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Wang M, Bian W, Qi X, He D, Lu H, Yang L. Cycles of solar ultraviolet radiation favor periodic expansions of cyanobacterial blooms in global lakes. WATER RESEARCH 2024; 255:121471. [PMID: 38503183 DOI: 10.1016/j.watres.2024.121471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 02/12/2024] [Accepted: 03/12/2024] [Indexed: 03/21/2024]
Abstract
Global warming and eutrophication are known to increase the prevalence of cyanobacterial blooms, posing a severe threat to the ecological stability and sustainability of water bodies. The long-term (over an annual time frame) effect of UV radiation on cyanobacterial blooms in lakes are rarely discussed though the substantial effects of high-intensity UV radiation on the growth inhibition of marine phytoplankton were studied. Here, we employed the datasets on surface solar UV radiation, nitrogen and phosphorus concentrations, and the annual scales and frequencies of cyanobacterial blooms in lakes across long-term spatial scales to probe the relationship of UV radiation with cyanobacterial blooms. The results indicated that enhanced solar UV radiation may unintentionally stimulate cyanobacterial growth and favor the expansions of cyanobacterial blooms in lakes around the world. The fluctuating UV radiation significantly affects the annual scales of cyanobacterial blooms in both eutrophic and oligotrophic lakes. Solar UV radiation enhances the positive impact of rising phosphorus levels on cyanobacterial blooms because UV radiation prompts the synthesis of polyphosphate in cyanobacteria cells, which helps cyanobacteria to alleviate the stress of UV light. The scales of cyanobacterial blooms are significantly impacted by solar UV radiation intensities as opposed to the annual frequency of cyanobacterial blooms. Furthermore, solar UV radiation fluctuation with a 9-year period over a 14-year main cycles significantly affects the periodicities of cyanobacterial blooms in global lakes, which provides a basis for predicting the peak value of the scales of cyanobacterial blooms in lakes. These findings opened up new avenues of inquiry into the mechanism and management strategies of cyanobacterial blooms in lakes worldwide.
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Affiliation(s)
- Mengmeng Wang
- State Key Laboratory of Pollution Control and Research Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Wenbin Bian
- State Key Laboratory of Pollution Control and Research Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Ximeng Qi
- Joint International Research Laboratory of Atmospheric and Earth System Sciences, School of Atmospheric Sciences, Nanjing University, Nanjing 210023, China
| | - Di He
- State Key Laboratory of Pollution Control and Research Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Hao Lu
- Nanjing Hydraulic Research Institute, Nanjing 210029, China
| | - Liuyan Yang
- State Key Laboratory of Pollution Control and Research Reuse, School of Environment, Nanjing University, Nanjing 210023, China.
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Parajuli S, Beattie GAC, Holford P, Yang C, Cen Y. Susceptibility of Diaphorina citri to Irradiation with UV-A and UV-B and the Applicability of the Bunsen-Roscoe Reciprocity Law. INSECTS 2023; 14:insects14050445. [PMID: 37233073 DOI: 10.3390/insects14050445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 05/01/2023] [Accepted: 05/01/2023] [Indexed: 05/27/2023]
Abstract
Populations of Diaphorina citri decline with elevation and, in a study in Bhutan, were rarely found above 1200 m ASL. The impact of ultraviolet (UV) radiation, particularly UV-B, on immature stages of the psyllid was proposed as limiting factor. As no studies have been undertaken on the influences of UV radiation on the development of D. citri, we examined the effects of UV-A and UV-B on different stadia of the psyllid. In addition, compliance with the Bunsen-Roscoe reciprocity law was examined. Irradiation with UV-A marginally reduced egg hatch and the survival times of emerging nymphs. Early instar nymphs were little affected by this waveband, but the survival of adults was reduced at the higher doses used. With UV-B, egg hatch and the survival times of early and late instar nymphs declined in proportion to UV-B dose. A dose of 57.6 kJ m-2 d-1 reduced the survival time of only adult females. Female fecundity was reduced at high UV-A and UV-B doses but increased at low doses. The Bunsen-Roscoe law held true for eggs and early instar nymphs for different durations and irradiances of UV-B. Eggs and nymphs had ED50 values for UV-B lower than the daily fluxes of this wavelength experienced worldwide. Thus, UV-B could be a factor causing the psyllid to be scarce at high elevations.
