Eutrophication Process Research Articles

ОБГРУНТУВАННЯ ШЛЯХІВ ПОДОЛАННЯ ЕВТРОФІКАЦІЇ ВОДОЙМ

Introduction. Increasingly, due to excessive growth of nutrients and decomposition of plants and animals in the reservoir, low turbulence, increased temperature, and due to this decrease in the solubility of oxygen in water, leads to eutrophication and as a consequence – “blooming” of the reservoir. It is the signal of trouble in a hydrosphere that needs immediate permission. Problem Statement. For today processes and conformities to law of growing speed of distribution of eutrophication of reservoirs, is studied not enough and there is not the only setting, the structural parameters of that will be able to provide optimal terms that will assist breeding of industrial fish, both in summer and in a winter period of year, and thus it is the issue of the day of present time. Purpose. Exposure on the basis of analysis of existing for today methods and facilities of prevention of excessive increase of reservoirs by cyanobacterias, to execute the review of methods airing of reservoir, that answer the requirements of seasonal temperature condition, the capable normalized necessary concentration of oxygen, as in a summer period of year so in winter. Id est creation of such terms an eutrophication will not develop at that. Materials and methods. Methods of analysis of literature sources, laboratory studies of the effect of nutrient concentration in water on the development of algae, microscopic control of the number of cyanobacteria in experimental vessels, chemical analysis of the presence of dissolved oxygen in water were used. Water samples from the Pokrovsk pond were selected as research material. Results. Excessive growth of cyanobacteria is observed at a water temperature of 15 ° C. And when exposed to elements such as nitrogen and phosphorus, the growth rate increases several times, as evidenced by a number of laboratory experiments. The results of the experiment showed that even a small concentration of fertilizers in the pond can lead to rapid flowering of algae, to a critical decrease in oxygen concentration, which in turn will lead to the death of fish and other aquatic organisms. The general analysis of modern methods and methods of combating eutrophication allowed us to identify their main advantages and defects. Different methods of preventing and combating eutrophication have their advantages, but they mainly have a unidirectional effect, low efficiency, some use toxic reagents that are unacceptable in fisheries. Conclusions. A review of recent studies on the occurrence of eutrophication of water bodies and as a result – harmful algal blooms, investigated the main environmental factors that mediate the expansion of cyanobacterial blooms. At present, there is no single way or means to combat eutrophication processes that can completely clean the reservoir, but their use in the complex can be effective. Of particular interest is the deep aeration, which can be used both in the warm season and in winter. Eutrophication today is mainly a consequence of human activity, and which requires mainly a comprehensive solution. It includes both preventive and regulatory methods. Promising is the use of aeration, the result of which is achieved in the fight against “blooming” of the reservoir by cyanobacteria, including those that produce toxins, both in the warm season and cold, preventing the formation of ice crusts. Keywords: cyanobacteria, algae, eutrophication, aeration, oxygen saturation, conditioning.

Features of dynamics of the Southern Buh river aquatic environment parameters during the summer low-water period

