Risks to the aquatic ecosystem from the application of Metarhizium anisopliae for locust control in Australia

Laboratory tests of Metarhizium anisopliae var acridum Driver & Milner, at a dose of 1.3 x 10(6) conidia ml-1, had no adverse effects on nymphs of mayfly, Ulmerophlebia sp or 8-week-old fry of the rainbow fish, Melanotaenia duboulayi Castelnau. This dose was toxic to the cladoceran, Ceriodaphnia dubia Richard, causing 100% mortality in 48 h. When this test was repeated at doses of up to 6.7 x 10(3) conidia ml-1, there was only 5% mortality after 192 h. Spraying of artificial water sources with a very high dose of the fungus as an aqueous spray resulted in 80-130 conidia ml-1 at 15 cm depth in the first 24 h after spraying. The conidia rapidly settled out and were absent from the top 15 cm layer of water after about 50 h. A similar experiment using the oil formulation as used in field control resulted in a 2- to 20-fold lower level of conidia in the water. Finally, sampling actual water sources in spray areas revealed a very low level of contamination of the water, with a maximum mean level of 29 conidia ml-1 in the first 24 h after treatment. Thus the level of conidia likely to enter water during control campaigns is a small fraction of that required to kill cladocerans, the only sensitive non-target organism tested. It is concluded that the biopesticide is very unlikely to pose any hazard to aquatic organisms.     

水产饲料环保特性评价体系的初步构建

利用筛绢吊篓、烧杯、水浴锅等,于实验室内模拟水产养殖生产条件,分别测定了20℃和30℃水温下豆粕、鱼粉入水后的干物质溶失率、粗蛋白溶失量以及水质化学耗氧量、氨氮含量,对这两种蛋白饲料原料的环保特性进行了比较和评估,进而以设备条件、测定方法、测定指标等为主要内容,初步构建了水产饲料环保特性的评价体系。     

牛磺酸在水产饲料中的应用

本文概述了牛磺酸的含量及分布、合成与代谢、生物学作用及其在水产饲料中的应用效果,并指出了牛磺酸在水产养殖中的应用前景及研究方向。     

谷氨酰胺对水生动物的抗氧化作用及其机理

文章主要综述了谷氨酰胺(glutamine, Gln)对水生动物的抗氧化作用及其机理,旨在深入理解、研究、利用和调控Gln在水生动物上的抗氧化作用,提高水生动物的健康水平,促进生长和发育,发展可持续的渔业.     

武汉地区几种常见水生花卉的应用

对武汉地区常见水生花卉资源进行了调查,统计分析了武汉市园林中常见的20种水生花卉的栽培管理及其园林应用,总结了其中存在的问题并提出了相应的建议。     

棉籽饼粕在水产养殖中的应用

本文综述了水生动物对棉籽饼粕的应用情况及影响水生动物对棉籽饼粕利用的制约因素.     

采煤沉陷区苦草的生物学特性及其竞争机制

采煤活动所致的动态沉陷湿地具有动态性、高潜水位和生态脆弱性等特点,探明此类人工重构湿地的水生植物群落的生物学特性及其竞争机制,有助于为采煤沉陷区湿地水生植物群落修复提供科学依据.本研究以淮南潘集区人工构建的苦草群落(Ass.Vallisneria natans)为倒,采用样方调查法,研究苦草的生物学特性及其与其他水生植物的竞争机制.结果表明,1)沉陷区苦草的生物学特性与浅水湖泊较一致.主要表现在苦草的繁殖方式、传粉方式、生活史方面,但研究区苦草以有性繁殖为主.2)沉陷区苦草能与以种子萌发形成的水烛群丛(Ass.Typha angustifolia)共生,但生物量低;在与形成两年以上的水烛群丛竞争中处于劣势,在水烛群丛盖度达到90％时苦草逐渐消失.3)沉陷区苦草在与浮叶植物莕菜群丛(Ass.Nymphoides peltatum)、苹群丛(Ass.Marsilea quadrifolia)竞争中处于弱势,其盖度、株高、生物量等指标都明显下降.4)沉陷区苦草在与沉水植物竹叶眼子菜群丛(Ass.Potamogeton malaianus)竞争中处于劣势,苦草与沉水植物黑藻群丛(Ass.Hydrilla verticillata)、狐尾藻群丛(Ass.Myrioph yllum verticillatum)、大茨藻群丛(Ass.Najas marina)、金鱼藻群丛(Ass.Ceratophyllum demersum)占据不同水层空间,种间竞争不强烈,能较好地共存.总之,苦草较之于相似生长型的植物具有较明显的竞争优势,对于具有不同生活型,尤其是挺水植物和浮叶植物,处于竞争劣势.     

