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Shang L, Ke F, Xu X, Feng M, Li W. Temporal Dynamics and Influential Factors of Taste and Odor Compounds in the Eastern Drinking Water Source of Chaohu Lake, China: A Comparative Analysis of Global Freshwaters. Toxins (Basel) 2024; 16:264. [PMID: 38922158 PMCID: PMC11209420 DOI: 10.3390/toxins16060264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2024] [Revised: 05/31/2024] [Accepted: 06/04/2024] [Indexed: 06/27/2024] Open
Abstract
The escalating proliferation of cyanobacteria poses significant taste and odor (T/O) challenges, impacting freshwater ecosystems, public health, and water treatment costs. We examined monthly variations in four T/O compounds from September 2011 to August 2012 in Chaohu Lake's eastern drinking water source (DECL). More importantly, we compared the reported T/O occurrence and the related factors in freshwater bodies worldwide. The assessment of T/O issues indicated a severe and widespread problem, with many cases surpassing odor threshold values. Remarkably, China reported the highest frequency and severity of odor-related problems. A temporal analysis revealed variations in odor occurrences within the same water body across different years, emphasizing the need to consider high values in all seasons for water safety. Globally, T/O issues were widespread, demanding attention to variations within the same water body and across different layers. Algae were crucial contributors to odor compounds, necessitating targeted interventions due to diverse odorant sources and properties. A correlation analysis alone lacked definitive answers, emphasizing the essential role of further validation, such as algae isolation. Nutrients are likely to have influenced the T/O, as GSM and MIB correlated positively with nitrate and ammonia nitrogen in DECL, resulting in proposed control recommendations. This study offers recommendations for freshwater ecosystem management and serves as a foundation for future research and management strategies to address T/O challenges.
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Affiliation(s)
- Lixia Shang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; (F.K.); (W.L.)
| | - Fan Ke
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; (F.K.); (W.L.)
| | - Xiangen Xu
- Changzhou Academy of Environmental Science, Changzhou 213022, China;
| | - Muhua Feng
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; (F.K.); (W.L.)
| | - Wenchao Li
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; (F.K.); (W.L.)
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Guo Y, Meng H, Zhao S, Wang Z, Zhu L, Deng D, Liu J, He H, Xie W, Wang G, Zhang L. How does Microcystis aeruginosa respond to elevated temperature? THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 889:164277. [PMID: 37211116 DOI: 10.1016/j.scitotenv.2023.164277] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 05/05/2023] [Accepted: 05/15/2023] [Indexed: 05/23/2023]
Abstract
Cyanobacteria and their toxins widely exist in freshwater ecosystems. Microcystis aeruginosa is among dominant bloom-forming cyanobacteria. Water temperature is a key factor influencing the life cycle of M. aeruginosa. We simulated elevated temperature (4-35 °C) experiment and cultured M. aeruginosa during the overwintering, recruitment and rapid growth phases. The results showed that M. aeruginosa recovered growth after overwintering at 4-8 °C and recruited at 16 °C. The total extracellular polymeric substance (TEPS) concentration increased rapidly at 15 °C. The actual quantum yield of photosystem II (Fv'/Fm') peaked at 20 °C during the rapid growth phase, and the optimum temperature of M. aeruginosa growth was 20-25 °C. Additionally, TEPS and microcystins (MCs) secretion peaked at 20-25 °C. The cell density accumulated rapidly from 26 °C to 35 °C. Furthermore, enzymes of RuBisCO and FBA related to photosynthetic activity were confirmed to contribute to the metabolism, as well as mcyB gene was affected by elevated temperature. Our results provide insights of the physiological effects and metabolic activity during annual cycle of M. aeruginosa. And it is predicted that global warming may promote the earlier recruitment of M. aeruginosa, extend the optimum growth period, enhance the toxicity, and finally intensify M. aeruginosa blooms.
