Eutrophication Process Research Articles

Decadal changes in zooplankton biomass, composition, and body mass in four shallow brackish lakes in Denmark subjected to varying degrees of eutrophication

ABSTRACT During the past century, many brackish shallow lakes worldwide have become eutrophic. How the zooplankton have responded to this development is not well elucidated. Here, we analysed the decadal changes (from 1999–2000 to 2017–2018) in zooplankton biomass, body mass, and potential top-down control on phytoplankton during summer in 4 Danish shallow brackish lakes (Lund Fjord, Han Vejle, Selbjerg, and Glombak) subjected to varying degrees of eutrophication. Significant reductions of zooplankton biomass, body mass, the ratio of large-sized cladoceran to total cladoceran biomass, and the ratio of zooplankton to phytoplankton biomass were observed in low to moderately vegetated lakes (Selbjerg and Glombak). However, in the macrophyte-dominated lake (Han Vejle), zooplankton biomass, body mass, and the contribution of large-sized cladocerans (Daphnia spp.) to total cladoceran biomass increased without a corresponding increase in the zooplankton to phytoplankton biomass ratio, which may be attributed to the refuge effect of submerged macrophytes. Using the pooled dataset, multivariate analysis indicated that total phosphorus concentrations and fish abundance were the main drivers of shifts in the zooplankton community and that zooplankton body mass was strongly negatively related to fish abundance. From a lake management perspective, our results suggest that eutrophication, through increased fish predation and reduced submerged vegetation abundance, has major effects on zooplankton communities in temperate coastal brackish shallow lakes, and a reduction in the zooplankton grazing pressure on phytoplankton is predicted if the eutrophication process continues.

Влияние химического состава снега водоохранных зон Учинского и Пестовского водохранилищ на качество вод

Ecological geochemical research of water protection areas was held in Moscow region. Precipitation (snow) is known to influence the formation of water chemical structure and determine geochemical effect. It shows the results of snow research in water protection area of Uchinsk and Pestovo reservoirs in order to find out the sources of pollution, to assess water quality
 and work out the recommendations to reduce and eliminate the sources of pollution. The article gives the evaluation of water quality depending on waterflow from the catchment area and various temporary flows. It shows the influence of excessive
 use of fertilizers on water quality (especially in spring) which leads to eutrophication processes and worsens the quality of water.

Internal phosphorus loading in a small shallow Lake: Response after sediment removal

Mankind is taking advantage of numerous services by small shallow lakes such as drinking water supply, irrigation, and recreational function; however, many of these lakes suffer from eutrophication. Given the key role of phosphorus (P) in eutrophication process, one of the effective restoration methods especially for small shallow lakes is removal of sediments enriched with nutrients. In our study, we used interannual, seasonal, and spatial data to examine the changes in sediment P mobility after removal of sediments in 2016 from a 1-ha highly eutrophic lake. We measured the sediment redox potential, analyzed soluble reactive P (SRP) in the pore water and P fractional composition of the surface sediments, and calculated the diffusive flux of P in three locations in two continuous years (2017 and 2018) after the excavation. Similar measurements were done before sediment removal at central site of the lake in 2015. Removing nutrient-rich sediment also removed 6400 kg of P, and thus the potential for release of P from sediments decreased on a long-term scale. However, a large pool of releasable P was rebuilt soon after the sediment removal due to high external P loading, resulting in extensive anoxia of sediment surface and associated internal P loading as high as 1450 mg m−2 summer−1. Moreover, the Fe-P and labile P fractions were the most important sources of P release, as evidenced by their considerable seasonal and interannual changes after the sediment removal. The sediment total Fe negatively correlated with diffusive flux of P, pore water SRP, and near-bottom water total P and SRP concentrations which indicated a strong linkage between sediment P dynamics and Fe after the restoration. Sediment removal could be a beneficial restoration approach, but the effects on lake water quality remain only short-term unless there is an adequate control on external loading to the lake.

Using Microcystin Gene Copies to Determine Potentially-Toxic Blooms, Example from a Shallow Eutrophic Lake Peipsi.

