共查询到19条相似文献,搜索用时 125 毫秒
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《水资源开发与管理》2017,(5)
近年来,以蓝藻水华为表征的水体富营养化已逐渐成为全球范围内湖泊和水库面临的主要生态环境问题。去除和控制藻类水华,特别是产毒蓝藻水华已经成为湖泊和水库生态修复的关键环节。目前,国内外学者研究了各种控藻技术来治理蓝藻水华,主要包括:化学杀藻法、化学絮凝法、黏土凝聚法和超声辐射法等。其中,超声波控(除)藻属于环境友好型技术,近年来越来越受到国内外的普遍关注,并逐渐应用于藻类水华应急处理。本文介绍了超声波除藻技术的进展及应用前景。 相似文献
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大多数蓝藻在较高温度下表现出最佳的生长速率,伴随着全球气温升高,我国很多地区的水资源遭受富营养化和有毒蓝藻暴发.文章以太湖为研究对象,以综合监测预报系统为基础,在预警的基础上提出了一系列应急措施.利用该综合监测系统,发现了可检测到的最大和平均蓝藻水华面积,说明蓝藻水华持续存在,没有明显缓解.研究表明,蓝藻水华发生在强烈风暴之后,这与蓝藻菌落浮力的增加有关.虽然蓝藻水华在监测期间持续存在,但蓝藻水华引起的黑水团聚的频率和强度有所降低,并没有进一步的饮用水危机. 相似文献
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混凝沉淀工艺对不同优势藻类的去除特性研究 总被引:1,自引:0,他引:1
为了考察混凝沉淀工艺的除藻性能在不同藻类优势期内的变化,将试验过程分为绿藻优势期和蓝藻优势期两个阶段,进行进水藻类群落结构特征及其变化对混凝沉淀除藻效能的影响研究.结果表明,混凝沉淀在绿藻优势期和蓝藻优势期的除藻效率分别为68.3%和40.4%,且各种藻类的去除效能并无明显的相互影响.蓝藻优势期的藻类去除率大大低于绿藻优势期,其根本原因在于占优势地位的微囊藻的生理生态特征.因此,把水中的所有藻类笼统地作为一个去除对象是不适宜的,应分析水中藻类群落结构特征,并根据特定原水中的优势藻种类进行针对性的除藻方案研究. 相似文献
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王洁 《水利与建筑工程学报》2017,15(4)
以西安鱼化湖为研究对象,通过原位观测总结了鱼化湖季节性蓝藻发生的现象和规律,表明蓝藻水华的发生季节与水质富营养化程度密切相关,人工湖蓝藻水华产生的原因主要可归纳为外源因素和内源因素。在蓝藻水华现象和原因分析的基础上针对鱼化湖具体特点提出了蓝藻的治理方法,所得结论与建议可为以后人工湖蓝藻预防与治理提供借鉴。 相似文献
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电磁场在灭藻方面的研究 总被引:1,自引:0,他引:1
研究了脉冲高压静电场与磁场复合作用对循环水的灭藻特性。发现经过电磁处理的蓝藻细胞随着处理时间的延长,细胞的继续繁殖受到阻碍,蓝藻的丝状体变短,丝状藻体断裂增多,内容物泄出,藻体的碎片越来越小,颜色也逐渐变浅。 相似文献
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水体富营养化所引起的藻华爆发现象是我国面临的重大环境问题之一。以内蒙古呼伦湖为研究区,采用基于离散粒子群优化的光谱匹配(SMDPSO)算法提取藻华,以浮游藻类指数(FAI)的分类结果作为验证数据进行精度检验。然后分析2009-2018年藻华的时空变化特征,并将此算法应用于黄海。结果表明:SMDPSO算法可以有效地识别呼伦湖藻华,与FAI分类结果之间的R2为0.97,RMSE为0.22 km2;呼伦湖藻华爆发于7-8月,且主要出现在湖泊边缘;SMDPSO算法既可以较好地识别以蓝藻为优势门的呼伦湖藻华,也可以提取黄海的浒苔(绿藻);SMDPSO算法不仅保留了光谱指数法精度高的特点,而且它还具有成本低、参数少、无需人工干预的优势。该研究为藻华遥感监测提供了新的工具,有助于控制湖泊水体富营养化和改善水生态环境。 相似文献
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《Journal of Great Lakes research》2022,48(6):1587-1598
While algal blooms are common in eutrophic lakes, blooms can also occur in tributaries that load nutrients into the lake. We sampled six sites along a 122-km stretch of the Maumee River May through October 2018 and 2019 at weekly to biweekly intervals to determine if algal blooms occur, in particular toxic cyanobacteria, and to provide insights on potential environmental drivers of blooms. Samples were analyzed for concentrations of potamoplankton (=riverine phytoplankton), chlorophyll a, nutrients, cyanobacterial toxins, microcystins and saxitoxins, and cyanotoxin genes (mcyE and sxtA). Extreme precipitation in 2019 resulted in more high discharge events during 2019 than in 2018. Chlorophyll a ranged from 50 µg/L to 300 µg/L during periods of low discharge (<50 m3/s), and green algae and diatoms accounted for the majority of the chlorophyll a. In both years, cyanobacteria comprised a low proportion of all chlorophyll a, usually<20 %, but microcystins and saxitoxins were detectable in 38.7 % and 16.7 % samples, respectively, and mcyE and sxtA were detected in 36.2 % and 59.7 % samples, respectively. Therefore, cyanotoxins were present even when cyanobacteria were not at bloom densities. Chlorophyll a, cyanotoxin genes, and microcystins negatively correlated with discharge rate measured on the date of sample collection. Together our results suggest that cyanotoxins can occur in any portion of the Maumee River during low discharge conditions. Climate change is expected to reduce precipitation during the warm summer months in the Maumee River watershed and thus possibly increase the frequency of low discharge conditions that favor cyanobacteria. 相似文献