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Affiliation(s)
- Sabina Parajuli
- Citrus Huanglongbing Research Laboratory/Key Laboratory of Bio-Pesticide Innovation and Application/National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou 510642, China
| | | | - Paul Holford
- School of Science, University of Western Sydney, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - Chuping Yang
- College of Electronic Engineering, South China Agricultural University, Guangzhou 510642, China
| | - Yijing Cen
- Citrus Huanglongbing Research Laboratory/Key Laboratory of Bio-Pesticide Innovation and Application/National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou 510642, China
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3
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Rivas-Zaballos I, Romero-Martínez L, Moreno-Garrido I, Acevedo-Merino A, Nebot E. Evaluation of three photosynthetic species smaller than ten microns as possible standard test organisms of ultraviolet-based ballast water treatment. MARINE POLLUTION BULLETIN 2021; 170:112643. [PMID: 34175694 DOI: 10.1016/j.marpolbul.2021.112643] [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: 01/30/2021] [Revised: 06/13/2021] [Accepted: 06/15/2021] [Indexed: 06/13/2023]
Abstract
The Ballast Water Management Convention (BWMC) establishes limits for viable organisms in discharged ballast water. However, organisms smaller than 10 μm are not considered in this regulation although they represent, in some regions, the majority of the phytoplankton organisms in marine water. The objective in this study is to assess three photosynthetic species smaller than 10 μm as potential standard test organism (STO) in experimentation focused on the inactivating efficacy of ultraviolet treatments (UV). A growth modelling method was employed to determine the reduction of the viable cell concentration under either light or dark post-treatment conditions to evaluate the importance of the photoreactivation. In spite of its moderate growth rate, the high UV resistance in combination with the abundance and worldwide distribution of Synechococcus sp. and the environmental importance of this species constitute important reasons for considering Synechococcus sp. as a valuable STO for ballast water treatment.
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Affiliation(s)
- Ignacio Rivas-Zaballos
- Department of Environmental Technologies, Faculty of Marine and Environmental Sciences, INMAR - Marine Research Institute, CEIMAR - International Campus of Excellence of the Sea, University of Cadiz, Spain..
| | - Leonardo Romero-Martínez
- Department of Environmental Technologies, Faculty of Marine and Environmental Sciences, INMAR - Marine Research Institute, CEIMAR - International Campus of Excellence of the Sea, University of Cadiz, Spain
| | - Ignacio Moreno-Garrido
- Institute of Marine Sciences of Andalusia (CSIC), Campus Río San Pedro, s/n, 11510 Puerto Real, Cádiz, Spain
| | - Asunción Acevedo-Merino
- Department of Environmental Technologies, Faculty of Marine and Environmental Sciences, INMAR - Marine Research Institute, CEIMAR - International Campus of Excellence of the Sea, University of Cadiz, Spain
| | - Enrique Nebot
- Department of Environmental Technologies, Faculty of Marine and Environmental Sciences, INMAR - Marine Research Institute, CEIMAR - International Campus of Excellence of the Sea, University of Cadiz, Spain
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4
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Romero-Martínez L, Rivas-Zaballos I, Moreno-Andrés J, Moreno-Garrido I, Acevedo-Merino A, Nebot E. Improving the microalgae inactivating efficacy of ultraviolet ballast water treatment in combination with hydrogen peroxide or peroxymonosulfate salt. MARINE POLLUTION BULLETIN 2021; 162:111886. [PMID: 33310544 DOI: 10.1016/j.marpolbul.2020.111886] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 11/23/2020] [Accepted: 11/25/2020] [Indexed: 06/12/2023]
Abstract
Due to the increasing number of ecosystem invasions with the introduction of exogenous species via ballast water, the International Maritime Organization adopted the Ballast Water Convention (BWMC). The BWMC establishes standards for the concentration of viable organisms in a ballast water discharge. Ultraviolet (UV) irradiation is commonly used for treating ballast water; however, regrowth after UV irradiation and other drawbacks have been reported. In this study, improvement in UV treatment with the addition of hydrogen peroxide or peroxymonosulfate salt was investigated using the microalgae Tetraselmis suecica as the target organism. Results reported that each of these reagents added in a concentration of 10 ppm reduced the concentration of initial cells by more than 96%, increased the UV inactivation rate, and enabled reaching greater level of inactivation with the treatment. These improvements imply a reduction of the UV doses required for a consistent compliance with the BWMC standards.