Formulation of the problem. Global climate change causes transformation in the humidification regime and, as a result, makes adjustments to economic activities and features of water use. In the context of Ukraine, against the background of climate change, the runoff of most domestic rivers is declining, which especially in the limited period exacerbates the issue of balanced use of ecosystem services of aquatic ecosystems and prioritization of needs during resource allocation, control of rivers and establishment of their functioning. The purpose of the article. Recognizing the strategic importance of freshwater ecosystems in ensuring sustainable regional and national development, the study of the Southern Bug River was aimed at assessing its ecological status in order to identify sources of negative anthropogenic impact and identify general ecosystem distortions that may affect the functional integrity of the aquatic ecosystem. Methods. The research points on the Southern Bug River were determined by the method of randomization. The total length of the route was about 200 km. Also, the spatial location of settlements was taken into account, so that the investigated points were both upstream and downstream. Measurement of physicochemical parameters was performed by instruments: TDS-3, TDS/ЕС/Temp-meter HM COM-100, pH-meter Ezodo 6011A. The task of hydrobiological research was to find and identify species at the family level. The research was conducted at the end of July 2020, when the river entered to low flow phase. Results. On the basis of field research, the assessment of the ecological state of the Southern Bug River in the lower course (from the city of Pivdennoukrainsk) was carried out in the work. Regularities of pH dynamics and mineralization of the aquatic environment are established. The limits of the spatial influence of the Black Sea waters on the Southern Bug, the continental advance of which (upstream) almost 100 km up is due to the high level of regulation of basin runoff, have been specified. The same processes, as a consequence, affect not only biodiversity, but also the features of industrial and domestic water use. Using the stenobiontic approach, the level of ecological safety of the Southern Bug ecosystem in the lower course was assessed. Based on the obtained results of stenobioindication, the zoning of the studied area of the Southern Bug is proposed, which compares quite well with the results of pH and mineralization measurements. Only 1% of the route, which corresponds to the porous section of the river channel, was classified as a "healthy ecosystem". The closer to the mouth, the pH of the water gradually increases, which contributes to the intensification of the eutrophication process. Scientific novelty and practical significance. The obtained results are considered to be an integral part of future field research on the identification of sources of negative impact on the aquatic ecosystem of the Southern Bug. The novelty of the results obtained is a comprehensive assessment of the ecological state of the river ecosystem in the low flow period, which, in contrast to the concept of maximum permissible concentration, characterizes the state of the Southern Bug not point, but takes into account the cumulative and synergistic effects of anthropogenic impact. The latter are best manifested during the summer season, as a result of which the structure and biomass of the river's food chain change significantly. In addition, the analysis of the rational use of water resources of rivers allowed us to state that the modern system of environmental standards, which in particular regulate the quality of the aquatic environment, cannot ensure the preservation of river ecosystems.

Monitoring of the Water Eutrophycation Process in Red Lake, from Harghita County, Romania

The main problem of freshwater lakes in the world, eutrophycation represents the over-enrichment of water by nutrients (nitrogen, phosphorus) and has emerged as one of the leading causes of surface water quality impairment. It is a rapidly growing environmental crisis, and worldwide, the number of coastal areas impacted by eutrophycation phenomenon stands at over 500. This important pollution process sets off a chain reaction in the ecosystem, starting with an overabundance of algae and other aquatic plants, excess which eventually decompose, producing large amounts of carbon dioxide. This paper is the result of researches located in Romania, performed over a period of eight years (2012-2019), in the area of a representative natural dam lake of the country - Red Lake, from Harghita County. Our researches aimed the quality parameters of the Red Lake water, the eutrophication process indicators, and their over time evolution. In order to predict the evolution of the studied pollution phenomenon in time, we used the software package “Surface-water Modeling System SMS 13.0” – the complete surface water solution, which was approached for the first time by Aquaveo. This software provides a comprehensive graphical environment for numerical modeling of eutrophycation, and tools for site characterization, model conceptualization and graphical visualization.

Using Remote Sensing & Geographical Information System to Study the Changes in the Coastal area between Port Said and Manzala (1973-2004)

Landsat images at 1973, 1984, 1996, 2000, and 2004 of Port Said - Manzala areas were possessed. SRTM Digital train model was analyzed. Land cover /Lake Manzala areas changes in five different periods (1973-1984, 1984-1996, 1996-2000, 1996-2004, 1973-2004) were assessed. The visual image analysis proved that the Lake Manzala area's decrease to -28% through 1973 to 2004. The decrease was obvious in 1984 and 2000. The annual rate of change was -5% through 1996 to 2000 and -3% though 2000 to 2001. Sea shore change is evident throughout 1984 to 2004. Sea shore erosion and accretion are obvious to the northeast and northwest of study area at Damietta and Barr Ad-Dahrah and to the east of Port-Said city. Urbanization encroachment is evident. 53% of the Damietta to Port Said study area will be vulnerable to sea level rise of 1 m above the main sea level. Throughout 1973 to 2004 the Lake Manzala water area's decrease from 55 to 21%. The aquatic natural vegetation areas increase from 23 to 27%. Due to the draining/drying processes at south of Port Said the agriculture land areas and the terrestrial natural vegetation areas increase to 14.1 and 14.5% of the study area by September 2004, respectively. The bare land/ urban area increases to 20% by 2000 and the fish ponds areas account 10% of the study area by 2004. The magnitude of change in Lake Manzala water areas was -61% whereas the change in agricultural land areas was +420% from 1973 to 2004. The magnitude of change in aquatic natural vegetation and fish ponds areas was significant in 1984 and 2004. It is evident that an intensive eutrophication processes has been taken place in Lake Manzala through 1973 to 2004. The percentage of the Lake Manzalawater area that transformed to aquatic natural vegetation increased to 19%, 33% by 1984 and 2004, respectively.

