Water blooms have become a worldwide environmental problem. Recently, algicidal bacteria have attracted wide attention as possible agents for inhibiting algal water blooms. In this study, one strain of algicidal bacte...Water blooms have become a worldwide environmental problem. Recently, algicidal bacteria have attracted wide attention as possible agents for inhibiting algal water blooms. In this study, one strain of algicidal bacterium B5 was isolated from activated sludge. On the basis of analysis of its physiological characteristics and 16S rDNA gene sequence, it was identified as Bacillusfusiformis. Its algaelysing characteristics on Microcystis aeruginosa, Chlorella and Scenedesmus were tested. The results showed that： （1） the algicidal bacterium B5 is a Gram-negative bacterium. The 16S rDNA nucleotide sequence homology of strain B5 with 2 strains of B. fusiformis reached 99.86%, so B5 was identified as B. fusiformis; （2） the algal-lysing effects of the algicidal bacterium B5 on M. aeruginosa, Chlorella and Scenedesrnus were pronounced. The initial bacterial and algal cell densities strongly influence the removal rates of chlorophyll-a. The greater the initial bacterial cell density, the faster the degradation of chlorophyll-a. The greater the initial algal cell density, the slower the degradation of chlorophyll-a. When the bacterial cell density was 3.6 × 10^7 cells/ml, nearly 90% of chlorophyll-a was removed. When the chlorophyll-a concentration was less than 550 μg/L, about 70% was removed; （3） the strain B5 lysed algae by secreting metabolites and these metabolites could bear heat treatment.展开更多
[Objective] The research aimed to know the ecological environment pollution characteristics of Hongfeng Lake water area and the evolution rule,which provided the theory basis for improving the water quality condition....[Objective] The research aimed to know the ecological environment pollution characteristics of Hongfeng Lake water area and the evolution rule,which provided the theory basis for improving the water quality condition.[Method] Based on the investigation and research of indoor and outdoor,the water quality,aquatic ecosystem,pollution characteristic of sediment and occurrence law of algae blooms in Hongfeng Lake were comprehensively analyzed by combining with the relevant literatures.[Result] Hongfeng Lake was in moderate-heavy eutrophication situation,and the water quality was V-bad V class.The sediment accumulated a lot of nutrient salt,which was the important pollution source of eutrophication in Hongfeng Lake Reservoir.The aquatic ecosystem degraded,and it was easy to form the algae blooms.[Conclusion] The pollution treatment of Hongfeng Lake was extremely urgent.展开更多
A nutrient-phytoplankton-zooplankton-detritus （NPZD） type of marine ecosystem model was developed in this study,and was further coupled to a three-dimensional primitive-equation ocean circulation model with a river ...A nutrient-phytoplankton-zooplankton-detritus （NPZD） type of marine ecosystem model was developed in this study,and was further coupled to a three-dimensional primitive-equation ocean circulation model with a river discharge model and a solar radiation model to reproduce the dynamics of the low nutrition level in the Bohai Sea （BS）.The simulation results were validated by observations and it was shown that the seasonal variation in the phytoplankton biomass could be characterized by the double-peak structure,corresponding to the spring and summer blooms,respectively.It was also found that both nitrogen and phosphate declined to the lowest level after the onset of the summer bloom,since the large amounts of nutrients were exhausted by phytoplankton for photosynthesis,and the concentrations of nutrients could resume in winter after a series of the biogeochemical-physical processes.By calculating the nitrogen/phosphorus （N/P） ratio,it is easy to see that the phytoplankton dynamics is nitrogen-limited as a whole in BS,though the phosphorus limitation may occur in the Yellow River （YR） Estuary where the input of riverine nitrogen is much more than that of phosphate.展开更多
Nuisance algal blooms have been a topic of discussion in Florida as a result of highly visible adverse impacts to coastal waters, but algae is hardly a new concern for warm weather communities. The typical treatment i...Nuisance algal blooms have been a topic of discussion in Florida as a result of highly visible adverse impacts to coastal waters, but algae is hardly a new concern for warm weather communities. The typical treatment is with copper sulfate. However, copper has been identified by regulatory agencies as a contaminant of concern in coastal waters and has been targeted for stricter regulations, potentially limiting its use in the future for algae control. The EMOH device was proposed as a means to test whether a “green” solution could be found to this algae concern. EMOH creates high volume oxidation in concert with activated organisms. The initial treatment effort covered one year (2016). During treatment, water quality was monitored with periodic measurements of the benthic detrital layer, which is a precursor to algal blooms in these ponds. Photographs of the extent of algal coverage on the surface, water quality in the pond and thickness measurements of the detrital layer defined success. Through the hot summer, despite regular influx of nutrients and rain, the amount of algae declined, and the detrital layer decreased in thickness from 22 - 24 inches to 7 - 8 inches. The decrease of the detrital layer means that over time, the benthic source of nutrient availability can be more controlled. The authors concluded that the EMOH process was successful and that physically removing the detrital layer may be an important step in long-term algal reductions.展开更多
文摘为了定量研究水动力条件对藻类生长影响,选择微囊藻进行了室内扰动实验.通过维持光照、温度、营养盐等生境因子的一致性,调整振荡器转速,研究了不同扰动强度对藻类生长规律的影响;提出了'水动力影响参数α'对藻类生长公式进行了修正,以内江为例建立了二维非稳态藻类生长模型,对不同方案下内江藻类暴发特征进行了预测分析.结果表明,水动力条件对藻类生长影响明显,低流速有利于藻类生长,而在静止与高流速条件下,藻类生长受到抑制;内江引航道节制闸关闭后,流速减缓,藻类易于暴发,可能发生水华的水域面积约2.5 km2,占总面积的36.8%;完全静止状态以及节制闸开启后内江水动力条件改善条件下,藻类暴发程度有所减小,可能发生水华面积分别为0.78 km2和0.18 km2.