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Affiliation(s)
- Yongqi Guo
- School of Environment, Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China; Jiangsu Engineering Lab of Water and Soil Eco-remediation, Nanjing 210023, China
| | - Han Meng
- School of Environment, Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China; Jiangsu Engineering Lab of Water and Soil Eco-remediation, Nanjing 210023, China
| | - Sichuan Zhao
- School of Environment, Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China
| | - Zixuan Wang
- School of Environment, Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China
| | - Lin Zhu
- School of Environment, Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China
| | - Dailan Deng
- School of Environment, Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China
| | - Jine Liu
- School of Environment, Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China; Jiangsu Engineering Lab of Water and Soil Eco-remediation, Nanjing 210023, China.
| | - Huan He
- School of Environment, Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China; Jiangsu Engineering Lab of Water and Soil Eco-remediation, Nanjing 210023, China
| | - Wenming Xie
- School of Environment, Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China; Jiangsu Engineering Lab of Water and Soil Eco-remediation, Nanjing 210023, China
| | - Guoxiang Wang
- School of Environment, Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China; Jiangsu Engineering Lab of Water and Soil Eco-remediation, Nanjing 210023, China
| | - Limin Zhang
- School of Environment, Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China; Green Economy Development Institute, Nanjing University of Finance and Economics, Nanjing 210023, China.
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Wang Y, Feng M, Wang J, Chen X, Chen X, Du X, Xun F, Ngwenya BT. Algal blooms modulate organic matter remineralization in freshwater sediments: A new insight on priming effect. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 784:147087. [PMID: 33894606 DOI: 10.1016/j.scitotenv.2021.147087] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 04/06/2021] [Accepted: 04/07/2021] [Indexed: 06/12/2023]
Abstract
This study provides a novel insight into the degradation of sediment organic matter (SOM) regulated by algae-derived organic matter (AOM) based on priming effect. We tracked the dynamics of SOM mineralization products and pathways, together with priming effects (PE) using the compound-specific stable isotope (δ13C) technique following addition of low- and high-density algal debris in sediments. We found that algal debris increased the total carbon oxidation rate, and resulted in denitrification and methanogenesis-dominated SOM mineralization. While iron reduction and sulphate reduction played important roles in the early period of algal accumulation. Total carbon oxidation rate and anaerobic rates (Ranaerobic) were higher in the amended treatments compared with that in the control. Analysis indicated that algal debris had a positive PE on SOM mineralization, which caused an intensified mineralization in the initial phase with over 80% of dissolved inorganic carbon deriving from SOM degradation. Total carbon oxidation rate of SOM deduced from priming effect (RTCOR-PE) was similar to Ranaerobic, further indicating SOM mineralization was a critical source of the end products. These findings deviate the causal focus from the decomposition of AOM, and confirm the accumulation of AOM as the facilitator of SOM mineralization. Our study offers empirical evidences to advance the traditional view on the effect of AOM on SOM mineralization.
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Affiliation(s)
- Yarui Wang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 Beijing East Road, Nanjing 210008, PR China; Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Muhua Feng
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 Beijing East Road, Nanjing 210008, PR China.
| | - Jianjun Wang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 Beijing East Road, Nanjing 210008, PR China
| | - Xinfang Chen
- Hydrology and Water Resources College, Hohai University, Nanjing 210098, PR China
| | - Xiangchao Chen
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 Beijing East Road, Nanjing 210008, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Xian Du
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 Beijing East Road, Nanjing 210008, PR China
| | - Fan Xun
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 Beijing East Road, Nanjing 210008, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Bryne Tendelo Ngwenya
- Microbial Geochemistry Laboratory, School of Geosciences, University of Edinburgh, EH9 3FE, UK
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Chen C, Wang Y, Chen K, Shi X, Yang G. Using hydrogen peroxide to control cyanobacterial blooms: A mesocosm study focused on the effects of algal density in Lake Chaohu, China. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 272:115923. [PMID: 33139095 DOI: 10.1016/j.envpol.2020.115923] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 10/19/2020] [Accepted: 10/22/2020] [Indexed: 06/11/2023]
Abstract
The application of hydrogen peroxide (H2O2) to control harmful algal blooms is affected by algal density and species. In the present study, a simulation field study was carried out to evaluate the removal of cyanobacteria with high algal density (chlorophyll a of approximately 220-250 μg/L) and low algal density (chlorophyll a of approximately 30-50 μg/L) using 10, 20 mg/L H2O2 and 5 mg/L H2O2. The dynamics of algal biomass, nutrients, microcystins, phytoplankton, and zooplankton were measured within 7 d. The results showed that 5 mg/L H2O2 effectively eliminated algal biomass (measured as chlorophyll a and phycocyanin) and inhibited 50% of the photosynthetic activity of the cyanobacteria at 7 d in the low algal cell density group, while the same inhibition rate was observed in the high algal cell density group when the H2O2 was 20 mg/L. However, using a high dosage of H2O2, such as 10 mg/L, to suppress cyanobacteria with high biomass could result in a dramatic increase in nutrients and microcystins in the water column. The portion of eukaryotic algae, such as Chlorophyta, Bacillariophyta and Euglenophyta, in the phytoplankton community increased with increasing H2O2 concentrations; moreover, the dominant species of cyanobacteria changed from the nontoxic genus Dactylococcopsis to the toxic genus Oscillatoria, which may result in acute toxicity to zooplankton. Our results demonstrated that the application of H2O2 to control cyanobacterial blooms at the early stage when algal cell density was low posed less potential ecological risks and may have increased the diversity of the phytoplankton community.
