卷 17, 编号 3 (2021)

Coastline change in the Surabaya coastal areas (Indonesia) is caused by erosion, accretion, and anthropogenic activities, which are caused by human activities in the coastal areas. All human activities in the Surabaya coastal areas have an impact on the coastline. The purpose of this study was to detect the coastline change in the Surabaya coastal areas from 1994 to 2018. The researchers used remote sensing method to detect the coastline change. The data were obtained from the satellites of Landsat 5 (1994), Landsat 7 (2003), and Landsat OLI 8 (2018). The researchers used the Digital Shoreline Analysis System software and the statistical calculation of End Point Rate. The results showed that from 1994 to 2018 the highest of the average accretion rate in Kalisari sub-district was 75.75 m/year, and the highest of the average erosion rate in Wonorejo subdistrict was measured as of −3.4 m/year. Accretion and erosion occur due to the land use change. In Wonorejo, some mangrove areas were reduced due to illegal logging. In addition, land use change due to new ponds and residential areas occurred in East Surabaya. Meanwhile, anthropogenic activities had an impact on several areas due to Tanjung Perak and Teluk Lamong ports. To improve the environmental situation, continuous monitoring of the coastal areas of Surabaya and cooperation between the Government and the population are necessary.

The consequences of climate change, which are currently observed in the region as a whole and in the Don estuary area in particular, determine a complex of negative effects. The interconnected rise in the level of the Sea of Azov and the Taganrog Bay, an increase in the height and frequency of surges, a decrease in the solid and liquid runoff of the Don, salinization of the Taganrog Bay, an increase in the contribution of marine factors to the development of the Don delta lead to the intensification of salt water intrusions into the Don delta. Under such conditions, the inflow of saline water into the water intakes of the cities of Azov and Taganrog may occur more often in the future. This has already become a tangible problem for the inhabitants of the Azov region in September 2014, December 2015 and February 2021. The article provides data on the characteristics of intrusions, such as the duration of penetration and the type of mixing. The inflow of salt water into the Don delta is usually short-lived and is mainly associated with surges. The intense wind action during the surge largely explains the prevalence of the first type of vertical mixing, characterized by weak stratification. The results of calculating the penetration range of saline waters are presented. It is noted that the changed natural conditions have led to the fact that at present there is an increase in the penetration range of saline waters by 2–3 times compared to the second half of the last century. An assessment of the consequences of salinization for water supply and the quality of incoming water was made. Recommendations for overcoming the negative consequences of the inflow of saline waters into the Don delta are given.

Since the beginning of the 21st century, the Sea of Azov – Don Basin has been affected by lowwater processes, which lead to the filling of the Don Delta and the adjacent water area of the Taganrog Bay of the Sea of Azov with atypical slightly salty and brackish waters. As a result, there is a transformation of the thermohaline, trophic, and biocenotic structure of the reservoir, degradation of the ichthyofauna, and radical restructuring in both planktonic and benthic biotopes. The consequences of these trends more often have the scale of a dangerous natural phenomenon. This paper describes a new phenomenon for the reservoir – the fouling of fishing nets with filamentous algae from the genus Spirogyra in the eastern shallow part of the Taganrog Bay. In the published sources, there is no data on the presence of Spirogyra in the fouling of the studied reservoir. The study of samples collected in May 2021 indicated that the morphological features of spirogyra fertile filaments corresponded to the description of Spirogyra cf. decimina. In addition to S. decimina, two more morphs are distinguished based on the morphological differences of vegetative thallome. The paper presents the results of qualitative analysis and quantitative assessment of macroalgae fouling of fishing nets, as well as micrographs of various stages of development of the studied algae. The article lists the main environmental factors that cause the mass development of representatives of the genus Spirogyra and analyzes the hydrological conditions of the Taganrog Bay with the intensive proliferation of algae on the nets.

The results of long-term monitoring (1986–2020) of the rare species Orchis purpurea Huds. on the “Cape Martian” Protected Area on the Southern coast of the Crimea are presented. In the Crimea this species is protected by the Red Books of the Russian Federation, the Republic of the Crimea and the city of Sevastopol. On the studied territory, it is found in the phytocenoses of the Querceta pubestentis formation, at altitudes of 100–200 m above sea level. From two to seven localities with a total number of 32 to 176 individuals were identified. Most of the local coenopopulations were small (from one to several individuals) and did not appear annually. Only three coenopopulations were stable, maintaining their localization in all the years of observation. The area of the coenopopulations is very small – 1, 5 and 10 m2. The absolute number is 1–14 individuals per 1 m2 (No 1), 5–15 individuals per 5 m2 (No 2) and 24–147 per 10 m2 (No 3). The density ranged from 2.1 individuals per 1 m2 (No 2) up to 6.7 (No 1) and 8.5 (No 3). The distribution of individuals is contagious, which is determined by the predominant vegetative type of reproduction. According to the age structure of the coenopopulations, based on the classification of A.A. Uranov and O.V. Smirnova, they are classified as normal, incomplete, and are represented by bimodal age spectra with two maxima on vegetative and generative individuals. The coenopopulations are characterized as young (according to the predominance of the group of the vegetative period) or in some years of observation – middle-aged (according to the predominance of generative individuals). Senile coenopopulations were not identified. According to L.A. Zhivotovsky classification “deltaomega” coenopopulations of the species are estimated as ripening, mature or aging. High values of the recovery index (1.88–5.24) and replacement index (1.9–5.2) indicate that there are sufficient opportunities for self-support of the coenopopulations. Monitoring of rare orchid species coenopopulations is a necessary measure to assess the prospects for their sustainability and conservation in natural conditions.

In order to assess the corrosion resistance of samples of aluminum alloy grade D16, full-scale bench tests were carried out at two stations in the Don River mouth area. Test period: December 2018 – December 2019. During the research, the hydrological and hydrochemical regimes of the water area were described. Fluctuations of the ionic composition in the areas of the experiment depended on the volume of river runoff, the frequency and amplitude of surges and the associated intrusions of saline waters during surges or a drop in the water level during surges. It is shown that environmental conditions affect the experimental plates both directly and indirectly through the influence on the composition and structure of the forming fouling community. The dynamics of microphytoperiphyton on samples D16 in different parts of the delta was characterized by a two-peak curve with a maximum at the nineth month after the beginning of the experiment. Diatoms predominated, which is typical of many water bodies. Microzooperiphyton on the experimental plates is represented mainly by ciliates. With an increase in the exposure period, there was a tendency to an increase in the proportion of colonial and large sessile ciliates. The formation of macro-fouling communities began on samples that have been in the water for more than three months. The dominating species on the plates exposed at full immersion for 6 months were bryozoans Fredericella sultana. After 9 and 12 months the mollusks Dreissena polymorpha were dominant. When testing samples in water for 12 months, it was revealed that the largest area of corrosion damage for alloy D16 was obtained at Station 2 – 50 %, while during tests at Station 1 the area of corrosion damage does not exceed 30 % of the surface. According to the results of determining the composition of corrosion products on all plates, oxidation products of the samples surface, elements that make up the aqueous medium, and also elements of organic origin prevail.