Global warming, paired with eutrophication processes, is shifting phytoplankton communities towards the dominance of bloom-forming and potentially toxic cyanobacteria. The ecosystems of shallow lakes are especially vulnerable to these changes. Traditional monitoring via microscopy is not able to quantify the dynamics of toxin-producing cyanobacteria on a proper spatio-temporal scale. Molecular tools are highly sensitive and can be useful as an early warning tool for lake managers. We quantified the potential microcystin (MC) producers in Lake Peipsi using microscopy and quantitative polymerase chain reaction (qPCR) and analysed the relationship between the abundance of the mcyE genes, MC concentration, MC variants and toxin quota per mcyE gene. We also linked environmental factors to the cyanobacteria community composition. In Lake Peipsi, we found rather moderate MC concentrations, but microcystins and microcystin-producing cyanobacteria were widespread across the lake. Nitrate (NO3−) was a main driver behind the cyanobacterial community at the beginning of the growing season, while in late summer it was primarily associated with the soluble reactive phosphorus (SRP) concentration. A positive relationship was found between the MC quota per mcyE gene and water temperature. The most abundant variant—MC-RR—was associated with MC quota per mcyE gene, while other MC variants did not show any significant impact.

Eutrophication Induction Via N/P and P/N Ratios Under Controlled Conditions\u2014Effects of Temperature and Water Sources

The current research outlines the course of eutrophication processes emerging when some critical physical and chemical factors interact altogether. For this purpose, investigations were carried out, where nitrogen [N as (NH4)2HPO4 and KNO3] and phosphorus [P as (NH4)2HPO4] were added to three different water sources (double distilled water, DDW; tap water, TW; and lacustrine water, LW) and the solutions were incubated at two distinct temperatures (17 and 23 °C). Treatments were kept in 1 dm3 glass jars and the incubation time lasted 7 weeks. The eutrophication process emerged only at 23 °C and was stronger for the lacustrine water (LW). In the case of DDW treatments, this process was observed at N/P = 5.1 and even at 60.0, whereas for the TW, no algal blooming was detected (N/P ratio 17.7–640.0). The lacustrine water (LW) outlined patterns with strong eutrophication at N/P = 4.40, but also at ratios 20.9–71.1. Algal blooming significantly intensified according to LW > TW > DDW but was reversely dependent on the P/N ratios, which followed the range DDW (P/N, 1.6–3.78) > TW (P/N, 0.050–0.100) > LW (P/N, 0.016–0.023). At P = constant (P = 0.10 mg dm−3) and the N inputs varying from 0.010 to 2.0 mg dm−3, it appeared that the higher the N concentrations, the more intensive the eutrophication process. For N/P ratios, phosphorus regulated for most of the intensity of the process, whereas in the case of P/N, the role of N and P was interchangeable. The main finding of the research is that nitrogen revealed in many cases to be a powerful eutrophication-regulating factor than did phosphorus.

The Color Formation Mechanism of the Blue Karst Lakes in Jiuzhaigou Nature Reserve, Sichuan, China

The karst lakes in Jiuzhaigou Nature Reserve are an integral part of the karst lake landscape, yet research on the formation mechanism for the color of the blue-green lakes in Jiuzhaigou is insufficient. With the help of hyperspectral instruments, coupled with hydro-chemical analysis, this paper elaborates on the unique color characteristics of the Jiuzhaigou karst lakes, delves into the color formation mechanism of the lakes, establishes a regression equation for the color of the lakes as well as the water quality parameters, and sheds light upon the causes for the color distinction between the karst lakes in Jiuzhaigou and the plateau freshwater lakes. The experiment shows that the Jiuzhaigou karst lakes are primarily blue and green, while the proportion of short-wavelength light in the normalized water-leaving radiance and the total incident irradiance of lake water is higher. Based on the redundancy analysis and the correlation analysis, travertine deposition is the core link in the color formation of the blue karst lakes in Jiuzhaigou, while the selective reflection and scattering of the suspended calcium carbonate particulate matters towards visible light represents the optical foundation for the formation. In addition, physical factors such as depth and transparency, changes to the water quality parameters that affect the travertine deposition rate, and the eutrophication process will all exert significant influence over the formation. By building on water-leaving radiance, this paper quantifies the lake color with the tristimulus values (R, G, B) via colorimetrical methods, which features solid goodness of fit with the linear regression equation established based on the water quality parameters. The principal component analysis and colorimetrical analysis show that the color of the karst lakes in Jiuzhaigou varies substantially from that of the plateau freshwater lakes, which mainly results from the difference in the water quality. Research conducted in this paper on the color formation mechanism of the distinct blue karst lakes in Jiuzhaigou illuminates the formation and maintenance mechanism of the plateau karst lakes, which is conducive to better understanding towards the relationship between the water quality and colors of the karst lakes, and provides scientific proof for the establishment of the water quality assessment indicator system based on the colors of the karst lakes.