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Affiliation(s)
- Leonardo Romero-Martínez
- Department of Environmental Technologies, Faculty of Marine and Environmental Sciences. INMAR - Marine Research Institute, CEIMAR - International Campus of Excellence of the Sea. University of Cadiz. Spain.
| | - Ignacio Rivas-Zaballos
- Department of Environmental Technologies, Faculty of Marine and Environmental Sciences. INMAR - Marine Research Institute, CEIMAR - International Campus of Excellence of the Sea. University of Cadiz. Spain
| | - Javier Moreno-Andrés
- Department of Environmental Technologies, Faculty of Marine and Environmental Sciences. INMAR - Marine Research Institute, CEIMAR - International Campus of Excellence of the Sea. University of Cadiz. Spain
| | - Ignacio Moreno-Garrido
- Institute of Marine Sciences of Andalusia (CSIC), Campus Río San Pedro, s/n 11510, Puerto Real, Cádiz, Spain
| | - Asunción Acevedo-Merino
- Department of Environmental Technologies, Faculty of Marine and Environmental Sciences. INMAR - Marine Research Institute, CEIMAR - International Campus of Excellence of the Sea. University of Cadiz. Spain
| | - Enrique Nebot
- Department of Environmental Technologies, Faculty of Marine and Environmental Sciences. INMAR - Marine Research Institute, CEIMAR - International Campus of Excellence of the Sea. University of Cadiz. Spain
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Li S, Tao Y, Zhan XM, Dao GH, Hu HY. UV-C irradiation for harmful algal blooms control: A literature review on effectiveness, mechanisms, influencing factors and facilities. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 723:137986. [PMID: 32222502 DOI: 10.1016/j.scitotenv.2020.137986] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Revised: 03/11/2020] [Accepted: 03/15/2020] [Indexed: 06/10/2023]
Abstract
UV-C irradiation has drawn much attention in recent years as a candidate for controlling harmful algal blooms (HABs). In this review, we have collated the recent knowledge about the UV-C irradiation technique for suppressing HABs, including the effectiveness, mechanisms, influencing factors, growth recovery pattern, and UV-C irradiation facilities. Most microalgal species have been proved to be effectively suppressed by UV-C irradiation and the suppression effects had positive correlation with UV-C dose. However, the effectiveness on difference algal species varied dramatically. The understanding for growth suppression mechanisms upon UV-C irradiation has been significantly deepened beyond pyrimidine dimers. The suppression effects on algal cell density were the results of UV-induced damage on nucleic acid, light harvesting and electron transfer and transportation, nitrogen fixation and assimilation, toxin synthesis, settle ability, antioxidative capacity and cellular membrane integrity. While several influencing factors, such as algal sensitivities, UV transmittance (UVT), salinity, pH, and microalgal growth recovery should be paid attention to in practical application. UV-C facilities with high maturity, especially flow-through reactors, make it possible to develop ship-born UV-C facilities and put UV-C irradiation technique into real practice on controlling HABs.
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Affiliation(s)
- Shang Li
- Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Tsinghua University, Shenzhen 518055, China
| | - Yi Tao
- Key Laboratory of Microorganism Application and Risk Control (MARC) of Shenzhen, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.
| | - Xin-Min Zhan
- Civil Engineering, College of Engineering & Informatics, National University of Ireland, Galway, Ireland
| | - Guo-Hua Dao
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, China
| | - Hong-Ying Hu
- Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Tsinghua University, Shenzhen 518055, China; Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, China.
