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On the horizontal distribution of algal-bloom in Chaohu Lake and its formation process

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Acta Mechanica Sinica 2014年第5期30卷 656-666页

作者： Yuan-Ying Chen Qing-Quan Liu Laboratory for Mechanics in Fluid Solid Coupling System Institute of Mechanics Chinese Academy of Sciences

Based on the remote sensing images of algae, the present work analyzes the horizontal distribution characteristics of algal blooms in Chaohu Lake, China, which also reveals the frequency of algal blooms under different wind directions. Further, an unstructured-grid, three-dimensional finite-volume coastal ocean model （FVCOM） is applied to investigate the wind-induced currents and the transport pro- cess to explain the reason why algal blooms occur at the detected places. We first deduce the primary distribution of biomass from overlaid satellite images, and explain the formation mechanism by analyzing the pollution sources, and simulating the flow field and transportation process under prevailing wind over Chaohu Lake. And then, we consider the adjustment action of the wind on the corresponding day and develop a two-time scale approach to describe the whole formation process of algae horizontal distribution in Chaohu Lake. That is, on the longer time scale, i.e., during bloom season, prevailing wind determines the primary distribution of biomass by inducing the characteristic flow field; on the shorter time scale, i.e., on the day when bloom occurs, the wind force adjusts the primary distribution of biomass to form the final distribution of algal bloom.

关键词： Chaohu Lake algal bloom Horizontal distri- bution - Wind-driven current Two-time scale process

algal-bloom control by allelopathy of aquatic macrophytes—A review

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Frontiers of Environmental Science & Engineering 2008年第4期2卷 421-438页

作者： Hongying HU Yu HONG Environmental Simulation and Pollution Control State Key Joint Laboratory Department of Environmental Science and EngineeringTsinghua UniversityBeijing 100084China College of Environmental Science and Engineering Beijing Forestry UniversityBeijing 100083China

algal-bloom control is an important issue for water environment protection as it induces several negative impacts on the lives of aquatic organisms,aquaculture,landscaping,and human health.The development of an environment-friendly,cost-effective,and convenient alternative for controlling algal bloom has gained much concern.Using the allelopathy of aquatic macrophytes as a novel and safe method for algal-bloom control is a promising alternative.This paper reviews the development and potential application about allelopathy of aquatic plants on algae,including the allelopathic research history,the potential research problems,the research methodology,and the reported aquatic macrophytes and their inhibitory allelochemicals.Potential modes of inhibition action of allelochemicals on algae,possible ways for application,and future development directions of research on algal-bloom control by aquatic macrophytes were also presented.

关键词： allelopathy allelochemical aquatic macrophyte algae algal bloom

Long-term joint effect of nutrients and temperature increase on algal growth in Lake Taihu,China

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Journal of Environmental Sciences 2011年第2期23卷 222-227页

作者： Chun Ye Zhemin Shen Tao Zhang Maohong Fan Yangming Lei Jianda Zhang School of Environmental Science and Engineering Shanghai Jiao Tong University Shanghai 200240 China Chinese Research Academy of Environmental Sciences Beijing 100012 China School of Civil and Environmental Engineering Georgia Institute of Technology Atlanta GA 30332 USA School of Energy Resources and Department of Chemical & Petroleum Engineering University of Wyoming Laramie WY 82071 USA Jiangsu Environmental Monitoring Center 241Fenghuangxijie Road Nanjiang 210036 China

To study how global warming and eutrophication affect water ecosystems, a multiplicative growth Monod model, modified by incorporating the Arrhenius equation, was applied to Lake Taihu to quantitatively study the relationships between algal biomass and both nutrients and temperature using long-term data. To qualitatively assess which factor was a limitation of the improved model, temperature variables were calculated using annual mean air temperature （AT）, water temperature （WT）, and their average temperature （ST）, while substrate variables were calculated using annual mean total nitrogen （TN）, total phosphorus （TP）, and their weighted aggregate （R）, respectively. The nine fitted curves showed that TN and AT were two important factors influencing algal growth; AT limited growth as algal photosynthesis is mainly carried out near the water surface; N leakage of phytoplankton and internal phosphorus load from sediment explains why TN was the best predictor of peak biomass using the Monod model. The fitted results suggest that annual mean algal biomass increased by 0.145 times when annual mean AT increased by 1.0℃. Results also showed that the more eutrophic the lake, the greater the effect AT had on algal growth. Subsequently, the long-term joint effect of annual temperature increase and eutrophication to water ecosystems can be quantitatively assessed and predicted.

