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1
Tay, Chai Jian, Su Yean Teh, and Hock Lye Koh. "Eutrophication Bifurcation Analysis for Tasik Harapan Restoration." International Journal of Environmental Science and Development 11, no. 8 (2020): 407–13. http://dx.doi.org/10.18178/ijesd.2020.11.8.1282.
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Regime shift is characterized by large, abrupt and persistent changes in ecosystem structure and dynamics. Bifurcation analysis is commonly used to identify regime shift equilibrium states and to distinguish their stability characteristics. Eutrophication in lake, a regime shift from clear-water oligotrophic state, is a stable equilibrium state that can persist for long duration. Characterized by undesirable turbid water condition, eutrophication has been known to impair valuable ecosystem services provided by lakes worldwide. The high incidence of eutrophication in Malaysian lakes (62%) mandates urgent need for lake restoration. The three-fold objectives of this paper are (1) to develop a mathematical model for analysing bifurcation criteria in regime shift, (2) to identify regime shift thresholds and (3) to propose effective ecosystem management strategy for shallow tropical lakes such as Tasik Harapan. A mathematical model consisting of four compartments: algae, phosphorus, dissolved oxygen and biochemical oxygen demand is formulated to analyse the eutrophication dynamics in the highly eutrophic Tasik Harapan (TH), a small shallow lake in Universiti Sains Malaysia (USM). Bifurcation analysis is performed by means of XPPAUT to identify the regime shift thresholds and to determine the type of lake response. Identified as irreversible, the eutrophication state of TH mandates an urgent lake restoration program to remove nutrients in the lake. Two restoration methods for reducing nutrients are assessed: (1) flushing of lake water and (2) hypothetical application of the invasive water hyacinth. Bifurcation analysis indicates that a flushing rate exceeding 0.042 day-1 is needed to restore TH to oligotrophic state. A complicated strategy of water hyacinth application would reduce the algae concentration from 300 μg/l to 120 μg/l after 9.6 years. A severe shortfall is the complicated and uncertain process of frequent removal of water hyacinth to prevent the lake from being overwhelmed by the invasive plants. The feasibility and sustainability of these two lake restoration methods are discussed. The insights gained would be useful to the relevant authorities in determining and implementing the best remediation measures for TH.
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Zhu, Konghao, Yao Wu, Chunhua Li, Jun Xu, and Min Zhang. "Ecosystem-Based Restoration to Mitigate Eutrophication: A Case Study in a Shallow Lake." Water 12, no. 8 (2020): 2141. http://dx.doi.org/10.3390/w12082141.
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Under the influence of human activities, eutrophication has become an increasingly serious global phenomenon, especially in shallow lakes. Many studies have shown that aquatic macrophytes play a significant role in controlling eutrophication, but only few of these studies are ecosystem based. In this paper, we applied a mass-balance ecosystem model to a shallow eutrophic lake (Lake Datong, China) as a case study with the aims of evaluating the status of ecosystem restoration via the recovery of aquatic vegetation and providing adaptive management suggestions. Results showed that the ecosystem was immature with weak energy flows and nutrient cycling largely due to the excessive submerged macrophytes and the lack of fish as consumer. In the early stages of restoration, the number of fish should be reduced, and aquatic vegetation needs to be recovered to mitigate eutrophication. When the aquatic vegetation community tends to be stable, herbivorous and omnivorous fish should be moderately stocked, and dead aquatic macrophytes should be harvested to maintain the healthy and sustainable development of the ecosystem. This study provided insights for the ecological restoration of shallow eutrophic lakes and revealed the urgent need for ecosystem-based restoration.
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Binhe, GU. "Eutrophication and Restoration of Lake Apopka, USA." Journal of Lake Sciences 17, no. 1 (2005): l—8. http://dx.doi.org/10.18307/2005.0101.
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Bozic, M., G. Nikolic, Z. Rudic, V. Raicevic, and B. Lalevic. "Constructed wetlands as an alternative restoration measure for shallow lakes." Water Science and Technology 68, no. 7 (2013): 1672–78. http://dx.doi.org/10.2166/wst.2013.412.
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This paper deals with the consequences of cultural eutrophication and unconventional solutions for shallow lake restoration. Cultural eutrophication is the primary problem that affects especially shallow lakes, due to their physical characteristics (e.g. shallow depth, lack of stratification). Palic Lake, a very shallow Pannonian lake, received treated municipal wastewaters coming from the lagoons of a wastewater treatment plant. The sewage discharge mainly increased the nutrient load to the lake in the last decades. The lake sustainability is affected by inappropriate quality of water that flows into the lake, and abundance of deposited sediment. The technology that can provide both improvement of water quality and resolution of the sediment problem is a constructed wetland, which is designed to utilise the natural processes involving wetland vegetation, soil and their associated microbial assemblages to assist in additional water treatment. The technical solution is based on three key aspects: quality and quantity of deposited sediment, enriched by nutrients; effluent quality; desired lake water quality. A designed constructed wetland can accomplish the desired water quality and gradually remediate deposited sediment.
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Su, Wei, Jiapeng Wu, Bei Zhu, Kaiqi Chen, Wenqi Peng, and Baoyue Hu. "Health Evaluation and Risk Factor Identification of Urban Lakes—A Case Study of Lianshi Lake." Water 12, no. 5 (2020): 1428. http://dx.doi.org/10.3390/w12051428.
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Health assessment and risk factor identification represent the premise and foundation of scientific management and ecological restoration of urban lakes. Based on in-depth understanding of the nature–society duality of urban lakes, a framework for evaluating urban lake health was constructed, including four modules, namely, establishing an index system; determining the index weight; identifying risk factors; and a comprehensive lake health evaluation. Employing this framework, we evaluated Lianshi Lake, Beijing, classifying the lake condition as “sub-healthy”. Based on the evaluation data, we identified the health risk factors of the lake. We applied standard difference rate (SDR) and risk degree (Rd) (safe degree (Sd)) concepts, and classified the indices of risk areas employing the Pareto analysis method. Finally, we identified the lake residence period, landscape connectivity, and eutrophication as the major risk factors in Lianshi Lake. Three factors constitute the basis of ecosystem health and are key targets of ecological restoration: the lake residence period represents the hydrological and hydrodynamic characteristics of the lake; landscape connectivity is described from an ecological perspective, and represents the integrity of the lake ecosystem; and the eutrophication states describe the water quality characteristics and represent the availability of lake water. The results contribute to decision-making for comprehensive urban lake management.
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Nazarova, T. V., K. M. Dzhanaleeva, G. J. Baryshnikov, P. S. Dmitriev, and Zh I. Inkarova. "Anthropogenic eutrophication and ways of lake systems restoration in northern Kazakhstan." BULLETIN of the L.N. Gumilyov Eurasian National University. Chemistry. Geography. Ecology Series 130, no. 1 (2020): 120–32. http://dx.doi.org/10.32523/2616-6771-2020-130-1-120-132.
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The article is concerned with the processes of eutrophication of lake systems in Northern Kazakhstan. A comprehensive assessment of the current state of the ecosystem of the Zhamanovskoe Lake was carried out. The main reasons for the eutrophication of the Zhamanovskoe Lake have been identified: plowing of the catchment area, use of pesticides, cattle grazing and watering. Activities on land reclamation were developed. The Zhamanovskoe Lake is a typical reservoir of Northern Kazakhstan in terms of size, water receiving, origin of the lake basin, etc. Research undertaken can be applied to more water bodies.
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Janse, J. H., W. Ligtvoet, S. Van Tol, and A. H. M. Bresser. "A Model Study on the Role of Wetland Zones in Lake Eutrophication and Restoration." Scientific World JOURNAL 1 (2001): 605–14. http://dx.doi.org/10.1100/tsw.2001.350.
