辣木种仁净水效果研究

通过辣木种仁净水剂与常用化学净水剂净水效果比较研究,表明辣木种仁净水剂有很好的净水效果,净水效率与聚合氯化铝相当,能使水的混浊度降到世界卫生组织饮用水标准以下(浊度≤5FTU),可作为化学净水剂的替代品使用;辣木种仁和辣木油渣都可作为净水剂使用,二者净水效果差异不显著,从净水成本和综合利用考虑,选用辣木油渣作为混水净水剂更加经济合理;当混水浊度为150.6FTU时,辣木油渣净水的最佳剂量为每升混水中加入0.2g辣木油渣粉。     

Ecological impacts of invasive carp in Australian dryland rivers

相似文献   

Effects of turbidity on feeding of the young-of-the-year pikeperch (Sander lucioperca) in fishponds

The effect of water turbidity on the prey selection and consumption of the young-of-the-year (YOY) pikeperch in the planktivorous feeding stage was studied. Attention was paid particularly to the question of how the food selectivity depends on the size of YOY pikeperch and how the turbidity affects feeding in different size classes. Studies were carried out in ponds of two fish farms in Estonia over 4 years. Small cladocerans were the most preferred prey in the smallest pikeperch size class. In larger size classes, the most selected prey were the large cladocerans. Water turbidity affected the prey selection of the planktivorous pikeperch significantly. In more turbid environments, the larger zooplankters were more positively selected than the smaller ones. Turbidity decreased both total zooplankton consumption and Fulton's condition factor of fish only in the largest size class of pikeperch. The effect of turbidity on foraging and growth, and thus on the size of juvenile pikeperch of a particular year class is substantial under conditions where juveniles cannot shift from planktivory to piscivory.     

苹果浑浊汁贮藏过程中浑浊稳定性的研究

为考察苹果浑浊汁在贮藏中的浑浊稳定性，进行了在4、22和40℃贮藏果汁120 d的试验。采用了电子显微镜学、光学显微镜学、Zeta电位和粒径分布分析等技术，结合高效液相色谱(HPLC)分析酚类物质进行研究。结果发现，果汁中相对大尺寸的颗粒先聚集下沉，造成浊度的迅速下降。随着留在瓶上部的大的颗粒数目的减小，颗粒下沉的速率降低。总酚、表儿茶素、绿原酸和单宁的损失随着贮藏温度的升高和储藏时间的延长增大。添加0.006%的维生素C可抑制由酚类物质的氧化聚合产生的不溶性小颗粒的产生，使果汁浊度变化减小。悬浮颗粒的尺寸大于其电性质对浑浊稳定性的影响。     

酶解工艺对山楂粗滤汁澄清效果的影响

分别以加热浸提和离心分离法制得的山楂粗滤汁为试材,研究不同酶类、不同酶浓度及酶解时间对山楂粗滤汁澄清效果的影响.结果表明,加热浸提法和离心法提取的山楂粗滤汁单独使用4号酶即液化酶(纤维素酶、淀粉酶为主,果胶酶为辅)处理时,对山楂汁的澄清效果改善不大,而单独使用3号酶即澄清酶(果胶酶为主,纤维素酶、淀粉酶为辅)或与液化酶...     

聚铝、聚铁和阳离子聚丙烯酰胺用

研究了聚合氯化铝（PAC）、聚合氯化铁（PFC）以及聚丙烯酰胺（PAM）三种高分子絮凝剂单独以及配合使用处理长江原水时pH值、温度、絮凝剂用量等因素对浊度去除效果的影响。结果表明，PAC、PFC与PAM配合使用除浊效果要优于单独使用的效果；PAC、PFC与PAM投加浓度比为30：1时，除浊效果最好,且浊度去除率在较宽的温度范围（10～40℃）和pH值范围（5.0～8.0）内均可达到90%以上。     

Field and model studies of the fate of particulate carbon in mangrove‐fringed Hinchinbrook Channel,Australia