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《Water science and technology》1998,37(2):153-159
Eutrophication as well as the removal of algae by the drinking water industry received dedicated attention in past three decades. An interdisciplinary approach will assist catchment and water purification managers to work to the same future - algal blooms in reservoirs dominated by the “ideal algae” which can be removed by conventional unit treatment processes. This paper will provide a futuristic picture of resource and product quality management, based on a historic perspective of eutrophication and algal removal research. 相似文献
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Casianes O. Olilo William A. Shivoga John J. Kitetu Simon Agembe 《Lakes & Reservoirs: Research and Management》2014,19(4):240-254
The dominance of cyanobacterial algae in light‐limited, shallow freshwater Lake Baringo is a major environmental concern in regard to Kenyan water quality and public health protection agencies. Accordingly, this study focused on determining the effect of different environmental factors on cyanobacteria dynamics in different sediment disturbance zones of the lake and in different seasons. This study also sought to bridge the knowledge gap regarding the influence of water clarity on cyanobacteria dynamics in the lake. Samples were collected from the field, stored in ice and transported to the laboratory for nutrient analyses. Cyanobacteria cultures isolated from the lake were grown under a 12:12 light/dark cycle. The frequency of dividing cells (FDC) technique, and a fluorescence microscopy technique, was used to count growing cyanobacteria cells. Specific cyanobacteria organic carbon synthesis was significantly negatively correlated with turbidity for the southern (r = ?0.6573; P < 0.05) and central sediment disturbance zones (r = ?0.6847; P < 0.05). This study indicated that water clarity is an environmental phenomenon that facilitates the movement of cyanobacteria into the turbid areas of the lake, where their production levels are significantly high, in contrast to the clear water along the edges of the water–land interface during the wet season (April to August) and dry season (September to March). Water clarity potentially enhances cell division inhibition and multiplication, thereby positively influencing cyanobacteria dynamics in Lake Baringo. Thus, it is concluded that the cyanobacteria growth rate resulting from use of the FDC technique suggests a link with inflowing water clarity that can be used to monitor in‐lake water quality, to better manage cyanobacteria blooms in Lake Baringo and in lakes and reservoirs elsewhere. 相似文献
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Harmful algal blooms are occurring in large river ecosystems and at the mouth of large rivers with increasing frequency. In lentic systems, the chemical and physical conditions that promote harmful algal blooms are somewhat predictable but tracking prevalence and conditions that promote harmful algal blooms in lotic systems is much more difficult. We captured two of the most extreme discharge years within the last 20 years occurring in the Upper Mississippi River, allowing a natural experiment that evaluated how major shifts in discharge drive environmental variation and associated shifts in phytoplankton. Statistical