Effects of guanotrophication and warming on the abundance of green algae, cyanobacteria and microcystins in Lake Lesser Prespa, Greece.

Lake Lesser Prespa in Greece is a vital breeding habitat for the Dalmatian and Great White Pelican and a shelter for numerous rare and endemic species. However, eutrophication processes are distressing the lake system and the outbreaks of cyanobacterial blooms during the warm months may pose a threat to aquatic organisms due to the presence of microcystins (MCs). In this study we hypothesize that nutrients (eutrophication), nutrient-rich pelican droppings (guanotrophication) and warming (climate change) can affect the algal growth and MCs production in the water layer of Lake Lesser Prespa. Seston collected from three lake sites was incubated at ambient (20°C) and high (30°C) temperature with or without the addition of nutrients (nitrogen (N), phosphorus (P)), or pelican droppings. Results showed increased chlorophyll-a at higher temperature (30°C). N addition yielded higher chlorophyll-a levels than the non-treated water or when only P was added. The addition of both N and P as well as the addition of pelican dropping resulted in the highest chlorophyll-a at both temperatures. Notably, in the dropping-treatments, cyanobacteria and MCs were promoted while changes were evoked in the relative contribution of toxic MC-variants. Guanotrophication may thus influence the cyanobacterial dynamics and most likely their toxicity profile at Lesser Prespa.

General education school: process of eutrophication

General education school: process of eutrophication

Assessment of the Efficiency of Nitrogen Slow-Release Fertilizers in Integrated Production of Carrot Depending on Fertilization Strategy

Optimization of plant nutrition is a very important part of primary production quality systems. Crop fertilization is the most important agrotechnical measure because it determines the amount and quality of the yield. Moreover, excess fertilization intensifies the eutrophication processes and the greenhouse effect. The study aimed to assess the suitability of slow-release fertilizers in cultivation of carrot subspecies Daucus carota L. ssp. sativus in the integrated production system. The objective was realized on the basis of a strict field experiment set up on a clay loam soil with low nutrient content. The dose of fertilizer was the experimental factor. The fertilizers were applied during the formation of the ridges. Traditional fertilizers (ammonium phosphate, potassium salt, ammonium nitrate, and a multi-component fertilizer Polifoska 6), as well as a multi-component fertilizer with slow release of nutrients, NPK Mg (18-12-24-4), were used. In individual variants of the experiment, different fertilization strategies were applied: integrated production fertilization, traditional fertilization, and fertilization based on the use of slow-release fertilizers. The control treatment comprised of unfertilized plants. The efficiency of nitrogen fertilization was evaluated based on agronomic efficiency, partial factor productivity, physiological efficiency, and removal efficiency. Fertilization strategy significantly impacted the quantity of obtained yield. In the control sample, prior to mineral fertilization, the crop yield was 33.53 Mg·ha−1. The largest yield was 82.30 Mg·ha−1.The largest yields were obtained from plants fertilized with a combination of slow-release fertilizers, with nitrogen introduced in the form of ammonium phosphate, and through conventional fertilization. The highest productivity and environmental efficiency were obtained in treatments with fertilization according to the principles of integrated production and with slow-release fertilizers. In terms of environmental efficiency, the best results were obtained through nitrogen fertilization using 400 kg of slow-release fertilizers. The use of slow-release fertilizers in carrot cultivation can significantly improve the efficiency of fertilization, both in terms of production and environmental protection.

