Internal loop sustains cyanobacterial blooms in eutrophic lakes: Evidence from organic nitrogen and ammonium regeneration

Cyanobacterial blooms occur in many parts of the world as a result of entirely natural causes or human activity. Due to their negative effects on water resources, efforts are made to monitor cyanobacteria dynamics. This study discusses the contribution of remote sensing methods for mapping cyanobacterial blooms in lakes in northern Italy. Semi-empirical approaches were used to flag scum and cyanobacteria and spectral inversion of bio-optical models was adopted to retrieve chlorophyll-a (Chl-a) concentrations. Landsat-8 OLI data provided us both the spatial distribution of Chl-a concentrations in a small eutrophic lake and the patchy distribution of scum in Lake Como. ENVISAT MERIS time series collected from 2003 to 2011 enabled the identification of dates when cyanobacterial blooms affected water quality in three small meso-eutrophic lakes in the same region. On average, algal blooms occurred in the three lakes for about 5 days a year, typically in late summer and early autumn. A suite of hyperspectral sensors on air- and space-borne platforms was used to map Chl-a concentrations in the productive waters of the Mantua lakes, finding values in the range of 20 to 100 mgm-3. The present findings were obtained by applying state of the art of methods applied to remote sensing data. Further research will focus on improving the accuracy of cyanobacteria mapping and adapting the algorithms to the new-generation of satellite sensors.

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Effects of Cyanobacteria on Phosphorus Cycling and Other Aquatic Organisms in Simulated Eutrophic Ecosystems

Water ◽

10.3390/w12082265 ◽

2020 ◽

Vol 12 (8) ◽

pp. 2265

Author(s):

Peng Gu ◽

Qi Li ◽

Hao Zhang ◽

Xin Luo ◽

Weizhen Zhang ◽

...

Keyword(s):

Nutrient Management ◽

Lake Taihu ◽

Cyanobacterial Bloom ◽

Aquatic Organisms ◽

Pilot Scale ◽

Freshwater Ecosystems ◽

Cyanobacterial Blooms ◽

Eutrophic Lakes ◽

P Concentration ◽

Bloom Formation

Cyanobacterial blooms caused by eutrophication in Lake Taihu have led to ecological threats to freshwater ecosystems. A pilot scale experiment was implemented to investigate the relationship between cyanobacteria and other aquatic plants and animals in simulated eutrophic ecosystems under different phosphorus (P) regimes. The results of this study showed that cyanobacteria had two characteristics favorable for bloom formation in eutrophic ecosystems. One is the nutrient absorption. The presence of alkaline phosphatase was beneficial for algal cells in nutrition absorption under low P concentration. Cyanobacteria exhibited a stronger ability to absorb and store P compared to Vallisneria natans, which contributed to the fast growth of algal cells between 0.2 and 0.5 mg·L−1 of P (p < 0.05). However, P loads affected only the maximum biomass, but not the growth phases. The growth cycle of cyanobacteria remained unchanged and was not related to P concentration. P cycling indicated that 43.05–69.90% of the total P existed in the form of sediment, and P content of cyanobacteria showed the highest increase among the organisms. The other is the release of microcystin. Toxic microcystin-LR was released into the water, causing indirectly the growth inhibition of Carassius auratus and Bellamya quadrata and the reduction of microbial diversity. These findings are of importance in exploring the mechanism of cyanobacterial bloom formation and the nutrient management of eutrophic lakes.

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Revealing Cryptic Changes of Cyanobacterial Community Structure in Two Eutrophic Lakes Using eDNA Sequencing

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17176356 ◽

2020 ◽

Vol 17 (17) ◽

pp. 6356

Author(s):

Yongguang Jiang ◽

Peng Xiao ◽

Gongliang Yu ◽

Gaofei Song ◽

Renhui Li

Keyword(s):

Community Structure ◽

High Throughput Sequencing ◽

Environmental Dna ◽

Cyanobacterial Blooms ◽

Erhai Lake ◽

Water Safety ◽

Cyanobacterial Community ◽

Eutrophic Lakes ◽

Abundant Otus ◽

Cyanobacterial Diversity

Harmful cyanobacterial blooms pose a risk to human health worldwide. To enhance understanding on the bloom-forming mechanism, the spatiotemporal changes in cyanobacterial diversity and composition in two eutrophic lakes (Erhai Lake and Lushui Reservoir) of China were investigated from 2010 to 2011 by high-throughput sequencing of environmental DNA. For each sample, 118 to 260 cpcBA-IGS operational taxonomic units (OTUs) were obtained. Fifty-two abundant OTUs were identified, which made up 95.2% of the total sequences and were clustered into nine cyanobacterial groups. Although the cyanobacterial communities of both lakes were mainly dominated by Microcystis, Erhai Lake had a higher cyanobacterial diversity. The abundance of mixed Nostocales species was lower than that of Microcystis, whereas Phormidium and Synechococcus were opportunistically dominant. The correlation between the occurrence frequency and relative abundance of OTUs was poorly fitted by the Sloan neutral model. Deterministic processes such as phosphorus availability were shown to have significant effects on the cyanobacterial community structure in Erhai Lake. In summary, the Microcystis-dominated cyanobacterial community was mainly affected by the deterministic process. Opportunistically dominant species have the potential to replace Microcystis and form blooms in eutrophic lakes, indicating the necessity to monitor these species for drinking water safety.

