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Yao X, Zhao Z, Wang J, Kimirei IA, Sekadende BC, Mgana HF, Zhang L. Microbial nitrogen nutrition links to dissolved organic matter properties in East African lakes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 950:175197. [PMID: 39094654 DOI: 10.1016/j.scitotenv.2024.175197] [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: 04/04/2024] [Revised: 07/18/2024] [Accepted: 07/30/2024] [Indexed: 08/04/2024]
Abstract
East African lakes, especially soda lakes, are home habitats for massive numbers of wildlife such as flamingos, mammals, and fishes. These lakes are known for their high primary production due to local high temperatures, light intensities, and alkalinity (inorganic carbon). However, these lakes, normally within remote areas, receive low nutrient inputs. Ammonium (NH4+) recycling and/or nitrogen fixation can become the major N supply mechanisms for phytoplankton. However, the driving forces on microbial N nutrition in lakes with minimal anthropogenic disturbance remain poorly understood. Using stable isotope tracer techniques, NH4+ recycling rates were measured in 18 lakes and reservoirs in East Africa (Tanzania and Kenya) during the dry season in early 2020. Three functional genes (nifH, gdh, and ureC) relating to microbial N nutrition were also measured. The regeneration of NH4+ supported up to 71 % of the NH4+ uptake. Positive community biological NH4+ demands (CBAD) for all lakes and reservoirs indicate an obvious N demand from microbial community. Our study provides clear evidence that microbial NH4+ uptake rates linked closely to the dissolved organic matter (DOM) properties (e.g., the absorption coefficient at 254 nm, percents of total fluorescence intensity contributed by microbial humic-like and protein-like components) and that water residence time drives microbial NH4+ recycling by regulating the duration of in-lake DOM processing and influencing algal growth. Phytoplankton, especially those of Cyanophyceae, showed maximum biomass and higher NH4+ recycling rates at a certain range of water residence time (e.g., 5-8 years). However, CBAD showed a decreasing trend with longer water residence time, which may be influenced by changes in the algal community composition (e.g., % Cyanophyceae vs. % Bacillariophyceae). These results indicate that DOM dynamics and the water residence time have the potential to facilitate the understanding of microbial nitrogen supply status in East African lakes.
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Affiliation(s)
- Xiaolong Yao
- Key Laboratory of Lake and Watershed Science for Water Security, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Zhonghua Zhao
- Key Laboratory of Lake and Watershed Science for Water Security, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; 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, Nanjing 211135, China
| | - Jianjun Wang
- Key Laboratory of Lake and Watershed Science for Water Security, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; 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, Nanjing 211135, China
| | | | | | | | - Lu Zhang
- Key Laboratory of Lake and Watershed Science for Water Security, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; 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, Nanjing 211135, China.
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2
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Kurniawan KIA, Putra AS, Ishizaki R, Rani DS, Rahmah DM, Al Husna SN, Ahamed T, Noguchi R. Life cycle assessment of integrated microalgae oil production in Bojongsoang Wastewater Treatment Plant, Indonesia. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:7902-7933. [PMID: 38168854 DOI: 10.1007/s11356-023-31582-6] [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: 01/02/2023] [Accepted: 12/12/2023] [Indexed: 01/05/2024]
Abstract
This study aims to determine the eco-friendliness of microalgae-based renewable energy production in several scenarios based on life cycle assessment (LCA). The LCA provides critical data for sustainable decision-making and energy requirement analysis, including net energy ratio (NER) and cumulative energy demand (CED). The Centrum voor Milieuwetenschappen Leiden (CML) IA-Baseline was used on environmental impact assessment method by SimaPro v9.3.0.3® software and energy analysis of biofuel production using native polyculture microalgae biomass in municipal wastewater treatment plants (WWTP) Bojongsoang, Bandung, Indonesia. The study was analyzed under three scenarios: (1) the current scenario; (2) the algae scenario without waste heat and carbon dioxide (CO2); and (3) the algae scenario with waste heat and carbon dioxide (CO2). Waste heat and CO2 were obtained from an industrial zone near the WWTP. The results disclosed that the microalgae scenario with waste heat and CO2 utilization is the most promising scenario with the lowest environmental impact (- 0.139 kg CO2eq/MJ), positive energy balance of 1.23 MJ/m3 wastewater (NER > 1), and lower CED value across various impact categories. It indicates that utilizing the waste heat and CO2 has a positive impact on energy efficiency. Based on the environmental impact, NER and CED values, this study suggests that the microalgae scenario with waste heat and CO2 is more feasible and sustainable to adopt and could be implemented at the Bojongsoang WWTP.