Biological Removal of Micropollutants in Human Supply Water Samples Using Nitrifying and Denitrifying Bacteria

Several regions of the world suffer from water quality degradation caused mainly by anthropogenic interference, domestic sewage discharge, industrial discharges, and contaminants from agricultural activities, which increase the amount of nutrients into water such as nitrogen and phosphorus intensifying the process of eutrophication. Considered as one of the main problems faced by supply water sources in the world, eutrophication represents a global phenomenon that also affects the socioeconomic and environmental sector. In the present study, a bacterial pool formed by the Nitrosomonas europae, Nitrobacter winogradskyi, and Paracoccus denitrificans strains was used to remove the compounds NH3, NO2−, NO3−, P, and PO43−, real water samples from human supply at time 0 to 24 h. At the final time (24 h), the bacterial pool obtained total removal (100%) of all compounds analyzed. With the removal of nutrients from water, there was also reduction in the amount cyanobacteria and saxitoxins of water. Thus, the bacterial pool can be applied as a remediators of micropollutants such as compounds N and P, since their performance in removel the compounds was satisfactory. The removal of micropollutants from water bodies aims to decrease the nutrients responsible for cyanobacteria blooms, eutrophication, as well as improve water quality, optimize, and reduce water treatment costs, benefiting both the aquatic ecosystem and human health.

Developed Method for Treatment of Industrial Wastewater from Edible Oil Industry using Membrane Technology

Microorganisms and algae growth on surface water are stimulated in surface water in the presence of effluent wastewater from edible oil industries. This leads to depletion of dissolved oxygen (DO) by eutrophication process result in negative impact on aquatic environment. The new regulation in environment agency and increasing market demand are forcing the industrial sectors to consider finding new solutions and sustainable techniques of the wastewater treatment. In this study, reverse osmosis (RO) membrane filtration has been applied to assess the removal performance of emulsified oil from wastewater. Polysorbate 20 (Tween 20) was used as an oil/water emulsifier. Effect of oil concentrations in terms of chemical oxygen demand (COD) and activated carbon unit on removal efficiency and permeate flux have been studied in details. The results elucidated significant improvement in removal efficiency reached to "98%". The obtained results show promising application of RO membrane (polyamide membrane) at flux "17 L/m2 hr-1". The experiments showed that membrane filtration of wastewater from edible oil is a convenient technique for a possible removal of high concentration of oil (up to 6000 mg/L) with "98%" removal efficiency at permeate flux "17 L/m2 hr-1 "and low fouling rate.

Removal of Nutrients from Fertilizer Plant Wastewater Using Scenedesmus sp.: Formation of Bioflocculation and Enhancement of Removal Efficiency

Eutrophication of surface water has become an environmental concern in recent decades. High concentrations of nutrients, especially nitrogen- and phosphorus-rich species, have contributed to the process of eutrophication, highlighting a demand for effective and economical methods of removing nitrogen and phosphorus from wastewater. This study aimed to investigate the ability of a green microalga species, Scenedesmus sp., to remove nitrogen and phosphorus, as well as chemical oxygen demand (COD) and biochemical oxygen demand (BOD5), from fertilizer plant wastewater. Different microalgae concentrations from 10 mg/L to 60 mg/L were used to assess the growth rate, biomass production, and removal ability. The results indicated that Scenedesmus sp. grew well in the wastewater (with a growth rate from 0.3 to 0.38/day) and produced up to 70.2 mg/L of dry biomass. The algal species was able to remove ammonium (NH4+), nitrate (NO3−), phosphate (PO43−), total phosphorus (TP), COD, and BOD5 with removal rates up to 93%, 84%, 97%, 96%, 93%, and 84%, respectively. Autobioflocculation (AFL) was observed in all cultures with flocculation activity of up to 88.3% in the highest algal biomass treatment. The formation of bioflocculation enhanced the removal of nutrients, COD, and BOD5 from wastewater effluent. The results indicated that wastewater from a fertilizer plant could be used as a cost-effective growth medium for algal biomass. The autoflocculation of microalgae could be used as a more practical approach for wastewater treatment using microalgae to eliminate eutrophication.