Small Floodplain Reservoirs in the Face of Climate Change—Sink or Source of Nutrients?

Despite various water protection measures, good water quality and reduction of nutrient loads seem very distant goals, largely due to limited knowledge of processes occurring in river valleys. Our study aimed at establishing the role of small floodplain reservoirs in the eutrophication processes, in the face of recent climate changes. The content of phosphorus and nitrogen compounds was determined in sediments and water of small floodplain reservoirs, (the Vistula River Valley, Poland) using spectrophotometric and Kjeldahl’s method. Nutrient loads in sediments were linked to the texture and total organic carbon content. Seasonal changes in water quality were strictly connected to changing weather conditions, flood and drought. The concentrations of PO43− and NO3− were found to rise after summer flooding. Increases in NH4+, total phosphorus (TP) and total nitrogen (TN) were correlated with the surface water area reduction in the reservoirs, which during the year of the study was on average 62%. Therefore, small floodplain reservoirs could be considered simultaneously as sinks and sources of nutrients. On the one hand, they accumulate P and N compounds carried by the river during the flood. On the other hand, climate change cause that small floodplain reservoirs may be responsible for enhanced biomass production.

Local and meso-scale pressures in the eutrophication process of a coastal subtropical system: Challenges for effective management

Natural and anthropogenic pressures drive coastal eutrophication worldwide, depending on the system's physical and biogeochemical dynamics in multiple spatial and temporal scales. Understanding the complexity of this process is essential to support management efforts and sustainability. Nutrients load to the Bay of Santa Catarina Island (BSCI), an important area for mollusc aquaculture, fisheries and tourism in Brazil, were assessed to identify the pressures of the eutrophication process. An updated Driver-Pressure-State-Impact-Response framework was used to facilitate the understanding of the relationship between human activities and impacts on human welfare. Pressures from runoff and effluents from combined sources resulted in inputs of 1998 t N.year−1 and 155 t P.year−1 to the system. The watersheds were characterized as meso-active to eury-active for both N and P yields. In addition to the local anthropogenic pressures, meso-scale events, such as the seasonal influence of the Plata Plume River, act as an external source of nutrients, sometimes associated with harmful algae bloom events. The results show that eutrophication and its symptoms could impact 85% of the ecosystem services of the region. Management of eutrophication at BSCI requires integrated actions between the nine municipalities of the watershed, but there are obstacles in environmental legislation and political interest to promote it. This study provides the scientific basis for stakeholders and decision-makers to establish priorities and actions in coastal municipalities to minimize eutrophication.

Ecological evaluation of natural water bodies in the south part of Noginscky Region Moscow District