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Shallow lakes respond in different ways to changes in nutrient loading (nitrogen, phosphorus). These lakes may be in two different states: turbid, dominated by phytoplankton, and clear, dominated by submerged macrophytes. Both states are self-stabilizing; a shift from turbid to clear occurs at much lower nutrient loading than a shift in the opposite direction. These critical loading levels vary among lakes and are dependent on morphological, biological, and lake management factors. This paper focuses on the role of wetland zones. Several processes are important: transport and settling of suspended solids, denitrification, nutrient uptake by marsh vegetation (increasing nutrient retention), and improvement of habitat conditions for predatory fish. A conceptual model of a lake with surrounding reed marsh was made, including these relations. The lake-part of this model consists of an existing lake model named PCLake[1]. The relative area of lake and marsh can be varied. Model calculations revealed that nutrient concentrations are lowered by the presence of a marsh area, and that the critical loading level for a shift to clear water is increased. This happens only if the mixing rate of the lake and marsh water is adequate. In general, the relative marsh area should be quite large in order to have a substantial effect. Export of nutrients can be enhanced by harvesting of reed vegetation. Optimal predatory fish stock contributes to water quality improvement, but only if combined with favourable loading and physical conditions. Within limits, the presence of a wetland zone around lakes may thus increase the ability of lakes to cope with nutrients and enhance restoration. Validation of the conclusions in real lakes is recommended, a task hampered by the fact that, in the Netherlands, many wetland zones have disappeared in the past.
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Reavie, Euan D., John P. Smol, and N. Bruce Carmichael. "Postsettlement eutrophication histories of six British Columbia (Canada) lakes." Canadian Journal of Fisheries and Aquatic Sciences 52, no. 11 (1995): 2388–401. http://dx.doi.org/10.1139/f95-831.
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Eutrophication is a serious problem in many British Columbia lakes. However, long-term nutrient data are rare or unavailable for most lake systems, so the natural, predisturbance characteristics of lakes are unknown, as are the trajectories of past environmental change. We used paleolimnological analyses of diatoms to quantitatively assess eutrophication trends for approximately the last 150 years in six British Columbia lakes. A transfer function was used to infer past lake-water total phosphorus concentrations from the sedimentary diatom assemblages in 210Pb-dated sediment cores: all of the lakes had relatively high total phosphorus levels (> 13 μg/L) prior to European settlement. Three of the lakes showed significant eutrophication since that time, whereas the others were only mildly affected. Total phosphorus inferences using the transfer function satisfactorily estimated the modern total phosphorus concentrations of our six study lakes. Minor quantitative problems arose when some fossil assemblages provided poor analogues to the calibration function, but eutrophication trends were still clearly apparent. Our results confirm that some British Columbia lakes have suffered considerable eutrophication as a result of anthropogenically related nutrient inputs, while others, although situated within human-influenced regions, have been relatively unaffected. These results can now be used to help set realistic goals for restoration projects.
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Joensuu, I., and M. Pekkarinen. "Cultural eutrophication, restoration and management of Lake Tuusulanjärvi, Finland." SIL Proceedings, 1922-2010 29, no. 5 (2006): 2197–200. http://dx.doi.org/10.1080/03680770.2006.11903081.
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Lau, S. S. S., and S. N. Lane. "Continuity and change in environmental systems: the case of shallow lake ecosystems." Progress in Physical Geography: Earth and Environment 25, no. 2 (2001): 178–202. http://dx.doi.org/10.1177/030913330102500202.
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Traditional ideas concerning environmental management tend to be based upon simple relationships between cause and effect. Such approaches make the design of environmental management strategies fairly straightforward: once the cause of a problem has been identified, it is necessary only to address the cause and/or help the system to recover through some sort of attempt at restoration. In the case of shallow lake eutrophication, research in the 1960s and 1970s identified phosphorus as the key control on the trophic state of a lake and, hence, recommended reductions in the supply of phosphorus to lakes as the necessary remedial measure. However, subsequent research has illustrated that such measures were not always successful. This article reviews the science of shallow lake eutrophication to demonstrate the role of ecosystem-specific biological and chemical interactions in conditioning the response of lakes to remedial measures and, hence, shows how new ideas of complexity help us to understand the behaviour of lake ecosystems so that we can develop alternative environmental management strategies.
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Wang, Yanping, Weiping Hu, Zhaoliang Peng, Ye Zeng, and Karsten Rinke. "Predicting Lake Eutrophication Responses to Multiple Scenarios of Lake Restoration: A Three-Dimensional Modeling Approach." Water 10, no. 8 (2018): 994. http://dx.doi.org/10.3390/w10080994.
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To improve the water quality and alleviate the eutrophication of Lake Yangchenghu, the third largest freshwater body within the Lake Taihu basin in China and an important source of drinking water, nutrient reduction strategies should be urgently addressed by decision makers, since virtually no improvement of water quality has taken place since the mid-1990s. Due to the lack of sufficient observation data and simulation results, a vertically compressed three-dimensional numerical model, the EcoTaihu model, was used to study the impact of three restoration measures on the water quality—namely, total nitrogen (TN), total phosphorus (TP) and biomass of phytoplankton (BP)—of Lake Yangchenghu: (i) total nutrient reduction, (ii) intensification of flushing by water transfer, and (iii) spatial adjustment of inflow channels. In particular, the spatial effects of the three restoration measures on the water quality were investigated. The results showed that the EcoTaihu model is applicable to other shallow lakes in China. The water quality responses to the different restoration scenarios showed significant spatio-temporal differences. The reduction of nutrient loads from inflows appeared to be the most effective measure for controlling the eutrophication and algal blooms in Lake Yangchenghu. The effectiveness of water transfer on the improvement of water quality for TN and TP was more influenced by the differences of nutrient concentrations between the transferred water and lake water, rather than flow rate, since no proportionate increase of improvement was observable in the case of larger transferred rates (60 m3 s−1). The spatial narrowing of inflowing rivers in the southwestern lake could preferentially improve the water quality in the southern bay of the western lake, but would also result in a deterioration trend of water quality in the total lake and drinking water abstraction areas.
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Wenchao, Li, Yang Qingxin, and Zhou Wanping. "Studies on eutrophication of Wuli Lake and possible restoration strategies." Journal of Lake Sciences 6, no. 2 (1994): 136–43. http://dx.doi.org/10.18307/1994.0206.
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Hamilton, D. P., and M. J. Landman. "Preface: Lake restoration: an experimental ecosystem approach for eutrophication control." Hydrobiologia 661, no. 1 (2010): 1–3. http://dx.doi.org/10.1007/s10750-010-0560-9.
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Lürling, Miquel, Maíra Mucci, and Guido Waajen. "Removal of Positively Buoyant Planktothrix rubescens in Lake Restoration." Toxins 12, no. 11 (2020): 700. http://dx.doi.org/10.3390/toxins12110700.
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The combination of a low-dose coagulant (polyaluminium chloride—‘Floc’) and a ballast able to bind phosphate (lanthanum modified bentonite, LMB—‘Sink/Lock’) have been used successfully to manage cyanobacterial blooms and eutrophication. In a recent ‘Floc and Lock’ intervention in Lake de Kuil (the Netherlands), cyanobacterial chlorophyll-a was reduced by 90% but, surprisingly, after one week elevated cyanobacterial concentrations were observed again that faded away during following weeks. Hence, to better understand why and how to avoid an increase in cyanobacterial concentration, experiments with collected cyanobacteria from Lakes De Kuil and Rauwbraken were performed. We showed that the Planktothrix rubescens from Lake de Kuil could initially be precipitated using a coagulant and ballast but, after one day, most of the filaments resurfaced again, even using a higher ballast dose. By contrast, the P. rubescens from Lake Rauwbraken remained precipitated after the Floc and Sink/Lock treatment. We highlight the need to test selected measures for each lake as the same technique with similar species (P. rubescens) yielded different results. Moreover, we show that damaging the cells first with hydrogen peroxide before adding the coagulant and ballast (a ‘Kill, Floc and Lock/Sink’ approach) could be promising to keep P. rubescens precipitated.
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Lyu, Tao, Lirong Song, Qiuwen Chen, and Gang Pan. "Lake and River Restoration: Method, Evaluation and Management." Water 12, no. 4 (2020): 977. http://dx.doi.org/10.3390/w12040977.
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Eutrophication has become one of the major environmental issues of global concern due to the adverse effects on water quality, public health and ecosystem sustainability. Fundamental research on the restoration of eutrophic freshwaters, i.e., lakes and rivers, is crucial to support further evidence-based practical implementations. This Special Issue successfully brings together recent research findings from scientists in this field and assembles contributions on lake and river restoration. The 12 published papers can be classified into, and contribute to, three major aspects of this topic. Firstly, a background investigation into the migration of nutrients, and the characteristics of submerged biota, will guide and assist the understanding of the mechanisms of future restoration. Secondly, various restoration strategies, including control of both external and internal nutrients loading, are studied and evaluated. Thirdly, an evaluation of the field sites after restoration treatment is reported in order to support the selection of appropriate restoration approaches. This paper focuses on the current environmental issues related to lake and river restoration and has conducted a comprehensive bibliometric analysis in order to emphasise the fast-growing attention being paid to the research topic. The research questions and main conclusions from all papers are summarised to focus the attention toward how the presented studies aid gains in scientific knowledge, engineering experience and support for policymakers.
