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Jiang X, Liu C, Cai J, Hu Y, Shao K, Tang X, Gong Y, Yao X, Xu Q, Gao G. Relationships between environmental factors and N-cycling microbes reveal the indirect effect of further eutrophication on denitrification and DNRA in shallow lakes. WATER RESEARCH 2023; 245:120572. [PMID: 37688860 DOI: 10.1016/j.watres.2023.120572] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 08/23/2023] [Accepted: 09/01/2023] [Indexed: 09/11/2023]
Abstract
Traditional views indicate that eutrophication and subsequent algal blooms favor denitrification and dissimilatory nitrate reduction to ammonium (DNRA) in lake ecosystems. However, lakes tend to show an increasing propensity for inorganic nitrogen (N) limitation as they become more eutrophic. Thus, the influence of further eutrophication on denitrification and DNRA in eutrophic lakes are unclear due to the uncertainty of N availability. To fill this gap, we investigated the genes abundance (AOA, AOB, nirS, nirK and nrfA) and the composition of N-cycling microbes through quantitative PCR and 16S rRNA sequencing analysis, respectively, in 15 shallow eutrophic lakes of the Yangtze-Huaihe River basin, China. The results indicated that denitrification and DNRA rates could be modulated mainly by their functional gene abundances (nirS, nirK and nrfA), followed by the environmental factors (sediment total organic carbon and nitrogen). Denitrification rates significantly increased from slightly to highly eutrophic lakes, but DNRA rates were not. An explanation is that nitrification provided ample nitrate for denitrification, and this cooperative interaction was indicated by the positive correlation of their gene abundances. In addition, Pseudomonas and Anaeromyxobacter was the dominant genus mediated denitrification and DNRA, showing the potential to perform facultative anaerobic and strict anaerobic nitrate reduction, respectively. High level of dissolved oxygen might favor the facultatively aerobic denitrifiers over the obligately anaerobic fermentative DNRA bacteria in these shallow lakes. Chlorophyll a had a weak but positive effect on the gene abundances for nitrification (AOA and AOB). Further eutrophication had an indirect effect on denitrification and DNRA rates through modulating the genes abundances of N-cycling microbes.
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Affiliation(s)
- Xingyu Jiang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Changqing Liu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jian Cai
- Xiangyang Polytechnic, Xiangyang 441050, China
| | - Yang Hu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Keqiang Shao
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Xiangming Tang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Yi Gong
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Xiaolong Yao
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Qiujin Xu
- Chinese Research Academy of Environmental Sciences, Beijing 100012, China
| | - Guang Gao
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
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Chen Z, Huang Y, Shen Y, Zhang J, Deng J, Chen X. Denitrification shifted autotroph-heterotroph interactions in Microcystis aggregates. ENVIRONMENTAL RESEARCH 2023; 231:116269. [PMID: 37257745 DOI: 10.1016/j.envres.2023.116269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 05/13/2023] [Accepted: 05/27/2023] [Indexed: 06/02/2023]
Abstract
Denitrification is the most important process for nitrogen removal in eutrophic lakes and was mostly investigated in lake sediment. Denitrification could also be mediated by cyanobacterial aggregates, yet how this process impacts nitrogen (N) availability and the associated autotroph-heterotroph relationships within cyanobacterial aggregates has not been investigated. In this study, incubation experiments with nitrate amendment were conducted with Microcystis aggregates (MAs). Measurement of nitrogen contents, 16S rRNA-based microbial community profiling and metatranscriptomic sequencing were used to jointly assess nitrogen turnover dynamics, as well as changes in microbial composition and gene expression. Strong denitrification potential was revealed, and maximal N removal was achieved within two days, after which the communities entered a state of severe N limitation. Changes of active microbial communities were further promoted both with regard to taxonomic composition and transcriptive activities. Expression of transportation-related genes confirmed competition for N sources by Microcystis and phycospheric communities. Strong stress response to reactive oxygen species by Microcystis was revealed. Notably, interspecific relationships among Microcystis and phycospheric communities exhibited a shift toward antagonistic interactions, particularly evidenced by overall increased expression of genes related to cell lysis and utilization of cellular materials. Patterns of fatty acid and starch metabolism also suggested changes in carbon metabolism and cross-feeding patterns within MAs. Taken together, this study demonstrated substantial denitrification potential of MAs, which, importantly, further induced changes in both metabolic activities and autotroph-heterotroph interactions. These findings also highlight the key role of nutrient condition in shaping autotroph-heterotroph relationships.