Floristic composition of terrestrial and aquatic plants in the ecotopes of surface water bodies, Blue Lakes and Lake Biserovo, was studied to assess environmental health of aquatic ecosystems in the Moscow region. The research was carried out both in the field and in the laboratory. Blue Lakes were lacking aquatic vegetation and the dominant synusia of the following plant species was found along the coastal zone: meadow clover (Trifolium pratense L.), meadow bluegrass (Poa pratensis L.), sedge coastal (Carex riparia Curt.), chamomile (Matricaria chamomilla L.), plantain (Plantago major L.), Timothy meadow (Phleum pratense L.). The vegetation cover of Lake Biserovo was patchy: submerged vegetation was most widespread, Canadian Elodea (Elodea canadensis Michx.) was the dominant species. Pure thickets of vegetation were formed only by the common American water plantain(Alisma plantago-aquatica L.), lake cattail (Schoenoplectus lacustris L.), common reed (Phragmites communis Trin.) and sedge coastal (Carex riparia Curt). It should be noted that in all the studied water bodies, the pH of the water area can be classified as very clean: Blue Lakes (7.8), samples from Lake Biserov (8.32). Water samples from Lake Biserova had the highest turbidity (11.5), which was associated with the accumulation of particles of the silt fraction of the reservoir, which began the process of eutrophication, high anthropogenic load. According to the results of a comprehensive assessment (hydrological indicators, calculation of the Mayer index) of the studied samples from the reservoirs, it was concluded that the water area of the Blue Lake had the best environmental status in the Noginsk region.

Influence of fish pond culture on the fish fauna of Ladoga Lake

The species composition and biological indices of Ladoga Lake fish near trout farms were studied. Water bodies with commercial rainbow trout production were found to be polluted mainly by nutrients and fish metabolic products that activate eutrophication processes. The functioning of a trout farm was shown to affect the fish population structure of the lake. Fish with spring spawning are preferred. Roach, perch and ruff now predominate in the fish farm area. Fish aggregates in the lake differ considerably in biomass from those in open lake zones. Fish density indices near the fish pond lines were observed to increase almost twofold. Local fish species aggregate near the fish ponds because they eat trout food. The linear and weight growth rates of roach, perch and ruff near the fish ponds were shown to be much higher than those in the remote zones of the lake, because the above fish also eat the leftovers of trout food washed out of the fish ponds. Commercial trout production requires integrated monitoring for assessment of the current condition of the water bodies affected by fish farming.

First Hydroacoustic Assessment Of Fish Abundance And Distribution In The Shallow Sub-Basin Of Lake Titicaca

For the last two decades, a rapid eutrophication process impacts Lake Titicaca, the largest tropical freshwater lake in South America and the main highest Great Lake. This is especially notorious in the Bolivian sector of its shallow Lago Menor sub-basin. Lago Menor is deteriorated by the combination of multiple contaminations (domestic, industrial and mining) from untreated wastewater discharged from the urban area of El Alto, indiscriminate overfishing, and climate change. These threats particularly affect the native Andean killifish genus Orestias, the ecology and dynamics of which require in-depth studies with non-invasive techniques.

A sustainable approach by using microalgae to minimize the eutrophication process of Mar Menor lagoon

The present study evaluates the removal capacity of microalgae photobioreactors of environmental pollutants present in wastewater from the dry riverbed El Albujón, as a way to minimize the eutrophication process of the Mar Menor. Particularly, the capacity of four autochthonous microalgae consortia collected from different locations of the salty lagoon to remove emerging contaminants (simazine, atrazine, terbuthylazine, adenosine and ibuprofen), nitrates, and phosphates, was evaluated.Among the four microalgae consortia, consortium 1 was the best in terms of biomass productivity (0.11 g L−1 d−1) and specific growth rate (0.14 d−1), providing 100% removal of emerging contaminants (simazine, atrazine, terbuthylazine, adenosine and ibuprofen), and a maximal reduction and consumption of macronutrients, especially nitrates and phosphates, reaching levels below 28 mg L−1, that is, a decrease of 89.90 and 99.70% of nitrates and phosphates, respectively. Therefore, this consortium (Monoraphidium sp., Desmodesmus subspicatus, Nannochloris sp.) could be selected as a green filter for successful large-scale applications. This study is the first one that combines the successful removal of herbicides, ibuprofen and adenosine as emerging contaminants, and nitrate removal.

Satellite evidence for pervasive water eutrophication in the Doce River reservoirs following the collapse of the Fundao dam in Brazil☆.