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Li S, Dao GH, Tao Y, Zhou J, Jiang HS, Xue YM, Yu WW, Yong XL, Hu HY. The growth suppression effects of UV-C irradiation on Microcystis aeruginosa and Chlorella vulgaris under solo-culture and co-culture conditions in reclaimed water. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 713:136374. [PMID: 31955073 DOI: 10.1016/j.scitotenv.2019.136374] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 12/25/2019] [Accepted: 12/26/2019] [Indexed: 06/10/2023]
Abstract
Harmful algal blooms (HABs) are serious problems in landscape waters sourced from reclaimed water. In this study, the suppression effects of UV-C irradiation on microalgal growth were researched to find a possible preventive approach. Microcystis aeruginosa and Chlorella vulgaris were exposed to UV-C irradiation and then cultured in real reclaimed water for 7-18 d. UV-C irradiation at 50-200 mJ cm-2 could inhibit the growth of M. aeruginosa, C. vulgaris, and both microalgae in co-culture for 3-14, 1-3, and 1-5 d respectively. In addition, UV-C irradiation could cause damage to the cell integrity. At 100-200 mJ cm-2 UV-C, the proportion of microalgal membrane damage (Pmd) in M. aeruginosa cells increased rapidly to 56%-76% from day 3, whereas that in C. vulgaris cells increased to 23%-62% within 3 d. The photochemical efficiency (represented by Y value) of the irradiated groups was negatively affected immediately after UV-C irradiation and recovered gradually during the incubation. The Y value of M. aeruginosa cells began to recover from days 3 to 14, whereas that of C. vulgaris recovered much more quickly, from days 0.1 to 1. Overall, the irradiation-induced suppressive effects on algal growth correlated positively with the UV-C doses. Because M. aeruginosa was more sensitive to UV-C irradiation, UV-C irradiation not only controlled the total biomass of the mixed algae but also selectively reestablished the dominance of the nontoxic C. vulgaris.
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Affiliation(s)
- Shang Li
- Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Tsinghua University, Shenzhen 518055, China
| | - Guo-Hua Dao
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, China
| | - Yi Tao
- Key Laboratory of Microorganism Application and Risk Control (MARC) of Shenzhen, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.
| | - Ji Zhou
- Chengdu Xingrong Environmental Co., Ltd., Chengdu 610041, China
| | - Hai-Sha Jiang
- Chengdu Xingrong Environmental Co., Ltd., Chengdu 610041, China
| | - Yuan-Mei Xue
- Chengdu Xingrong Environmental Co., Ltd., Chengdu 610041, China
| | - Wen-Wen Yu
- Chengdu Xingrong Environmental Co., Ltd., Chengdu 610041, China
| | - Xiao-Lei Yong
- Chengdu Xingrong Environmental Co., Ltd., Chengdu 610041, China
| | - Hong-Ying Hu
- Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Tsinghua University, Shenzhen 518055, China; Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, China.
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7
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Romero-Martínez L, Rivas-Zaballos I, Moreno-Andrés J, Moreno-Garrido I, Acevedo-Merino A, Nebot E. Effect of the length of dark storage following ultraviolet irradiation of Tetraselmis suecica and its implications for ballast water management. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 711:134611. [PMID: 31810674 DOI: 10.1016/j.scitotenv.2019.134611] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 09/20/2019] [Accepted: 09/21/2019] [Indexed: 06/10/2023]
Abstract
Meeting the recent biological standards established by the Ballast Water Management Convention requires the application of ballast water treatment systems; ultraviolet irradiation is a frequently used option. However, organisms can repair the damage caused by ultraviolet irradiation primarily with photo-repair mechanisms that are dependent on the availability of light. The objective of this study is to quantify the impact of dark storage following ultraviolet irradiation on the viability of the microalgae Tetraselmis suecica. Results showed that one day of dark storage after ultraviolet irradiation enhanced the inactivation rate by 50% with respect to the absence of dark storage and increased up to the 84% with five days of dark storage. These results are consistent with photorepair, mostly in the first two days, prevented in the dark. The dose required to inactivate a determined ratio of organisms was correlated with the length of the dark post-treatment according to an inverse proportional function. This correlation may help to optimize the operation of ultraviolet ballast water treatment systems. Further, the results show that growth assays can detect organisms that are capable of repair after treatment with UV.
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Affiliation(s)
- Leonardo Romero-Martínez
- Department of Environmental Technologies, INMAR-Marine Research Institute, University of Cádiz, Campus Universitario Puerto Real, 11510 Puerto Real, Cádiz, Spain.