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Affiliation(s)
| | - Agusta Samodra Putra
- Research Center for Sustainable Production System and Life Cycle Assessment, National Research and Innovation Agency, Puspiptek Area, Serpong, 15314, Indonesia
| | | | - Devitra Saka Rani
- Research Organization for Energy and Manufacture, National Research and Innovation Agency, Puspiptek Area, Serpong, 15314, Indonesia
| | - Devi Maulida Rahmah
- Faculty of Agricultural Industrial Technology, Universitas Padjadjaran, Sumedang, Indonesia
| | - Shabrina Nida Al Husna
- Department of Microbiology, School of Life Sciences and Technology, Institut Teknologi Bandung, Jl. Ganesa No.10, Lb. Siliwangi, Kecamatan Coblong, Kota Bandung, Jawa Barat, 40132, Indonesia
| | - Tofael Ahamed
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Ryozo Noguchi
- Laboratory of Agricultural Systems Engineering, Division of Environmental Science and Technology, Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502, Japan.
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Yao X, Zhao Z, Wang J, Ding Q, Ren M, Kimirei IA, Zhang L. Sediment organic matter properties facilitate understanding nitrogen transformation potentials in East African lakes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 841:156607. [PMID: 35690192 DOI: 10.1016/j.scitotenv.2022.156607] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 06/06/2022] [Accepted: 06/06/2022] [Indexed: 06/15/2023]
Abstract
East African lakes include the most productive and alkaline lake group in the world. Yet, they generally receive fewer nutrient inputs than the densely populated subtropical and temperate lakes in the northern hemisphere. In these lakes with insufficient supplies of inorganic nitrogen, the mineralization of benthic organic matter can play an important role in driving the nutrient cycle and nitrogen loss. Using a suite of stable 15N isotope dilution and tracer techniques, we examined five main processes of the sediment nitrogen cycle in 16 lakes and reservoirs of Tanzania and Kenya, East Africa: gross nitrogen mineralization, ammonium immobilization, dissimilatory nitrate reduction to ammonium (DNRA), and the dinitrogen (N2) production via denitrification and anaerobic ammonium oxidation (anammox). Gross nitrogen mineralization and ammonium immobilization showed the maximum values of 9.84 and 12.39 μmol N kg-1 h-1, respectively. Potential DNRA rates ranged from 0.22 to 8.15 μmol N kg-1 h-1 and accounted for 10 %-74 % (average 25 %) of the total dissimilatory nitrate reduction. Potential nitrate reduction rates in most lakes were dominated by denitrification with a contribution of 26 %-85 % and a mean of 65 %. We further found that the sediment nitrogen transformations were driven mainly by benthic organic matter properties and water column phosphate concentrations, reflecting microbial metabolic responses to the changing carbon and nutrients availability. For instance, autochthonous production of protein-like organic matter attributed to active sediment nitrogen mineralization, DNRA, and denitrification. In contrast, the high degree of humification caused by the inputs of terrestrial humic-like substances slowed down the sediment nitrogen transformations. The contribution of DNRA to total dissimilatory nitrate reduction was significantly positively correlated to sediment C: N ratios. These results indicate that predictions of sediment N supply and loss in East African lakes can be improved by incorporating sediment organic matter properties.