A field and model study was undertaken in 1996/1997 of the dynamics of water, fine sediment and particulate carbon in the northern region of the mangrovefringed Hinchinbrook Channel, Australia. The currents were primarily tidal and modulated by the wind. Biological detritus acted as a coagulant for the fine cohesive sediment in suspension in the mangrovefringed, muddy coastal waters. Plankton and bacteria were the major aggregating agents at neap tides, and mangrove detritus at spring tides. The microaggregates were typically several hundreds of micrometer in diameter and enhanced the settling rate. The fate of fine sediment and particulate carbon was controlled by the dynamics of the coastal boundary layer, a turbid shallow coastal water zone along the mangrovefringed coast. A tidallymodulated, turbidity maximum zone was found in this layer. Wind stirring increased the turbidity by a factor of five.The channel behaves as a sink trapping fine sediment and particulate carbon. However, the sink was leaky because the dynamics of the coastal boundary layer generated a net outflow of fine sediment out of the channel along the western coast. The biologically enhanced settling of cohesive sediment limited the offshore extent of the muddy suspension to within a few hundreds of meters from the coast.At spring flood tides, some of this particulate carbon was advected into the mangrove forest where it would remain trapped. On a yearly basis about six times as much particulate carbon was exported out of Hinchinbrook Channel through the coastal boundary layer than was trapped in the fringing mangroves.     

Trophic polymorphism and water clarity in northern Australian Scortum (Pisces: Terapontidae)

Davis AM, Pusey BJ. Trophic polymorphism and water clarity in northern Australian Scortum (Pisces: Terapontidae).
Ecology of Freshwater Fish 2010: 19: 638–643. © 2010 John Wiley & Sons A/S Abstract – The diets and relative intestinal length of two typically herbivorous terapontid fish from contrasting high and low clarity environments were compared. Fish of both species collected from high clarity habitats were almost exclusively herbivorous, whereas conspecifics from low clarity habitats were omnivores. Relative intestinal lengths in both species were significantly shorter in low clarity environments. Pronounced contrasts in water transparency have the apparent capacity to produce dietary niche shifts in these two species that in turn induce and maintain trophic polymorphisms in a riverine environment.     

Potential reasons for the changes in the abundance of pike, Esox lucius, in the western Gulf of Finland, 1939–2007

Abstract  Pike, Esox lucius L., catch-per-unit-effort (CPUE) in rod and line fishing fluctuated considerably in the western Gulf of Finland between 1939 and 2007. Since the beginning of the 1980s, CPUE has been only 3–4% of the highest CPUE during the period, suggesting a drastic decrease in population size. The collapse of the population coincided with a rise in the nutrient level in the Baltic Sea and consequent changes in productivity, turbidity and vegetation. The differences in the food web that followed the environmental change may partly explain the variation both in CPUE and in the mean weight of pike caught. Long-term fluctuations in salinity and temperature, however, did not seem to affect the population size. The mean weight of pike fluctuated inversely with CPUE, indicating changes in the recruitment of pike to the study area.     

Microdistribution and feeding dynamics of Coilia nasus (Engraulidae) larvae and juveniles in relation to the estuarine turbidity maximum of the macrotidal Chikugo River estuary,Ariake Sea,Japan

To evaluate the nursery value of the estuarine turbidity maximum (ETM) for the anadromous engraulid fish Coilia nasus, physical and biological samples were collected along the macrotidal Chikugo River estuary, southwestern Japan, from June 2005 to January 2006. Generally, eggs were distributed upstream of the ETM, whereas larvae were distributed in the ETM. The first cohort was washed out of the estuary by a large flood in early July. The second cohort appeared after the flood, gradually extending its distributional area through the estuary and growing to 100 mm in standard length (SL) by December. Larvae and juveniles (20–100 mm SL) fed selectively on copepods, specifically large calanoid species, whereas more developed juveniles fed on mysids. Prey organisms in guts were significantly more abundant and present in greater weights in the ETM (salinity <10) than in the lower estuary (salinity >10). The better feeding conditions were primarily attributable to consistently high densities of two large calanoid species, Sinocalanus sinensis and Pseudodiaptomus inopinus, in the ETM. In contrast, the poor feeding conditions in the lower estuary were likely due to a seasonal decrease in copepod density and the dominance of small copepods such as Oithona spp. Given that better feeding conditions contribute positively to the growth and survival of larvae and juveniles, we conclude that the ETM has a significantly higher nursery value for C. nasus compared with other habitats in the Chikugo River estuary.