| | - Ignacio Rivas-Zaballos
- Department of Environmental Technologies, INMAR-Marine Research Institute, University of Cádiz, Campus Universitario Puerto Real, 11510 Puerto Real, Cádiz, Spain
| | - Javier Moreno-Andrés
- Department of Environmental Technologies, INMAR-Marine Research Institute, University of Cádiz, Campus Universitario Puerto Real, 11510 Puerto Real, Cádiz, Spain
| | - Ignacio Moreno-Garrido
- Institute of Marine Sciences of Andalucía (CSIC), Campus Río San Pedro, s/n 11510, Puerto Real, Cádiz, Spain
| | - Asunción Acevedo-Merino
- Department of Environmental Technologies, INMAR-Marine Research Institute, University of Cádiz, Campus Universitario Puerto Real, 11510 Puerto Real, Cádiz, Spain
| | - Enrique Nebot
- Department of Environmental Technologies, INMAR-Marine Research Institute, University of Cádiz, Campus Universitario Puerto Real, 11510 Puerto Real, Cádiz, Spain
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Lundgreen K, Holbech H, Pedersen KL, Petersen GI, Andreasen RR, George C, Drillet G, Andersen M. Use of standard test organisms for sound validation of UV-based ballast water treatment systems. MARINE POLLUTION BULLETIN 2019; 144:253-264. [PMID: 31179995 DOI: 10.1016/j.marpolbul.2019.04.072] [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: 03/11/2019] [Revised: 04/27/2019] [Accepted: 04/28/2019] [Indexed: 06/09/2023]
Abstract
To challenge ballast water treatment system (BWTS) efficacy for organisms in the size-class 10-50 μm, intake concentration during tests must reach certain minimum requirements. Often, natural concentrations are too low to meet intake requirements and standard test organisms (STOs) are added. We tested the robustness of Tetraselmis suecica and Odontella sp. to a range of UV-treatments to explore fluences needed to meet the IMO discharge standard (<10 org. ml-1) evaluated using two viability assessment methods. To meet discharge standards, fluences of >1000 mJ cm-2 were required using vital stain whereas 135-500 mJ cm-2 were needed using regrowth assays. Besides, results suggest that T. suecica and Odontella sp. were at least as robust as natural algae towards UV-treatments. We suggest the advantageous use of these species as STOs in test water to support intake water requirements and to obtain more conservative validation of UV-based BWTS to ensure more environmental protective procedures.
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Affiliation(s)
- Kim Lundgreen
- Department of Biology, University of Southern Denmark, Odense M, Denmark.
| | - Henrik Holbech
- Department of Biology, University of Southern Denmark, Odense M, Denmark
| | | | | | | | - Christaline George
- Integrative Microbiology, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
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MacIntyre HL, Cullen JJ, Whitsitt TJ, Petri B. Enumerating viable phytoplankton using a culture-based Most Probable Number assay following ultraviolet-C treatment. JOURNAL OF APPLIED PHYCOLOGY 2017; 30:1073-1094. [PMID: 29755205 PMCID: PMC5928191 DOI: 10.1007/s10811-017-1254-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 08/21/2017] [Accepted: 08/21/2017] [Indexed: 06/02/2023]
Abstract
Ballast water management systems (BWMS) must be tested to assess their compliance with standards for the discharge of organisms, for example in the ≥ 10- and < 50-μm size category, which is dominated by phytoplankton. Assessment of BWMS performance with the vital stains fluorescein diacetate + 5-chlorofluorescein diacetate, required by regulations in the USA, is problematic in the case of ultraviolet-C (UVC) radiation. This is because UVC targets nucleotides-and thus reproduction, hence viability-rather than membrane integrity, which is assayed by the stains. The Serial Dilution Culture-Most Probable Number (SDC-MPN) method, long used to enumerate fragile phytoplankton from natural communities, is appropriate for counting viable phytoplankton. We developed QA/QC "best practice" criteria for its application as a robust and repeatable assay of viable cells in cultures of phytoplankton before and after experimental treatment, then constructed dose-response curves for UVC-induced loss of viable cells in 12 species of phytoplankton from seven divisions. Sensitivity to UVC, expressed as the dose required to reduce viability by 99%-the criterion for type approval of treatment systems-varied more than 10-fold and was not correlated with cell size. The form of the dose-response curves varied between taxa, with most having a threshold dose below which there was no reduction in viability. Analysis of the patterns of growth indicates that if recovery from treatment occurred, it was complete in 1 or 2 days in > 80% of cases, long before the assays were terminated. We conclude that the SDC-MPN assay as described is robust and adaptable for use on natural phytoplankton.