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Affiliation(s)
- Xiaolong Yao
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; Sino-Africa Joint Research Center, Chinese Academy of Sciences, Wuhan 430074, China
| | - Zhonghua Zhao
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; Sino-Africa Joint Research Center, Chinese Academy of Sciences, Wuhan 430074, China
| | - Jianjun Wang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; Sino-Africa Joint Research Center, Chinese Academy of Sciences, Wuhan 430074, China
| | - Qiqi Ding
- 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 10049, China
| | - Minglei Ren
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | | | - Lu Zhang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; Sino-Africa Joint Research Center, Chinese Academy of Sciences, Wuhan 430074, China.
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4
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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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5
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Identifying the Mechanisms behind the Positive Feedback Loop between Nitrogen Cycling and Algal Blooms in a Shallow Eutrophic Lake. WATER 2021. [DOI: 10.3390/w13040524] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Algal blooms have increased in frequency, intensity, and duration in response to nitrogen (N) cycling in freshwater ecosystems. We conducted a high-resolution sedimentary study of N transformation and its associated microbial activity in Lake Taihu to assess the accumulation rates of the different N fractions in response to algal blooms, aiming to understand the mechanisms of N cycling in lacustrine environments. Downcore nitrification and denitrification processes were measured simultaneously in situ via diffusive gradients in thin-films technique, peeper, and microelectrode devices in a region of intensified algal blooms of shallow lake. The decomposition of different biomasses of algal blooms did not change the main controlling factor on different N fractions in profundal sediment. However, the decomposition of different algal biomasses led to significant differences in the nitrification and denitrification processes at the sediment–water interface (SWI). Low algal biomasses facilitated the classic process of N cycling, with the balanced interaction between nitrification and denitrification. However, the extreme hypoxia under high algal biomasses significantly limited nitrification at the SWI, which in turn, restricted denitrification due to the lack of available substrates. Our high-resolution results combined with estimates of apparent diffusion fluxes of the different N fractions inferred that the lack of substrates for denitrification was the main factor influencing the positive feedback loop between N and eutrophication in freshwater ecosystems. Moreover, this positive feedback can become irreversible without technological intervention.
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Huang Y, Li Y, Ji D, Nwankwegu AS, Lai Q, Yang Z, Wang K, Wei J, Norgbey E. Study on nutrient limitation of phytoplankton growth in Xiangxi Bay of the Three Gorges Reservoir, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 723:138062. [PMID: 32217395 DOI: 10.1016/j.scitotenv.2020.138062] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 03/17/2020] [Accepted: 03/18/2020] [Indexed: 06/10/2023]
Abstract
After the impoundment of the Three Gorges Reservoir (TGR), algal blooms in the sidearm tributaries have resulted from increasing nutrient loads along the major tributaries. Field sampling and in situ nutrient addition bioassay were implemented to examine the nutrient limitation of phytoplankton growth and bloom initiation during autumn in Xiangxi Bay of the TGR. Result shows that P is the primary limiting nutrient for algal growth and bloom in Xiangxi Bay during autumn. The treatment involving the combination of N, P and Si had a significant (p < .05) additional effect on the growth of phytoplankton. The N, P, Si combined treatment increased growth by 10-50% relative to the N and P treatments from day 1 to day 4, respectively. Trace metal additions involving Fe, Zn, Mn, and Cu and/or in combination with N, P, and Si initially resulted in an extremely low growth rate which later increased significantly (p < .05) towards the end of the study. The present study provides an insight into the responses of different phytoplankton taxa in autumn under nutrient conditions in the tributary bay. The nutrient limitation study is recognized as the first step to mitigating the bloom while proposing an effective nutrient control strategy. The outcome of which can provide the basis for formulating sustainable watershed management. Multiple nutrients reductions with P as primary concern are required for a lasting management solution to the risk of bloom in the TGR.