关键词： lake eutrophication algal bloom global warming

^(15)N isotope fractionation in an aquatic food chain:Bellamya aeruginosa(Reeve) as an algal control agent

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Journal of Environmental Sciences 2010年第2期22卷 242-247页

作者： Shiqun Han Shaohua Yan Kaining Chen Zhenhua Zhang Rengel Zed Jianqiu Zhang Wei Song Haiqin Liu Institute of Agricultural Resources and Environments Jiangsu Academy of Agricultural Sciences Nanjing 210014 China Nanjing Institute of Geography & Limnology Chinese Academy of Sciences Nanjing 210014 China School of Earth and Environment The University of Western Australia 35 Stirling Highway Crawley WA 6009 Australia

^ 15N isotope tracer techniques and ecological modeling were adopted to investigate the fractionation of nitrogen, its uptake and transformation in algae and snail （Bellamya aeruginosa Reeve）. Different algal species were found to differ in their uptake of nitrogen isotopes. Microcystis aeruginisa Ktitz. demonstrated the greatest ^15N accumulation capacity, with the natural variation in isotopic ratio （δ^15N） and the isotope fractionation factor （ε,‰） being the highest among the species investigated. The transformation and utilization of ^15N by snails differed depending on the specific algae consumed （highest for Chlorella pyrenoidosa Chick., lowest for M. aeruginisa）. When snails was seeded in the experimental pond, the algae population structure changed significantly, and total algal biomass as well as the concentration of all nitrogen species decreased, causing an increase in water transparency. A model, incorporating several chemical and biological parameters, was developed to predict algal biomass in an aquatic system when snails was present. The data collected during this investigation indicated that the gastropods such as snails could significantly impact biological community and water quality of small water bodies, suggesting a role for biological control of noxious algal blooms associated with eutrophication.

关键词： ^15N fractionation algal bloom Bellamya aeruginosa ecological modeling eutrophication

Eutrophication and algal blooms in channel type reservoirs:A novel enclosure experiment by changing light intensity

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Journal of Environmental Sciences 2011年第10期23卷 1660-1670页

作者： Chengjin Cao Binghui Zheng Zhenlou Chen Minsheng Huang Jialei Zhang School of Resource and Environmental Sciences East China Normal University Shanghai 200062 China River and Coastal Environment Research Center Chinese Research Academy of Environmental Sciences Beijing 100012 China Key Laboratory of Geographic Information Science Ministry of Education East China Normal University Shanghai 200062 China

To explore eutrophication and algal bloom mechanisms in channel type reservoirs, a novel enclosure experiment was conducted by changing light intensity （LI） in the Daning River of the Three Gorges Reservoir （TGR）. Square enclosures （side 5.0 m） were covered on the surface with shading materials of different thickness, and with their bases open to the river. Changes and characteristics of the main eutrophication factors under the same water quality and hydrodynamic conditions but different LI were evaluated. All experimental water samples were neutral and alkalescent, with high nitrogen and phosphate concentrations, low potassium permanganate index, stable water quality, and different LI. At the same water depth, LI decreased with increasing shade material, while dissolved oxygen and water temperature were both stable. The growth peak of phytoplankton was with light of 345-4390 lux underwater or 558-7450 lux above the water surface, and water temperature of 25.6--26.5℃. Algae were observed in all water samples, accounting for 6 phylum and 57 species, with algal density changing frequently. The results showed that significantly strong or weak light was unfavorable for phytoplankton growth and the function together with suitable temperature and LI and ample sunshine encouraged algal blooms under the same water quality and hydrodynamic conditions. Correlation analysis indicated that algae reduced gradually lengthwise along water depth in the same enclosure while pH became high. The power exponent relationship between chlorophyll a （Chl-a） and LI was found by curve fitting, that is Chl-a = K（LI）n.