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Affiliation(s)
- Chao Chen
- College of Environmental Sciences, Sichuan Agricultural University, Chengdu, 611130, China
| | - Yiyao Wang
- Chengdu Environmental Protection Research Institute, Chengdu, 610072, China
| | - Kaining Chen
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Xiaoli Shi
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China.
| | - Gang Yang
- College of Environmental Sciences, Sichuan Agricultural University, Chengdu, 611130, China.
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Seasonal Succession of Phytoplankton Functional Groups and Driving Factors of Cyanobacterial Blooms in a Subtropical Reservoir in South China. WATER 2020. [DOI: 10.3390/w12041167] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Freshwater phytoplankton communities can be classified into a variety of functional groups that are based on physiological, morphological, and ecological characteristics. This classification method was used to study the temporal and spatial changes in the phytoplankton communities of Gaozhou Reservoir, which is a large municipal water source in South China. Between January 2015 and December 2017, a total of 155 taxa of phytoplankton that belong to seven phyla were identified. The phytoplankton communities were classified into 28 functional groups, nine of which were considered to be representative functional groups (relative biomass > 10%). Phytoplankton species richness was greater in the summer and autumn than in the winter and spring; cyanobacterial blooms occurred in the spring. The seasonal succession of phytoplankton functional groups was characterized by the occurrence of functional groups P (Staurastrum sp. and Closterium acerosum) and Y (Cryptomonas ovata and Cryptomonas erosa) in the winter and spring, and functional groups NA (Cosmarium sp. and Staurodesmus sp.) and P (Staurastrum sp. and Closterium acerosum) in the summer and autumn. The temperature, nitrogen, and phosphorus levels were the main factors driving seasonal changes in the phytoplankton communities of Gaozhou Reservoir. The functional group M (Microcystis aeruginosa) dominated the community during the cyanobacterial blooms in spring 2016, with the maximum algal cell density of 3.12 × 108 cells L−1. Relatively low temperature (20.8 °C), high concentrations of phosphorus (0.080–0.110 mg L−1), suitable hydrological and hydrodynamic conditions (e.g., relatively long retention time), and relatively closed geographic location in the reservoir were the key factors that stimulated the cyanobacterial blooms during the early stages.
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Fan YY, Li BB, Yang ZC, Cheng YY, Liu DF, Yu HQ. Mediation of functional gene and bacterial community profiles in the sediments of eutrophic Chaohu Lake by total nitrogen and season. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 250:233-240. [PMID: 30999200 DOI: 10.1016/j.envpol.2019.04.028] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Revised: 03/24/2019] [Accepted: 04/06/2019] [Indexed: 06/09/2023]
Abstract
Microbes in sediments contribute to nutrient release and play an important role in lake eutrophication. However, information about the profiles of functional genes and bacterial communities and the most important environmental factor affecting them in the sediments of eutrophic lake remains unrevealed. In this work, the real-time fluorescent quantitative polymerase chain reaction (qPCR) assay and 16S ribosomal RNA gene next generation sequencing analysis were used to explore the profiles of functional genes and bacterial communities in the sediments of Chaohu Lake. The selected 18 functional genes involved in C, N and P cycles were detected in most of samples. Seasonal variation and sediment variables were found to affect the profiles of functional genes and bacterial communities, and total nitrogen was the dominant environmental factor to drive the formation of bacterial community structure. Proteobacteria and Firmicutes were observed to be the two dominant phyla in the sediments with relative abundance ranging from 10.8% to 36.0% and 7.7%-46.7%, respectively. Three bacterial phyla, i.e., Actinobacteria, Proteobacteria, and Spirochaetes, were found to be significantly positively correlated with the C, N and P-cycle related functional genes. Bacterial community structure was the most important driver to shape the profiles of functional genes. Seasonal variation also influenced the co-occurrence patterns between functional genes and bacterial taxa as revealed by network analysis. The findings from this work facilitate a better understanding about the C, N, and P cycles in the sediments of eutrophic lakes.