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Zhang, Yixing, Yutao Wang, and Zhongze Zhou. "The impact of withdrawing aquaculture facilities on metazooplankton communities in the lakes are connected to the Yangtze River, China." PLOS ONE 16, no. 5 (2021): e0252100. http://dx.doi.org/10.1371/journal.pone.0252100.
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The withdrawal of aquaculture facilities has an important impact on the aquatic ecosystem of the lakes connected to the Yangtze River. In order to elucidate the response mechanism of metazooplankton to the changes in water environment after the removal of aquaculture facilities, we collected metazooplankton samples and investigated the water environment in the Huayanghe Lakes from the summer of 2018 to the spring of 2019. Aquatic plants recovered quickly, and water eutrophication was relieved, especially in Lake Huangda, followed by Lake Bo. During our study, the highest regional (γ) diversity was 71 in summer, while the lowest was 32 in winter. Species turnover in space (β diversity) varied between 10.01 and 56.52, which was highest in summer. Based on redundancy analysis, environmental factors such as transparency, Chl α, water temperature and water depth, had greatly effects on the metazooplankton community structure. The results showed that the restoration of aquatic plants increased species diversity and metazooplankton density. This study provides a data basis for lakes restoration and a scientific basis for the management and protection of lakes water ecosystem.
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Xu, Z. H., X. A. Yin, and Z. F. Yang. "An optimisation approach for shallow lake restoration through macrophyte management." Hydrology and Earth System Sciences 18, no. 6 (2014): 2167–76. http://dx.doi.org/10.5194/hess-18-2167-2014.
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Abstract. Lake eutrophication is a serious global environmental issue. Phytoremediation is a promising, cost-effective, and environmentally friendly technology for water quality restoration. However, besides nutrient removal, macrophytes also deeply affect the hydrologic cycle of a lake system through evapotranspiration. Changes in hydrologic cycle caused by macrophytes have a great influence on lake water quality restoration. As a result of the two opposite effects of macrophytes on water quality restoration (i.e. an increase in macrophytes can increase nutrient removal and improve water quality while also increasing evapotranspiration, reducing water volume and consequently decreasing water quality), rational macrophyte control through planting and harvest is very important. In this study, a new approach is proposed to optimise the initial planting area and monthly harvest scheme of macrophytes for water quality restoration. The month-by-month effects of macrophyte management on lake water quality are considered. Baiyangdian Lake serves as a case study, using the common reed. It was found that water quality was closest to Grade III on the Chinese water quality scale when the reed planting area was 123 km2 (40% of the lake surface area) and most reeds would be harvested at the end of June. The optimisation approach proposed in this study will be a useful reference for lake restoration.
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Xu, Z. H., X. A. Yin, and Z. F. Yang. "An optimisation approach for shallow lake restoration through macrophyte management." Hydrology and Earth System Sciences Discussions 11, no. 1 (2014): 807–32. http://dx.doi.org/10.5194/hessd-11-807-2014.
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Abstract. Lake eutrophication is a serious global environmental issue. Phytoremediation is a promising, cost-effective, and environmentally friendly technology for water quality restoration. However, besides nutrient removal, macrophytes also deeply affect the hydrologic cycle of lake system through evapotranspiration. Changes in hydrologic cycle caused by macrophytes have a great influence on lake water quality restoration. As a result of the two opposite effects of macrophytes on water quality restoration (i.e. an increase in macrophytes can increase nutrient removal and improve water quality while also increasing evapotranspiration, reducing water volume and consequently decreasing water quality), rational macrophyte control through planting and harvest is very important. In this study, a new approach is proposed to optimise the initial planting area and monthly harvest scheme of macrophytes for water quality restoration. The month-by-month effects of macrophyte management on lake water quality are considered. Baiyangdian Lake serves as a case study, using the common reed. It was found that water quality was closest to Grade III on the Chinese water quality scale when the reed planting area was 123 km2 (40% of the lake surface area) and most reeds would be harvested at the end of June. The optimisation approach proposed in this study will be a useful reference for lake restoration.
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Liu, Xujun, and Hailing Wang. "Dianchi Lake, China: Geological formation, causes of eutrophication and recent restoration efforts." Aquatic Ecosystem Health & Management 19, no. 1 (2016): 40–48. http://dx.doi.org/10.1080/14634988.2016.1145022.
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Ferriol, Carmen, Maria Rosa Miracle, and Eduardo Vicente. "Effects of nutrient addition, recovery thereafter and the role of macrophytes in nutrient dynamics of a Mediterranean shallow lake: a mesocosm experiment." Marine and Freshwater Research 68, no. 3 (2017): 506. http://dx.doi.org/10.1071/mf15291.
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Eutrophication in coastal wetlands has increased greatly because of human impact, reducing water quality and affecting aquatic plants. The aim of the present study was to investigate the eutrophication of Mediterranean wetlands and their possible recovery. An in situ mesocosm nutrient enrichment experiment was performed in a coastal shallow lake from eastern Spain, holding dense Chara meadows. In this lake, 36 mesocosms were installed and fertilised weekly with four levels of N and P addition over an 8-week period from June to August. Mesocosms fertilised with the two higher levels (N:P ≥5:0.5mgL–1) shifted to turbid status with macrophyte loss before Week 4. Saturation concentrations were similar under these two conditions, with averages ~1.0mgL–1 total particulate P and 700µgL–1chlorophyll-a reached in the last 3 weeks. After 5 weeks of the experiment, macrophytes were removed from the mesocosms without nutrient addition and those fertilised with 1:0.1mgL–1 N:P. Macrophyte removal resulted in a release of phosphate and ammonium from sediments, enhancing eutrophication. Three months after stopping nutrient addition, high nutrient and chlorophyll concentrations persisted in the highly fertilised mesocosms, but decreased in the low fertilised mesocoms, which shows that restoration of eutrophic Mediterranean shallow lakes depends to a great extent on previous external loads.
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Jilbert, Tom, Sami Jokinen, Timo Saarinen, et al. "Impacts of a deep reactive layer on sedimentary phosphorus dynamics in a boreal lake recovering from eutrophication." Hydrobiologia 847, no. 21 (2020): 4401–23. http://dx.doi.org/10.1007/s10750-020-04289-9.
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AbstractUsing biogeochemical analyses of sediments and porewaters, we investigate the legacy of a brief, intense period of eutrophication on sedimentary phosphorus (P) cycling in a boreal lake (Enonselkä basin, Lake Vesijärvi, Finland). Point-source sewage inputs in the twentieth century caused deoxygenation of the lake and accelerated the focusing of iron (Fe) and manganese (Mn) oxides into deeper areas. Early diagenesis under Fe–Mn-rich conditions now favors rapid burial of P in these areas, likely as a combination of both oxide-bound P phases and authigenic manganous vivianite. A new P budget for Enonselkä basin shows that P burial causes an annual drawdown of 1.2% (± 0.2%) of the surface sediment P inventory, supporting a long-term trend towards recovery since the construction of a wastewater treatment plant in the mid-1970s. However, remineralization of organic matter and associated dissolution of Fe–Mn oxides continues to regenerate P from a deep reactive layer (20–60 cm depth) deposited at the height of past eutrophication, leading to an upwards diffusive flux of dissolved phosphate towards the surface sediments. The magnitude of this flux is similar to that of external P loading to the lake. The combined incoming fluxes of P are likely to retard the complete recovery from eutrophication by decades, despite ongoing restoration actions.
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Tórz, Agnieszka, Małgorzata Bonisławska, Agnieszka Rybczyk, Arkadiusz Nędzarek, and Adam Tański. "Susceptibility to Degradation, the Causes of Degradation, and Trophic State of Three Lakes in North-West Poland." Water 12, no. 6 (2020): 1635. http://dx.doi.org/10.3390/w12061635.
