The article considers the Pacific vector of spatial development of Russia and the United States during the XVII–XXI centuries. Its purpose is to establish the features of this process in line with the geopolitical relations of these countries. Analysis of evidence on this topic, interstate treaties, statements by political figures has become the main research method. It was established that the expansion of Russia and the United States to the Pacific Ocean went largely synchronously and out of mutual territorial claims. It has been determined that Russian-American relations from the moment of their establishment and then for a long time had a friendly character, often acquiring the appearance of a military-political alliance. The reasons for their transformation into rivalry, including in the field of water disputes in the North Pacific and the Arctic, are highlighted.

The development of the agricultural land use system within the modern borders of the Irkutsk region over a long period of time and the impact on this development of socio-economic factors are studied. Land development by agriculture is considered against the background of similar processes in Siberia and Russia. Socio-economic factors, along with natural ones, influenced the formation of a “pattern” of distribution of lands, their composition, the intensity of land development, the efficiency of agricultural production. It was determined that resettlement campaigns, agrarian and land reforms, general economic development of the territory and, in general, the entire land policy of the state, aimed at optimizing, streamlining land relations, strengthening interest in agricultural land cultivation, had the most important impact on the development of agricultural land use. Based on the analysis of agricultural land development, nine main stages are identified (from the middle of the 17th century to the present day) and characterized. Each of them has features concerning the scale and geography of development, agronomic and technical methods of land cultivation, the level of development and application of scientific knowledge. The main conclusion is made that the development of agriculture and land cultivation in particular played an important role in the development of natural resources, a positive change in the economy, strengthening the economic position of the study area and Siberia as a whole.

The article presents new results of paleoecological studies in the South-Eastern part of the Meshchera Lowlands. Reconstruction of the Holocene vegetation and fires dynamics were based on radiocarbon dating, pollen analysis and LOI measurements of a peat deposits in the Kapel’ka mire, located in the Kasimovsky district of the Ryazan region. The obtained data show that between 9700–8000 cal. years BP the study area was occupied by birch-pine forests, apparently maintained in this part of the Meshchera Lowlands since the beginning of the Holocene. The high frequency of natural and human-induced fires was determined for this period. During the period of 8000–4000 cal. years BP, the regional vegetation included a combination of broad-leaved and pine forests with an undergrowth of hazel, birchpine forests and floodplain woodlands with alder. During this time the frequency of fires has significantly decreased. In the period of 4000–300 cal. years BP, broad-leaved forests were most widespread, and spruce forests expanded into the Meshchera Lowlands. About 1200 cal. years BP, the increased frequency of fires had led to an increase in tree-less areas. The vegetation of the last 300 years is represented by secondary spruce-pine-birch forests and agricultural land. The significant changes of vegetation has occurred due to human influence in the Neolithic time (about 8500 cal. years BP), in the early Slavic period (about 1200 cal. years BP) and during the last 300 years.

Based on the results of long-term field measurements (2009–2019), the variability of the concentrations of chlorophyll “a” in the water column of a small lake Vendyurskoe (Karelia) during the open water period was investigated. The depth of the euphotic zone was estimated based on the solar radiation fluxes, and the stability of the lake’s water column (BrentVäisälä frequency) was calculated based on water temperature. When water mass was in a state of homothermy, the concentration of chlorophyll “a” was evenly distributed over the water column, with some increase of cryptophytes and cyanobacteria within the euphotic zone. When thermal stratification developed and gravitational stability in the water column increased (N ≥ 0.025 rad/s), the heterogeneity of chlorophyll “a” distribution within a water column appeared, the maximum concentrations of chlorophyll “a” were fixed within a surface mixed layer, and below the thermocline, the concentrations sharply decreased. Green algae (30–50% in May, 35–55% in June) and diatoms (30–50% in May, 17–47% in June) prevailed in the composition of the plankton community (in terms of chlorophyll “a” concentration) in spring and summer. In autumn, the proportion of green algae sharply decreased to 5–20% and the proportion of diatoms increased to 40–80%. In some years, in autumn, there was a massive development of cyanobacteria (up to 30–55%) and cryptophytes (up to 40%). The functioning of the trout farm on the lake Vendyurskoe for 12 years did not lead to significant changes in the total concentration of chlorophyll ”a”. During the study period in autumn (except for two years of observations), the proportion of diatoms chlorophyll “a” concentration gradually increased from 40–50 to 80%, the proportion of green algae, cryptophytes and cyanobacteria decreased.

The article is devoted to the characteristics of sulfate karst in gypsum of the Kungurian stage of the Permian system in the Isheevsky plot in the lower reaches of the river Seleuk (right tributary of the Belaya River) in the Southern Cis-Urals (Ishimbay municipal district of the Republic of Bashkortostan). The regularities of the intensity of distribution of karst landforms are established depending on the composition of the non-karst rocks overlying gypsum and its direct dependence on the time of formation of the geomorphological elements. At the site, the highest density of erosion-corrosion wells in the Southern Cis-Urals was revealed. The characteristic of the Isheevskaya karst system is given, with all stages of the development of karst cavities that can be observed here. The general length of the system is 1002 m, the square is 4.6 thousand m² , the volume is 9.6 thousand m³ , the depth is 26 m, an amplitude is 31 m. It was established that the Isheevskaya system in the past was a single cave, which in the process of speleogenesis and collapse of the vaults has been divided into eight independent caves. It was shown that due to the rare components of the cave environment, the system deserves the status of a state natural reserve. It is recommended to create on the Isheevsky karst-speleological site a scientific testing area to study the development of sulfate karst and conduct educational excursions.

The paper examines the evolution of views on the place of tourism in the economic and social development of the northern territories of Canada. It is noted that the North of Canada in different periods of history was determined on the basis of different grounds; if initially the approach from the standpoint of a single (physical-geographical) factor was dominated, then the approach which was proposed by L.-E. Hamelin and suggesting a combination of natural, social and cultural factors was prevailed later. Another distinguishing feature of modern ideas about the southern border of the North and the borders within the North: they are becoming more and more dynamic. The main stages in the development of scientific research in the Canadian North have been identified and characterized. A gradual transition from the almost complete ignorance of tourism activity as a factor in the development of the northern economy by researchers to the recognition of tourism as a driver of economic development has been fixed. The co-evolution of tourism and scientific research in the North of Canada was traced: tourism has evolved from a “travel” towards the tourism industry, and then to tourism as a social phenomenon, while tourism research has evolved from the study of the geography of recreational potential to the study of the tourism industry and, finally, the study of tourism as a social phenomenon. There is a transition from the study of tourism within the framework of individual subdisciplines (geography, economics, sociology, cultural studies, management) to the interdisciplinary research. The current stage of tourism research in the North of Canada is characterized by an orientation towards the requests of both local communities and provincial and federal institutions within the framework of a strategic community-based tourism planning system.