One of the worst socio-environmental disasters to mark the history of Brazil and the world occurred in November 2015 and involved the mining sector. The collapse of the Fundao dam released approximately 43 million m³ of iron ore tailings, which moved downstream to reach the Doce River. This resulted in the contamination of water, soil, and sediments along the entire course of the river, which also affected its mouth in the Atlantic Ocean. Four years after the disaster, several socio-environmental problems continue to persist in the affected areas. In this context, the reservoirs built along the Doce River deserve special attention as they are artificial environments that are highly vulnerable to changes in water parameters. This study aims to determine water quality indicators of these reservoirs using remote sensing data and image processing methods, including semi-analytical algorithms, to comprehend the progress of eutrophication processes. Operational land imager/Landsat-8 data (from 2013 to 2019) were used to map the suspended particulate matter (SPM), euphotic zone (Zeu) and chlorophyll-a (Chl-a) before and after the collapse. The results showed significant changes in SPM and Zeu in the reservoirs after the collapse. Non-conformity of these parameters is observed even now, and they tend to intensify during rainy periods when resuspension processes of sediments occur. Moreover, there has been an increase in the eutrophication of reservoirs as noticed by the significant increase in Chl-a after the disaster, especially in January, July, and August.

MULTITEMPORAL SPECTRAL ANALYSIS FOR ALGAE DETECTION IN AN EUTROPHIC LAKE USING SENTINEL 2 IMAGES

Abstract. Eutrophication is characterized by excessive plant and algal growth due to the increased of organic matter, carbon dioxide and nutrients in water body. Although eutrophication naturally occurs over centuries as lakes age, human activities have accelerated it processes and caused dramatic changes to the aquatic ecosystems including elevated algae blooms and risk for hypoxia as well as degradation in the quality of drinking water and fisheries. Monitoring eutrophic processes is therefore highly important to human health and to the aquatic environment. However, the spatial and seasonal distribution of the phenomena and its dynamic are difficult to be resolved using conventional methods as water sampling or sparse acquisition of remote sensing data. This research work proposes a methodology that takes advantage of the high temporal resolution of Sentinel-2 (S2) for monitoring eutrophic reservoir. Specifically, it uses large temporal series of S2 images and advanced temporal unmixing model to estimate the abundance of [Chl-a] and algae species in San Roque reservoir, Argentina, in the period August 2016 to August 2019. The spatial patterns and the temporal tendencies of these aquatic indicators, that have a direct link to Eutrophication, were analysed and evaluated using in situ data in order to assess their contribution to the local water management.

The Process of Microbiological Remediation of the Polluted Słoneczko Reservoir in Poland: For Reduction of Water Pollution and Nutrients Management

The article discusses the impact of nutrients from sewage on the state of the sewage receiver. Bioremediation was carried out through the use of effective microorganisms. The potential recovery of valuable mineral and organic substances in the form of fertilizers was also examined. The Słoneczko Reservoir is a bathing area and serves many people in the summertime as a place of water recreation. Water quality deteriorated intensively from 2006 as a result of illegal wastewater discharge and the impact of fecal pollution from bathers. The high concentration of nutrients in the water was the cause of the eutrophication process and blooms of cyanobacteria, which pose a threat to human health in the bathing area. The bathing area was also closed many times by sanitary services as a result of exceeding the number of Escherichia coli and Enterococcus faecalis in the water. At the bottom of the reservoir, there was a layer of sediments with a thickness of 30–70 cm. Thus, the processes of anaerobic decomposition generated odor, causing nuisance in the reservoir area. Water transparency varied from 30 to 50 cm, due to the accumulation of suspensions and biomass of planktonic algae. The reservoir was subjected to microbiological bioremediation in 2017 and 2018 to polluted water treatment and to reduce the organic content of bottom sediments. Already after the first application of biopreparations putrefactive odors and the eutrophication process disappeared at the end of the 2017 summer season. Bioremediation reduced the value of E. coli and E. feacalis to the acceptable level. After the second application in 2018, the organic fraction of the bottom sediments was reduced to a very low level and the water transparency reached the bottom (maximum depth was 2.2 m) throughout the entire bathing area. The effect of the water remediation was maintained until 2019, and the surface water quality remained at a very good level. An important aspect in this case is also the exploitation of bottom sediments, because they are rich in nutrients and organic matter, and therefore it may have some potential as a fertilizer. The recovery of nutrients can be used in plant or pot production. However, they contain compounds that degrade quickly, causing unpleasant odors and threatening the environment. Thus, they should be managed and handled in an environmentally friendly and sustainable way.