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Affiliation(s)
- Zhijie Chen
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restorations, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Yingying Huang
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restorations, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China; Technology Innovation Center for Land Spatial Eco-restoration in Metropolitan Area, Ministry of Natural Resources, Shanghai, China.
| | - Yingshi Shen
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restorations, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Junyi Zhang
- Jiangsu Wuxi Environmental Monitoring Center, Jiangsu, China
| | - Jie Deng
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restorations, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China; Technology Innovation Center for Land Spatial Eco-restoration in Metropolitan Area, Ministry of Natural Resources, Shanghai, China.
| | - Xuechu Chen
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restorations, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China; Technology Innovation Center for Land Spatial Eco-restoration in Metropolitan Area, Ministry of Natural Resources, Shanghai, China
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Chen S, Chen J, Zhang L, Huang S, Liu X, Yang Y, Luan T, Zhou S, Nealson KH, Rensing C. Biophotoelectrochemical process co-driven by dead microalgae and live bacteria. THE ISME JOURNAL 2023; 17:712-719. [PMID: 36823233 PMCID: PMC10119253 DOI: 10.1038/s41396-023-01383-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Revised: 02/08/2023] [Accepted: 02/10/2023] [Indexed: 02/25/2023]
Abstract
Anaerobic reduction processes in natural waters can be promoted by dead microalgae that have been attributed to nutrient substances provided by the decomposition of dead microalgae for other microorganisms. However, previous reports have not considered that dead microalgae may also serve as photosensitizers to drive microbial reduction processes. Here we demonstrate a photoelectric synergistic linkage between dead microalgae and bacteria capable of extracellular electron transfer (EET). Illumination of dead Raphidocelis subcapitata resulted in two-fold increase in the rate of anaerobic bioreduction by pure Geobacter sulfurreducens, suggesting that photoelectrons generated from the illuminated dead microalgae were transferred to the EET-capable microorganisms. Similar phenomena were observed in NO3- reduction driven by irradiated dead Chlorella vulgaris and living Shewanella oneidensis, and Cr(VI) reduction driven by irradiated dead Raphidocelis subcapitata and living Bacillus subtilis. Enhancement of bioreduction was also seen when the killed microalgae were illuminated in mixed-culture lake water, suggesting that EET-capable bacteria were naturally present and this phenomenon is common in post-bloom systems. The intracellular ferredoxin-NADP+-reductase is inactivated in the dead microalgae, allowing the production and extracellular transfer of photoelectrons. The use of mutant strains confirmed that the electron transport pathway requires multiheme cytochromes. Taken together, these results suggest a heretofore overlooked biophotoelectrochemical process jointly mediated by illumination of dead microalgae and live EET-capable bacteria in natural ecosystems, which may add an important component in the energetics of bioreduction phenomena particularly in microalgae-enriched environments.
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Affiliation(s)
- Shanshan Chen
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou, China
| | - Jin Chen
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Lanlan Zhang
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou, China
| | - Shaofu Huang
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xing Liu
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yuting Yang
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou, China
| | - Tiangang Luan
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou, China
| | - Shungui Zhou
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China.
