resistivity tomography data were obtained in a field with following hydrological and...

The northern polar region is under the influence of cold temperatures, increasing the effect of snow Arctic aquatic ecosystems affected by climate warming as well as human impact. Different scenarios of climate change show a possibility of temperature increase on 1-2?C and more depending of CO2 emission accounting. All global models give significant valuation to the Arctic exactly. Aquatic ecosystems take several parameters that allow to save their inner stable state and resilience. According to water physical par...

The Ob and the Lena Rivers are considered in the research. They are two biggest rivers of Russian Arctic and have the annual runoff 405 and 530 km3/year correspondingly. Analyse of multiyear data of Russian Hydrometeorological Survey (Roshydromet) and own measurements in the mouths areas allow to describe a tendency of water resource and water quality development in these regions according to climate change and human impact. Long-term river runoff and concentration of major and trace elements in water have been co...