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Affiliation(s)
- Yanan Huang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Yiping Li
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China.
| | - Daobin Ji
- College of Hydraulic and Environmental Engineering, Three Gorges University, Yichang 443002, Hubei, China
| | - Amechi S Nwankwegu
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Qiuying Lai
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Zhengjian Yang
- College of Hydraulic and Environmental Engineering, Three Gorges University, Yichang 443002, Hubei, China
| | - Kai Wang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Jin Wei
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Eyram Norgbey
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
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7
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Glibert PM. Harmful algae at the complex nexus of eutrophication and climate change. HARMFUL ALGAE 2020; 91:101583. [PMID: 32057336 DOI: 10.1016/j.hal.2019.03.001] [Citation(s) in RCA: 120] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 03/07/2019] [Indexed: 05/21/2023]
Abstract
Climate projections suggest-with substantial certainty-that global warming >1.5 °C will occur by mid-century (2050). Population is also projected to increase, amplifying the demands for food, fuel, water and sanitation, which, in turn, escalate nutrient pollution. Global projections of nutrient pollution, however, are less certain than those of climate as there are regionally decreasing trends projected in Europe, and stabilization of nutrient use in North America and Australia. In this review of the effects of eutrophication and climate on harmful algae, some of the complex, subtle, and non-intuitive effects and interactions on the physiology of both harmful and non-harmful taxa are emphasized. In a future ocean, non-harmful diatoms may be disproportionately stressed and mixotrophs advantaged due to changing nutrient stoichiometry and forms of nutrients, temperature, stratification and oceanic pH. Modeling is advancing, but there is much yet to be understood, in terms of physiology, biogeochemistry and trophodynamics and how both harmful and nonharmful taxa may change in an uncertain future driven by anthropogenic activities.
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Affiliation(s)
- Patricia M Glibert
- University of Maryland Center for Environmental Science, Horn Point Laboratory, PO Box 775, Cambridge, MD, 21613, United States.
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Lu K, Liu Z, Dai R, Gardner WS. Urea dynamics during Lake Taihu cyanobacterial blooms in China. HARMFUL ALGAE 2019; 84:233-243. [PMID: 31128808 DOI: 10.1016/j.hal.2019.03.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 01/04/2019] [Accepted: 03/18/2019] [Indexed: 06/09/2023]
Abstract
Lake Taihu, the third largest freshwater lake in China, suffers from harmful cyanobacteria blooms caused by Microcystis spp., which do not fix nitrogen (N). Reduced N (i.e., NH4+, urea and other labile organic N compounds) is an important factor affecting the growth of Microcystis. As the world use of urea as fertilizer has escalated during the past decades, an understanding of how urea cycling relates to blooms of Microcystis is critical to predicting, controlling and alleviating the problem. In this study, the cycling rates of urea-N in Lake Taihu ranged from non-detectable to 1.37 μmol N L-1 h-1 for regeneration, and from 0.042 μmol N L-1 h-1 to 2.27 μmol N L-1 h-1 for potential urea-N removal. The fate of urea-N differed between light and dark incubations. Increased 15NH4+ accumulated and higher quantities of the removed urea-15N remained in the 15NH4+ form were detected in the dark than in the light. A follow-up incubation experiment with 15N-urea confirmed that Microcystis can grow on urea but its effects on urea dynamics were minor, indicating that Microcystis was not the major factor causing the observed fates of urea under different light conditions in Lake Taihu. Bacterial community composition and predicted functional gene data suggested that heterotrophic bacteria metabolized urea, even though Microcystis spp. was the dominant bloom organism.