Impact of harvesting and logging slash on nitrogen and carbon dynamics in soils from upland spruce forests in northeastern Ontario

The potential impact of timber harvesting in the boreal forest on aquatic ecosystem water quality and productivity depends in part on the production of nutrients within the soil of the harvested catchment. Nitrogen supplied by organic matter decomposition is of particular interest because of the important role that N plays in biotic processes in surface waters, and in forest nutrition in general. Logging slash quality and input to the forest floor has the potential to influence N availability after harvest on clearcut sites. Net production of organic and inorganic-N and microbial biomass C and N concentrations were determined during a 90-day laboratory incubation at constant temperature and moisture. Incubated soils included F horizon and shallow mineral soil horizons (0-5 cm) from unharvested and full-tree harvested (2 and 12 growing seasons since harvest) boreal forest sites at the Esker Lakes Research Area (ELRA), in northeastern Ontario, Canada. In an ancillary experiment, black spruce foliage was added to unharvested forest floor material after 30 days during a 90-day laboratory incubation to simulate the influence of logging slash from full-tree harvesting on C and N dynamics. Twelve-year old clearcut F horizon material released on average 75 and 5 times more -N and 3 and 2 times as much inorganic-N than soil collected from unharvested and 2-year-old clearcuts, respectively. This increase in -N accumulation during the incubation was accompanied by decreases in both exchangeable -N and microbial biomass C and N levels. Net daily changes in microbial biomass N were significantly related to organic and inorganic-N accumulation or loss within the F horizon. Mineral soil release of inorganic-N was lower than release from the forest floor. Nitrate-nitrogen accumulation was lower, and -N accumulation was higher in mineral soil from unharvested sites when compared to 12-year-old clearcuts. Calculated harvest response ratios indicated that incubated mineral soil from the 12-year-old clearcut sites released significantly greater amounts of -N than 2-year-old clearcuts. Incorporation of black spruce needles into F horizon material reduced the production of organic and inorganic-N and increased microbial biomass N. Laboratory incubations of F horizon and shallow mineral soil from 12-year-old clearcuts suggested that these boreal soils have the capacity for increased inorganic-N production compared to uncut stands several years after harvesting. This has the potential to increase N availability to growing boreal forest plantations and increase N leaching due to greater -N levels in the forest soil.     

Uptake and translocation of non-ionised pesticides in the emergent aquatic plant parrot feather Myriophyllum aquaticum

The uptake of four (14)C-labelled non-ionised compounds, the methyl carbamoyloxime insecticide/nematicide oxamyl and three model phenylureas, from solution by rooted stems of the aquatic plant parrot feather [Myriophyllum aquaticum (Vell.) Verdc], together with translocation to the emergent shoots, was measured over periods of 24 and 48 h. Uptake into the submerged tissues of roots and stem base could be ascribed to two processes: movement into the aqueous phase of cells and then partitioning onto the plant solids. This latter process was related to lipophilicity (as measured by the l-octanol/water partition coefficient, K(ow)) and gave rise to high uptake rates of the most lipophilic compounds. Translocation to shoots was passive and was optimal at log K(ow) approximately 1.8, at which the efficiency of translocation of compound was about 40% of that of water. This optimum log K(ow) was identical to that observed previously in barley, although the translocation efficiency was somewhat less in parrot feather. Solvation parameters were applied to model uptake and translocation of a set of ten compounds by barley with the particular objective of understanding why translocation efficiency is lower at log K(ow) > 1.8.