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Effective protection of lakes against degradation requires a detailed recognition of the factors leading to their eutrophication. This also pertains to small lakes, which constitute an important element of various ecosystems and are crucial for maintaining biodiversity. Therefore, the aim of the study is to determine the trophic state as well as the susceptibility to degradation of three small lakes in north-western Poland: Maszewo, Starzyca, and Nowogardzkie. This study analyzes the morphometric characteristics of the lakes, the impact of the catchment, their actual trophic state, and phosphorus levels. The analysis showed varying regeneration potentials of the lakes. Maszewo Lake is eutrophic-hypertrophic, nonresilient, strongly exposed to influence from the catchment, with phosphorus levels within the norm. Starzyca Lake is a eutrophic lake, not very resilient to the influence of the catchment, with excessive phosphorus levels. Nowogardzkie Lake is a eutrophic lake with moderate resilience to degradation, but with excessive phosphorus levels, which endangers the functioning of this aquatic ecosystem. In all the lakes, phosphorus supply was predominantly internal. Restoration of these lakes could be performed by completely cutting off the inflow of nutrients, as well as reclamation involving the deactivation of phosphorus (e.g., by precipitation) as well as the removal of the bottom sediments responsible for the internal supply of phosphorus.
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Li, Yan, Hong Zhu Wang, Xiao Min Liang, et al. "Total phytoplankton abundance is determined by phosphorus input: evidence from an 18-month fertilization experiment in four subtropical ponds." Canadian Journal of Fisheries and Aquatic Sciences 74, no. 9 (2017): 1454–61. http://dx.doi.org/10.1139/cjfas-2016-0057.
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There is a heated debate over the necessity of nitrogen (N) reduction, in addition to phosphorus (P) reduction, for the control of eutrophication. Whole-lake fertilization experiments and lake restoration practices in high latitudes have demonstrated that P is the primary factor regulating total phytoplankton. Recognizing the limited large-scale evidence in warmer climatic zones, a fertilization experiment was conducted in four ponds located in the subtropical Yangtze River Basin, China. Total phytoplankton abundance in a pond receiving P (+P) was similar to that in a pond receiving both N and P (+N+P). Both had higher phytoplankton than a pond receiving no additional nutrient (Control). Total nitrogen concentration (TN) in the +P pond increased with the appearance of N-fixing cyanobacteria. Total phytoplankton abundance was similar in the ponds without P addition (+N, Control), and both ponds had lower phytoplankton levels than the +N+P pond. These results showed that P, not N, determines total phytoplankton abundance and that N deficiency is offset by N fixation in subtropical lakes. This experiment supports the idea that attention should be mainly focused on P reduction in mitigating eutrophication.
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Bernát, Gábor, Nóra Boross, Boglárka Somogyi, Lajos Vörös, László G.-Tóth, and Gergely Boros. "Oligotrophication of Lake Balaton over a 20-year period and its implications for the relationship between phytoplankton and zooplankton biomass." Hydrobiologia 847, no. 19 (2020): 3999–4013. http://dx.doi.org/10.1007/s10750-020-04384-x.
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Abstract Lake Balaton, the largest lake in Central Europe, underwent severe eutrophication from the 1960s to the 1990s, due to phosphorus loadings from external anthropogenic sources. The subsequent and complex eutrophication control and lake restoration program resulted in a significant decrease in the external phosphorus loading to the lake. Consequently, Lake Balaton has been returning to its former meso-eutrophic character. In this paper, we explore the long-term dynamics of chlorophyll a (Chl a) concentration, a proxy for phytoplankton biomass, and zooplankton biomass in Lake Balaton during its re-oligotrophication period from 2001 to 2017, and attempt to draw some conclusions on the subsequent changes in the fish stock. We found a proportional decrease in zooplankton and phytoplankton biomasses at moderate phytoplankton levels. However, below a certain phytoplankton concentration (< 10 μg l−1 Chl a), the decrease in phytoplankton biomass was not coupled with a further decline in zooplankton biomass because the fraction of small phytoplankton, edible for zooplankton, showed a much smaller decrease in biomass compared with large non-edible phytoplankton. Thus, improvements in water quality (i.e., reduced nutrient loading), partly via concomitant changes in the phytoplankton size distribution, did not cause a large difference in the fish stock in this shallow lake.
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Klein, Günter. "Rationale and Implementation of a Strategy to Restore Urban Lakes in Berlin: Results after Ten Years of Phosphorus Removal." Water Quality Research Journal 27, no. 2 (1992): 239–56. http://dx.doi.org/10.2166/wqrj.1992.017.
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Abstract All lakes in the Berlin area have received excessive phosphorus loads during the last century. Restoration measures during the 1980s reduced the phosphorus input to three of these lakes considerably (from about 0.5-2 mg/L down to 0.005-0.02 mg/L total P). Although the chief measure—phosphate precipitation (flocculation, sedimentation and filtration)—reduced input to the greatest extent exercised so far worldwide, it became evident that such lakes may nevertheless need 4-6 years to show significant signs of recovery. Although the nutrient budget reacted rapidly, biocoenotic reactions differed between the lake types. The Berlin experience shows that urban lake areas cannot be restored by conventional sewage treatment and restoration techniques, but will need a great variety of additional techniques in order to show success. P- removal from the main inflow down to a few µg/L of total P is a minimum requirement. However, further well suited techniques have to be developed for the specific situation in each of the Berlin lakes in order to achieve nutrient removal to the extent which is in accordance with the present knowledge of eutrophication processes as well as with the special situation of each case. This refers to dosage of chemicals, removal of algae from treated surface water, filtration techniques, and hypolimnetic drainage. The costs of lake restoration in Berlin amount to less than 0.30 DM per m3 of treated water—a price which has demonstrated good results in the last few years. These results are of greatest importance for the further planning of water resources management, recreation, and for a safe drinking water supply for the growing urban area of reunified Berlin with its 4 million inhabitants.
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Grochowska, Jolanta, and Renata Tandyrak. "The Influence of the Modernization of the City Sewage System on the External Load and Trophic State of the Kartuzy Lake Complex." Applied Sciences 11, no. 3 (2021): 974. http://dx.doi.org/10.3390/app11030974.
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A study was carried out in the Kartuzy lake complex, which has been a receiver of raw domestic sewage since the 1950s. In 2018, the city’s sewage system of Kartuzy was modernized. An analysis of the water quality prior to the modernization of the sewage system revealed that the total phosphorus (TP) load that was introduced to the individual lakes from external sources substantially exceeded the dangerous load concentration (defined by Vollenweider) that causes accelerated eutrophication. The annual TP load introduced to the analyzed lakes in 2017 exceeded the critical load by 200% (Mielenko) to 1000% (Klasztorne Duże). Protective measures reduced the external loading of nutrients. In the case of Mielenko Lake, a 37% decrease in the external TP load was noted, and also a 32% decrease in the external TP load in Karczemne Lake, a 66% decrease in Klasztorne Małe Lake and a 54% decrease in Klasztorne Duże Lake was noted. The protective measures resulted in a slight decrease in the concentrations of phosphorus and nitrogen in the water. However, these changes did not improve the environmental conditions in the lakes. In a situation where the internal fertilization process in the lakes has started, the improvement of water quality will only be possible through restoration efforts with methods adjusted to the individual characteristics of each lake.
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Klinge, M., M. P. Grimm, and S. H. Hosper. "Eutrophication and ecological rehabilitation of Dutch lakes: Presentation of a new conceptual framework." Water Science and Technology 31, no. 8 (1995): 207–18. http://dx.doi.org/10.2166/wst.1995.0300.
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Lake restoration is a major issue in water management in The Netherlands. In this context biomanipulation is considered an important tool following the reduction of the nutrient load. Here we present a new conceptual framework and try to quantify the productivity level below which predator control of the fish population, which is considered a prerequisite for successful biomanipulation, occurs. The conceptual framework focuses on a balance between preyfish production and piscivorous fish consumption. When the piscivorous fish consumption (top-down control) is too low to control the preyfish community (bottom-up forces), the abundance of small planktivorous fishes will increase, leading to the cascading effects of a heavy predation on zooplankton and an excessive development of algae resulting in an increase of turbidity. With the framework the total-P concentrations characterising lake productivity at such turning points can be calculated. The framework is used to explain the eutrophication process of Dutch lakes, which is described as a series of stages between which shifts in community structure including the dominant piscivorous fish species occurred. Furthermore, based on the framework some predictions and methods for ecological rehabilitation will be presented.