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Affiliation(s)
- Kaijun Lu
- The University of Texas at Austin, Marine Science Institute, Port Aransas, TX, 78373, USA.
| | - Zhanfei Liu
- The University of Texas at Austin, Marine Science Institute, Port Aransas, TX, 78373, USA
| | - Ruihua Dai
- Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China
| | - Wayne S Gardner
- The University of Texas at Austin, Marine Science Institute, Port Aransas, TX, 78373, USA
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Zhang X, Li B, Xu H, Wells M, Tefsen B, Qin B. Effect of micronutrients on algae in different regions of Taihu, a large, spatially diverse, hypereutrophic lake. WATER RESEARCH 2019; 151:500-514. [PMID: 30641465 DOI: 10.1016/j.watres.2018.12.023] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 12/04/2018] [Accepted: 12/05/2018] [Indexed: 05/03/2023]
Abstract
Eutrophication or excessive nutrient richness is an impairment of many freshwater ecosystems and a prominent cause of harmful algal blooms. It is generally accepted that nitrogen and phosphorus nutrients are the primary causative factor, however, for systems subject to large anthropogenic perturbation, this may no longer be true, and the role of micronutrients is often overlooked. Here we report a study on Lake Tai (Taihu), a large, spatially diverse and hypereutrophic lake in China. We performed small-scale mesocosm nutrient limitation bioassays using boron, iron, cobalt, copper, molybdenum, nitrogen and phosphorus on phytoplankton communities sampled from different locations in Taihu to test the relative effects of micronutrients on in situ algal assemblages. In addition to commonly-used methods of chemical and biological analysis (including algal phytoplankton counting), we used flow cytometry coupled with data-driven analysis to monitor changes to algal assemblages. We found statistically significant effects of limitation or co-limitation for boron, cobalt, copper and iron. For copper at one location chlorophyll-a was over four times higher for amendment with copper, nitrogen and phosphorous than for the latter two alone. Since copper is often proposed as amendment for the environmental management of harmful algal blooms, this result is significant. We have three primary conclusions: first, the strong effects for Cu that we report here are mutually consistent across chlorophyll-a results, count data, and results determined from a data-driven approach to flow cytometry. Given that we cannot rule out a role for a Fe-Cu homeostatic link in causing these effects, future research into MNs and how they interact with N, P, and other MNs should be pursued to explore new interventions for effective management of HABs. Second, in view of the stimulatory effect that Cu exhibited, management of HABs with Cu as an algal biocide may not always be advisable. Third, our approach to flow cytometry offers data confirming our results from chemical and biological analysis, however also holds promise for future development as a high-throughput tool for use in understanding changes in algal assemblages. The results from this study concur with a small and emerging body of literature suggesting that the potential role of micronutrients in eutrophication requires further consideration in environmental management.
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Affiliation(s)
- Xiaokai Zhang
- Department of Biological Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, Jiangsu, 215123, PR China; Department of Environmental Science, University of Liverpool, Brownlow Hill, Liverpool, L69 7ZX, United Kingdom
| | - Boling Li
- Department of Biological Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, Jiangsu, 215123, PR China; Department of Environmental Science, University of Liverpool, Brownlow Hill, Liverpool, L69 7ZX, United Kingdom
| | - Hai Xu
- Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, PR China
| | - Mona Wells
- Freshwater Ecology Group, National Institute of Water and Atmospheric Research, Dunedin, 9016, New Zealand.
