Comprehensive study of the coastal zone of the sea is one of the urgent tasks of modern geography. Underwater landscape studies in Russia are based on the theoretical principles of the Russian geographical school of V. Dokuchaev–L. Berg. The development of marine landscape research in the XX century was facilitated by the advent of scuba diving and remote sensing. The article discusses the general points of the concept of underwater landscape, gives its definition, discusses the features of the morphological structure and the main landscape-forming factors. The landscape of the coastal zone of the sea is defined as a relatively homogeneous section of the underwater coastal slope, which has the same type of geological structure, topography, deposits, hydro-climate (temperature, salinity, currents, wave processes) and similar groups of hydrobionts. It is characterized by a certain combination of intra-landscape natural complexes (facies, landforms), which are special biotopes of bottom biocoenoses. Landscapes of the coastal zone of the sea cover the coastal land exposed to surf (supralitoral), the edge of the land flooded at high tide (litoral) and the underwater coastal slope to a depth where the impact of wave processes fades and illumination is insufficient for the formation of macrophyte communities (sublitoral). The underwater landscape is considered as the main initial unit of landscape zoning of shallow sea waters. Work programs developed with these provisions in mind will ensure the completeness and comparability of research performed by different authors. The concept of an underwater landscape is illustrated by an example of the results of studying the Taman landscape in the Northeastern part of the Black Sea.

As the network of specially protected natural areas develops and expands, the question of scientific substantiation often arises: is it possible to characterize this or that territory or water area as “unique”. Using the example of lake ecosystems it is proposed to consider the possibility of applying statistical approaches to such justification. Each lake ecosystem is different in its own way, however, in order to recognize its uniqueness, there must be a specific set of properties or characteristics indicating its exceptional nature. The article discusses the question of what kind of lakes can be considered as unique from a scientific perspective. It has been proposed to evaluate the uniqueness taking into account the analysis of samples constructed according to various characteristics (parameters) characterizing the lake ecosystems and the processes occurring in them. If all the lakes of the world are presented as a statistical aggregate with a set of characteristics (parameters) characterizing the lake ecosystems themselves and the processes occurring in them, then most of the samples built on these parameters based on real-world data can be described using theoretical distributions. At the same time, several parameters will have outliers that stand out drastically from the complete sample. Since the lake ecosystems are characterized by mutual dependence of the processes occurring in them, these outliers will be detected generally for the same units of the sample, i.e. for lakes that have abnormal values in a number of characteristics. At the same time, extreme values for one characteristic (parameter) can lead to the emergence of outliers in a number of parameters. These lakes should be considered as unique in terms of a statistics. This approach allows to distinguish not only the extreme values of any parameter, but also the values drastically standing out of the sample. It is especially important due to the multiplicity of small local lake systems which can be distinguished only with this approach. The article also analyzes non-parameterizable features that may indicate the uniqueness of the lake, since to this day expert assessments remain the main way to determine uniqueness, although it must be recognized that they have a certain subjectivity.

Based on the results of simulations using the numerical model FLake, the variability of the thermal regime of small lakes (with an area of less than 5 km2 ) of different types in Karelia under different weather conditions (1999–2012) was studied. The response of temperature, thickness and heat content of the surface mixed layer of lakes during the period of maximum heating of their water column (the second decade of July) to the weather conditions of cold 2007 and anomalously hot 2010 years is considered. In a hot year, the increase in the temperature of the surface layer in the “colored” lakes is noticeably higher than in the transparent ones. At the same time, the depth of the mixed layer decreases most noticeably in deep transparent lakes. The heat storage of the surface layer in epi- and metathermal “colored” and transparent lakes increases, and in hypothermic lakes it decreases. Calculations have shown that with increasing transparency, the most pronounced increase in the depth of the surface layer and its heat storage is observed in deep transparent water bodies, as compared with “colored” epi- and metathermal ones. With possible climatic changes in evaporation and input of dissolved substances into lakes from catchments, one can expect the most expressed changes in the thermal regime of deep transparent lakes.

The purpose of this research was an analysis of the impact of main climatic factors on tree growth and current treeline dynamics under the climate changes in the mountains of Western Tuva. Tree-ring width chronologies were built based on larch samples (Larix sibirica) of living trees from the upper timberline, the chronologies were compared, their statistics were estimated, and correlation with temperatures and precipitations were received. Correlations between chronologies and climatic factors revealed different climatic influences on radial growth along a north-south gradient in the study area. In conditions of sufficient moisture tree ring width correlates positively with average summer temperatures and negative with precipitations.