models describing significant environmental covariates for phytoplankton assemblages and specific taxa were developed and used to identify management‐relevant numeric breakpoints at which environmental variables may promote the growth of specific phytoplankton and/or cyanobacteria. Our analyses supported that potentially toxin‐producing cyanobacteria dominate under high phosphorus concentration, low nitrogen concentration, low nitrogen‐to‐phosphorus ratio, low turbulence, low flushing, adequate light and warm temperatures. Cyanobacteria dominated in 2009 when low discharge and low flushing likely led to optimal growth environments for Dolichospermum, Aphanizomenon and Microcystis. Rarely will a single factor lead to the dominance, but multiple positive factors working in concert can lead to cyanobacteria proliferation in large rivers. Certain isolated backwaters with high phosphorus, low nitrogen, warm water temperatures and low potential for flushing could benefit from increased connection to channel inputs to reduce cyanobacterial dominance. Numerous examples of this type of habitat currently exist in the Upper Mississippi River and could benefit from reconnection to channel habitats. 相似文献
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Miquel Lurling Yora Tolman Marieke Euwe 《Lakes & Reservoirs: Research and Management》2009,14(4):353-363
This study examined the effects of ‘Effective Microorganisms (EM)’ on the growth of cyanobacteria, and their ability to terminate cyanobacterial blooms. The EM was tested in the form of ‘mudballs’ or ‘Bokashi‐balls’, and as a suspension (EM‐A) in laboratory experiments. No growth inhibition was observed for a laboratory strain of Microcystis aeruginosa and for M. aeruginosa from the field at the recommended dosage of 1 EM‐mudball per square‐metre (≈0.1–0.3 g L?1). Cyanobacteria were inhibited only at very high concentrations (5–10 g L?1 cyanobacteria), and a bloom was reduced, being attributed to the high amount of clay and high water turbidity. For these high dosage treatments, the dissolved oxygen concentration dropped initially to very low levels, with longer incubation indicating that nutrients were released from the material. The EM‐A suspension appeared ineffective in hampering cyanobacterial growths at recommended usage concentrations. EM‐mudballs released phosphate (160 μg P g?1) and metals (aluminium, copper, traces of lead and lanthanum). The results of this study did not support the hypothesis that EM are effective in preventing cyanobacterial proliferation or in terminating blooms, thereby suggesting lake restoration by ‘Effective Microorganisms’ is not a convincing eutrophication control option. 相似文献
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《Journal of Great Lakes research》2019,45(3):573-586
Since the early 2000s Lake Erie has seen a dramatic increase in phytoplankton biomass, manifested in particular by the rise in the severity of cyanobacteria blooms and the prevalence of potentially toxic taxa such as Microcystis. Satellite remote sensing has provided a unique capacity for the synoptic detection of these blooms, enabling spatial and temporal trends in their extent and severity to be documented. Algorithms for satellite detection of Lake Erie algal blooms often rely on a single consistent relationship between algal or cyanobacterial biomass and spectral indices such as the Maximum Chlorophyll Index (MCI) or Cyanobacteria Index (CI). Blooms, however, are