Influence of submerged macrophytes on phosphorus in a eutrophic reservoir in a semiarid region

Phosphorus (P) is the main nutrient responsible for the harmful effects caused by the enrichment of aquatic systems, and submerged macrophytes play an important role in this process, since they can both remove and release this nutrient in environmental compartments. The present study aimed to evaluate the influence of submerged macrophytes on P in the water, sediment, and water-sediment interface in a eutrophic reservoir in a semiarid region and to evaluate the relationship between the concentration of this nutrient in macrophyte tissue and that available in the different compartments. Were performed ten collection campaigns, in three reservoir locations: at the entrance of the Paraíba River; in the intermediate area between the river entrance and the dam and at the dam. We observed a difference in the P concentration inside and outside macrophyte banks, and this difference was determined by the abundance and intensity of macrophyte growth and decomposition. In sites with extensive vegetation banks and where decomposition was more intense, macrophytes released P to the water-sediment interface and sediment compartments. By contrast, in sites with smaller vegetation banks and where macrophytes did not show reduced abundance, P was removed from these compartments. The entry of new water originating from river water transfer was an important modifying factor of the physical and chemical characteristics and macrophyte abundance. The zone where the river enters the reservoir was the area most affected by the water transfer. The macrophyte decomposition in this zone resulted in the highest P concentration in the water-sediment interface and sediment compartments, which demonstrates the importance of macrophytes in the fertilization of water bodies and, consequently, in the eutrophication process. In turn, in the dam zone, where the macrophyte banks were more stable and without large variations in abundance, P was removed from the compartments. A relationship between P in macrophyte tissue and that available in the environment was observed, particularly at the water-sediment interface, indicating that this compartment was the main P source for these plants, which demonstrated that these plants store higher amounts of P in nutrient-rich sediment and water, functioning as an indicator of the nutritional status of a reservoir.

Avaliação da qualidade da água da lagoa de Marapendi – Rio de Janeiro, RJ

Lagoas costeiras são ambientes naturais, localizados entre o continente e o oceano, proporcionam uma série de serviços ambientais e servem como corpo receptor de águas pluviais. No entanto, estas zonas têm sido submetidas a constantes processos de degradação, devido às atividades antrópicas. O presente trabalho teve como principal objetivo realizar o diagnóstico ambiental da Lagoa de Marapendi, localizada no município de Rio de Janeiro, utilizando-se como base os dados históricos de qualidade da água de três estações de monitoramento, no período de 2010 a 2017. As variáveis utilizadas foram a Demanda Bioquímica de Oxigênio (DBO), Oxigênio Dissolvido (OD), Fósforo Total (PT), Série Nitrogenada e Coliformes Termotolerantes. Os dados foram comparados com os padrões estabelecidos pela legislação e os resultados, para todos os parâmetros físico-químicos, não estavam em conformidade com os valores da Resolução CONAMA nº 357/2005 na maior parte do período, revelando que a Lagoa de Marapendi não apresenta um grau de qualidade adequado, provavelmente em razão de lançamentos irregulares de esgoto sem tratamento. A parte leste da Lagoa, por ter maior influência do regime de marés, apresentou os menores valores dos parâmetros de qualidade da água. O ponto localizado a montante da Lagoa apresentou a pior condição de qualidade ambiental, que pode ser justificada pela mesma razão, i.e., a baixa capacidade de renovação de águas nesta região da Lagoa.