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Cyanobacterial blooms in shallow lakes of the Iławskie Lake District

Limnological Review ◽

10.2478/v10194-011-0028-y ◽

2011 ◽

Vol 11 (2) ◽

pp. 69-79 ◽

Cited By ~ 6

Author(s):

Ewa Dembowska

Keyword(s):

Green Algae ◽

Trophic Level ◽

Shallow Lakes ◽

Algal Blooms ◽

Catchment Area ◽

Cyanobacterial Blooms ◽

Lake District ◽

Eutrophic Lakes ◽

Blue Green Algae ◽

Catchment Areas

Cyanobacterial blooms in shallow lakes of the Iławskie Lake DistrictThe dominance of blue-green algae observed in many lakes is related to a high trophic level. Shallow eutrophic lakes are particularly often abundant in blue-green algae. The research on phytoplankton, the results of which are presented in this paper, was carried out between 2002 and 2005 in six lakes. These lakes differed considerably in their size and management methods applied in the catchment (drainage) area. A few types of water blooms were distinguished, which is related to the catchment area management, the intensity of mixing and the trophic level. Algal blooms of the Planktothrix type appeared in lakes situated in an open area of agricultural catchment basins. Algal blooms of the Limnothrix type were characteristic of lakes with a forest-agricultural catchment area but surrounded by high shores, which reduced the wind influence on the mixing. Sporadic mixed algal blooms were typical of lakes situated in forest catchment areas.

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Control and remediation methods for eutrophic lakes in the past 30 years

Water Science & Technology ◽

10.2166/wst.2020.218 ◽

2020 ◽

Vol 81 (6) ◽

pp. 1099-1113 ◽

Cited By ~ 6

Author(s):

Yuan Zhang ◽

Pingping Luo ◽

Shuangfeng Zhao ◽

Shuxin Kang ◽

Pengbo Wang ◽

...

Keyword(s):

New Technologies ◽

Management Strategies ◽

Cyanobacterial Blooms ◽

Small Scale ◽

Short Term ◽

Eutrophic Lakes ◽

Lake Ecosystems ◽

The Past ◽

Incomplete Removal

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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Restoration and Purification of Dissolved Organic Nitrogen by Bacteria and Phytoremediation in Shallow Eutrophic Lakes Sediments

E3S Web of Conferences ◽

10.1051/e3sconf/20183801027 ◽

2018 ◽

Vol 38 ◽

pp. 01027

Author(s):

Xin Li ◽

Yi Yue

Keyword(s):

Amino Acid ◽

Microbial Activity ◽

Dissolved Organic Nitrogen ◽

Organic Nitrogen ◽

Potential Temperature ◽

Eutrophic Lakes ◽

Oxidation Reduction ◽

Oxidation Reduction Potential ◽

Nitrogen Loadings

Endogenous organic nitrogen loadings in lake sediments have increased with human activity in recent decades. A 6-month field study from two disparate shallow eutrophic lakes could partly reveal these issues by analysing seasonal variations of biodegradation and phytoremediation in the sediment. This paper describes the relationship between oxidation reduction potential, temperature, microbial activity and phytoremediation in nitrogen cycling by calculation degradative index of dissolved organic nitrogen and amino acid decomposition. The index was being positive in winter and negative in summer while closely positive correlated with biodegradation. Our analysis revealed that rather than anoxic condition, biomass is the primary factor to dissolved organic nitrogen distribution and decomposition. Some major amino acids statistics also confirm the above view. The comparisons of organic nitrogen and amino acid in abundance and seasons in situ provides that demonstrated plants cue important for nitrogen removal by their roots adsorption and immobilization. In conclusion, enhanced microbial activity and phytoremediation with the seasons will reduce the endogenous nitrogen loadings by the coupled mineralization and diagenetic process.

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Rapid adaptation of harmful cyanobacteria to rising CO2

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1602435113 ◽

2016 ◽

Vol 113 (33) ◽

pp. 9315-9320 ◽

Cited By ~ 49

Author(s):

Giovanni Sandrini ◽

Xing Ji ◽

Jolanda M. H. Verspagen ◽

Robert P. Tann ◽

Pieter C. Slot ◽

...