| | - Boris Tefsen
- Department of Biological Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, Jiangsu, 215123, PR China
| | - Boqiang Qin
- Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, PR China
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10
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Hampel JJ, McCarthy MJ, Neudeck M, Bullerjahn GS, McKay RML, Newell SE. Ammonium recycling supports toxic Planktothrix blooms in Sandusky Bay, Lake Erie: Evidence from stable isotope and metatranscriptome data. HARMFUL ALGAE 2019; 81:42-52. [PMID: 30638497 DOI: 10.1016/j.hal.2018.11.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 08/10/2018] [Accepted: 11/16/2018] [Indexed: 05/03/2023]
Abstract
Sandusky Bay, Lake Erie, receives high nutrient loadings (nitrogen and phosphorus) from the Sandusky River, which drains an agricultural watershed. Eutrophication and cyanobacterial harmful algal blooms (cyanoHABs) persist throughout summer. Planktothrix agardhii is the dominant bloom-forming species and the main producer of microcystins in Sandusky Bay. Non-N2 fixing cyanobacteria, such as Planktothrix and Microcystis, thrive on chemically reduced forms of nitrogen, such as ammonium (NH4+) and urea. Ammonium regeneration and potential uptake rates and total microbial community demand for NH4+ were quantified in Sandusky Bay. Potential NH4+ uptake rates in the light increased from June to August at all stations. Dark uptake rates also increased seasonally and, by the end of August, were on par with light uptake rates. Regeneration rates followed a similar pattern and were significantly higher in August than June. Ammonium uptake kinetics during a Planktothrix-dominated bloom in Sandusky Bay and a Microcystis-dominated bloom in Maumee Bay were also compared. The highest half saturation constant (Km) in Sandusky Bay was measured in June and decreased throughout the season. In contrast, Km values in Maumee Bay were lowest at the beginning of summer and increased in October. A significant increase in Vmax in Sandusky Bay was observed between July and the end of August, reflective of intense competition for depleted NH4+. Metatranscriptome results from Sandusky Bay show a shift from cyanophycin synthetase (luxury NH4+ uptake; cphA1) expression in early summer to cyanophycinase (intracellular N mobilization; cphB/cphA2) expression in August, supporting the interpretation that the microbial community is nitrogen-starved in late summer. Combined, our results show that, in late summer, when nitrogen concentrations are low, cyanoHABs in Sandusky Bay rely on regenerated NH4+ to support growth and toxin production. Increased dark NH4+ uptake late in summer suggests an important heterotrophic contribution to NH4+ depletion in the phycosphere. Kinetic experiments in the two bays suggest a competitive advantage for Planktothrix over Microcystis in Sandusky Bay due to its higher affinity for NH4+ at low concentrations.
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Affiliation(s)
- Justyna J Hampel
- Department of Earth & Environmental Sciences, Wright State University, Dayton, OH, United States.
| | - Mark J McCarthy
- Department of Earth & Environmental Sciences, Wright State University, Dayton, OH, United States
| | - Michelle Neudeck
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH, United States
| | - George S Bullerjahn
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH, United States
| | - Robert Michael L McKay
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH, United States
| | - Silvia E Newell
- Department of Earth & Environmental Sciences, Wright State University, Dayton, OH, United States
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11
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Dominance and Growth Factors of Pseudanabaena sp. in Drinking Water Source Reservoirs, Southern China. SUSTAINABILITY 2018. [DOI: 10.3390/su10113936] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Pseudanabaena sp. is a common and harmful species in freshwater cyanobacteria blooms. There are very few studies on its distribution characteristics and growth influencing factors. In the current study, it was found to be dominant in three cascading reservoirs in Southern China. Field observations and laboratory experiments were integrated to investigate the dominance and growth factors of Pseudanabaena sp. The effects of temperature, light intensity, nutrients, chemical oxygen demand (COD), pH, and disturbance on Pseudanabaena sp. growth were evaluated. The results indicated that Pseudanabaena sp. had significant positive correlations with water temperature, pH, and COD (p < 0.01) and a positive correlation with NH3-N (p < 0.05). The optimum growth temperature range for Pseudanabaena sp. was from 20 to 30 °C; hence, it usually has outbreaks in May and August. The optimum light intensity and pH for Pseudanabaena sp. were 27 μmol photons m−2s−1 and from 7 to 9, respectively. The superior tolerance for low light, disturbance, and phosphorus deficiency of Pseudanabaena sp. may be the main factors affecting its dominance in reservoirs. Controlling nitrogen was more effective than controlling phosphorus to avoid the risk that was brought by Pseudanabaena sp. This study contributed to the theoretical knowledge for the prediction and control of the growth of Pseudanabaena sp.
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Beyond Eutrophication: Vancouver Lake, WA, USA as a Model System for Assessing Multiple, Interacting Biotic and Abiotic Drivers of Harmful Cyanobacterial Blooms. WATER 2018. [DOI: 10.3390/w10060757] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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