known to vary significantly in community composition over space and time. A suite of phytoplankton and optical property measurements during the western Lake Erie algal bloom of 2017 showed highly diverse bloom composition with variable absorption and backscatter properties. Elevated backscattering coefficients were observed in the Maumee Bay, likely due to phytoplankton cell morphology and buoyancy regulating gas vacuoles, compared with typically Planktothrix dominated blooms in Sandusky Bay. MCI and CI calibrated to historical chlorophyll observations and applied to Sentinel 3's OLCI sensor accurately captured the 2017 bloom in Maumee Bay but underestimated the Sandusky Bay bloom by nearly 80%. The phycoerythrin-rich picocyanobacteria Aphanothece and Synechococcus were found in abundance throughout the western and central basins, resulting in substantial biomass underestimations using blue to green ratio-based algorithms. Potential misrepresentation of bloom severity resulting from phytoplankton optical properties should be considered in assessments of bloom conditions on Lake Erie. 相似文献
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三峡水库大宁河春季水华藻类分布及影响因子 总被引:2,自引:0,他引:2
以三峡水库支流大宁河2010年3月中旬的水华调查数据为依据,分析浮游藻类分布规律,并探讨其影响因子。结果表明,在容易暴发水华的库湾开阔地带之外,狭窄的峡谷地带亦会暴发严重水华,并且持续时间更长;河口区域的浮游藻类则表现出比其他区域更好的群落稳定性和生物均匀性。在此次水华的前、中期,浮游藻类的群落稳定性随生物量增大而降低;后期则随其增大而增加。通过对样品的定量分析,共鉴定浮游藻类7门24属,主要为绿藻和甲藻,第一优势种为拟多甲藻,占到总藻类的38%,其次为小球藻和衣藻。观察到藻类群体有垂直迁移现象,可能因藻类有趋光性所致。拟多甲藻水华的暴发会降低水体氮磷比,而随着水华的消退,水体氮磷比会较迅速地恢复到一个较高水平。在水华前期,总磷与浮游藻类群落稳定性呈现高度负相关,在中、后期其相关性减弱。 相似文献
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Justin D. Chaffin Sachidananda Mishra Douglas D. Kane Darren L. Bade Keara Stanislawczyk Kristen N. Slodysko Kevin W. Jones Eric M. Parker Erica L. Fox 《Journal of Great Lakes research》2019,45(2):277-289
Lake Erie western basin (WB) cyanobacterial blooms are a yearly summer occurrence; however, blooms have also been reported in the offshore waters of the central basin (CB), and very little is known about what drives these blooms or their potential for cyanobacterial toxins. Cyanobacteria Index was quantified using MODIS and MERIS data for the CB between 2003 and 2017, and water samples were collected between 2013 and 2017. The goals were to 1) quantify cyanobacteria, 2) determine environmental drivers of CB blooms, and 3) determine the potential for cyanobacterial toxins in the CB. Dolichospermum (Anabaena) occurred in the CB during July before the onset of the WB bloom, and then in August and September, the cyanobacteria community shifted towards Microcystis. The largest Dolichospermum blooms (2003, 2012, 2013, and 2015) were associated with reduced water clarity (Secchi disk depth?<?4?m), whereas large CB Microcystis blooms (2011 and 2015) were associated with large WB blooms. Dolichospermum blooms occurred in high nitrate concentrations (>20?μmol/L) and high nitrogen-to?phosphorus ratios (>100), which indicate nutrient concentrations or ratios did not select for Dolichospermum. Additionally, the sxtA gene, but not mcyE or microcystins, were detected in the CB during July 2016 and 2017. The mcyE gene and microcystins were detected in the CB during August 2016 and 2017. The results indicate the CB's potential for cyanotoxins shifts from saxitoxins to microcystins throughout the summer. Continued monitoring of cyanobacteria and multiple cyanobacterial toxins is recommended to ensure safe drinking water for CB coastal communities. 相似文献