Morphostructural malformations of graceful cattail Typha laxmannii Lepech. (Typhaceae) in the Don River delta

The article describes first findings of three multi-tiered anomalous pistillate morpho-structures (proliferation, “branching”, and fasciation) of Typha laxmannii inhabiting the coasts of the Donskoy Island, the Don River delta. It is suggested that these malformations are associated with an increasing technogenic load on the region as well as the transformation of the landscape in the historical and geological past, which led to the isolation of archaic and migratory Typha species in the delta branches

The Structure of Aquatic Plants in Lakes of the Marginal Zone of Glaciations in the North-Eastern of European Russia

Проанализирована структура озёрных фитоценосистем зоны краевых оледенений Северо- Запада Европейской России. Озера уникальны в гидробиологическом отношении. Особый интерес представляют сообщества гидрофитов, как пример современного расселения растений. Вместе с тем гидробионты озёр, включая и гидрофиты, находятся под усиливающимся антропогенным прессом, роль которого отражена при характеристике сообществ.The structure of phytocenosystems in lakes of the marginal glaciation zone in the European northeastern part of Russia has been analyzed. Hydrobiology of the lakes is unique. Of special interest are communities of hydrophytes as an example of the modern distribution of plants. At the same time hydrobionts in the lakes including hydrophytes are subjected to strong anthropogenic effect. Its role is described when characterizing the communities

The Structure of Aquatic Plants in Lakes of the Marginal Zone of Glaciations in the North-Eastern of European Russia

Проанализирована структура озёрных фитоценосистем зоны краевых оледенений Северо- Запада Европейской России. Озера уникальны в гидробиологическом отношении. Особый интерес представляют сообщества гидрофитов, как пример современного расселения растений. Вместе с тем гидробионты озёр, включая и гидрофиты, находятся под усиливающимся антропогенным прессом, роль которого отражена при характеристике сообществ.The structure of phytocenosystems in lakes of the marginal glaciation zone in the European northeastern part of Russia has been analyzed. Hydrobiology of the lakes is unique. Of special interest are communities of hydrophytes as an example of the modern distribution of plants. At the same time hydrobionts in the lakes including hydrophytes are subjected to strong anthropogenic effect. Its role is described when characterizing the communities

Isotope stratification of meromictic Lake Trekhtzvetnoe at the White Sea coast (Russia)

Postglacial isostatic uplift of the coastal zone resulted in the formation of isolated lakes along the shores of White Sea developed into permanently stratified (meromictic) lakes. On the basis of monitoring the vertical distribution of selected water quality parameters including temperature, salinity, concentration of major ions, microbial activity, dissolved oxygen and hydrogen sulfide, seasonal changes in the structure of the stratified water column are explored and governing factors identified. Lake Trekhtzvetnoe has a strong vertical stratification with seasonal mixing being confined to the upper part of the water column (mixolimnion). Сhemical water composition in the mixolimnion reflects the influence of precipitation with the underlying chemocline being defined by sharp gradients of salinity, dissolved oxygen and hydrogen sulphide levels. We found strong stable isotope stratification of water column in winter-early spring seasons of 2013, 2015 and 2016 and in the early autumn of 2015. The lowest isotope values were obtained near the surface in the mixolimnion. There was a gradual increase of isotope values towards the chemocline reaching the maximum in the bottom layer (monimolimnion). It was found that water in the mixolimnion was isotopically depleted in winter as a result of ice formation and isotopically enriched in the early autumn due to evaporation. Obvious desalination of mixolimnion and upper chemocline from 2012 to 2016 was possibly caused by the increase of precipitation and freshwater inflow in lake supply. Monimolimnion is a stable layer of high salinity, and it has enriched isotope composition that corresponds with meromictic structure of water column.In meromictic coastal lake separated from the sea stable isotope composition of mixolimnion varied due to ice formation in winter and evaporation in summer. From 2012 to 2016 desalination of mixolimnion and upper chemocline was observed. Monimolimnion has highest salinity and enriched isotope composition indicating lack of mixing with overlying water