Keyword(s):

Cyanobacterial Bloom ◽

Eutrophic Lake ◽

Cyanobacterial Blooms ◽

High Flux ◽

Flux Rate ◽

Eutrophic Lakes ◽

Field Evidence ◽

Evolutionary Changes ◽

Lakes And Reservoirs ◽

Harmful Cyanobacterial Blooms

Rising atmospheric CO2 concentrations are likely to affect many ecosystems worldwide. However, to what extent elevated CO2 will induce evolutionary changes in photosynthetic organisms is still a major open question. Here, we show rapid microevolutionary adaptation of a harmful cyanobacterium to changes in inorganic carbon (Ci) availability. We studied the cyanobacterium Microcystis, a notorious genus that can develop toxic cyanobacterial blooms in many eutrophic lakes and reservoirs worldwide. Microcystis displays genetic variation in the Ci uptake systems BicA and SbtA, where BicA has a low affinity for bicarbonate but high flux rate, and SbtA has a high affinity but low flux rate. Our laboratory competition experiments show that bicA + sbtA genotypes were favored by natural selection at low CO2 levels, but were partially replaced by the bicA genotype at elevated CO2. Similarly, in a eutrophic lake, bicA + sbtA strains were dominant when Ci concentrations were depleted during a dense cyanobacterial bloom, but were replaced by strains with only the high-flux bicA gene when Ci concentrations increased later in the season. Hence, our results provide both laboratory and field evidence that increasing carbon concentrations induce rapid adaptive changes in the genotype composition of harmful cyanobacterial blooms.

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Odorous Substances and Cyanobacterial Toxins in Prairie Drinking Water Sources

Water Science & Technology ◽

10.2166/wst.1992.0046 ◽

1992 ◽

Vol 25 (2) ◽

pp. 147-154 ◽

Cited By ~ 31

Author(s):

S. L. Kenefick ◽

S. E. Hrudey ◽

E. E. Prepas ◽

N. Motkosky ◽

H. G. Peterson

Keyword(s):

Drinking Water ◽

Water Samples ◽

Algal Blooms ◽

Algal Biomass ◽

Cyanobacterial Blooms ◽

Eutrophic Lakes ◽

Cyanobacterial Toxins ◽

Eutrophic Water ◽

Odorous Substances ◽

Water Uses

Algal blooms in eutrophic lakes have been regarded by some as primarily an aesthetic nuisance for recreational and drinking water uses despite well documented incidents of livestock and wildlife poisoning attributed to cyanobacterial toxins. A survey was conducted of three eutrophic, water supply lakes and eight rural dugouts experiencing cyanobacterial blooms. Biomass was characterized for dominant cyanobacterial genera and analyses were conducted for the hepatotoxins, microcystin LR and RR and the neurotoxin, anatoxin-a. Some water samples collected simultaneously were screened for geosmin, 2-methylisoborneol and β-cyclocitral. Results showed that microcystin LR (LD50 of 50 µg/kg in mice) was present in concentrations up to 500 µg/g of algal biomass and microcystin LR levels were generally related to the proportion of Microcystis in the collected algal biomass. There was no relationship between the presence of microcystin LR and the presence of any of the odour compounds. Consequently, cyanobacterial odour-causing compounds in water did not provide reliable warning of the presence of the microcystin LR in these cyanobacterial blooms.

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Nitrite Enhances MC-LR-Induced Changes on Splenic Oxidation Resistance and Innate Immunity in Male Zebrafish

Toxins ◽

10.3390/toxins10120512 ◽

2018 ◽

Vol 10 (12) ◽

pp. 512 ◽

Cited By ~ 2

Author(s):

Wang Lin ◽

Honghui Guo ◽

Lingkai Wang ◽

Dandan Zhang ◽

Xueyang Wu ◽

...

Keyword(s):

Oxidative Stress ◽

Innate Immunity ◽

Cyanobacterial Blooms ◽

Complement C3 ◽

Orthogonal Experimental Design ◽

Eutrophic Lakes ◽

Antioxidant Responses ◽

Splenic Macrophages ◽

Total Antioxidant ◽

Induced Changes

Hazardous contaminants, such as nitrite and microcystin-leucine arginine (MC-LR), are released into water bodies during cyanobacterial blooms and may adversely influence the normal physiological function of hydrobiontes. The combined effects of nitrite and MC-LR on the antioxidant defense and innate immunity were evaluated through an orthogonal experimental design (nitrite: 0, 29, 290 μM; MC-LR: 0, 3, 30 nM). Remarkable increases in malondialdehyde (MDA) levels have suggested that nitrite and/or MC-LR exposures induce oxidative stress in fish spleen, which were indirectly confirmed by significant downregulations of total antioxidant capacity (T-AOC), glutathione (GSH) contents, as well as transcriptional levels of antioxidant enzyme genes cat1, sod1 and gpx1a. Simultaneously, nitrite and MC-LR significantly decreased serum complement C3 levels as well as the transcriptional levels of splenic c3b, lyz, il1β, ifnγ and tnfα, and indicated that they could jointly impact the innate immunity of fish. The severity and extent of splenic lesions were aggravated by increased concentration of nitrite or MC-LR and became more serious in combined groups. The damages of mitochondria and pseudopodia in splenic macrophages suggest that oxidative stress exerted by nitrite and MC-LR aimed at the membrane structure of immune cells and ultimately disrupted immune function. Our results clearly demonstrate that nitrite and MC-LR exert synergistic suppressive effects on fish innate immunity via interfering antioxidant responses, and their joint toxicity should not be underestimated in eutrophic lakes.

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