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Nemirovskaya, I. A. "Content and composition of organic compounds in separate lakes in Antarctica and the Arctic." Arctic and Antarctic Research, no. 4 (December 30, 2017): 76–85. http://dx.doi.org/10.30758/0555-2648-2017-0-4-76-85.
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The results of long-term studies of organic compounds in separated water bodies in two regions: Lake Stepped, Prydz Bay, Commonwealth Sea, (Antarctica) and lakes of the periphery of the Kandalaksha Gulf of the White Sea (the Arctic) are presented. It is established that the eutrophication of these reservoirs largely depends on the connection of these lakes with the sea. Coastal anthropogenic activity affects to a lesser extent. The restoration of the ecosystem of these lakes occurs at the launch of sea waters. The greatest differences between organic compounds in the Arctic and Antarctic waters are established in hydrocarbons. In Antarctica, due to the lack of vegetation, alkanes are dominated by autochthonous compounds, and in the Arctic along with autochthonous, allochthonous.
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Tasnim, Bushra, Xing Fang, Joel S. Hayworth, and Di Tian. "Simulating Nutrients and Phytoplankton Dynamics in Lakes: Model Development and Applications." Water 13, no. 15 (2021): 2088. http://dx.doi.org/10.3390/w13152088.
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Due to eutrophication, many lakes require periodic management and restoration, which becomes unpredictable due to internal nutrient loading. To provide better lake management and restoration strategies, a deterministic, one-dimensional water quality model MINLAKE2020 was modified from daily MINLAKE2012 by incorporating chlorophyll-a, nutrients, and biochemical oxygen demand models into the regional year-around temperature and dissolved oxygen (DO) model. MINLAKE2020 was applied to six lakes (varying depth and trophic status) in Minnesota focusing on studying the internal nutrient dynamics. The average root-mean-square errors (RMSEs) of simulated water temperature and DO in six lakes are 1.51 °C and 2.33 mg/L, respectively, when compared with profile data over 2–4 years. The average RMSE of DO simulation decreased by 24.2% when compared to the MINLAKE2012 model. The internal nutrient dynamics was studied by analyzing time series of phosphorus, chlorophyll-a, and DO over several years and by performing a sensitivity analysis of model parameters. A long-term simulation (20 years) of Lake Elmo shows that the simulated phosphorus release from sediment under the anoxic condition results in surface phosphorus increase, which matches with the observed trends. An average internal phosphorus loading increase of 92.3 kg/year increased the average daily phosphorus concentration by 0.0087 mg/L.
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Ajeagah, Gideon A., W. Victorien B. Abanda, and George E. Nkeng. "An application of a water assessment and simulation model in the remediation of the eutrophication capacity of a tropical water system: Case study the Lake Obili in Yaounde (Cameroon)." Journal of Water and Land Development 33, no. 1 (2017): 11–22. http://dx.doi.org/10.1515/jwld-2017-0014.
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Abstract Lake Obili is one of the most famous lakes in the city of Yaounde, Cameroon. Studies carried out in this lake showed that it was hyper eutrophic and therefore it represents a great danger because it is used for aquaculture, tourism and a suitable laboratory for hydro-biological engineering. It is thus very vital to restore this lake ecosystem that singles itself in the heart of the city of Yaounde. This can be greatly facilitated through the use of Water Quality Analysis Simulation Program (WASP) of the United State Environmental protection Agency (USEPA). The outcomes of the previous results obtained from EUTRO, a Subroutine of the WASP model specialised in determining eutrophication level have proven that the remediation of this lake can be achievable through the implementation of a wet dredging, the construction and restoration of a wastewater treatment plant, the implementation of environmental incentive policies and the arrangement of the access to the lake. The application of the model is a contribution to the scientific mastery of nutrient flow, lake functioning and possibilities of restauration of highly polluted tropical water bodies subjected to domestic and industrial pollution.
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Dondajewska, Renata, Katarzyna Kowalczewska-Madura, Ryszard Gołdyn, Anna Kozak, Beata Messyasz, and Sławek Cerbin. "Long-Term Water Quality Changes as a Result of a Sustainable Restoration—A Case Study of Dimictic Lake Durowskie." Water 11, no. 3 (2019): 616. http://dx.doi.org/10.3390/w11030616.
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Nature-based solutions in lake restoration enable gradual ecosystem reconstruction without drastic and expensive intervention. Sustainable lake restoration involves limited external interference strong enough to initiate and maintain positive changes in the ecosystem. It was introduced in Lake Durowskie, an urban, flow-through lake situated in Western Poland, using hypolimnetic aeration, phosphorus precipitation with small doses of chemicals and biomanipulation in 2009, and is continued until today. Oxygen conditions in the lake hypolimnion after initial deterioration were gradually improved, and finally a shortening of the duration and range of oxygen deficits was observed. Nitrogen transformations were induced in the hypolimnion by water aeration as well, reducing ammonium N (30% during 2013–2017 in comparison to 2008) and increasing nitrates (90% in 2013–2017 in comparison to 2008). Phosphorus content was diminished (19% during 2015–2017 in relation to 2008 for SRP) due to effective iron-binding and a smaller amount of fresh organic matter being decomposed. Its reduction was related to lower phytoplankton biomass, expressed in a decrease of chlorophyll-a concentrations (55% reduction during 2013–2017 in comparison to 2008) and an increase in water transparency (two-fold during 2013–2017 in relation to 2008) throughout the nine years of treatment. A long-term restoration program, based on non-aggressive, multiple in-lake techniques was applied and, despite the lack of a reduction in total external loading, was able to suppress progressive eutrophication.
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Chang, Manqi, Sven Teurlincx, Jan Janse, Hans Paerl, Wolf Mooij, and Annette Janssen. "Exploring How Cyanobacterial Traits Affect Nutrient Loading Thresholds in Shallow Lakes: A Modelling Approach." Water 12, no. 9 (2020): 2467. http://dx.doi.org/10.3390/w12092467.
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Globally, many shallow lakes have shifted from a clear macrophyte-dominated state to a turbid phytoplankton-dominated state due to eutrophication. Such shifts are often accompanied by toxic cyanobacterial blooms, with specialized traits including buoyancy regulation and nitrogen fixation. Previous work has focused on how these traits contribute to cyanobacterial competitiveness. Yet, little is known on how these traits affect the value of nutrient loading thresholds of shallow lakes. These thresholds are defined as the nutrient loading at which lakes shift water quality state. Here, we used a modelling approach to estimate the effects of traits on nutrient loading thresholds. We incorporated cyanobacterial traits in the process-based ecosystem model PCLake+, known for its ability to determine nutrient loading thresholds. Four scenarios were simulated, including cyanobacteria without traits, with buoyancy regulation, with nitrogen fixation, and with both traits. Nutrient loading thresholds were obtained under N-limited, P-limited, and colimited conditions. Results show that cyanobacterial traits can impede lake restoration actions aimed at removing cyanobacterial blooms via nutrient loading reduction. However, these traits hardly affect the nutrient loading thresholds for clear lakes experiencing eutrophication. Our results provide references for nutrient loading thresholds and draw attention to cyanobacterial traits during the remediation of eutrophic water bodies.
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Tu, Luyao, Paul Zander, Sönke Szidat, Ronald Lloren, and Martin Grosjean. "The influences of historic lake trophy and mixing regime changes on long-term phosphorus fraction retention in sediments of deep eutrophic lakes: a case study from Lake Burgäschi, Switzerland." Biogeosciences 17, no. 10 (2020): 2715–29. http://dx.doi.org/10.5194/bg-17-2715-2020.