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Affiliation(s)
- Hugh L. MacIntyre
- Department of Oceanography, Dalhousie University, PO Box 15000, Halifax, NS B3H 4R2 Canada
| | - John J. Cullen
- Department of Oceanography, Dalhousie University, PO Box 15000, Halifax, NS B3H 4R2 Canada
| | - Trina J. Whitsitt
- Department of Oceanography, Dalhousie University, PO Box 15000, Halifax, NS B3H 4R2 Canada
| | - Brian Petri
- Trojan Technologies, 3020 Gore Rd, London, ON N5V 4T7 Canada
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Sun Z, Blatchley ER. Tetraselmis as a challenge organism for validation of ballast water UV systems. WATER RESEARCH 2017; 121:311-319. [PMID: 28570870 DOI: 10.1016/j.watres.2017.05.052] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 05/20/2017] [Accepted: 05/24/2017] [Indexed: 06/07/2023]
Abstract
Transport and release of waterborne organisms as a result of ballasting and de-ballasting operations is widely acknowledged to represent an important mechanism for invasions by non-indigenous species. Regulatory requirements have been implemented globally to require treatment of ballast water before its release to the environment as a means of minimizing risks of invasion. UV-based processes represent an option for ballast water treatment; however, their use will require development of appropriate methods for reactor validation. To address this need, Tetraselmis was examined as challenge organism using a most probable number (MPN) assay for quantification of the concentration of viable (reproductively active) cells in suspension. A low pressure collimated-beam reactor was used to investigate UV254 dose-response behavior of Tetraselmis. Based on the experimental conditions applied, Tetraselmis indicated 4.5-5 log10 units of inactivation for UV254 doses of approximately 120 mJ/cm2, with no apparent change of resistance resulting from repeated exposure. A medium pressure UV collimated-beam reactor equipped with a series of narrow bandpass optical filters was used to investigate the action spectrum of Tetraselmis for wavelengths ranging from 228 nm-297 nm. Radiation with wavelengths in the range 254-280 nm was observed to be most efficient for inactivation of Tetraselmis. Additionally, DNA was extracted from Tetraselmis to allow measurement of its absorption spectrum. These results indicated strong absorbance from 254 nm to 280 nm, thereby suggesting that damage to DNA plays an important role in the inactivation of Tetraselmis sp. However, deviations of the action spectrum shape from the shape of the DNA absorption spectrum suggest that UV-induced damage to biomolecules other than DNA may contribute to Tetraselmis inactivation at some wavelengths in the UVC range.
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Affiliation(s)
- Zhe Sun
- Lyles School of Civil Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Ernest R Blatchley
- Lyles School of Civil Engineering, Purdue University, West Lafayette, IN 47907, USA; Division of Environmental & Ecological Engineering, Purdue University, West Lafayette, IN 47907, USA.
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Barrado-Moreno MM, Beltran-Heredia J, Martín-Gallardo J. Microalgae removal with Moringa oleifera. Toxicon 2015; 110:68-73. [PMID: 26688055 DOI: 10.1016/j.toxicon.2015.12.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 11/24/2015] [Accepted: 12/02/2015] [Indexed: 10/22/2022]
Abstract
Moringa oleifera seed extract was tested for algae (Chlorella, Microcystis, Oocystis and Scenedesmus) removal by Jar-test technique. This coagulant can be used in drinking water treatment. Jar-test has been carried out in order to evaluate the efficiency of this natural coagulant agent inside real surface water matrix. The influence of variables has been studied in this process, including operating parameters such as coagulant dosage, initial algae concentration, pH, agitation time and water matrix. Removal capacity is verified for water with high contamination of algae while the process is not affected by the pH and water matrix. Coagulation process may be modelling through Langmuir and Freundlich adsorption hypothesis, so acceptable r2 coefficients are obtained.
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Affiliation(s)
- M M Barrado-Moreno
- Department of Chemical Engineering and Physical Chemistry, University of Extremadura, Avda, De Elvas, s/n, 06071 Badajoz, Spain.
| | - J Beltran-Heredia
- Department of Chemical Engineering and Physical Chemistry, University of Extremadura, Avda, De Elvas, s/n, 06071 Badajoz, Spain.
| | - J Martín-Gallardo
- Department of Plant Biology, Ecology and Earth Science, University of Extremadura, Avda, De Elvas, s/n, 06071 Badajoz, Spain.
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