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Affiliation(s)
- Yang-Yang Fan
- School of Life Sciences, University of Science & Technology of China, Hefei, 230026, China; CAS Key Laboratory of Urban Pollutant Conversion, Department of Applied Chemistry, University of Science & Technology of China, Hefei, 230026, China
| | - Bing-Bing Li
- School of Life Sciences, University of Science & Technology of China, Hefei, 230026, China; CAS Key Laboratory of Urban Pollutant Conversion, Department of Applied Chemistry, University of Science & Technology of China, Hefei, 230026, China
| | - Zong-Chuang Yang
- School of Life Sciences, University of Science & Technology of China, Hefei, 230026, China
| | - Yuan-Yuan Cheng
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Applied Chemistry, University of Science & Technology of China, Hefei, 230026, China
| | - Dong-Feng Liu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Applied Chemistry, University of Science & Technology of China, Hefei, 230026, China
| | - Han-Qing Yu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Applied Chemistry, University of Science & Technology of China, Hefei, 230026, China.
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Co-Occurrence of Microcystins and Taste-and-Odor Compounds in Drinking Water Source and Their Removal in a Full-Scale Drinking Water Treatment Plant. Toxins (Basel) 2018; 10:toxins10010026. [PMID: 29301296 PMCID: PMC5793113 DOI: 10.3390/toxins10010026] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 12/25/2017] [Accepted: 12/28/2017] [Indexed: 11/16/2022] Open
Abstract
The co-occurrence of cyanotoxins and taste-and-odor compounds are a growing concern for drinking water treatment plants (DWTPs) suffering cyanobacteria in water resources. The dissolved and cell-bound forms of three microcystin (MC) congeners (MC-LR, MC-RR and MC-YR) and four taste-and-odor compounds (geosmin, 2-methyl isoborneol, β-cyclocitral and β-ionone) were investigated monthly from August 2011 to July 2012 in the eastern drinking water source of Lake Chaohu. The total concentrations of microcystins and taste-and-odor compounds reached 8.86 μg/L and 250.7 ng/L, respectively. The seasonal trends of microcystins were not consistent with those of the taste-and-odor compounds, which were accompanied by dominant species Microcystis and Dolichospermum. The fate of the cyanobacteria and metabolites were determined simultaneously after the processes of coagulation/flocculation, sedimentation, filtration and chlorination in the associated full-scale DWTP. The dissolved fractions with elevated concentrations were detected after some steps and the breakthrough of cyanobacteria and metabolites were even observed in finished water. Chlorophyll-a limits at intake were established for the drinking water source based on our investigation of multiple metabolites, seasonal variations and their elimination rates in the DWTP. Not only microcystins but also taste-and-odor compounds should be taken into account to guide the management in source water and in DWTPs.