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Abstract. Hypolimnetic anoxia in eutrophic lakes can delay lake recovery to lower trophic states via the release of sediment phosphorus (P) to surface waters on short timescales in shallow lakes. However, the long-term effects of hypolimnetic redox conditions and trophic state on sedimentary P fraction retention in deep lakes are not clear yet. Hypolimnetic withdrawal of P-rich water is predicted to diminish sedimentary P and seasonal P recycling from the lake hypolimnion. Nevertheless, there is a lack of evidence from well-dated sediment cores, in particular from deep lakes, about the long-term impact of hypolimnetic withdrawal on sedimentary P retention. In this study, long-term sedimentary P fraction data since the early 1900s from Lake Burgäschi provide information on benthic P retention under the influence of increasing lake primary productivity (sedimentary green-pigment proxy), variable hypolimnion oxygenation regimes (Fe∕Mn ratio proxy), and hypolimnetic withdrawal since 1977. Results show that before hypolimnetic withdrawal (during the early 1900s to 1977), the redox-sensitive Fe∕Mn-P fraction comprised ∼50 % of total P (TP) in the sediment profile. Meanwhile, long-term retention of total P and labile P fractions in sediments was predominantly affected by past hypolimnetic redox conditions, and P retention increased in sedimentary Fe- and Mn-enriched layers when the sediment-overlaying water was seasonally oxic. However, from 1977 to 2017, due to eutrophication-induced persistent anoxic conditions in the hypolimnion and to hypolimnetic water withdrawal increasing the P export out of the lake, net burial rates of total and labile P fractions decreased considerably in surface sediments. By contrast, refractory Ca–P fraction retention was primarily related to lake primary production. Due to lake restoration since 1977, the Ca–P fraction became the primary P fraction in sediments (representing ∼39 % of total P), indicating a lower P bioavailability of surface sediments. Our study implies that in seasonally stratified eutrophic deep lakes (like Lake Burgäschi), hypolimnetic withdrawal can effectively reduce P retention in sediments and potential for sediment P release (internal P loads). However, after more than 40 years of hypolimnetic syphoning, the lake trophic state has not improved nor has lake productivity decreased. Furthermore, this restoration has not enhanced water column mixing and oxygenation in hypolimnetic waters. The findings of this study are relevant regarding the management of deep eutrophic lakes with mixing regimes typical for temperate zones.
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Moyle, Madeleine, and John F. Boyle. "A method for reconstructing past lake water phosphorus concentrations using sediment geochemical records." Journal of Paleolimnology 65, no. 4 (2021): 461–78. http://dx.doi.org/10.1007/s10933-021-00174-0.
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AbstractAn existing steady state model of lake phosphorus (P) budgets has been adapted to allow reconstruction of long-term average historic lake water total phosphorus (TP) concentrations using lake sediment records of P burial. This model can be applied without site-specific parameterisation, thus potentially having universal application. In principle, it is applicable at any site where there is both a sediment P burial record and knowledge of the current water budget, although we advise caution applying it to problematic sediment records. Tested at six published case study sites, modelled lake water TP concentrations agree well with water-quality monitoring data, and limited testing finds good agreement with wholly independent diatom inferred lake water TP. Our findings, together with a review of the literature, suggest that well preserved lake sediments can usefully record a long-term average P burial rate from which the long-term mean lake water TP can be reliably estimated. These lake water TP reconstructions can provide meaningful site-specific reference values to support decision making in lake eutrophication management, including establishing targets for lake restoration.
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Muhammetoğlu, A., H. Muhammetoğlu, and S. Soyupak. "Evaluation of efficiencies of diffuse allochthonous and autochthonous nutrient input control in restoration of a highly eutrophic lake." Water Science and Technology 45, no. 9 (2002): 195–203. http://dx.doi.org/10.2166/wst.2002.0238.
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Mogan Lake is an important recreational area for Metropolitan Ankara-Turkey. It is a shallow eutrophic lake with a dense growth of macrophytes. The main contributors of nutrients and other pollutants to the lake are the creeks carrying the runoff water from the watershed and upland farming land, in addition to the domestic and industrial wastewater discharges from a nearby town and industries. Hydrodynamic and water quality modeling techniques were used to determine the optimum management schemes for the lake restoration and diffuse pollution control. Management scenarios were devised and tested to control allochthonous and autochthonous nutrient inputs to the lake. Phosphorus and nitrogen load reductions were the main test elements for the control of allochthonous nutrient inputs. The scenario analysis revealed that reduction of phosphorus and nitrogen loads from diffused sources will have a marginal effect on controlling eutrophication if macrophyte growth is left uncontrolled. Scenarios employing macrophyte harvesting and sediment dredging have been evaluated for autochthonous nutrient input control. Sediment dredging alone has been shown to yield the most favorable conditions for water quality improvement in Mogan Lake. Further, control of diffuse pollution was an essential final step to achieve an acceptable long-term sustainable water quality improvement in the lake.
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Taipale, S. J., K. Kuoppamäki, U. Strandberg, E. Peltomaa, and K. Vuorio. "Lake restoration influences nutritional quality of algae and consequently Daphnia biomass." Hydrobiologia 847, no. 21 (2020): 4539–57. http://dx.doi.org/10.1007/s10750-020-04398-5.
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AbstractFood quality is one of the key factors influencing zooplankton population dynamics. Eutrophication drives phytoplankton communities toward the dominance of cyanobacteria, which means a decrease in the availability of sterols and long-chain polyunsaturated fatty acids (EPA and DHA). The effects of different restoration measures on the nutritional quality of the phytoplankton community and subsequent impacts on zooplankton biomass have rarely been considered. We analyzed the nutritional quality of phytoplankton in the eutrophic Lake Vesijärvi in southern Finland over a 37-year period, and studied the impacts of two restoration measures, biomanipulation and hypolimnetic aeration, on the abundance of high-quality phytoplankton. We found that biomanipulation had a positive impact on the abundance of taxa synthesizing sterols, EPA, and DHA and, concurrently, on the biomass of the keystone species Daphnia. In contrast, hypolimnetic aeration did not result in such a beneficial outcome, manifested as a decrease in the abundance of Daphnia and frequent phytoplankton blooms dominated by cyanobacteria suggesting reduction in the nutritional quality of food for Daphnia. Our analysis shows that the determination of the nutritional value of algae and the contribution of essential fatty acids and sterols is an effective method to evaluate the success of various restoration measures.
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Qin, Chengxin, Zhiyi Li, Pengcheng Xie, et al. "Temporal Variation and Reduction Strategy of Nutrient Loads from an Urban River Catchment into a Eutrophic Lake, China." Water 11, no. 1 (2019): 166. http://dx.doi.org/10.3390/w11010166.
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Excessive nutrient input from urban areas increases the occurrence of eutrophication. Control of nutrient loads is perceived as the primary restoration method. Quantifying temporal variation of nutrient loads is essential to understand the dynamic relationships of nutrient source-impacts in the urban water system and investigate the operational efficiency of treatment facilities for eutrophication control. Here, a holistic approach was developed to estimate nutrient loads from different sources and evaluate nutrient impacts on the urban water environment. An integrated catchment model of nutrient loads was built and applied to calculate river nutrient loads from untreated rainfall runoff, untreated sewage, and treated recharge into the eutrophic Dianchi Lake from an urban river catchment with limited infrastructure. Nutrient impacts on the lake were evaluated and a load reduction strategy was given a hint to reduce nutrient impacts of urban rivers. During the study period 2014–2016, nutrient loads from the urban river generally decreased except during heavy winter rainfall events and high-intensity pollution events associated with rainfall runoff. The average contribution of annual nutrient loads to the lake capacity indicated the underestimation of nutrient impacts of urban rivers. This approach provides new insights into urban water management and underscores the importance of sewage infrastructure.
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Xie, Fazhi, Kang Song, Shixiong Geng, and Lu Li. "Phosphate sequestration and recovery from eutrophication water by in situ magnesium phosphate formation." Water Supply 20, no. 6 (2020): 2226–36. http://dx.doi.org/10.2166/ws.2020.123.
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Abstract Phosphate removal from eutrophic lakes has caused wide concern in the world, while an effective process is still lacking. A novel synthetic magnesium carbonate with spherical flower-like structure (MCSF) was prepared. Its performance for phosphorus adsorption from a eutrophic lake by in situ magnesium phosphate formation was tested and characterized. The effect of initial phosphorus concentration, adsorption time, adsorption dose, temperature, ionic strength and pH on phosphorus adsorption by MCSF was investigated. Results showed that higher initial phosphorus concentration and longer adsorbing time could improve the adsorption capacity. The maximum sorption capacity was 143.27 mg/g under initial pH value 7.0. The phosphate adsorption process was fitted with the Langmuir isotherm model and pseudo-second-order model. Thermodynamic parameter values revealed that the sorption process at 298–318 K was spontaneous and endothermic. The X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) characterization of MCSF revealed that electrostatic attraction and chemical conversion were the major contributors for phosphate adsorption. MCSF releases magnesium ions from its surface and rapidly combines with phosphate to form insoluble magnesium phosphate precipitate. The prepared MCSF has the potential to be used for the restoration of eutrophic lakes by removing phosphate with higher adsorption capacity.