Estimation of Internal Loading of Phosphorus in Freshwater Wetlands

Freshwater wetlands are found in various climatic zones ranging from tropics to tundra, and their roles from groundwater recharge and flood control to water quality management and biodiversity protection are well recognized. Phosphorus (P) is a limiting nutrient for algal growth in freshwater systems, including wetlands. Various physico-chemical and biological characteristics of wetlands regulate cycles of nutrients such as P. Thus, estimating internal loading of P in wetlands would be crucial in the formulation of effective P management strategies in the wetland systems. This review and limnological data presented may offer needed knowledge/evidence for the effective control of P inputs in wetlands and provide insights on possible ways for interventions in controlling eutrophication and saving the ecosystem from collapse. Various ways of P losses such as agriculture, urbanization, etc., to the water bodies have severely impacted water quality of wetlands by altering physical and chemical nature of the P compounds and release bound P to the water columns. Studies indicate that P sorption–desorption dynamic, mineralization, and enzymatic hydrolysis of P in freshwater wetlands’ soils/sediments are crucial in causing internal loading or sink of P in wetland systems. Thus, extensive studies on abovementioned arenas are crucial to restore natural freshwater wetlands or to increase the efficiency of constructed wetlands in retaining P. In general, researchers have elucidated significant amounts of limnological data to understand eutrophication processes in freshwater wetlands; however, studies on the interactions of P stability and hydro-climatic changes are not well understood. Such changes could significantly influence localized limnology/microenvironments and exacerbate internal P loading in freshwater wetlands; thus, studies in such direction deserve the attention of scientific communities.

Ecological and chemical characteristics of small river Arguzikha (Zeya-Bureya plain, Russia)

The article considers the results of research from 2015 to 2019 on the study of hydrochemical indicators and the content of heavy metals in the ecosystem components of the small Arguzikha river , a left-Bank tributary of the Amur river (water, bottom sediments, macrophytes, birds ’ feathers). High oxygen content in the water (8.8-15.9 mgO2/dm3) and high BOD5 values (6-12 mgO2/dm3) in the middle and lower reaches of the Arguzikha river indicate the process of eutrophication. The value of permanganate oxidability (6.8-15.5 mgO/dm3) characterizes the high content of organic substances in water. In the spring, nitrate nitrogen (3.45-6.39 mgN-NO3-/dm3) was found in the water of the Arguzikha river, which had a pyrogenic origin. In the summer the rainy season was dominated by ammonium nitrogen (2.34 mgN-NН +/dm3). The high content of total phosphorus (0.337-0.609 mg/dm3) in the river water was in the spring. In the spring of 2015, the concentration of lead in the lower reaches of the river reached 6.36 µg/dm3, during the subsequent time, the lead content in the Arguzikha water was less than the MPC. Toxic concentrations of lead (> 30 mg / kg) and manganese (> 300 mg/kg) were found in macrophytes of Nymphoides peltata and Myriophyllum spicatum. In the feathers of waterfowl of the Arguzikha river the content of heavy metals decreases in a row Fe>Zn>Cu>Pb>Mn>Сг>Ni>Cо>Cd. The feathers of Anas acuta and Anas querquedula contained Pb 17.7 mg/kg and 22.2 mg/kg, Cd 0.15 mg/kg and 0.08 mg/kg, respectively.

Hydrochemical Investigations of the Rivers and Water Bodies of the Dniester River Basin in Retrospective and under Modern Conditions

The main hydrochemical indices, including ionic composition, dissolved solids content, water hardness, dissolved oxygen content, nutrients content, and the content of organic matter with regard to chemical oxygen demand (ChODMn and ChODCr) were investigated in the Dniester River, and also in watercourses and water bodies of its basin. It has been shown that in different sections of the Dniester River dissolved solids content increased downstream of the river, which is accounted for by the influence of both natural and anthropogenic factors. It has been found that the increase in dissolved solids content is accounted for mainly by the increase in the concentration of SO42- and Cl- ions, and also by the increase in the concentration of the sum of Na+ and K+ ions. The oxygen regime of the Dniester River is satisfactory along its whole length. However, sometimes oxygen deficiency is observed in the lower reaches of the river near its estuary, which is conditioned by the process of eutrophication. The modern state of the Dniester River in terms of the main hydrochemical indices was assessed in the sections located in different ecological regions. An effort was made to determine reference hydrochemical indices for different sections of the river.