| | - Kenneth H Nealson
- Department of Earth Science, University of Southern California, Los Angeles, CA, USA
| | - Christopher Rensing
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China
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Zhao F, Xu H, Kang L, Zhao X. Spatial and seasonal change in algal community structure and its interaction with nutrient dynamics in a gravel-bed urban river. JOURNAL OF HAZARDOUS MATERIALS 2022; 425:127775. [PMID: 34844802 DOI: 10.1016/j.jhazmat.2021.127775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 11/09/2021] [Accepted: 11/10/2021] [Indexed: 06/13/2023]
Abstract
Harmful algal blooms frequently occur in urban rivers due to intense human activities. However, little is known about the change in algal community structure and its interactions with nutrient dynamics in gravel-bed urban rivers. In present study, water samples were collected from a gravel-bed River Xin'an, China for five months over four seasons and a rainy month to measure algal community structure, dissolved nitrogen gas (N2) and Argon (Ar) concentrations, and other water quality parameters. The results showed that the harmful Cyanophyta accounted for 31.6 ± 24.1% of the total community in the hot season while Bacillariophyta contributed more than 60% to the community in the other three seasons. The N2 was supersaturated in the moderate and cold seasons but it was unsaturated in the hot season, along with high concentrations of nitrogen-fixing cyanobacteria (Anabaena), indicating that the nitrogen fixation capacity was strong and even stronger than denitrification and anammox in the hot season. However, nitrogen fixation was not the main source of nitrogen in the water column. The concentrations of nutrients and Chla in the downstream river were significantly higher than those in the upstream river (p < 0.001 for nutrients and p = 0.029 for Chla), suggesting that human activities along the river greatly affected nutrient concentrations, as well as algal growth. Our study provides new insights into the algal community succession in a gravel-bed urban river and puts forward effective measures such as controlling exogenous nutrient input and dredging organic sediment for mitigating the harmful algal blooms in urban rivers.
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Affiliation(s)
- Feng Zhao
- State Key Laboratory of Lake and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China; School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, PR China
| | - Hai Xu
- State Key Laboratory of Lake and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China.
| | - Lijuan Kang
- State Key Laboratory of Lake and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China
| | - Xingchen Zhao
- State Key Laboratory of Lake and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China
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Significant Temporal and Spatial Variability in Nutrient Concentrations in a Chinese Eutrophic Shallow Lake and Its Major Tributaries. WATER 2022. [DOI: 10.3390/w14020217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Sediment nutrients can be released to the surface water when hydraulic disturbance becomes strong in shallow lakes, which contributes to nutrient enrichment and subsequent lake eutrophication in the water column. To explore the seasonal variations and spatial distributions exhibited by nutrients in the water column, surface sediment, and pore water of Lake Yangcheng and its major tributaries, we determined the concentrations of nitrogen (N) and phosphorus (P) throughout the lake in different seasons of 2018. Total N (TN) and total P (TP) concentrations in the connected rivers were much greater than those in the lake, indicating that external loading greatly contributed to the nutrient enrichment. TN concentration in the water column was highest in the winter, whereas TP peaked in the summer. A similar temporal pattern was observed for TN and TP in the sediment with maxima in the winter and minima in the summer; however, nutrients in the pore water were highest in the summer, in contrast to the temporal variation in the sediment. Additionally, high TN values in the water column and high TP in the three compartments were distributed primarily in the west part of the lake, while high TN concentrations in the sediment and pore water were observed mainly in the east portion of the lake. According to the enrichment factor index (an indicator evaluating the nutrient enrichment by comparing the detected contents and standard values), nutrients in the lake sediment were severely enriched with TN and TP averaging 2195.8 mg/kg and 543.0 mg/kg, respectively. The vertical distribution of TN and TP generally exhibited similar decreasing patterns with an increase in sediment depth, suggesting mineralization of TN and TP by microbes and benthic organisms. More attention and research are needed to understand the seasonality of nutrient exchange across the sediment–water interface, especially in eutrophic lakes.
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Herath A, Reid C, Perez F, Pittman CU, Mlsna TE. Biochar-supported polyaniline hybrid for aqueous chromium and nitrate adsorption. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 296:113186. [PMID: 34256294 DOI: 10.1016/j.jenvman.2021.113186] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 06/17/2021] [Accepted: 06/28/2021] [Indexed: 06/13/2023]
Abstract
Biochar adsorbents can remove environmental pollutants and the remediation of Cr(VI) and nitrate are considered. Cr(VI) is a proven carcinogen causing serious health issues in humans and nitrate induced eutrophication causes negative effect on aquatic systems around the world. Douglas fir biochar (DFBC), synthesized by fast pyrolysis during syn gas production, was treated with aniline. Then, a polyaniline biochar (PANIBC) composite containing 47 wt% PANI was prepared by precipitating PANI on DFBC surfaces by oxidative chemical polymerization of aniline in 2M HCl. PANIBC exhibited a point of zero charge (PZC) of 3.0 and 8.2 m2/g BET (N2) surface area. This modified biochar was characterized by thermogravimetric analysis (TGA), scanning electron microscopy (SEM) morphology and surface elements, and oxidation states by X-ray photoelectron spectroscopy (XPS). PANIBC exhibited positive surface charge below pH 3, making it an outstanding adsorbent, for Cr(VI) removal. Cr(VI) and nitrate removal mechanisms are presented based on XPS analysis. DFBC and PANIBC Cr(VI) and nitrate adsorption data were fitted to Langmuir and Freundlich isotherm models with maximum Langmuir adsorption capacities of 150 mg/g and 72 mg/g, respectively. Cr(VI) and nitrate removal at pH 2 and 6 were evaluated by reducing the amount of PANI (9 wt%) dispersed on to DFBC. Adsorption capacities verses temperature studies revealed that both Cr(VI) and nitrate adsorption are endothermic and thermodynamically favored. Regeneration studies were conducted on both DFBC and PANIBC using 0.1M NaOH and PANIBC exhibited excellent sorption capacities for Cr(VI) and nitrate in lake water samples and in the presence of competitive ions.