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Pan, Gang, Xiaojun Miao, Lei Bi, et al. "Modified Local Soil (MLS) Technology for Harmful Algal Bloom Control, Sediment Remediation, and Ecological Restoration." Water 11, no. 6 (2019): 1123. http://dx.doi.org/10.3390/w11061123.
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Harmful algal blooms (HABs), eutrophication, and internal pollutant sources from sediment, represent serious problems for public health, water quality, and ecological restoration worldwide. Previous studies have indicated that Modified Local Soil (MLS) technology is an efficient and cost-effective method to flocculate the HABs from water and settle them onto sediment. Additionally, MLS capping treatment can reduce the resuspension of algae flocs from the sediment, and convert the algal cells, along with any excessive nutrients in-situ into fertilisers for the restoration of submerged macrophytes in shallow water systems. Furthermore, the capping treatment using oxygen nanobubble-MLS materials can also mitigate sediment anoxia, causing a reduction in the release of internal pollutants, such as nutrients and greenhouse gases. This paper reviews and quantifies the main features of MLS by investigating the effect of MLS treatment in five pilot-scale whole-pond field experiments carried out in Lake Tai, South China, and in Cetian Reservoir in Datong city, North China. Data obtained from field monitoring showed that the algae-dominated waters transform into a macrophyte-dominated state within four months of MLS treatment in shallow water systems. The sediment-water nutrient fluxes were substantially reduced, whilst water quality (TN, TP, and transparency) and biodiversity were significantly improved in the treatment ponds, compared to the control ponds within a duration ranging from one day to three years. The sediment anoxia remediation effect by oxygen nanobubble-MLS treatment may further contribute to deep water hypoxia remediation and eutrophication control. Combined with the integrated management of external loads control, MLS technology can provide an environmentally friendly geo-engineering method to accelerate ecological restoration and control eutrophication.
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Zhang, Peng, Rui-Feng Liang, Peng-Xiao Zhao, et al. "The Hydraulic Driving Mechanisms of Cyanobacteria Accumulation and the Effects of Flow Pattern on Ecological Restoration in Lake Dianchi Caohai." International Journal of Environmental Research and Public Health 16, no. 3 (2019): 361. http://dx.doi.org/10.3390/ijerph16030361.
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Due to rapid increases in socioeconomic development and the human population over the past few decades, the shallow lakes in China have suffered from eutrophication and poor water quality. The conditions in Lake Dianchi Caohai, which is in the northern part of Lake Dianchi, are considered the most serious. The ecological restoration of Lake Dianchi Caohai began in the late 1980s. Lake managers and the public have been puzzled by the lack of a significant response of the water quality to the flow pattern despite the tremendous investment in water quality improvements. Therefore, lake managers desperately need to understand the responses of pollutant behaviors to proposed management measures. In this paper, a depth-averaged two-dimensional hydrodynamic and water quality model based on hydrological data, measured lake bed elevation, and water quality data is developed to simulate the flow field and water quality of Lake Dianchi Caohai. This model was validated using water quality data from the Caohaizhongxin site in 2016, and a close agreement was found between the model results and observations. Wind-driven circulation in Lake Dianchi Caohai was observed in the model results, which revealed that the lake flow pattern was dominated by wind-driven circulation, while the inflow/outflow played only a subsidiary role during this period. The formation of the wind-driven current in Lake Dianchi Caohai could be roughly divided into three stages. The hydrodynamic processes connected with the distribution of chlorophyll a are evaluated and discussed to adequately understand the hydraulic mechanisms driving the accumulation of cyanobacteria. Moreover, we designed three scenarios after comparing all possible operation scenarios to analyze the contributions of each different operation scenario to the water quality improvements. The optimal ecological operation scenario which has the best impacts on the water quality, especially the reduction in Chla and NH3-N concentration, is proposed based on our comprehensive analysis. The water quality improvement and management suggestions proposed in this paper are based on lake flow patterns and make up for previous studies that did not consider the effects of hydraulic characteristics on water quality improvement in Lake Dianchi Caohai.
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Arnoux, Marie, Florent Barbecot, Elisabeth Gibert-Brunet, John Gibson, and Aurélie Noret. "Impacts of changes in groundwater recharge on the isotopic composition and geochemistry of seasonally ice-covered lakes: insights for sustainable management." Hydrology and Earth System Sciences 21, no. 11 (2017): 5875–89. http://dx.doi.org/10.5194/hess-21-5875-2017.
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Abstract. Lakes are under increasing pressure due to widespread anthropogenic impacts related to rapid development and population growth. Accordingly, many lakes are currently undergoing a systematic decline in water quality. Recent studies have highlighted that global warming and the subsequent changes in water use may further exacerbate eutrophication in lakes. Lake evolution depends strongly on hydrologic balance, and therefore on groundwater connectivity. Groundwater also influences the sensitivity of lacustrine ecosystems to climate and environmental changes, and governs their resilience. Improved characterization of groundwater exchange with lakes is needed today for lake preservation, lake restoration, and sustainable management of lake water quality into the future. In this context, the aim of the present paper is to determine if the future evolution of the climate, the population, and the recharge could modify the geochemistry of lakes (mainly isotopic signature and quality via phosphorous load) and if the isotopic monitoring of lakes could be an efficient tool to highlight the variability of the water budget and quality. Small groundwater-connected lakes were chosen to simulate changes in water balance and water quality expected under future climate change scenarios, namely representative concentration pathways (RCPs) 4.5 and 8.5. Contemporary baseline conditions, including isotope mass balance and geochemical characteristics, were determined through an intensive field-based research program prior to the simulations. Results highlight that future lake geochemistry and isotopic composition trends will depend on four main parameters: location (and therefore climate conditions), lake catchment size (which impacts the intensity of the flux change), lake volume (which impacts the range of variation), and lake G index (i.e., the percentage of groundwater that makes up total lake inflows), the latter being the dominant control on water balance conditions, as revealed by the sensitivity of lake isotopic composition. Based on these model simulations, stable isotopes appear to be especially useful for detecting changes in recharge to lakes with a G index of between 50 and 80 %, but response is non-linear. Simulated monthly trends reveal that evolution of annual lake isotopic composition can be dampened by opposing monthly recharge fluctuations. It is also shown that changes in water quality in groundwater-connected lakes depend significantly on lake location and on the intensity of recharge change.
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Zhengwen, LIU, ZHANG Xiufeng, CHEN Feizhou, et al. "The responses of the benthic-pelagic coupling to eutrophication and regime shifts in shallow lakes: Implication for lake restoration." Journal of Lake Sciences 32, no. 1 (2020): 1–10. http://dx.doi.org/10.18307/2020.0101.
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Straškraba, Milan. "Ecotechnological methods for managing non-point source pollution in watersheds, lakes and reservoirs." Water Science and Technology 33, no. 4-5 (1996): 73–80. http://dx.doi.org/10.2166/wst.1996.0490.
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Ecotechnological methods are considered those using technological means for environmental management in a way to minimize the harm to the global environment. Three reasons to use ecotechnological methods are given: they are cheap, minimize the use of raw materials and protect the global environment. In the article the most cost-efficient and environmentally friendly ecotechnologies for non-point source pollution management are given. These are divided into two categories: those done in the watershed and those used within the lake or reservoir. In the first category wetland use, restoration and construction is shown to efficiently reduce different kinds of pollution. The construction of small pre-impoundments is effective for trapping phosphorus as the main cause of eutrophication. In the category of in-lake approaches several are mentioned: biomanipulation or food web manipulation leading to decreased eutrophication, many approaches of mixing and aeration based on recent limnological knowledge, selective withdrawal as a manipulation of outflow and drinking water intake depths in reservoirs, the diversion of polluted inflow waters and sucking of hypolimnion waters. The limitations of the methods are given. Mathematical models helpful in optimizing the use of the corresponding methods are shown.
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Silvino, RF, and FAR Barbosa. "Eutrophication potential of lakes: an integrated analysis of trophic state, morphometry, land occupation, and land use." Brazilian Journal of Biology 75, no. 3 (2015): 607–15. http://dx.doi.org/10.1590/1519-6984.18913.
