城市湖泊生态修复及水生植物群落构建研究进展

介绍了经典的湖泊生态修复理论在国内外的应用及发展现状,并总结了在该理论指导下实施城市湖泊生态修复过程中,内源及外源性营养盐、光照、浮游植物、底泥、生物扰动等因子对水生植物群落恢复的影响,及其应对策略。针对外源性点源、面源污染多的问题,通过修建污水管网以及人工湿地等水利设施进行控制;内源性污染如底泥,则可采用原位以及异位等处理技术进行控制;对水质产生较大影响的浮游植物可采用物理、化学、生物-生态学方法进行调控;人类干扰、鱼类牧食及其他水生动物、浮游植物等综合作用共同影响水生植物生长、分布。因此,在利用水生植物修复湖泊水体时,必须综合考虑多方面生态因子对其所造成的影响。     

Evidence for biotic control of Australian reservoir phytoplankton communities and the potential for applied biomanipulation

Although some concerns have been expressed with respect to the applicability of biomanipulation to Australian reservoirs and other inland waters, no major obstacles were found in this review. The previous doubts stimulated research, which has provided evidence for unexpected mechanisms of food web interactions, such as positive effects of small copepods on planktonic algae, higher than usual grazing potential of cladoceran communities, and direct positive effects of planktivores on phytoplankton. Further research into zooplankton-cyanobacteria interactions should indicate how widespread is the previously reported ability of some southern hemisphere crustaceans to benefit at a population level from feeding on cyanobacteria. Quantitative fisheries acoustics, which has not been widely used in biomanipulation trials before, is a promising new tool in the assessment of the biomass of planktivorous fish in the pelagic zone of reservoirs.     

Grazing by a resident macrozooplankton community and non-resident Daphnia carinata King: A preliminary in situ incubation study

A 24 h incubation study was conducted in situ in Manly Dam reservoir, Sydney, Australia. The study aimed to evaluate the relative effectiveness of grazing on phytoplankton by a resident macrozooplankton community, dominated by the cladoceran Ceriodaphnia and some copepods, in comparison with grazing by added, non-resident Daphnia carinata in the absence of the resident macrozooplankton community. Although there was some variability in the measured grazing rates among incubation bottles (volume: 1.28 L), D. carinata with a mean body size of 30.8 μg dry weight were more efficient grazers than the reservoir macrozooplankton community with a mean body size of 2.5 μg dry weight. The weight-specific clearance rate of D. carinata was 2–65 times higher than that of the resident reservoir community for five taxa of reservoir phytoplankton examined. In comparing the evidence from the literature on the limited ability of D. carinata to graze on cyanobacteria, a management strategy using D. carinata for the reduction of phytoplankton biomass may need to be considered separately from one designed to specifically control undesirable taxa, such as the cyanobacteria Microcystis and Anabaena .     

Preliminary Study on Biological Control of Cyclops of Zooplankton in Drinking Water Source

An ecological project called fish biomanipulation, other than the conventional fishery culture tech-nique, was put forward in this paper for the excess propagation control of Cyclops. The control effects on Cyclops of four species of fish were investigated experimentally at stocking density of 30 g per cubic meter of water. The experimental results showed that the food habit of the fish had significant influence on the biological control of Cyclops. The propagation of Cyclops could be controlled effectively and also the water quality was improved simultaneously by stocking the filter-feeding fishes, such as silver carp and bighead carp. Whereas, herbivorous Ctenopharyngodon idellus and omnivorous Cyprinus carpio had no obvious biological effects on controlling the growth of Cyclops and restoring water quality. The results further proved that under condition of proper poly-culture density of silver carp and bighead carp, the number of Cyclops might be controlled at very low level and the eutrophication might be abated by removing the nutrients from water body.     

水环境生态修复国内外研究进展

我国的江河湖库水体污染主要包括氮、磷等营养物和有机物污染两方面。目前国际上采用的技术主要有物理方法、化学方法和生物一生态方法。本文从外源和内源两方面对目前国内外的生态修复方法加以阐述，分析了近年国内外的相关文献资料．从方法上总结了河流、湖泊等水体生态修复的研究进展，并比较了各自的优点及缺陷。     

