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陆源排污对邻近海域底栖海藻群落的影响 总被引：1，自引：0，他引：1
伴随着经济的发展,我国沿海海域富营养化日趋严重。为了明确富营养化对底栖海藻群落的影响及作用机制,本文选择了与大连凌水河口(污水河)毗邻的海藻床作为野外观测点,研究底栖海藻群落对营养盐自然衰减梯度的响应规律;在实验室内,选择了在排污口附近优势分布、营r-生态策略的绿藻缘管浒苔和仅在寡营养区域分布、营k-生态策略的红藻柔质仙菜作为实验材料,开展了营养吸收动力学和生长动力学研究。通过二者在营养盐吸收、利用和繁殖策略方面的比较研究,剖析了底栖海藻群落对不同营养环境的响应机制。结果显示:随着海水中营养盐浓度的降低,底栖海藻群落呈现种类数增加、优势种覆盖度降低的趋势。根据底栖海藻在群落水平对氮源营养的响应,认为现行海水水质标准中无机氮一类水质标准的限值应该由目前的14.29 μmol/L降低为6.69 μmol/L。在富营养环境中,营养盐浓度的上升促进了r-策略海藻幼体的竞争力和种群繁殖力,使其占据了大量的生态位,形成优势种群,导致底栖海藻多样性较低;在寡营养环境中,由于得不到充足的营养盐供应,r-策略海藻幼体的竞争力和种群繁殖力都受到制约,占据的空间生态位有限,为其他种类的生存提供了条件,而那些对营养盐需求较低但利用效率高的k-策略海藻则表现出更强的竞争力,在竞争中取得优势,能快速突破早期环境筛的限制,形成成体,因此,在寡营养海域,底栖海藻的多样性比较丰富。 相似文献
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A simple, low cost, highly effective, and useful Fenton oxidation treatment of synthetic dye bath waste with pickling liquor as a source of iron (Fe2+ catalyst) is reported. Optimizations of contact time, Fe2+ and H2O2 doses are carried out. Oxidative de‐colorization and degradation of Reactive Blue 4 and Reactive Orange 16 was measured in terms of decrease in absorbance at their wavelength of maximum absorption (RB4, 599 nm; and RO16, 493 nm) and also as reduction in chemical oxygen demand (COD). Approximately, 62% COD was removed in 2 h at optimized doses of Fe2+ (8.95 mM) and H2O2 (61.8 mM) by using pickling waste as a source of Fe2+ catalyst. Similar performance efficiency was observed when neat FeSO4 was used as a source of Fe2+, indicating that pickling liquor can be a low cost source of Fe2+ to treat synthetic dye bath waste by Fenton method. 相似文献
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收集十几块和田玉仔料和数十块仿和田玉仔料样品,进行肉眼与镜下观察。简要总结和田玉仔料与仿和田玉仔料以及染色和田玉仔料的肉眼鉴别要领。 相似文献
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Purification of Wastewaters Containing Azo Dyes This study describes the degradability of the azo dye C.I. Reactive Violet 5 by a continuous flow biological treatment system consisting of three rotating disc reactors. The azo dye was first decolorized in an anaerobic reactor. Decolorization was improved by adding an auxiliary substrate (yeast extract and acetic acid). Although severe operating conditions were experienced due to failures in the temperature and pH-controllers, the reactor recovered quickly and continued to decolorize reliably. The removal of the auxiliary substrate in the anaerobic reactor was not satisfactory, probably due to the copper in the azo dye. Batch experiments showed that copper was removed from the dye molecule and precipitated during the decolorization. In the continuous flow reactor, the copper precipitate on the disc can redissolve due to a pH-gradient in the fixed biomass becoming toxic again for the bacteria. In the following two aerobic reactors, the auxiliary substrate was degraded, but mineralization of the dye metabolites was insufficient. The aromatic amines produced by the anaerobic decolorization are more toxic in the bacterial luminescence test than the azo dye. Therefore, decolorization alone cannot be used to treat colored wastewater. Since the amines can also be produced in anaerobic parts of rivers, the dyes have to be removed in a more efficient way. That is the reason why in further experiments ozonation is being tested to increase the biological degradability of the azo dye for a following aerobic stage. Either ozonation can be used after the two stage treatment of the dye in anaerobic/aerobic reactors or the dye can be oxidized directly, making the addition of auxiliary substrate unnecessary. These configurations are being tested with the goal to degrade the dye with the least ozone consumption. 相似文献
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Martin Sharp Keith Richards Ian Willis Neil Arnold Peter Nienow Wendy Lawson Jean-Louis Tison 《地球表面变化过程与地形》1993,18(6):557-571