Balance of nitrogen and phosphorus in a reservoir in the tropical semiarid region

In relation to the process of eutrophication of water reservoirs, it is necessary to understand the nitrogen and phosphorus supply, as well as they support the process of eutrophication. In seeking to quantify the balance of nitrogen and phosphorus, as well as to identify the effect of climatic seasonality on their dynamics, 21 campaigns were carried out for water collection. The campaigns took place from April 2008 to December 2012 at the Oros reservoir, located in the semi-arid region of Brazil in the south-central part of the State of Ceara. Based on dataset it was possible to calculate the inflow and outflow of total nitrogen (TN) and total phosphorus (TP). The reservoir becoming a storage place for the nutrients transported by the flow of water from the drainage network. A total of 176 tons of nitrogen and 230 tons of phosphorus were retained in the reservoir. The TN and TP retained in the reservoir can lead to the water being compromised by eutrophication, increasing the financial cost of water treatment and compromising water availability for consumption use. Because it is a predominantly agricultural basin, and the nutrients show a similar input trend in the reservoir, it is believed that the primary source of nutrients is agriculture and livestock. There has been an increase in nutrient input of over time. Reservoirs in semi-arid regions are unique as regards nutrient load during dry periods, since even without fluvial input, nutrient concentrations generally remain steady or increase.

Методика геоинформационного моделирования выноса биогенных веществ в Финский залив из лесного растительного покрова

Biogenic pollution of water bodies and their eutrophication is one of the most serious environmental problems of our time. One of the sources of water pollution with biogenic substances is forests, which belong to the background sources of biogenic load. Currently available methods for assessing the removal of nutrients from the forest vegetation cover do not provide the desired results, which causes an urgent need for their improvement. This article describes the method developed by the authors of geoinformation modeling of removal of biogenic substances from the forest vegetation cover to water bodies, taking into account the spatial distribution of vegetation in the catchment area, its species composition and absorption of biogenic substances during their migration. The Eastern part of the Gulf of Finland was adopted as the object of testing of the developed method. this is due to the fact that eutrophication processes are actively manifested within its water area. The volume of the background biogenic load on the Gulf of Finland, formed during the decomposition of the fall of the natural vegetation cover in the catchment area, was determined based on the specific removal of biogenic substances from plant communities and their absorption during migration “plant community — water object”. The total background biogenic load on the eastern part of the Gulf of Finland, formed as a result of decomposition of natural vegetation cover, was 170.21 t/year for the northern catchment for nitrogen, 12.14 t/year for phosphorus, and 207.31 t/year for the southern catchment for nitrogen , and 15.68 t/year for phosphorus. The data obtained do not contradict the results of other authors who study the background biogenic load on the Gulf of Finland. The method can be effectively used in the development of measures to reduce the nutrient load on water bodies and planning of economic activities in catchments.

Potential Areas for Managed Aquifer Recharge in the Eastern Lower Jordan Valley Area

The article deals with the feasibility of using the recent geological formations in the eastern Jordan Valley for water storage through artificial recharge due to water scarcity and water needs in this area. Water storage in surface reservoirs in arid and semi-arid areas is afflicted with a variety of issues such as high evaporation, eutrophication processes and exposure to contamination and accidents. Dams to capture all rare-event floods are, generally, big and expensive structures. Artificially recharging aquifers and storing the water in the underground offer a competing alternative. In this study, hydrogeological, geological, geophysical and hydrochemical investigations were carried out to study the potentials of the eastern side of the Lower Jordan Valley for artificial recharge. The results reveal that relatively extended areas on the eastern side of the Lower Jordan Valley have the potential to accommodate large amounts of recharge water and that the impacts of artificially storing the water in aquifers are to be judged very positive compared to surface storage, especially when the amounts of available recharge water can quantitatively be accommodated in recharge facilities. In addition, the study shows, the advantages of underground water storage compared to surface storage in dams. The potential storage capacities in the different parts of the Lower Jordan Valley are quantified based on rechargeable aquifer volumes and porosities. The potential uses of the recharged water are also elaborated on depending on recharge and aquifer water qualities.