scholarly journals Exploring How Cyanobacterial Traits Affect Nutrient Loading Thresholds in Shallow Lakes: A Modelling Approach

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2467 ◽  
Author(s):  
Manqi Chang ◽  
Sven Teurlincx ◽  
Jan Janse ◽  
Hans Paerl ◽  
Wolf Mooij ◽  
...  

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.

2017 ◽  
Vol 77 (5) ◽  
pp. 1186-1195 ◽  
Author(s):  
Fei Zhong ◽  
Wei Liu ◽  
Mengdan Lv ◽  
Zifa Deng ◽  
Juan Wu ◽  
...  

Abstract Eutrophication often leads to the periodic proliferation of harmful cyanobacterial blooms (HCBs), which threaten the sustainability of freshwater ecosystems and lead to serious environmental, health and economic damage. Hence, it is vitally important to take effective measures to manage HCBs and associated problems. In this study, vertical flow constructed wetlands (CWs) were operated under different hydraulic loading rates (HLRs) to treat a hyper-eutrophic water body with HCBs. Six sampling ports (representing different layers) were evenly distributed along the water flow direction to study the purification processes of CWs. With HLRs ranging from 0.2 m/d to 0.8 m/d, total nitrogen (TN), total phosphorus (TP), COD, total suspended solid (TSS) and Chlorophyll a (Chl.a) were efficiently treated by CWs, and they were mainly removed at the second layer of CWs. The concentrations of two cyanobacterial metabolites (geosmin and β-cyclocitral) in the effluent were mostly below their odorous threshold concentrations. As the HLRs increased, the treatment efficiencies of the CWs decreased gradually. There was no removal of TP, Chl.a, geosmin, or β-cyclocitral at an HLR of 1.0 m/d. Under suitable HLRs, this type of CW could provide a promising way to control HCBs and associated odorous problems in hyper-eutrophic water bodies.


2021 ◽  
Author(s):  
Aimin Hao ◽  
Qi Mi ◽  
Kai He ◽  
Dong Xia ◽  
Bingjun Liu ◽  
...  

Abstract In this study, laboratory experiments were used to compare the effects of two LED light sources (blue and red) combined with fiber membranes on the increase of Dissolved Oxygen (DO) in eutrophic water bodies for improvement of water quality. The results showed that the application of these two LED light sources can increase the DO concentration and oxidation-reduction potential (ORP), and eliminate the NH4+-N in water bodies and the phosphorus release from the sediment, resulting in the improvement of sediment. Specifically, the blue LED light source is more benefitable to the increase of the DO concentration than the red LED light source. After 28 days, the DO concentration increases to 10 mg/L, and the redox potential is higher than 50 mV with the elimination of NH4+-N. This study illustrated that LED light sources can significantly increase the DO and effectively improve the water quality in eutrophic water bodies.


2019 ◽  
Vol 55 (5) ◽  
pp. 100-106
Author(s):  
Ye. N. Volkova ◽  
V. V. Belyayev ◽  
S. P. Prishlyak ◽  
A. A. Parkhomenko

Author(s):  
I. Saakian ◽  
Aleksandr, Grigor’ev ◽  
E. Kravets ◽  
E. Rudakov ◽  
A. Faddeev ◽  
...  

Выполнен анализ действующей редакции Методики разработки нормативов допустимых сбросов веществ и микроорганизмов в водные объекты для водопользователей , утвержденной приказом Минприроды России от 17 декабря 2007 г. 333, на предмет непротиворечивости и соответствия нормам водоохранного законодательства. Выявлена неопределенность применения Методики в условиях воздействия на качество воды природных и антропогенных факторов, не зависящих от конкретного водопользователя. Положения Методики противоречат принципам нормирования воздействия на водные объекты на основе наилучших доступных технологий, что было показано на примерах утвержденных технологических показателей содержания загрязняющих веществ в сточных водах различных отраслей промышленности. Анализ системы нормирования допустимых воздействий на водные объекты и географической дифференциации нормативов качества воды в пределах Российской Федерации вместе с системой целевых показателей качества воды также показал несоответствие Методики основным принципам водоохранного законодательства.The analysis of the current edition of the Methods of developing standards for permissible discharges of substances and microorganisms into water bodies for water users , approved by the Order of the Ministry of Natural Resources of Russia dated December 17, 2007 No. 333 for consilience and compliance with the regulations of the water protection legislation, is carried out. Uncertainty of the application of the Methods in the conditions of the impact of natural and anthropogenic factors that are independent of a specific water user on the quality of water has been identified. The provisions of the Methods contradict the principles of regulating the impact on water bodies based on the best available technologies shown on the examples of approved process indicators of the concentrations of various industrial pollutants in wastewater. An analysis of the system of regulating the permissible impact on water bodies and the geographical differentiation of water quality standards within the boundaries of the Russian Federation, together with the system of water quality targets, also showed that the Methods do not comply with the basic principles of the water protection legislation.


1991 ◽  
Vol 23 (1-3) ◽  
pp. 1-10 ◽  
Author(s):  
Takeshi Goda

The management and status of public water bodies in Japan is discussed. The environmental quality standards which have been set and the levels of compliance with these standards are shown. The water quality of Japanese rivers, lakes, reservoirs, wetlands and coastal waters is described, and eutrophication problems are mentioned. The effects of changes in population density and levels of recycling of industrial wastewaters on the quality of water bodies are discussed. Almost 75% of industrial wastewater is now recycled. Per capita availability of freshwater in Japan is comparatively low, and the construction of 530 dams, in addition to the 2393 dams already in operation, is planned. Irrigation effluents from paddy fields are a major factor which influences river water quality in Japan. The improvement of water quality using various methods is discussed.


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