基金Project supported by the Special Funds for Doctor's Station of University(No.20060246024)Young Fund of Fudan University,and the Shanghai Tongji Gao Tingyao Environmental Science and Technology Developmem Fundation
文摘Water blooms have become a worldwide environmental problem. Recently, algicidal bacteria have attracted wide attention as possible agents for inhibiting algal water blooms. In this study, one strain of algicidal bacterium B5 was isolated from activated sludge. On the basis of analysis of its physiological characteristics and 16S rDNA gene sequence, it was identified as Bacillusfusiformis. Its algaelysing characteristics on Microcystis aeruginosa, Chlorella and Scenedesmus were tested. The results showed that： （1） the algicidal bacterium B5 is a Gram-negative bacterium. The 16S rDNA nucleotide sequence homology of strain B5 with 2 strains of B. fusiformis reached 99.86%, so B5 was identified as B. fusiformis; （2） the algal-lysing effects of the algicidal bacterium B5 on M. aeruginosa, Chlorella and Scenedesrnus were pronounced. The initial bacterial and algal cell densities strongly influence the removal rates of chlorophyll-a. The greater the initial bacterial cell density, the faster the degradation of chlorophyll-a. The greater the initial algal cell density, the slower the degradation of chlorophyll-a. When the bacterial cell density was 3.6 × 10^7 cells/ml, nearly 90% of chlorophyll-a was removed. When the chlorophyll-a concentration was less than 550 μg/L, about 70% was removed; （3） the strain B5 lysed algae by secreting metabolites and these metabolites could bear heat treatment.
基金Supported by Department of Education Key Item in Guizhou Province (200910040)Guizhou Province UNRISD Research Item (SY20103176)Guizhou Province Fund Item(20082239)~~
文摘[Objective] The research aimed to know the ecological environment pollution characteristics of Hongfeng Lake water area and the evolution rule,which provided the theory basis for improving the water quality condition.[Method] Based on the investigation and research of indoor and outdoor,the water quality,aquatic ecosystem,pollution characteristic of sediment and occurrence law of algae blooms in Hongfeng Lake were comprehensively analyzed by combining with the relevant literatures.[Result] Hongfeng Lake was in moderate-heavy eutrophication situation,and the water quality was V-bad V class.The sediment accumulated a lot of nutrient salt,which was the important pollution source of eutrophication in Hongfeng Lake Reservoir.The aquatic ecosystem degraded,and it was easy to form the algae blooms.[Conclusion] The pollution treatment of Hongfeng Lake was extremely urgent.
基金supported by Key Subject Fund of Shanghai Education Committee (No. J50702)Open Foundation of the Key Subject in Environmental Engineering of Shanghai Ocean University(No. B820609000404)Initial Foundation for Ph. D. of ShanghaiOcean University (No. B820607000402)
文摘A nutrient-phytoplankton-zooplankton-detritus （NPZD） type of marine ecosystem model was developed in this study,and was further coupled to a three-dimensional primitive-equation ocean circulation model with a river discharge model and a solar radiation model to reproduce the dynamics of the low nutrition level in the Bohai Sea （BS）.The simulation results were validated by observations and it was shown that the seasonal variation in the phytoplankton biomass could be characterized by the double-peak structure,corresponding to the spring and summer blooms,respectively.It was also found that both nitrogen and phosphate declined to the lowest level after the onset of the summer bloom,since the large amounts of nutrients were exhausted by phytoplankton for photosynthesis,and the concentrations of nutrients could resume in winter after a series of the biogeochemical-physical processes.By calculating the nitrogen/phosphorus （N/P） ratio,it is easy to see that the phytoplankton dynamics is nitrogen-limited as a whole in BS,though the phosphorus limitation may occur in the Yellow River （YR） Estuary where the input of riverine nitrogen is much more than that of phosphate.
文摘Nuisance algal blooms have been a topic of discussion in Florida as a result of highly visible adverse impacts to coastal waters, but algae is hardly a new concern for warm weather communities. The typical treatment is with copper sulfate. However, copper has been identified by regulatory agencies as a contaminant of concern in coastal waters and has been targeted for stricter regulations, potentially limiting its use in the future for algae control. The EMOH device was proposed as a means to test whether a “green” solution could be found to this algae concern. EMOH creates high volume oxidation in concert with activated organisms. The initial treatment effort covered one year (2016). During treatment, water quality was monitored with periodic measurements of the benthic detrital layer, which is a precursor to algal blooms in these ponds. Photographs of the extent of algal coverage on the surface, water quality in the pond and thickness measurements of the detrital layer defined success. Through the hot summer, despite regular influx of nutrients and rain, the amount of algae declined, and the detrital layer decreased in thickness from 22 - 24 inches to 7 - 8 inches. The decrease of the detrital layer means that over time, the benthic source of nutrient availability can be more controlled. The authors concluded that the EMOH process was successful and that physically removing the detrital layer may be an important step in long-term algal reductions.
