The use of biospheric monitoring in the study of reservoirs in the Volga-Don interfluve of Russia

. With anthropogenic activity, as well as with changes in climatic, hydrological and landscape regimes, significant structural and spatial shifts occur in existing ecosystems. The deterioration of water quality also significantly affects the state of coastal water zones, structural and species composition. In the course of monitoring the Tsimlyansk reservoir using the AQUA-1 automated watercraft, the quality of natural water was determined, formalized relationships between the abiotic and biotic components of the ecosystem were identified, the ecological state of the water intake zone was predicted, and the functioning of a number of structures that affect the regime and level of the reservoir. In order to improve the quality of water intake water, bioremediation was carried out using the planktonic microalgae Chlorella vulgaris , calculations of the invasion were made using computer programs. On the basis of the conducted monitoring studies, a hydrodynamic model of the reservoir bay was compiled, a model of an automated watercraft for biospheric monitoring was developed, an optimized scheme for the introduction of Chlorella vulgaris into the reservoir. The main biological indicators-indicators of water intake zones have been established, taking into account changes in the hydrological regime. The positive impact of the environmentally safe bioremediation of water at the water intakes of the Tsimlyansk reservoir in order to improve the quality of natural water used for drinking purposes and fish farming is shown.


Introduction
The Intergovernmental Panel of Experts from 197 countries on climate change (IPCC) presented a report in which 80% of the planet's territory has undergone changes under the influence of a changing global climate.Four factors have become decisive in this direction: the increasing frequency of "heat waves"; sharp and excessive cooling in territories where it has not been observed before; increased droughts, especially on the African continent; manifesting shortage of freshwater (according to the journal AGU Earth's Future, by 2050, 80% of arable land in the world will experience water shortages) [1].An additional circumstance that is not related to natural resources, but nevertheless is very sensitive, is the global underfunding of small farms in rural areas that use natural water.Small businesses have access to only 1.7% of global climate change finance, which is directed primarily towards efforts to curb climate change rather than adapting agricultural production to it.One of the indicators of the use of water resources is "water stress", which occurs when more than 25% of renewable resources are used [2].In 2018, the global water withdrawal amounted to 18.4% of the total volume of renewable natural waters; by 2040, 50 countries may face a "high" level of water stress, which will lead to pollution of natural water bodies [2].
The relevance of the study is due to the fact that the organization of monitoring of natural water bodies allows to analyze and predict the state of natural water bodies in the immediate vicinity of a person's place of residence.The study of the natural spatio-temporal structure of water bodies under the influence of anthropogenic factors makes it possible to organize the process of bioremediation.As before, the main task in biomonitoring remains the identification of processes that can be classified into two groups: irreversible and supporting homeostasis of the biosphere.In the Russian Federation, the leading centers for the study of natural reservoirs and biological resources are: Moscow State University.M. Lomonosov, Institute of Water Problems of the Russian Academy of Sciences, Institute of Natural and Technical Systems, Moscow State University of Geodesy and Cartography, Taurida National University.IN AND.Vernadsky, Institute of Biology of Inland Waters.I.D. Papanin, FGBNU VNIIOZ (Volgograd).One of the stages of monitoring is the establishment of the biological boundaries of water protection zones, which in their outlines may not coincide with the boundaries of administrative-territorial entities [3,4].In accordance with Article 65 of the Water Code of the Russian Federation, a special regime for the implementation of economic activities is established in water protection zones in order to prevent pollution, clogging, siltation of these water bodies and depletion of biological resources.Most artificial reservoirs located between the Volga and Don rivers are subject to exogenous eutrophication due to increased anthropogenic impact.The water area of the Tsimlyansk Reservoir (Russia), created in 1953 on the Don River during the construction of a hydroelectric power station, is quite intensively used for national economic purposes; The development of algal masses in coastal zones causes deterioration in the quality of water used for irrigation and drinking water supply.The scientific and methodological base for managing the quality of natural waters is far from perfect; it continues to focus on integral indices, which do not fully reflect the physicochemical and hydrobiological state of water and bottom sediments.
Scientists from the Volgograd region (Russia) have been conducting research in the field of monitoring natural water bodies for a long time, developing conceptual and methodological foundations for the formation of ecologically balanced irrigated agrolandscapes at the level of watersheds and natural water bodies.One of the important stages in the evolution of water bodies is the formation of a natural ability to self-cleanse, the adaptation of chemical and biological processes to the conditions of existence of living organisms.The Tsimlyansk reservoir belongs to the polluted class, 50% of water samples do not meet sanitary and hygienic standards; the value of the Shannon index (the degree of structuredness of the biocenosis) is less than 1, which indicates a significant death of zooplankton and the formation of silt masses [5,6,7].The scientific problem, to which the research materials are directed, is connected with the development of the conceptual and methodological foundations for the organization of biospheric monitoring and the allocation of bioremediation zones.

