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191.
Altemaria alternata were isolated from wheat seeds collected from villages in Tianshui area of Gansu Province where Kaschin-Beck disease is prevalent. TLC, IR and UV analyses of metabolic extract of A. alternata show that A. alternata produce main secondary metabolites, including alternariol, alternariol methyl ether, and tenuazonic acid.There was a significant decrease in Se-GSH-Px and SOD activities, and an acceleration in lipid peroxidation in rats fed with a diet containing metabolites produced by A. alternata.  相似文献   
192.
利用小麦秸控制赤潮生物生长的研究   总被引:13,自引:0,他引:13  
以球形棕囊藻为研究对象,探讨了小麦秸用于赤潮生物控制的可行性,研究了微生物、吸附作用在抑藻效应中的可能作用,运用扫描电子显微镜观察了小麦秸对藻细胞形态的影响,对小麦秸抑藻机理进行了分析和讨论。结果表明,小麦秸是一种比较理想的抑藻材料,无需微生物的降解,适度切割后能够吸附藻细胞、释放出抑藻活性物质,从而有效控制赤潮生物——球形棕囊藻的生长。抑藻活性物质的释放是小麦秸抑藻的主要机制。  相似文献   
193.
An evaluation of water quality and phytoplankton composition position was carried out in order to determine the trophic conditions of Lake Patzcuaro (2035 m above sea level), a high altitude tropical lake. Temperatures ranged from 15 to 23 degrees C. Total phosphorus and inorganic nitrogen showed a seasonal variation; highest values coincided with the rainy season (0.48 and 2.1 mg litre(-1), respectively). Dissolved oxygen ranged from 2 to 7.9 mg litre(-1) at the surface and from 0.6 to 7.3 mg litre(-1) on the bottom, the lowest values being found in shallow zones. Average transparency varied from 0.62 to 1.4 m Secchi depth. Rainfall was a primary factor in seasonal variability as it influenced both physical and biological conditions by contributing to the transport and deposition of silt, which mixed with sinking algal cells. The composition of the surface phytoplankton segregated along five major divisions comprising a total of 49 species. General seasonal patterns of dominance alternated in a sequence beginning with Bacillariophyta, through Chlorophyta to Cyanophyta. Diatoms, the dominant group from February to early June, included Melosira granulata, Stephanodiscus sp., Synedra sp. and Fragilaria sp. During the rainy season (late June to September), Microcystis aeruginosa, Oscillatoria sp., Anabaena sp., Merismopedia sp., Crucigenia cuadrata, Oocystis lacustris, Selenastrum gracile, Mallomonas sp. and Tetraediella sp. were important. Melosira granulata was present throughout the period of study. Spatial and temporal variability in both physical and biological conditions make it difficult to assign a specific trophic state to Lake Patzcuaro. Nevertheless, analysis of the algal community indicates a generally mesotrophic condition.  相似文献   
194.
ABSTRACT A water quality investigation on Utah Lake was conducted during the same time period that the Heat Capacity Mapping Mission (HCMM) satellite was collecting thermal infrared and reflectivity data. Relationships were established and evaluated among HCMM data and lake water quality parameters. Although remotely sensed reflective data have been previously utilized, this study was unique in that thermal emitted data were also correlated to algae concentrations and other indicators. Standard statistical evaluations were made along with utilization of color graphics techniques to identify and plot relationships. The emitted thermal energy was found to have high positive correlations with net algal concentrations and with the predominant species, Aphanizomenon flos-aquae, a blue-green alga. No continuous correlation was found for a less abundant red pigment phytoplankton, Ceratium hirundinella. Similar trends, though for negative correlations, were shown for reflectivity data and algal concentrations throughout the spring and summer. Coincidence of areas of warmer emitted energy and darker relfected energy on colorgraphics displays clearly indicate lake areas of high algal concentrations. Night thermal data displayed a strong negative correlation with algal concentration, opposite to day thermal data. Color graphics of warmer day emitted energy and cooler night emitted energy further verify areas of high algal concentrations.  相似文献   
195.