The relationship between diversity and productivity from a three-dimensional space view in a natural mesotrophic lake

The relationship between diversity and productivity (DPR) is a hot topic in ecology, whereas most evidence comes from studies of manipulated terrestrial ecosystems or from two-dimensional space views. In this study, we determined DPR of submerged plants in a natural mesotrophic lake, Lake Erhai, along its water depth in 2013 and 2019. Our results demonstrated that the community productivity was significantly negatively correlated with plant biodiversity from a three-dimensional space view (all of the water depths) in Lake Erhai due to strong competition effects among submerged species. However, DPR patterns at each water depth (from two-dimensional space views) were various, which might be because these DPR patterns were disturbed by many biotic and abiotic factors or their interplays. Both total biomass and biomass of dominant species negatively correlated with species richness. Moreover, total biomass was positively correlated with biomasses of dominant species. Accordingly, we can presume that DPR patterns are largely determined by relationships between biomasses of dominant species and biodiversity in our study. Our results showed that species number in 2019 was generally smaller than that in 2013 and submerged species were migrating from deep water to shallow water with lake eutrophication in such a short time. Accordingly, measurements should be conducted quickly to control the eutrophication process of Lake Erhai to improve its multiple valuable functions and services.

Diffuse CO2 emissions from Sete Cidades volcanic lake (São Miguel Island, Azores): Influence of eutrophication processes

Sete Cidades Lake (São Miguel Island, Portugal) is subdivided into two interconnected branches: the Green Lake and Blue Lake. The lake has an area and maximum depth of 4.39 km2 and 29.5 m (Blue Lake), respectively, with evidence of eutrophication, particularly in the northern area of the Green Lake. In this study, we conducted a sampling survey during January 2017 to measure CO2 fluxes from the lake using a floating accumulation chamber. We also produced two hydrogeochemical profiles for each of the lake’s branches. A total of 1760 CO2 flux measurements were taken along the lake’s surface. The lake water was relatively cold (14.0 °C on average) and weakly mineralised (average electrical conductivity of 116 μS cm−1) with a neutral pH (7.7 on average). The relative composition of major ions occurred in the following decreasing order: Na+ > Mg2+ > Ca2+ > K+ for cations and Cl− > HCO3− > SO42− for anions. The lake water was mainly the Na–Cl type due to sea salt input from seawater spraying. CO2 fluxes ranged from 0.3 to 17.2 g m−2 d−1 and from 2.1 to 17.9 g m−2 d−1 for the Blue and Green Lakes, respectively. Highest CO2 degassing occurred in areas dominated by macrophytes and algal blooms. The measured values suggest that the CO2 was predominantly biogenically sourced, which was further supported by the δ13C isotopic data. The estimated total CO2 emissions varied between 5.8 t d−1 (Green Lake; area = 0.81 km2) and 24.9 t d−1 (Blue Lake; area = 3.58 km2). This study further elucidates the lake’s trophic and chemical pollution status and has major implications for lacustrine CO2 emissions to the atmosphere. Our study also provides a reference for understanding potential future variations in volcanic activity.