Materials and methods
The organization of monitoring is quite a complex and multidisciplinary process.The use of stationary posts for hydrochemical monitoring does not allow covering all water bodies, and expanding the network of stationary posts requires significant costs.Traditional monitoring methods with analysis in stationary laboratories require significant time and money.The use of numerous devices (thermo-oximeters, pH-meters, water level sensors) requires the deployment of qualified employees to the water body, the use of vehicles.A significant part of the tasks of monitoring water resources can be transferred to robotic mobile complexes capable of conducting an express analysis of water parameters quite quickly, with saving and transmitting information online.The Aqua MP-700.010digital sensor presented on the market allows you to simultaneously measure 9 physical and chemical parameters of water bodies: medium pH, temperature, liquid turbidity (mg/l), electrical conductivity, salinity, total amount of dissolved solids.The sensor has compact dimensions (diameter 75 mm, length 288 mm) and a durable polymer housing that meets the IP68 dust and moisture protection class.
In the course of the study, an automated watercraft developed by Volgograd scientists was tested.The object of the study was the bays of the Tsimlyansk reservoir, which occupies the vast Don valley with a total catchment area of 255 thousand km 2 .Morphometric data of the Tsimlyansk reservoir: the catchment area is 255 thousand km 2 , the average annual runoff of the river.Don at the dam site -22.3 km 3 , the area of the water protection zone is 222.9 thousand hectares, the length of the coastline is 912 km.Over the time of the existence of the reservoir, its area, coastline, depths and other morphometric indicators have changed greatly.The greatest flow of water into the reservoir is observed in spring, the period of rising water temperature and activation of all biological processes.At this time, along with the flood, the reservoir receives the largest amount of biogenic substances that ensure the intensive development of phytoplankton and determine the entire complex process of biological production.
International studies have shown that green microalgae can act as an antagonist of bluegreen algae.Chemical methods can be used to clean reservoirs: the introduction of copper sulphate, gaseous chlorine, bleach into the reservoir, and for small reservoirs -silver compounds.Despite the temporary positive effect, data confirming the safety for humans and other living organisms from the effects of chemical compounds are not presented.Ultrasonic devices for cleaning water bodies are successfully used in the USA and Japan, but they also have disadvantages: ultrasonic emitters affect not only pathogenic organisms.They are widely used to prevent the "blooming" of reservoirs of the "constructed wetlands" (bioplateau) structures, which are located on the water surface and do not let the sun's rays into the reservoir, thereby preventing the rapid "blooming" of blue-green algae.The scientists of the Federal State Budget Scientific Institution VNIIOZ (Russia) are working on the problem of improving the quality of natural water in reservoirs.Studies in 2022 at the Tsimlyansk reservoir showed that during the period of maximum water heating of 25-30 degrees C (July -August), the greatest species diversity of plankton is recorded -42 species, of which blue-green algae make up 50 %, green, diatoms and cryptophytes -30 % .The structure of blue-green algae is dominated by: Anabaena flos-aquae, Aphanizomenon flos-aquae., Microcystis aeruginosa, their biomass in the surface layers of the reservoir reaches: 2.0 -3.5 kg/m 3 .The "explosive bloom" of water is provided by the genus Microcystis aeruginosa; in the windward coastal zone of the reservoir, it accumulates up to 10.5 kg/m 3 .According to the results of the study, the water in the experimental bay of the Veseliy farm was classified as pollution class II.
Observations of the hydrophysical state of water showed that the change in transparency was associated with the level of development of phytoplankton, the presence of suspended solids, the amount of which was regulated by the intensity of agitation during wind mixing of water.The content of dissolved oxygen in the bay of the Cheerful farm after algolization changed in the range: 7.5 -19.4 mgO2 / dm 3 [6,8].

Results and discussion
To organize monitoring and determine the quality of water and bioresources in the water intake zone of the Tsimlyansk reservoir, a test was carried out, developed by scientists from the Volgograd region of the Russian Federation, a floating craft capable of transmitting data on 16 parameters online.A catamaran was chosen as the basis for the design of a remotely controlled, automated watercraft.The watercraft structurally consists of two hydrodynamically streamlined hulls, which provide the necessary stability margin.In the wheelhouse there are: block-systems for controlling the floating craft with an integrated system of geolocation positioning; turning mechanism with a block of sensors for monitoring water parameters; a block for wireless transmission of information from sensors for monitoring water parameters to a remote device; mechanism for rotating the motor mounting console; power supply with charge controller.The proposed concept of a floating facility designed for biospheric monitoring ensures maximum readiness for use and minimization of time for its transfer to working condition.The watercraft is controlled from a remote control or a tablet via wireless communication channels.The signal from the sensors is transmitted to a remote device, where you can see the measured parameters in real time.On a remote device, using special software, the monitoring parameters are archived and stored for further analytical processing (Figure 1) [11,12.13].An analysis of the results of studies conducted from May to September 2022 and aimed at identifying the impact of the introduction of the Chlorella vulgaris strain IGF No. C-111 into the bay near the Veseliy farm showed that after the algolization of the bay's water area, the hydrochemical parameters of the water began to comply with MPC standards (Table 1) .It can be seen from the table that for the entire observation period, the water in the bay, according to all the main indicators: color, turbidity, mineralization, hardness, etc., fully complies with the requirements of SanPiN 2.1.4.1074-01 "Water for centralized drinking water supply".

Fig. 1 .Fig. 2 .
Fig. 1.Model of a remotely controlled, automated watercraft designed for biospheric monitoring in water bodies.With the help of an automated watercraft, water samples are taken for hydrochemical indicators, Figure2.

Fig. 3 .
Fig. 3.The route of the watercraft for water analysis and the introduction of Chlorella vulgaris into the bay of the Veseliy farm of the Tsimlyansk reservoir, Volgograd region.