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AbstractDespite being inside a protected area, Lake Sumidouro has been impacted by the anthropogenic occupation of the surrounding area since the 1970’s, compromising the ecological integrity of the lake and the sustainable use of natural resources. This study examined the current trophic classification of the lake and developed methods for improving it through an integrated analysis of morphometric and limnological parameters, land use and land occupation in the watershed, and eutrophication potential. Data for the limnological parameters, land use and land occupation, and morphometric characteristics of Lake Sumidouro were collected in the rainy and dry seasons of 2009 and 2010. Depending on the trophic classification system used, Lake Sumidouro is classified as oligotrophic to hypereutrophic. In our study, the highest concentration of nutrients occurred in the rainy season, indicating that high nutrient inputs played an important role during this period. Areas of anthropogenic occupation comprised approximately 62.9% of the total area of the watershed, with pasture and urban settlement as the main types of land use. The influent total phosphorus load was estimated to be 15,824.3 kg/year. To maintain mesotrophic conditions, this load must be reduced by 29.4%. By comparing the isolated use of trophic state indices, this study demonstrated that comparing the trophic state classification with morphometric analyses, land use and land occupation types in the watershed, and potential phosphorus load provided better information to guide management actions for restoration and conservation. Furthermore, this approach also allowed for evaluating the vulnerability of the environment to the eutrophication process.
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Lin, Zhenmei, Chen Zhong, Guolong Yu, et al. "Effects of Sediments Phosphorus Inactivation on the Life Strategies of Myriophyllum spicatum: Implications for Lake Restoration." Water 13, no. 15 (2021): 2112. http://dx.doi.org/10.3390/w13152112.
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Eutrophication often results in the loss of submerged vegetation in shallow lakes and turns the lake to be a turbid state. Recovery of submerged macrophytes is the key in the restoration of shallow eutrophic lakes to create a clear water state. However, internal loading control was considered as the critical process for the recovery of submerged macrophytes in shallow lakes after the external nutrient reduction. Phoslock® (Lanthanum modified bentonite) is a useful passivation material in controlling the internal loadings (release of phosphorus from the sediments), which was applied to restore the eutrophic lakes. However, the effects of Phoslock® on the growth and life strategies of submerged macrophytes are less focused so far. In the present study, we studied the responses in the growth and morphological characteristics of Myriophyllum spicatum to the addition of Phoslock® to the sediments. Our results showed that the addition of Phoslock® significantly decreased the contents of bioavailable forms of phosphorus in the sediments, such as redox-sensitive phosphorus bound to Fe and Mn compounds (BD–P), phosphorus bound to aluminum (Al–P) and organic phosphorus (Org–P). However, the concentration of the non-bioavailable forms of phosphorus in the sediments, such as calcium bound phosphorus (Ca–P), increased significantly in the Phoslock® treatments compared with the controls. At the end of the experiments, the total biomass, aboveground biomass and relative growth rate (RGR) of M. spicatum decreased significantly in the Phoslock® mesocosms compared with the controls. In contrast, the wet root biomass, root–shoot biomass ratio, root numbers and root length of M. spicatum were significantly higher in the Phoslock® treatments than that in the controls. Our results indicated that the growth of M. spicatum was suppressed by the addition of Phoslock®, and thus the biomass was decreased; however, the increase of root biomass might be beneficial to the inhibition of phosphorus release and resuspension of sediments and to the restoration of the lake ecosystem.
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Osuch, Ewa, Andrzej Osuch, Piotr Rybacki, and Andrzej Przybylak. "Analysis of the Theoretical Performance of the Wind-Driven Pulverizing Aerator in the Conditions of Góreckie Lake—Maximum Wind Speed Method." Energies 13, no. 2 (2020): 502. http://dx.doi.org/10.3390/en13020502.
Full textAbstract:
The eutrophication of surface waters is a natural process; however, anthropogenic activities significantly accelerate degradation processes. Most lakes in Poland and in the world belong to the poor and unsatisfactory water quality class. It is therefore necessary to limit negative anthropogenic impacts and introduce restoration methods, in particular those that are safe for the aquatic ecosystem. One of these is a pulverizing aeration Podsiadłowski method that uses only wind energy. The method allows for the moderate oxygenation of hypolimnion water, which maintains the oxygen conditions in the overlying water zone in the range of 0–1 mg O2·dm-1. The purpose of the work was to develop a new method of determining the efficiency of the aerator pulverization unit in the windy conditions of the lake. The method consists in determining the volumetric flow rates of water in the aerator pulverization unit, based on maximum hourly wind speeds. The pulverization efficiency in the conditions of Góreckie Lake was determined based on 6600 maximum hourly wind speeds in 2018. Based on the determined model, the theoretical performance of the machine was calculated, which in the conditions of Góreckie Lake in 2018 amounted to less than 79,000 m3 per year (nine months of the effective aerator operation).
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Braig, Emanuel, Christoph Mayr, Gerald Kirchner, Andrea Hofmann, Uta Raeder, and Arnulf Melzer. "Fifty years of eutrophication and lake restoration reflected in sedimentary carbon and nitrogen isotopes of a small, hardwater lake (south Germany)." Journal of Limnology 72, no. 2 (2013): 21. http://dx.doi.org/10.4081/jlimnol.2013.e21.
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Galvez-Cloutier, Rosa, Sumathi K. M. Saminathan, Clotilde Boillot, Gaëlle Triffaut-Bouchet, Alexandre Bourget, and Gabriel Soumis-Dugas. "An Evaluation of Several In-Lake Restoration Techniques to Improve the Water Quality Problem (Eutrophication) of Saint-Augustin Lake, Quebec, Canada." Environmental Management 49, no. 5 (2012): 1037–53. http://dx.doi.org/10.1007/s00267-012-9840-7.
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Zhang, Yuan, Pingping Luo, Shuangfeng Zhao, et al. "Control and remediation methods for eutrophic lakes in the past 30 years." Water Science and Technology 81, no. 6 (2020): 1099–113. http://dx.doi.org/10.2166/wst.2020.218.
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Abstract Accelerated eutrophication, which is harmful and difficult to repair, is one of the most obvious and pervasive water pollution problems in the world. In the past three decades, the management of eutrophication has undergone a transformation from simple directed algal killing, reducing endogenous nutrient concentration to multiple technologies for the restoration of lake ecosystems. This article describes the development and revolution of three remediation methods in application, namely physical, chemical, and biological methods, and it outlines their possible improvements and future directions. Physical and chemical methods have obvious and quick effects to purify water in the short term and are more suitable for small-scale lakes. However, these two methods cannot fundamentally solve the eutrophic water phenomenon due to costly and incomplete removal results. Without a sound treatment system, the chemical method easily produces secondary pollution and residues and is usually used for emergency situations. The biological method is cost-effective and sustainable, but needs a long-term period. A combination of these three management techniques can be used to synthesize short-term and long-term management strategies that control current cyanobacterial blooms and restore the ecosystem. In addition, the development and application of new technologies, such as big data and machine learning, are promising approaches.
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Boers, P. C. M., W. Van Raaphorst, and D. T. Van der Molen. "Phosphorus retention in sediments1." Water Science and Technology 37, no. 3 (1998): 31–39. http://dx.doi.org/10.2166/wst.1998.0169.
Full textAbstract:
Phosphate is usually the most important growth limiting nutrient in aquatic environments. The availability of P is the result of external load and retention in the sediments. This latter is the result of a number of transport, microbial and chemical processes. The role of P in the productivity in systems and in the eutrophication process has initiated a large number of studies to the behaviour of P in sediments. Case studies in Veluwemeer, IJsselmeer, Wadden Sea and German Bight show that sorption on and binding in ferric (oxi)hydroxides, occlusion in calcium carbonates and authigenic mineral formation are the most important retention processes. However, all this research did not result in totally new approaches in lake restoration, nor did knowledge of internal P loading result in large scale applications of well-known sediment restoration techniques. It did result in more realistic expectations of lake restoration programmes. At the same time, renewed interest in the overall role of phosphate in the functioning and productivity of systems is emerging. The most important new items are: the role of the productivity is examined at large scale levels; the coupling of productivity with several large scale material cycles and global environmental problems and the study of the behaviour and fate of phosphate within the context of the functioning of entire watersheds.