Quality changes of fluvial sediments impacted by urban effluents in Ushuaia, Tierra del Fuego, southernmost Patagonia

Bottom sediments play a fundamental role in the eutrophication process because they are one of the most active compartments in the biogeochemical cycle of nutrients. In Ushuaia city, Tierra del Fuego, Argentina, sewage effluents have been discharged into natural watercourses without treatment for many years. Organic matter has been introduced until 2016 when improvements in sewage infrastructure were done. The quality of surface sediments from three watercourses with different degree of impact has been studied taking into account contrasting hydrological periods. pH, organic carbon (OC), total nitrogen (TN) and soluble reactive phosphorus (SRP) were measured in austral autumn and spring between 2013 and 2018 in three sections of each watershed. Nutrient content in sediments of upstream sites derives from the contribution of Nothofagus spp. forests through litter-fall. Middle and downstream sites were the most affected by wastewater discharges evidencing that fluvial sediments act as a receptor of the allochthonous organic loads. Particularly, sediments of Buena Esperanza Stream had the lowest mean pH (5.44) and the highest mean concentrations of OC (42.95 mg g−1), TN (2.53 mg g−1) and SRP (0.067 mg g−1), along with the lowest mean annual flow and the largest urbanized area. No differences between hydrological periods were found, although TN and SRP contents were higher in autumn than in the snowmelt season. Minimal differences in nutrients between before and after infrastructure improvement were found. Even when external contributions have been decreased, more time will be necessary to reduce eutrophic conditions of fluvial sediments in southernmost Patagonia.

The effects of climate change on the development of phytoplankton in the Uchinsk Reservoir of the Moscow Canal

In the climate of European Russia, there are significant changes: before the year 2010, the tendency of warm period temperature to drop with a simultaneous increase in precipitation was dominated but nowadays it is dominated a reverse trend to increase average and maximum temperatures, decrease in precipitation, and increase in the number of sunny days. This creates the most favourable conditions for the development of phytoplankton and zooplankton consuming it. Our research exemplified by the Uchinsky Reservoir has established that since 2010 the number of phytoplankton has been increasing multiply with the development of blue-green algae at the end of the warm period, and it adversely affects the quality of water, leading to the development of eutrophication processes. The factors limiting the number of phytoplankton are the development of zooplankton and almost total consumption of ammonium nitrogen by phytoplankton. To manage the development of phytoplankton due to the most favourable climate conditions, a set of measures is required to reduce the intake of biogenic elements into the water of the Reservoir.

НАУКОВЕ ОБҐРУНТУВАННЯ РЕГУЛЮВАННЯ ПРОЦЕСІВ ЕВТРОФІКАЦІЇ ВОДНИХ ОБ’ЄКТІВ (НА ПРИКЛАДІ РІЧКИ ВОРСКЛИ)

У статті проведено дослідження процесу евтрофікації водних екосистем. Визначено, що нині усвіті активно здійснюється розробка теоретичних основ і пошук практичних заходів з боротьби змасовим розвитком ціанобактерій у поверхневих водоймах. Водночас питання використання бакте-рій для очищення поверхневих водних об’єктів є на сьогодні недостатьо вивченими, постає потребав дослідженні евтрофікаційних процесів водних об’єктів при використанні різних методів біологіч-ного очищення. Зважаючи на це, метою роботи стало дослідження хімічних та біологічних методіввідновлення водних об’єктів через зменшення в них кількості ціанобактерій, на основі чого наданінаукові рекомендації щодо боротьби із «цвітінням» поверхневих водоймищ. Методика дослідженнявключала проведення аналітичних, натурних та лабораторних досліджень, розрахункову частину.Для дослідження процесу евтрофікації води в річці Ворскла було взято проби на глибині 0,2‒0,5 м відповерхні водойми (в різних районах м. Полтави та на околицях міста). На першому етапі дослі-дження вивчали хімічні методи боротьби із «цвітінням води». Найкращий результат спостерігалипри застосуванні перманганату калію (0,2*106 кл/л), молібденової рідини (0,3*106), магнезіальної су-міші (0,4*106), хлору (0,5*106) та хелату заліза (0,6*106). На другому етапі дослідження проводилививчення пробіотиків для боротьби із «цвітінням води» на наявність токсичної дії до ціанобактерій.З’ясовано, що використання біологічних методів очищення водних об’єктів від ціанобактерій є більшефективним порівняно з хімічними методами, зокрема використання пробіотику Світеко-Агробіотик-01, який ефективно знищує ціанобактерії до 94 %. Такий результат отримано при за-стосуванні перманганату калію (0,2*106), але негативним наслідком цього є те, що використанняхімічних методів загалом створює вторинне забруднення водоймищ. Також визначено ефективністьінших хімічних методів боротьби із «цвітінням води»: молібденової рідини (ефективність – 91 %),магнезіальної суміші (88 %), хлору (85 %) та хелату заліза (82 %). Дещо гірші результати дало за-стосування нітрату срібла (70 %) та хлориду барію (41 %). Найбільша кількість синьо-зелених водо-ростей залишилася при дії на останні сульфату алюмінію спільно з мідним купоросом (26 %). Прове-дені дослідження є основою розробки комплексних систем очистки водних екосистем екологічно без-печними методами від ціанобактерій, що є одним із пріоритетів розвитку урбанізованих територійта сталого розвитку суспільства.

