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61.
应用多样性指数、丰富度指数和均匀性指数对长江4条支流水域的藻类多样性进行了评价.比较了4条支流春、秋两季浮游藻类优势种、细胞密度和生物量等指标,对三峡蓄水后库区“水华”成因进行了初步分析.结果表明,4条支流的营养水平均属于中-富营养型,童庄河的水质最差,其次为香溪河和青干河,九畹溪的水质较好.春季硅藻的种类数多,绿藻种类数少;秋季则相反.藻类细胞密度的最高值出现在香溪河(6.036×106个/L),生物量的最高值出现在童庄河(19.997mg/L).2项指标的最低值均出现在九畹溪.在春季,童庄河还出现了拟多甲藻(Peridiniopsissp.)“水华”,并伴有较大量的小环藻(Cyclotellasp.)和卵形隐藻(Cryptomonasovata).三峡库区的水华属于季节性水华,可通过控制外源污染和增加水体流速来控制. 相似文献
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64.
太湖出入湖河道与湖体水质季节差异分析 总被引:3,自引:0,他引:3
基于2016年太湖16条主要河道及对应湖体的水质逐月监测数据,深入探讨了太湖流域不同分区河道的外源营养盐输入对湖体水质影响及其季节变化.结果发现:(1)太湖流域河道总氮(TN)、溶解性总氮(DTN)、总磷(TP)和溶解性总磷(DTP)的月平均浓度均高于对应湖体,主要入流区河道与临近湖体的营养盐浓度呈现显著正相关,表明外源补给对湖体营养盐浓度产生巨大影响;(2)无论是河道还是湖体的营养盐浓度,均呈现明显的季节变化,且峰值产生月份不同:河道平均TN最高值出现在3月,为4.82 mg·L-1,平均TP最高值出现在12月,为0.218 mg·L-1;湖体TN、TP峰值均出现在蓝藻水华暴发期间(7月),分别为4.13 mg·L-1和0.255 mg·L-1;(3)极端降水过程短期内能明显降低河道营养盐浓度,但会引起湖体营养盐外源负荷的明显增高,不利于湖体富营养化控制.本研究表明,对于空间异质性较高的大型浅水湖泊,流域河道入湖污染对湖体营养盐时空格局具有重要的塑造作用,而湖体的污染物自净能力、蓝藻水华物质的空间堆积及风浪引发的底泥再悬浮作用等也都对湖体营养盐浓度、时空格局产生重要影响. 相似文献
65.
The effect of cyanobacterial bloom decay on water quality and the complete degradation of cyanobacterial blooms in a short period were examined by an enclosure experiment in Gonghu Bay of Lake Taihu,China.Water quality parameters as well as taste and odor compounds during the breakdown of cyanobacterial blooms were measured.Results showed that the decay of cyanobacterial blooms caused anoxic water conditions,decreased pH,and increased nutrient loading to the lake water.The highest concentrations of dimethyl sulfide (DMS),dimethyl trisulfide (DMTS),and β-cyclocitral were observed in the anoxic water,at 62331.8,12413.3,and 1374.9 ng/L,respectively.2-Methylisoborneol was dominant during the live growth phase of cyanobacterial blooms,whereas DMS and DMTS were dominant during the decomposition phase.Dissolved oxygen,pH,and chlorophyll a were negatively correlated with DMS,DMTS,and β-cyclocitral,whereas total phosphorus,total nitrogen,and ammonium (NH4+-N) were positively correlated with DMS,DMTS,β-cyclocitral,and β-ionone.The experimental results suggested that preventing the anaerobic decomposition of cyanobacterial blooms is an important strategy against the recurrence of a malodor crisis in Lake Taihu. 相似文献
66.
Physicochemical analyses and cyanobacterial diversity of Ramgarh Lake water were performed at five sampling sites during winter, summer, and monsoon seasons. Higher load of solids, carbon, and nutrients were persistent throughout the analysis that indicates the conversion of lake from oligotrophic to eutrophic nature. High nutrients load enhanced cyanobacterial biomass, while low nutrients load produced relatively less biomass. The physicochemical parameters of water samples revealed minimum 2.9 mg L?1 dissolved oxygen (DO) at site-1 during summer, while maximum (5.6 mg L?1) at site-4 in monsoon season. Maximum biochemical oxygen demand (BOD) (40 mg L?1) and chemical oxygen demand (COD) (126 mg L?1) were recorded at site-1 during summer, whereas minimum BOD (18 mg L?1) and COD (52 mg L?1) were evident at site-3 in monsoon season. Minimum concentration of nitrate (0.72 mg L?1) was recorded at site-3 in summer, whereas maximum 2.7 mg L?1 was present at site-5 in winter season. The phosphate concentration was maximum (0.52 mg L?1) at site-5 in summer, and minimum (0.18 mg L?1) was observed at site-4 in monsoon season. Cyanobacterial diversity was higher during all the seasons, and dominated by the species of Microcystis at all the five sampling sites. 相似文献
67.