关键词： eutrophication algal bloom enclosure experiment channel type reservoirs Three Gorges Reservoir

Linking bacterial and archaeal community dynamics to related hydrological,geochemical and environmental characteristics between surface water and groundwater in a karstic estuary

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海洋学报:英文版 2023年第8期42卷 158-170页

作者： Xiaogang Chen Qi Ye Jinzhou Du Neven Cukrov Nuša Cukrov Yan Zhang Ling Li Jing Zhang State Key Laboratory of Estuarine and Coastal Research East China Normal UniversityShanghai 200241China Key Laboratory of Coastal Environment and Resources of Zhejiang Province School of EngineeringWestlake UniversityHangzhou 310024China Division for Marine and Environmental Research Ruđer BoškovićInstituteZagreb 10000Croatia

Subterranean estuaries(STEs)are characterized by the mixing of terrestrial fresh groundwater and seawater in coastal aquifers.Although microorganisms are important components of coastal groundwater ecosystems and play critical roles in biogeochemical transformations in STEs,limited information is available about how their community dynamics interact with hydrological,geochemical and environmental characteristics in STEs.Here,we studied bacterial and archaeal diversities and distributions with 16S rRNA-based Illumina MiSeq sequencing technology between surface water and groundwater in a karstic STE.Principal-coordinate analysis found that the bacterial and archaeal communities in the areas where algal blooms occurred were significantly separated from those in other stations without algal bloom occurrence.Canonical correspondence analysis showed that nutrients and salinity can explain the patterns of bacterial and archaeal community dynamics.The results suggest that hydrological,geochemical and environmental characteristics between surface water and groundwater likely control the bacterial and archaeal diversities and distributions in STEs.Furthermore,we found that some key species can utilize terrestrial pollutants such as nitrate and ammonia in STEs,indicating that these species(e.g.,Nitrosopumilus maritimus,Limnohabitans parvus and Simplicispira limi)may be excellent candidates for in situ degradation/remediation of coastal groundwater contaminations concerned with the nitrate and ammonia.Overall,this study reveals the coupling relationship between the microbial communities and hydrochemical environments in STEs,and provides a perspective of in situ degradation/remediation for coastal groundwater quality management.

关键词： submarine groundwater discharge surface water and groundwater interaction algal bloom microbial ecology nutrient biogeochemistry ammonia-oxidizing archaea nitrate-utilizing bacteria Krka River Estuary

Spatial and diel variations of the prokaryotic community in the Phaeocystis globosa blooms area of Beibu Gulf,China

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Acta Oceanologica Sinica 2022年第12期41卷 87-97页

作者： Cheng He Sha Xu Shuqun Song Caiwen Li North China Sea Environmental Monitoring Center State Oceanic AdministrationQingdao 266033China Key Laboratory of Ecological Prewarning Protection and Restoration of Bohai SeaMinistry of Natural ResourcesQingdao 266033China Key Laboratory of Marine Ecology and Environmental Sciences Chinese Academy of SciencesQingdao 266071China Marine Ecology and Environmental Science Laboratory Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao 266071China Shaanxi Provincial Academy of Environmental Science Xi’an 710061China

While prokaryotes play key roles in nutrient cycling and energy flow during Phaeocystis globosa blooms,the information on the spatial and diel temporal distribution of the prokaryotic community during Phaeocystis blooms remains scarce.In January 2019,we used high-throughput sequencing of the 16S rRNA gene to explore the spatial and diel variations of particle-attached(PA)and free-living(FL)prokaryotic communities during the blooming phase of P.globosa in Beibu Gulf,Guangxi,China.The results suggested a significant spatial variation pattern in the horizontal distribution of prokaryotic communities,while there was no significant difference in the vertical direction.Both spatial distance and environmental variables shaped the horizontal distribution of the prokaryotic community structure,while environmental variables,particularly the abundance of P.globosa colony and Chl a,showed more significant influence and were closely related to the structure and variation of the prokaryotic community.Strong vertical mixing of the water column disrupted the vertical structure heterogeneity of the prokaryotic community in winter.There were significant differences in the diel samples of PA prokaryotic communities,but not in the FL prokaryotic communities.Nitrate,ammonium and the abundance of P.globosa colony were the key environmental variables impacting the diel variations of prokaryotic communities over the sampling period.The present study provided valuable information to depict the spatial-temporal variations of the microbial community and its association with environmental parameters during P.globosa bloom in the tropical gulf.

