Impact of cyanobacterial bloom on microbiomes of freshwater lakes

Urban freshwater lakes play an indispensable role in maintaining the urban environment and are suffering great threats of eutrophication. Until now, little has been known about the seasonal bacterial communities of the surface water of adjacent freshwater urban lakes. This study reported the bacterial communities of three adjacent freshwater lakes (i.e., Tangxun Lake, Yezhi Lake and Nan Lake) during the alternation of seasons. Nan Lake had the best water quality among the three lakes as reflected by the bacterial eutrophic index (BEI), bacterial indicator (Luteolibacter) and functional prediction analysis. It was found that Alphaproteobacteria had the lowest abundance in summer and the highest abundance in winter. Bacteroidetes had the lowest abundance in winter, while Planctomycetes had the highest abundance in summer. N/P ratio appeared to have some relationships with eutrophication. Tangxun Lake and Nan Lake with higher average N/P ratios (e.g., N/P = 20) tended to have a higher BEI in summer at a water temperature of 27 °C, while Yezhi Lake with a relatively lower average N/P ratio (e.g., N/P = 14) tended to have a higher BEI in spring and autumn at a water temperature of 9–20 °C. BEI and water temperature were identified as the key parameters in determining the bacterial communities of lake water. Phosphorus seemed to have slightly more impact on the bacterial communities than nitrogen. It is expected that this study will help to gain more knowledge on urban lake eutrophication.

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Occurrence of a single-species cyanobacterial bloom in a lake in Cyprus: monitoring and treatment with hydrogen peroxide-releasing granules

Environmental Sciences Europe ◽

10.1186/s12302-021-00471-5 ◽

2021 ◽

Vol 33 (1) ◽

Author(s):

Eleni Keliri ◽

Christia Paraskeva ◽

Angelos Sofokleous ◽

Assaf Sukenik ◽

Dariusz Dziga ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Harmful Algal Blooms ◽

Algal Blooms ◽

Animal Health ◽

Cyanobacterial Bloom ◽

Single Species ◽

Eutrophic Lake ◽

Liquid Hydrogen ◽

Bioactive Metabolites ◽

Forest Park

AbstractBackgroundExcess loads of nutrients finding their way into waterbodies can cause rapid and excessive growth of phytoplankton species and lead to the formation of cyanobacterial harmful algal blooms (cyano-HABs). Toxic cyanobacteria produce a broad range of bioactive metabolites, some of which are known as cyanotoxins. These metabolites can negatively impact the ecosystem, and human and animal health, thus their presence needs to be closely monitored and mitigated. This study aimed to monitor St. George Lake (Athalassa National Forest Park, Cyprus) for its water quality characteristics, and initiate a new methodology to control the bloom that occurred in the lake during summer 2019, by comparing hydrogen peroxide treatment with novel metallic peroxide granules as source of hydrogen peroxide.ResultsLake monitoring showed that pH, salinity, total dissolved solids and conductivity varied throughout the year, and nutrients concentration was high, indicating a eutrophic lake. The cyanobacteriumMerismopediasp. bloomed in the lake between June and September 2019, comprising up to 99% of the phytoplankton biovolume. The presence of microcystin synthase encoding gene (mcyB, mcyE) was documented, however microcystins were not detected by tandem mass spectroscopy. Treatment with liquid hydrogen peroxide in concentrations 1 to 5 mg L−1had no effect on the phycocyanin fluorescence (Ft) and quantum yield of PSII (Fv/Fm) indicating an ineffective treatment for the denseMerismopediabloom (1 million cells mL−1 ± 20%). Metallic peroxide granules tested for their H2O2releasing capacity in St. George Lake water, showing that CaO2released higher H2O2concentration and therefore have better mitigation efficiency than MgO2granules.ConclusionThe present study highlights the importance of monitoring several water parameters to conclude on the different actions to be taken to limit eutrophication in the catchment area. The findings demonstrated that testing for the presence of genes involved in cyanotoxin production may not be sufficient to follow cyanotoxins in the water, therefore it should be accompanied with analytical confirmation. Treatment experiments indicated that slow release of H2O2from peroxide granules may be an alternative to liquid hydrogen peroxide when applied in appropriate doses, but further investigation is needed before it is applied at the field.Graphic Abstract

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Contributions of external nutrient loading and internal cycling to cyanobacterial bloom dynamics in Lake Taihu, China: Implications for nutrient management

Limnology and Oceanography ◽

10.1002/lno.11700 ◽

2021 ◽

Vol 66 (4) ◽

pp. 1492-1509

Author(s):

Hai Xu ◽

Mark J. McCarthy ◽

Hans W. Paerl ◽

Justin D. Brookes ◽

Guangwei Zhu ◽

...

Keyword(s):

Nutrient Loading ◽

Nutrient Management ◽

Lake Taihu ◽

Cyanobacterial Bloom ◽

External Nutrient ◽

Internal Cycling

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Nutrients and phytoplankton in three shallow, freshwater lakes of different tropic status in Western Australia

Marine and Freshwater Research ◽

10.1071/mf9810541 ◽

1981 ◽

Vol 32 (4) ◽

pp. 541 ◽

Cited By ~ 14

Author(s):

DM Gordon ◽

CM Finlayson ◽

AJ McComb

Keyword(s):

Green Algae ◽

Western Australia ◽

Organic Phosphorus ◽

Environmental Parameters ◽

Strongly Correlated ◽

Freshwater Lakes ◽

Nitrogen And Phosphorus ◽

Water Conductivity ◽

Blue Green Algae ◽

Nitrogen Concentrations

The trophic status of three shallow, freshwater lakes on the Swan coastal plain near Perth, Western Australia, was assessed from February 1975 to January 1976. Loch McNess is in a National Park, Lake Joondalup is in an area becoming urbanized, and Lake Monger is in a suburb near the centre of Perth. Monthly measurements were made of phytoplankton numbers and environmental parameters, including forms of nitrogen and phosphorus. Populations tended to be high when lake levels were low. Phytoplankton numbers were dominated by blue-green 'algae' in summer in each lake, with the lowest numbers in Loch McNess. Green algae were most prominent in autumn and winter. Diatoms were present at relatively lower numbers throughout the year. Phytoplankton numbers were strongly correlated with phosphorus levels, particularly for blue-green algae, and less so with nitrogen. Green algae were also strongly correlated with water conductivity. Nearly 80% of variance in phytoplankton numbers was accounted for in multiple linear regression by temperature, sunlight hours, depth, pH, conductivity and phosphate, organic phosphorus, ammonia, nitrate-nitrite, and organic nitrogen concentrations. Much of the variance was accounted for by the nutrients alone. Comparisons with data in the literature suggest that Lakes Joondalup and Monger are eutrophic by world standards, and are far more eutrophic than Loch McNess.

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