绿潮藻类暴发对天鹅湖水体和沉积物磷含量的影响 总被引:1,自引:0,他引:1
在荣成天鹅湖藻类暴发区域采集新鲜沉积物和丝状硬毛藻(Chaetomorpha spp.),进行室内模拟试验,监测了生长过程中硬毛藻的生物量、磷富集量以及不同处理水体总磷(TP)和可溶性磷(SRP)质量浓度的变化,并分析了藻类生长对沉积物中各形态磷含量的影响。结果表明,当水体磷含量较高时,硬毛藻生长较快,相对生长速率高达14.88%,之后随着水体磷浓度的下降,生长速率逐渐减小。不同处理间硬毛藻的生物量相差很大,高磷含量处理显著高于低磷处理,最大差值可达26.50 g。随着藻类的生长,水体TP和SRP含量明显降低,其中高磷含量处理的TP质量浓度由0.93 mg·L-1降至0.01 mg·L-1,低磷含量处理水体SRP质量浓度均降至0.006 mg·L-1以下。当水体磷含量降至一定水平,沉积物中磷可向水体释放,其中可还原态磷和铁铝结合态磷的降幅分别为23.98%和12.61%。在高磷含量处理组,藻体中磷的富集量显著升高,且当水体磷含量相同的条件下,有沉积物处理的富集量显著高于无沉积物处理。相关分析表明,藻体生物量与水体TP和SRP的相关性较好,其中高磷含量处理组生物量与水体TP、SRP呈高度负相关,而相对生长速率与之呈显著正相关。结果说明,水体及沉积物中磷均可作为硬毛藻生长的营养来源;另一方面,藻类生长可明显降低水体磷含量,并促进沉积物中磷的释放。 相似文献
68.
蓝藻衰亡过程中上覆水溶解性有机物变化特征 总被引:4,自引:2,他引:2
为探究蓝藻水华衰亡过程中溶解性有机物(DOM)的迁移转化机制,本文对蓝藻衰亡过程进行室内模拟实验,基于紫外-可见光谱(UV-vis)和三维荧光光谱(EEMs)表征上覆水溶解性有机物的光谱特征,同时分析水质理化指标及溶解性有机碳(DOC)、溶解性无机碳(DIC)含量变化.结果表明,蓝藻衰亡初期阶段释放出大量有机质,溶解氧(DO)急剧降低,随着反应时间延长,DOC逐渐转变为DIC,改变了水体氧化还原环境和酸碱环境;UV-vis光谱显示蓝藻衰亡释放出大量芳香性很高、腐殖化程度高的DOM,并且DOM随反应时间被逐渐降解.通过三维荧光光谱平行因子分析(EEM-PARAFAC),解析出3种荧光组分,分别为难降解的类腐殖质(C1),藻类产生的类蛋白质色氨酸(C2),以及与微生物活动有关的类腐殖质富里酸(C3).蓝藻衰亡产生的类蛋白质大部分被微生物降解成类富里酸,异养型微生物促进了藻源性DOM的生成,同时也加快了对新生DOM的降解.蓝藻衰亡产生的DOM最终大部分转化为较难降解类腐殖质.对水质参数、UV-vis光谱和EEMs光谱参数进行相关性分析可知,ORP与DO呈显著正相关(P<0.05),pH与DOC呈显著负相关(P<0.05),与DOC向DIC转变趋势相吻合;C1与Fn355有显著正相关关系(P<0.05),C2与DOC和Fn280都有显著正相关关系(P<0.05),C3与FI、BIX以及β∶α呈显著正相关(P<0.05),这些光谱参数的变化趋势与DOM组分变化一致.综上所述,通过对蓝藻水华衰亡过程中上覆水DOM的水质特征和光谱特征的探究,为分析湖泊DOM的动态迁移转化和碳循环的变化提供技术支持. 相似文献
69.
Economists are increasingly interested in causally interpretable estimates of environmental health externalities, particularly on infant health. This paper focuses on a specific case by investigating microcystin, a toxin produced by freshwater blue-green algal blooms. We exploit a natural experiment caused by a zebra mussel die-off in a large lake located in the state of Michigan, USA to identify changes in microcystin-related infant outcomes surrounding the lake. Using both the synthetic control method and a difference-in-differences strategy, we find that instances of low birth weight around the lake fell by 1.4 percentage points after lake water quality improved. Along the intensive margin, birth weight and length of gestation increased by 17.1 g and 0.47 weeks, respectively. Improvements to low birth weight result in $768,500 in average annual hospitalization cost savings. Many robustness and falsification tests are performed including using both annual and monthly data and accounting for possible weather confounders and seasonality. Results suggest that microcystin can affect infant health at levels below current water advisory guidelines. 相似文献
70.
Impacts of algal blooms removal by chitosan-modified soils on zooplankton
community in Taihu Lake, China 总被引:1,自引:0,他引:1
Jiajia Ni Yuhe Yu Weisong Feng Qingyun Yan Gang Pan Bo Yang Xiang Zhang Xuemei Li 《环境科学学报(英文版)》2010,22(10):1500-1507
It is important to assess the e ect on zooplankton when perform the environmental protection or restoration technology, especially
removing algal blooms, because algae were the major primary producer in algal lakes. The influence on zooplankton community after
half a year of algal blooms removed by chitosan-modified soils in Taihu Lake was assessed and the rationality of carrying out the
process semiannually was evaluated in the present study. Morphological composition and genetic diversity of zooplankton community
were investigated by microscope checkup and polymerase chain reaction-denatured gradient gel electrophoresis (PCR-DGGE). A total
of 44 zooplankton taxa (23 protozoa, 17 rotifers, 3 copepoda and 1 cladocera) were detected by microscope checkup, and a total of
91 bands (28 bands amplified by primers F1427-GC and R1616, 63 bands amplified by primers Fung-GC and NS1) were detected by
PCR-DGGE. The results of cluster analysis or detrended correspondence analysis indicated that there was no considerable di erence
in morphological composition of zooplankton and DGGE profiles between experimental and control sites, and DGGE profiles could
represent the biologic diversity. The study showed that zooplankton community could recover original condition after half year of algal
blooms removed by chitosan-modified soils and it was acceptable to apply this process semiannually. In addition, the results revealed
that PCR-DGGE could be applied to investigate the impacts of the environmental protection or restoration engineering on zooplankton
community diversity. 相似文献