Expression of the “4.2 ka event” drought in the southern Rocky Mountains, USA

The use of the climatic anomaly known as the “4.2 ka event” as the stratigraphic division between the mid- and late Holocene has prompted debate over its impact, geographic pattern, and significance. The anomaly has primarily been described as abrupt drying, but evidence of hydroclimate change at ca. 4 ka is inconsistent among sites globally, and few sites in North America document a major drought. Climate records from the southern Rocky Mountains demonstrate the challenge with diagnosing the extent and severity of the anomaly. Dune-field chronologies and a pollen record in southeast Wyoming reveal several centuries of low moisture at around 4.2 ka and prominent low stands in lakes in Colorado suggest the drought was unique amid Holocene variability, but detailed carbonate oxygen isotope (δ18Ocarb) records from Colorado do not record it. We find new evidence from δ18Ocarb in a small mountain lake in southeast Wyoming of an abrupt reduction in effective moisture or snowpack from approximately 4.2–4 ka that coincides in time with the other evidence from the southern Rocky Mountains and the western Great Plains of regional drying at around 4.2 ka. We find that the δ18Ocarb in our record may reflect cool-season inputs into the lake, which do not appear to track the strong enrichment of heavy oxygen by evaporation during summer months today. The modern relationship differs from some widely applied conceptual models of lake-isotope systems and may indicate reduced winter precipitation rather than enhanced evaporation at ca. 4.2 ka. Inconsistencies among the North American records, particularly in δ18Ocarb trends, thus show that site-specific factors can prevent identification of the patterns of multi-century drought. However, the prominence of the drought at ca. 4 ka among a growing number of sites in the North American interior suggests it was a regionally substantial climate event amid other Holocene variability.

Simulating thermal dynamics of the largest lake in the Caucasus region: The mountain Lake Sevan

Lake Sevan is the largest freshwater body in the Caucasus region, situated at an altitude of 1,900 m asl. While it is a major water resource in the whole region, Lake Sevan has received little attention in international limnological literature. Although recent studies pointed to algal blooms and negative impacts of climate change and eutrophication, the physical controls on thermal dynamics have not been characterized and model-based assessments of climate change impacts are lacking. We compiled a decade of historical data for meteorological conditions and temperature dynamics in Lake Sevan and used a one-dimensional hydrodynamic model (GLM 3.1) in order to study thermal structure, the stratification phenology and their meteorological drivers in this large mountain lake. We then evaluated the representativeness of meteorological data products covering almost 4 decades (EWEMBI-dataset: 1979-2016) for driving the model and found that these data are well suited to restore long term thermal dynamics in Lake Sevan. This established model setting allowed us to identify major changes in Lake Sevan’s stratification in response to changing meteorological conditions as expected from ongoing climate change. Our results point to a changing mixing type from dimictic to monomictic as Lake Sevan will experience prolonged summer stratification periods and more stable stratification. These projected changes in stratification must be included in long-term management perspectives as they will intensify water quality deteriorations like surface algal blooms or deep water anoxia.

Draft Genome Sequence of the Anoxygenic Phototrophic Bacterium Rhodoferax sp. Strain U11-2br, Isolated from a Mountain Lake on the Ulagan Plateau

We report the draft genome sequence of an anoxygenic phototrophic bacterium, Rhodoferax sp. strain U11-2br, which was isolated from a freshwater mountain lake on the Ulagan Plateau (Altai, Russia). The assembly contains 4,514,979 bp, with a GC content of 59.9%.

On the poetry features at the turn of the century (from the creative work of Muliat Emizh)

Задача выявить в творчестве Мулиат Емиж конца ХХ - начала XXI века типологические особенности национальной литературы определяет исследование проблемно-тематического содержания, эволюции конфликта и жанровых форм художественных явлений. Устанавливаются усиление проблемности и попытки углубления концепции личности в сборниках «Возвратившиеся песни», «Таинственный знак», «Горное озеро» и др. Отмечается движение к художественной объемности и концентрации поэтических средств. Определяется влияние фольклора и традиций литературы на формирование жанровых форм поэзии. Опора на историко-литературный и сравнительно-типологический методы позволяет сделать вывод об отражении в творчестве М. Емиж таких особенностей современной литературы, как освобождение от декларативности, публицистического многословия и торжественности. Работа может быть востребована при изучении теоретических проблем формирования отечественной литературы ХХ века. The authors set objectives to identify the typological features of national literature in the work of Muliat Emizh of the late 20 - early 21 centuries, which determine the study of the problem-thematic content, the evolution of the conflict and genre forms of artistic phenomena. The authors establish the strengthening of the problematic nature and attempts to deepen the concept of personality in the collections "Returned Songs", "The Mysterious Sign", "Mountain Lake", etc. The movement towards artistic volume and concentration of poetic means is noted. The influence of folklore and literary traditions on the formation of genre forms of poetry is determined. The reliance on historical-literary and comparative-typological methods makes it possible to draw a conclusion about the reflection in the work of M. Emizh of such features of contemporary literature as liberation from declarativity, journalistic pleonasm and solemnity. This work may be in demand in the study of theoretical problems of the formation of Russian literature of the twentieth century.

Summer plankton of high mountain Lake Dzhulukul (Altai, Russia) in August 2020

The summer phytoplankton composition of high mountain Lake Dzhulukul located in Altai Mountainsat the source of Chulyshman River was studied in August 2020. Under the electron microscopic examination of thephytoplankton samples algae from four taxa groups – Chrysophyta, Bacillariophyta, Chlorophyta and Euglenophyta wererevealed, that has been supplemented the list of algae for the lake. Stomatocysts of chrysophycean algae various in shapeand structure have been revealed firstly for the lake algaflora.