首先介绍了高效藻类塘的发展历史和特点,其次简述了高效藻类塘的生物特性和物理化学变化规律,并重点论述了高效藻类塘的氮磷去除机理及其影响因素,最后对高效藻类塘在控制非点源污染中的应用前景进行展望.  相似文献   
196.
雷国元  范唯  李媛  邓慧敏  李俊叶 《生态环境》2007,16(4):1166-1170
针对富营养化水体生物修复和污水深度处理氮磷的去除,将细颤藻、水绵、水网藻、栅裂藻固定在纤维填料上,形成固定化藻膜。用固定化藻膜处理模拟富营养化湖水、实际富营养化湖水、城市污水二级出水、低质量浓度生活污水,考察固定化藻膜去除氮磷的效果。实验结果表明,固定化藻膜具有良好的去除磷、氨氮能力,对水中有机物去除也有一定的促进作用。对TP质量浓度小于5.0mg·L-1,NH4 -N质量浓度小于34.0mg·L-1的污染水体,四种藻膜都有良好的去除氮磷能力,其中栅裂藻去除TP、NH4 -N的能力最强。综合除污能力和藻细胞的可固定性,水绵应是最佳的备选藻种。研究结果显示,固定化藻膜具有良好的除污性能,预示了悬浮载体将在水体生物修复、氧化塘污水处理方面具有重要的潜在应用价值。  相似文献   
197.
Nitrogen (N) and phosphorus (P) are significant pollutants that can stimulate nuisance blooms of algae. Water quality models (e.g., Water Quality Simulation Program, CE‐QUAL‐R1, CE‐QUAL‐ICM, QUAL2k) are valuable and widely used management tools for algal accrual due to excess nutrients in the presence of other limiting factors. These models utilize the Monod and Droop equations to associate algal growth rate with dissolved nutrient concentration and intracellular nutrient content. Having accurate parameter values is essential to model performance; however, published values for model parameterization are limited, particularly for benthic (periphyton) algae. We conducted a 10‐day mesocosm experiment and measured diatom‐dominated periphyton biomass accrual through time as chlorophyll a (chl a) and ash‐free dry mass (AFDM) in response to additions of N (range 5–11,995 µg nitrate as nitrogen [NO3‐N]/L) and P (range 0.89–59.51 µg soluble reactive phosphorus/L). Resulting half‐saturation coefficients and growth rates are similar to other published values, but minimum nutrient quotas are higher than those previously reported. Saturation concentration for N ranged from 150 to 2,450 µg NO3‐N/L based on chl a and from 8.5 to 60 µg NO3‐N/L when based on AFDM. Similarly, the saturation concentration for P ranged from 12 to 29 µg‐P/L based on chl a, and from 2.5 to 6.1 µg‐P/L based on AFDM. These saturation concentrations provide an upper limit for streams where diatom growth can be expected to respond to nutrient levels and a benchmark for reducing nutrient concentrations to a point where benthic algal growth will be limited.  相似文献   
198.
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.  相似文献   
199.
为探索化感物质在蓝藻水华治理方面的应用潜力,选取在凤眼莲根系分泌物中发现的5种化感物质(亚油酸、亚油酸甘油酯、丙酰胺、N-苯基—2-萘胺和壬酸),研究了3种剂量下(0.1、1.0、10.0mg.L-1)其对单一、混合培养铜绿微囊藻和斜生栅藻生长的影响.结果发现,化感物质成分、剂量和藻类培养方式对铜绿微囊藻和斜生栅藻生长...  相似文献   
200.
利用络氨铜控制景观水体藻华   总被引:1,自引:0,他引:1  
王蕾  石利利  蔡道基 《环境科学学报》2011,31(11):2440-2446
研究了络氨铜对不同生长期的典型蓝藻(铜绿微囊藻,Microcystis aeruginosa)15d生长抑制影响的基础上,开展了络氨铜对不同时期景观池水中叶绿素a含量的影响,并跟踪测定了其中的有效铜离子浓度变化.结果表明,络氨铜在0.10mg·L-1(络氨铜的有效浓度,下同)时,可完全抑制适应期铜绿微囊藻的生长;在4d...  相似文献   
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