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Affiliation(s)
- Amali Herath
- Department of Chemistry, Mississippi State University, Mississippi State, MS 39762, USA
| | - Claudia Reid
- Department of Chemistry, Mississippi State University, Mississippi State, MS 39762, USA
| | - Felio Perez
- Material Science Lab, Integrated Microscopy Center, University of Memphis, Memphis, TN 38152, USA
| | - Charles U Pittman
- Department of Chemistry, Mississippi State University, Mississippi State, MS 39762, USA
| | - Todd E Mlsna
- Department of Chemistry, Mississippi State University, Mississippi State, MS 39762, USA.
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Chen X, Wang K, Li X, Qiao Y, Dong K, Yang L. Microcystis blooms aggravate the diurnal alternation of nitrification and nitrate reduction in the water column in Lake Taihu. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 767:144884. [PMID: 33636785 DOI: 10.1016/j.scitotenv.2020.144884] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 12/25/2020] [Accepted: 12/28/2020] [Indexed: 06/12/2023]
Abstract
To explore the effects of Microcystis blooms on nitrogen (N) cycling in the water column, the community structures of the Microcystis-attached and free-living bacteria in Lake Taihu were assessed and a mesocosm experiment was further conducted on the shore of Lake Taihu. The bacterial communities of Microcystis-attached and free-living bacteria were dominated by heterotrophic bacteria, such as Pseudomonas and Massilia, while the relative abundances of the genera related to traditional autotrophic nitrification were surprisingly low. However, the dramatic increase in nitrate (NO3-) levels at the daytime suggested that in the mesocosms nitrification did occur, during which the heterotrophic nitrifiers played a predominant role as revealed by the acetylene inhibition experiment. The ammonium (NH4+) concentrations were always maintained at a low level, indicating that most of the substrates for daytime nitrification originated from organic N. The total N being removed during the experiment was much less than the sum of daily NO3- reduction, while the decrease in NO3- concentration was much higher than the increase in NH4+ concentration during the night, indicating that assimilation was the main explanation for nocturnal NO3- reduction. Thus, the cycling of organic N (remineralization) - heterotrophic nitrification - NO3- assimilation (reduction) promoted by Microcystis blooms aggravates the diurnal variation of NO3- in the water column.
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Affiliation(s)
- Xiaofeng Chen
- School of Environmental Science and Engineering, Yangzhou University, West Huayang Road 196, Yangzhou 225127, People's Republic of China; State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Xianlin Road 163, Nanjing 210146, People's Republic of China.