Succession of phytoplankton functional groups and driving variables in a young canyon reservoir

Reservoir eutrophication is a global problem that needs to be urgently solved, and exploring phytoplankton dynamics in young reservoirs is extremely important for artificial intervention during the process of eutrophication. However, the succession of phytoplankton communities and their responses to environmental variables in young canyon reservoirs remain obscure. Therefore, phytoplankton functional group data were collected from a young canyon reservoir for 2 years, and the succession pattern and its response to environmental variables were simultaneously evaluated. The results revealed significant spatial differences and rapid interannual changes in some environmental variables (water temperature, suspended solids) in the young canyon reservoir. Non-metric multidimensional scaling showed that phytoplankton functional group structure differed obviously among the zones of the reservoir, while significant interannual succession (from the Lo and Y groups to the X2 group) occurred in the lacustrine zone. Additionally, redundancy analysis demonstrated that the structure of phytoplankton functional groups varied significantly between the spatially different environments. Finally, the succession of phytoplankton functional groups in the lacustrine zone was mainly driven by increases in nutrients and water temperature. The rules underlying and dominant mechanism driving short-term succession in the young canyon reservoir revealed in this study may provide a deeper understanding of the intervention mechanisms that could be implemented to alleviate reservoir eutrophication.

Identification of nitrate sources and transformations in basin using dual isotopes and hydrochemistry combined with a Bayesian mixing model: Application in a typical mining city

The external nitrogen load input caused by human activities exacerbates the eutrophication process of aquatic ecosystems in mining areas, causing water quality problems. However, knowledge of the sources and environmental behavior of nitrate in the surface water of mining areas is still very limited. This study investigated the nitrate content and spatiotemporal variation characteristics of surface water in the Linhuan mining area, identified the sources and transformation processes of nitrate using isotopes and hydrochemistry, and evaluated the contribution rates of different potential nitrate sources based on a Bayesian mixing model. The nitrogen pollution in the surface water in the mining area seriously exceeded class Ⅴ of the Environmental Quality Standard of Surface Water of China (GB3838-2002). The NO3− content ranged from 0.87 to 3.41 mg/L, showing obvious seasonal and spatial differences. Isotope and NO3−/Cl− analysis indicated that nitrate in the subsidence area water (SAW) was mainly derived from chemical fertilizer (NF) and soil organic nitrogen (NS), while nitrate in the mainstream of the Huihe River water (HRW) was mainly derived from manure/sewage (MS). The nitrate in the tributary of the Baohe River water (BRW) was mainly derived from soil NS, and nitrification was a nitrogen conversion pathway in the soil. The results of the Bayesian mixing model showed that the main sources of nitrate in the BRW, HRW and SAW were NF (34.5%), MS (68.8%) and NF (40.8%) in the wet season, and NS (33.4%), MS (70.9%) and NF (58.1%) in the dry season, respectively. The results of this study provide a new integrated method for the identification of nitrate pollution sources in mining areas, and this method can be used to improve the biogeochemical information of nitrogen in the aquatic ecosystems of mining areas and help formulate relevant measures to reduce water nitrogen pollution.