As part of an integrated study of the hydrology, meltwater quality and dynamics of the Haut Glacier d'Arolla, Switzerland, the glacier's drainage network structure was determined from patterns of dye recovery in 342 injection experiments conducted from 47 moulins distributed widely across the glacier. This structure was compared with theoretical predictions based upon reconstructed patterns of water flow governed by (a) the subglacial hydraulic potential surface, and (b) the subglacial bedrock surface. These reconstructions were based on measurements of ice surface and bedrock topography obtained by a combination of ground survey and radio-echo sounding techniques. The two reconstructions simulate the drainage system structures expected for (a) closed channels, in which water is pressurized by the overlying ice, and (b) gravity-driven, open-channel flow. The closed-channel model provides the best fit to the observed structure, even though theoretical calculations suggest that, under summer discharge conditions, open-channel flow may be widespread beneath the glacier. Possible reasons for this apparent discrepancy are discussed. 相似文献
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R. E. Wallace III 《Environmental Geology》1993,22(4):362-366
This paper summarizes over four years of studies and testing of a sinkhole/spring system in north Tampa. Sulphur Springs Pool delivers an average of 95 million l/d to the Hillsborough River, which is tributary to Tampa Bay. In 1986, owing to increasingly erratic bacterial levels at the natural bathing area adjacent to Sulphur Springs, the Hillsborough County Health Department closed the pool for swimming. The City of Tampa, Southwest Florida Water Management District (SWFWMD), Hillsborough County Environmental Protection Commission, and the United States Geological Survey have gathered data in an attempt to better understand the system and possible sources of contamination. The Sulphur Springs Action League is a civic group in the area, which has an objective of reopening the pool for recreational purposes. Environmental Engineering Consultants, Inc. provided pro bono technical assistance and expertise in assisting the Action League with its goal. The Action League obtained a grant from SWFWMD to outfit underwater divers for sinkhole exploration as well as water quality and dye trace analysis. The main suspects for bacterial contamination of the pool were two significant sinkholes located 1950 and 2300 m north of the spring. A series of dye tests and water-quality tests were performed. It was estimated that the underground velocity of water was between 90–100 m/h. Using a dye trace, bacteria testing, and travel time estimating, a new source of contamination was found in a Department of Transportation (DOT) stormwater retention basin in which a sinkhole had opened up and was receiving stormwater. The two significant sinkholes received stormwater from commercial and residential areas, and this stormwater brings a large amount of bacteria into the sinkhole, which funnels into the underground system and induces a bacteria spike at Sulphur Springs pool that exceeds the bathing water standards. The City of Tampa has constructed an experimental initial flush capture basin that will sand-filter stormwater to see if this will favorably affect bacteria levels. A mayor's task force in Tampa has recommended ultraviolet disinfection as an interim solution to the contamination problem. 相似文献
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Xanthoceras sorbifolia seed coat (XSSC), a bioenergy forest waste, was used for the adsorption of methylene blue (MB) from aqueous solutions. The effects of adsorbent dosage, pH, adsorbate concentration and contact time on MB biosorption were studied. The equilibrium adsorption data was analyzed by Langmuir and Freundlich isotherm models. The results indicated that the Langmuir model provided the best correlation with the experimental data. The adsorption capacity of XSSC for MB was determined with the Langmuir model and was found to be 178.6 mg/g at 298 K. The adsorption kinetic data was modeled using the pseudo‐first order, pseudo‐second order, and intraparticle diffusion kinetic equations. It was seen that the pseudo‐second order equation could describe the adsorption kinetics, and intraparticle diffusion was not the sole rate controlling factor. Thermodynamic parameters were also evaluated. Standard Gibbs free energy was spontaneous for all interactions, and the biosorption process exhibited exothermic standard enthalpy values. The results indicated that XSSC is an attractive alternative for removing cationic dyes from wastewater. 相似文献