| | - Kun Wang
- School of Environmental Science and Engineering, Yangzhou University, West Huayang Road 196, Yangzhou 225127, People's Republic of China
| | - Xing Li
- School of Environmental Science and Engineering, Yangzhou University, West Huayang Road 196, Yangzhou 225127, People's Republic of China
| | - Yuqi Qiao
- School of Environmental Science and Engineering, Yangzhou University, West Huayang Road 196, Yangzhou 225127, People's Republic of China
| | - Kunming Dong
- School of Environmental Science and Engineering, Yangzhou University, West Huayang Road 196, Yangzhou 225127, People's Republic of China
| | - Liuyan Yang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Xianlin Road 163, Nanjing 210146, People's Republic of China
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Roles of Nutrient Limitation on Western Lake Erie CyanoHAB Toxin Production. Toxins (Basel) 2021; 13:toxins13010047. [PMID: 33435505 PMCID: PMC7828104 DOI: 10.3390/toxins13010047] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 01/04/2021] [Accepted: 01/06/2021] [Indexed: 11/16/2022] Open
Abstract
Cyanobacterial harmful algal bloom (CyanoHAB) proliferation is a global problem impacting ecosystem and human health. Western Lake Erie (WLE) typically endures two highly toxic CyanoHABs during summer: a Microcystis spp. bloom in Maumee Bay that extends throughout the western basin, and a Planktothrix spp. bloom in Sandusky Bay. Recently, the USA and Canada agreed to a 40% phosphorus (P) load reduction to lessen the severity of the WLE blooms. To investigate phosphorus and nitrogen (N) limitation of biomass and toxin production in WLE CyanoHABs, we conducted in situ nutrient addition and 40% dilution microcosm bioassays in June and August 2019. During the June Sandusky Bay bloom, biomass production as well as hepatotoxic microcystin and neurotoxic anatoxin production were N and P co-limited with microcystin production becoming nutrient deplete under 40% dilution. During August, the Maumee Bay bloom produced microcystin under nutrient repletion with slight induced P limitation under 40% dilution, and the Sandusky Bay bloom produced anatoxin under N limitation in both dilution treatments. The results demonstrate the importance of nutrient limitation effects on microcystin and anatoxin production. To properly combat cyanotoxin and cyanobacterial biomass production in WLE, both N and P reduction efforts should be implemented in its watershed.
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Li J, Liao R, Tao Y, Zhuo Z, Liu Z, Deng H, Ma H. Probing the Cyanobacterial Microcystis Gas Vesicles after Static Pressure Treatment: A Potential In Situ Rapid Method. SENSORS 2020; 20:s20154170. [PMID: 32727053 PMCID: PMC7435630 DOI: 10.3390/s20154170] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 07/24/2020] [Accepted: 07/24/2020] [Indexed: 11/21/2022]
Abstract
The vertical migration trend of cyanobacterial cells with gas vesicles in water ecosystems can reflect the changes in the natural environment, such as temperature, nutrients, light conditions, etc. The static pressure treatment is one of the most important approaches to study the properties of the cyanobacterial cell and its gas vesicles. In this paper, a polarized light scattering method is used to probe the collapse and regeneration of the cyanobacterial gas vesicles exposed to different static pressures. During the course, both the axenic and wild type strain of cyanobacterial Microcystis were first treated with different static pressures and then recovered on the normal light conditions. Combining the observation of transmission electron microscopy and floating-sinking photos, the results showed that the collapse and regeneration of the cyanobacterial gas vesicles exposed to different static pressures can be characterized by the polarization parameters. The turbidity as a traditional indicator of gas vesicles but subjected to the concentration of the sample was also measured and found to be correlated with the polarization parameters. More analysis indicated that the polarization parameters are more sensitive and characteristic. The polarized light scattering method can be used to probe the cyanobacterial gas vesicles exposed to different static pressures, which has the potential to provide an in situ rapid and damage-free monitoring tool for observing the vertical migration of cyanobacterial cells and forecasting cyanobacterial blooms.
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Affiliation(s)
- Jiajin Li
- Department of Biomedical Engineering, Tsinghua University, Beijing 100084, China; (J.L.); (Z.L.); (H.D.)
| | - Ran Liao
- Division of Ocean Science and Technology, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
- Correspondence: ; Tel.: +86-755-869-75-301
| | - Yi Tao
- Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China;
| | - Zepeng Zhuo
- Department of Physics, Tsinghua University, Beijing 100084, China; (Z.Z.); (H.M.)
| | - Zhidi Liu
- Department of Biomedical Engineering, Tsinghua University, Beijing 100084, China; (J.L.); (Z.L.); (H.D.)
| | - Hanbo Deng
- Department of Biomedical Engineering, Tsinghua University, Beijing 100084, China; (J.L.); (Z.L.); (H.D.)
| | - Hui Ma
- Department of Physics, Tsinghua University, Beijing 100084, China; (Z.Z.); (H.M.)
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