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Buratti FM, Manganelli M, Vichi S, Stefanelli M, Scardala S, Testai E, Funari E. Cyanotoxins: producing organisms, occurrence, toxicity, mechanism of action and human health toxicological risk evaluation. Arch Toxicol 2017; 91:1049-1130. [DOI: 10.1007/s00204-016-1913-6] [Citation(s) in RCA: 258] [Impact Index Per Article: 36.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 12/13/2016] [Indexed: 12/11/2022]
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Chen C, Yang Z, Kong F, Zhang M, Yu Y, Shi X. Growth, physiochemical and antioxidant responses of overwintering benthic cyanobacteria to hydrogen peroxide. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2016; 219:649-655. [PMID: 27352766 DOI: 10.1016/j.envpol.2016.06.043] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 06/15/2016] [Accepted: 06/20/2016] [Indexed: 06/06/2023]
Abstract
The recruitment of overwintering benthic cyanobacteria from the sediment surface is important for the development of cyanobacterial blooms during warm spring seasons. Thus, controlling the growth of cyanobacteria at the benthic stage to inhibit their recruitment is vital to control or delay the formation of summer blooms. In this study, overwintering benthic cyanobacteria were exposed to ascending hydrogen peroxide (H2O2) concentrations (0, 1, 5, and 20 mg/L) in a simulated overwintering environment. Photosynthetic pigments, physiochemical features, and antioxidant responses were evaluated to determine the inhibitory effects of H2O2 on the growth of benthic cyanobacteria and to identify the potential mechanisms thereof. These H2O2-treated cyanobacteria were then collected through filtration and transferred to an optimum environment to evaluate their recovery capacity. The results showed that chlorophyll a and phycocyanin contents, photosynthetic yield, and esterase activity decreased significantly in H2O2 treated groups compared to the control. The activities of superoxide dismutase (SOD) and catalase (CAT) in benthic cyanobacteria were inhibited after 72 h exposure to H2O2, while the malondialdehyde (MDA) contents were stimulated at the same time. These results indicate that H2O2 can inhibit the growth of benthic cyanobacteria, and H2O2-induced oxidative damage might be one of the mechanisms involved. The recovery experiment showed that the impairment of benthic cyanobacteria was temporary at a low dose of 1 mg/L H2O2, but permanent damage was induced when H2O2 concentrations were increased to 5 and 20 mg/L. Overall, our results highlight that H2O2 is a potential cyanobacteria inhibitor and can be used to decreasing the biomass of overwintering cyanobacteria, and could further control the intensity of cyanobacteria during the growth seasons.
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Affiliation(s)
- Chao Chen
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing, 210008, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhen Yang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing, 210008, China
| | - Fanxiang Kong
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing, 210008, China
| | - Min Zhang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing, 210008, China
| | - Yang Yu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing, 210008, China
| | - Xiaoli Shi
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing, 210008, China.
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Spatiotemporal Dynamics of Microcystin Variants and Relationships with Environmental Parameters in Lake Taihu, China. Toxins (Basel) 2015; 7:3224-44. [PMID: 26295260 PMCID: PMC4549747 DOI: 10.3390/toxins7083224] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 08/05/2015] [Accepted: 08/11/2015] [Indexed: 01/07/2023] Open
Abstract
Excessive anthropogenically-caused nutrient loading from both external and internal sources has promoted the growth of cyanobacteria in Lake Taihu from 2005 to 2014, suggesting increased production and release of cyanotoxins. In order to explain the spatial distribution and temporal variation of microcystins (MCs), the intracellular concentrations of MCs (MC-LR, -RR and -YR, L, R and Y are abbreviations of leucine, arginine and tyrosine) were monitored monthly from July 2013 to June 2014. Three MC variants are present simultaneously in Lake Taihu; the MC-LR and -RR variants were dominant (accounting for 40% and 39% of the total), followed by MC-YR (21%). However, MC-YR accounted for a higher proportion in colder months, especially in March. The highest concentrations of intracellular MCs were found in July and October when cyanobacteria cell density also reached the maximum. The average concentrations of MC-LR, -RR and -YR in July were 4.69, 4.23 and 2.01 μg/L, respectively. In terms of the entire lake, toxin concentrations in northern parts were significantly higher than the eastern part in summer, when MC concentrations were several times higher than the guideline value by WHO throughout much of Lake Taihu. Results from correlation and redundancy analysis (RDA) showed that total MCs, including all variants, were strongly and positively correlated with cyanobacteria cell density, water temperature, total phosphorus (TP) and pH, whereas each variant had different correlation coefficients with each of the considered environmental variables. MC-RR showed a stronger relationship with temperature, in contrast to MC-YR and -LR. Dissolved inorganic carbon (DIC) showed a negative relationship with each variant, suggesting that rising DIC concentrations may inhibit cyanobacterial growth and thereby reduce MC production in the future.
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