Lake restoration in Denmark

Lake restoration in Denmark has involved the use of several different restoration techniques, all aiming to improve lake water quality and establishing clear‐water conditions. The most frequently used method, now used in more than 20 lakes, is the reduction of zooplanktivorous and benthivorous fish (especially roach (Rutilus rutilus) and bream (Abramis brama)) with the objective of improving the growth conditions for piscivores, large‐sized zooplankton species, benthic algae and submerged macrophytes. Piscivore stocking (mainly Esox lucius (pike)), aiming especially at reducing the abundance of young‐of‐the‐year fish, has been used in more than 10 lakes and frequently as a supplement to fish removal. Hypolimnetic oxidation, with oxygen and nitrate, has been undertaken in a few stratified lakes and sediment dredging, with the purpose of diminishing the internal phosphorus loading, has been experimented with in one large, shallow lake. Submerged macrophyte implantation has been conducted in some of the biomanipulated lakes to increase macrophyte abundance and distribution. Overall, the results from lake restoration projects, in the mainly shallow Danish lakes, show that external nutrient loading must be reduced to a level below 0.05–0.1 mg P L^–1 under equilibrium conditions to gain permanent effects on lake water quality. By using fish removal, at least 80% of the fish stock should be removed over a period of not more than 1–2 years to obtain a substantial effect on lower trophic levels and to avoid regrowth of the remaining fish stock. Stocking of piscivores requires high densities (>0.1 individuals m^–2) if an impact on the plankton level is to be obtained and stocking should be repeated yearly until a stable clear‐water state is reached. The experiments with hypolimnetic oxygenation and sediment dredging confirm that internal phosphorus loading can be reduced. Experience from macrophyte implantation experiments indicates that protection against grazing by herbivorous waterfowl may be useful in the early phase of recolonization.     

Universal Soft Robotic Microgripper

Here, a soft robotic microgripper is presented that consists of a smart actuated microgel connected to a spatially photopatterned multifunctional base. When pressed onto a target object, the microgel component conforms to its shape, thus providing a simple and adaptive solution for versatile micromanipulation. Without the need for active visual or force feedback, objects of widely varying mechanical and surface properties are reliably gripped through a combination of geometrical interlocking mechanisms instantiated by reversible shape‐memory and thermal responsive swelling of the microgel. The gripper applies holding forces exceeding 400 µN, which is high enough to lift loads 1000 times heavier than the microgel. An untethered version of the gripper is developed by remotely controlling the position using magnetic actuation and the contractile state of the microgel using plasmonic absorption. Gentle yet stable robotic manipulation of biological samples under physiological conditions opens up possibilities for high‐throughput interrogation and minimally invasive interventions.     

浅水湖泊稳态转换模型PCLake研究进展

总结了能够全面模拟浅水湖泊生物及非生物过程的PCLake模型的发展历程、技术框架、适用性及局限性,从营养盐转换阈值、气候变化、生物操纵等3方面详述了PCLake模型的研究进展,并针对PCLake模型优势及存在问题,结合当前研究热点,展望了该模型未来发展趋势:开发全球尺度规模以及更易于使用且更灵活的模型,涵盖更多湖泊特征,形成多种组合,用于稳态转换阈值及预警识别,将敏感性分析、不确定性分析等功能嵌套于模型,提高模型的模拟精度。     

五里湖富营养水体生态重建试验

为了改善五里湖水环境,从2002年起,展开对五里湖及其周边地区综合整治、西五里湖生态重建与示范工程。初步结果表明,西五里湖水质得到一定的改善,水体透明度也有所提高,尤其是示范工程区内透明度的平均值比湖区的高1.6倍。最好的水质出现在示范工程区内,与未进行生态恢复的东五里湖相比,水体中的TN、TP、Chl.a、NH4-N及NO2-N均有较大幅度降低,但CODMn、NO3-N、SD差异不大。湖滨生态景观有了较大改善,建立了具有生态景观效果的芦苇、狭叶香蒲、水菖蒲、水生类鸢尾及美人蕉等湖滨湿地近1.0万m2;在敞水区恢复了浮叶、沉水植物超过3.5万m2。通过生态重建实践,对浅水湖泊生态恢复提出了建议。     

Covalent coupling of polyacrylic acid coated magnetic-nanoparticles to multi-wall carbon nanotubes for manipulation targets

This research effort investigated the chemical heterojunction between magnetic nanoparticles coated with polyacrylic acid and multi-wall carbon nanotubes (MWCNTs). Here, magnetic nanoparticles were covalently attached to open-ended nanotubes in the presence of diclohexylcarbodiiimide. Initial evidence demonstrated that short functionalised multi-wall nanotubes can be continuously connected at their terminals ends to build-up relatively large nanostructures. It has also been shown that magnetic-carbon nanotubes (CNTs) systems exhibited defined arrangements due to the influence of magnetic fields. Indeed, linear arrays of CNTs interconnected through magnetic nanoparticles were prone to be manipulated in the presence of a magnetic device. A potential application of these kind of magnetic nanostructures was shown here by successfully manipulating agarose beads in a buffer solution. These results suggest that the use of continuously connected magnetic nanostructures with non-modified sidewall surfaces will find potential applications in the area of bio-sensing, force transduction and cancer screening-manipulation among many others.