关键词： algal bloom 16S rRNA genes prokaryotic community diversity spatial patterns diel distribution

Three-dimensional unstructured-mesh eutrophication model and its application to the Xiangxi River,China

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Journal of Environmental Sciences 2012年第9期24卷 1569-1578页

作者： Jian Li Danxun Li Xingkui Wang State Key Laboratory of Hydroscience and Engineering Department of Hydraulic Engineering Tsinghua University Beijing 100084 China

The Xiangxi River is one of the main tributaries in the Three Gorges reservoir, with the shortest distance to the Three Gorges Project Dam. Severe and frequent algal bloom events have occurred frequently in the Xiangxi River in recent years. Therefore, the current study develops a three-dimensional unstructured-mesh model to investigate the dynamic process of algal bloom. The developed model comprises three modules, namely, hydrodynamics, nutrient cycles, and phytoplankton ecological dynamics. A number of factors, including hydrodynamic condition, nutrient concentration, temperature, and light illumination, that would affect the evolution of phytoplankton were considered. Moreover, the wave equation was used to solve the free surface fluctuations and vertical Z-coordinates with adjustable layered thicknesses. These values, in turn, are suitable for solving the algal bloom problems that occurred in the fiver style reservoir that has a complex boundary and dramatically changing hydrodynamic conditions. The comparisons between the modeling results and field data of years 2007 and 2008 indicate that the developed model is capable of simulating the algal bloom process in the Xiangxi River with reasonable accuracy. However, hydrodynamic force and external pollution loads affect the concentrations of nutrients, which, along with the underwater light intensity, could consequently affect phytoplankton evolution. Thus, flow velocity cannot be ignored in the analysis of fiver algal bloom. Based on the modeling results, building an impounding reservoir and increasing the releasing discharge at appropriate times are effective ways for controlling algal bloom.

关键词： unstructured-mesh model algal bloom phytoplankton Xiangxi River

Modelling the thresholds of nitrogen/phosphorus concentration and hydraulic retention time for bloom control in reclaimed water landscape

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Frontiers of Environmental Science & Engineering 2022年第10期16卷 53-63页

作者： Keying Song Shufeng Zhu Yun Lu Guohua Dao Yinhu Wu Zhuo Chen Shengnan Wang Junhan Liu Wenguang Zhou Hong-Ying Hu Environmental Simulation and Pollution Control State Key Joint Laboratory State Environmental Protection Key Laboratory of Microorganism Application and Risk Control(SMARC)School of EnvironmentTsinghua UniversityBeijing 100084China Beijing Laboratory for Environmental Frontier Technologies Beijing 100084China Faculty of Environmental Science and Engineering Kunming University of Science and TechnologyKunming 650500China Key Laboratory of Poyang Lake Environment and Resource Utilization Ministry of Educationand School of ResourcesEnvironmental&Chemical EngineeringNanchang UniversityNanchang 330031China Research Institute for Environmental Innovation(Suzhou)Tsinghua JiangsuSuzhou 215163China

The risks posed by algal blooms caused by nitrogen and phosphorus in reclaimed water used in urban water landscapes need to be carefully controlled.In this study,the combined effects of the nitrogen and phosphorus concentrations and the light intensity and temperature on the specific growth rates of algae were determined using Monod,Steele,and Arrhenius models,then an integrated algal growth model was developed.The algae biomass,nitrogen concentration,and phosphorus concentration mass balance equations were used to establish a new control model describing the nitrogen and phosphorus concentration and hydraulic retention time thresholds for algal blooms.The model parameters were determined by fitting the models to data acquired experimentally.Finally,the control model and numerical simulations for six typical algae and mixed algae under standard conditions were used to determine nitrogen/phosphorus concentration and hydraulic retention time thresholds for landscape water to which reclaimed water is supplied(i.e.,for a reclaimed water landscape).

关键词： Reclaimed water landscape algal bloom Nitrogen and phosphorus Hydraulic retention time Threshold Control model