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431.
水母类在自然海区的食物组成是摄食生态学研究的核心问题,本研究利用高通量测序技术分析了管花萨氏水母(Sarsia tubulosa)和八斑芮氏水母(Rathkea octopunctata)的现场食物组成。结果表明:管花萨氏水母和八斑芮氏水母现场摄食食物具有较高的多样性,管花萨氏水母摄食食物31种,八斑芮氏水母29种;两种水母从食物组成上看,属于杂食性生物,其食物包括浮游动物、真菌、浮游植物、陆地植物碎屑等;管花萨氏水母和八斑芮氏水母二者互为捕食对象;二者摄食的食物类群具有相似性,主要来源于节肢动物门和颚足纲,均以太平真宽水蚤为摄食优势种,分别贡献两者食物总量的45.14%和42.42%。高通量测序技术是深入探究水母现场食物组成新的技术手段,两种水母的现场食物组成结果为水母摄食生态学的研究提供了重要参考。  相似文献   
432.
胡仲杰  张利明 《探矿工程》2008,35(10):28-29,32
分析了机械动力头、液压控制长行程给进钻机研发的必要性,提出了新型机械动力头钻机需要解决的相关问题,介绍了XL-5型钻机的结构形式、参数、特点及生产试验情况。  相似文献   
433.
Viable cell count was used to determine whether Metschnikowia sp.C14 can colonize the intestine of juvenile sea cucumber Apostichopus japonicus.Sea cucumber individuals were divided into two groups,which were fed the control diet for 38 days or the C14-supplemented diet at 105 cells g−1 diet for 28 days,then the control diet from day 29 to day 38.The number of C14 cells in the intestine of sea cucumber fed the C14-supplemented diet significantly increased from day 7 to day 28,and decreased from day 29 to day 38.Sea cucumber fed with the diet containing C14 showed a significant increase in trypsin activity and lipase activity from day 21 to day 33 compared with the control.Feeding C14 significantly improved the phagocytic activity and respiratory burst in coelomocytes from day 21 to day 35 and from day 14 to day 38,respectively.In addition,there was an obvious enhancement in lysozyme activity(from day 21 to day 38 or day 33),phenoloxidase activity(from day 21 to day 28)and total nitric oxide synthase activity(from day 14 to day 38)in coelomic fluid supernatant and/or coelomocyte cell lysate supernatant compared with the control.There were significant positive correlations between the number of C14 cells colonizing the intestine and trypsin activity of the intestine,lysozyme activity of the coelomic fluid supernatant and coelomocyte lysate supernatant from sea cucumber.These data suggested that the number of C14 cells should be maintained at 105 cfu(colony-forming units)g−1 intestine material for the maximum benefit.  相似文献   
434.
实验生态条件下研究十溴联苯醚(BDE-209)的急性毒性胁迫对褶皱臂尾轮虫(Branchionus plicatilis)运动行为与摄食行为的影响,探讨可用以表征胁迫-响应的生物标志物。结果表明:(1)BDE-209胁迫24h显著性增加了褶皱臂尾轮虫的运动抑制率,由此得到24h半数有效抑制浓度(24h-EC_(50))为9.084mg/L,但未达到半数致死作用;(2)当分别以四种海洋微藻:小球藻(Chlorella vulgaris)、青岛大扁藻(Platymonas helgolandica)、等鞭金藻8701(Isochrysis galbana)和小新月菱形藻(Cylindrotheca closterium)为单一饵料来源时,褶皱臂尾轮虫对四种饵料单胞藻的滤水率(F)和摄食率(G)均随着胁迫时间和胁迫浓度的增加而不断下降,呈现出明显的浓度依赖性,说明BDE-209胁迫能显著抑制褶皱臂尾轮虫的摄食作用。(3)将其中三种微藻等生物量混合投喂时,褶皱臂尾轮虫对三种微藻的滤水率和摄食率与单一饵料投喂条件相比均发生变化,且对各种微藻的选食率(Sr)和摄食总生物量均随着胁迫时间和浓度的增加呈下降趋势,选择性指数(Si)发生变化,对小球藻的摄食选择性最高。滤水率的变化较其它指标更敏感,可用以指示浮游动物在个体水平上响应外源环境变化的标志物。结果表明,BDE-209胁迫能有效改变褶皱臂尾轮虫的摄食与选食行为,且其最适宜的饵料是小球藻。  相似文献   
435.
Scorpaena notata is a small, sedentary scorpaenid species widely distributed in the Mediterranean and adjacent waters of the Atlantic. In the western Mediterranean it inhabits coastal continental shelf bottoms. In the Balearic Islands, these bottoms are characterised by the presence of the facies with red algae, including both Peyssonnelia and mäerl beds. These beds enhance the structural complexity, biodiversity and secondary production of the soft bottoms. Due to the oceanographic conditions of the Islands, the facies with red algae are especially rich in terms of biomass and algal coverage, and are widespread distributed between 40 and 90 m depth, where trawlers exploiting the continental shelf operate. The present work studies the biology of S. notata and its relationship with habitat characteristics. Special attention is focused on the aspects related to fish condition and growth as a tool to assess the importance of the facies with red algae for fish.  相似文献   
436.
To investigate feeding habits of juvenile flounder (Platichthys flesus) and turbot (Psetta maxima) in relation to habitat characteristics a field survey with push net sampling was conducted in nursery areas with different ecological characteristics in the northern Baltic proper. Sampling sites were stratified to cover several different habitat types defined by substrate and wave exposure. Apart from flatfishes and epifauna, samples of macrofauna, meiofauna and hyperbenthic planktons were collected from each site together with data on vegetation, depth, salinity, temperature and turbidity. The diet differed between species where flounder diet was dominated by chironomids, copepods and oligochaetes while turbot apart from chironomids had a high incidence of amphipods, gobies and mysids. In both species there was a shift in diet with size, although this shift was influenced by the habitat. Among the environmental variables investigated, wave exposure was found to significantly influence flounder diet. Food preference in the most exposed areas was dominated by oligochaetes and copepods instead of chironomids, which dominated in sheltered areas. This study shows that habitat characteristics can have a major influence on feeding habits of juvenile flatfish.  相似文献   
437.
Eight species of Pycnogonida collected by University of Canterbury Expeditions and the New Zealand Oceanographic Institute are recorded from the Snares Islands, which lie at 48° 05’ S, 166° 20’ E, 60 miles SW of South Cape, Stewart Island. The following species are recorded: Pallenopsis obliqua (Thomson, 1884), Cheilopallene trappa n.sp., Ammothea magniceps Thomson, 1884, Achelia dohrni (Thomson, 1884), Tanystylum cavidorsum Stock, 1957, Ascorhynchus insularum n.sp., Austrodecus minutum n.sp. and Austrodecus enzoi n.sp.  相似文献   
438.
An IBM 1130 computer program system for preliminary processing of copious biological data is described. Its advantage ia comparison with the more usual manual calculation methods is the speed at which data can be handled, sorted, and analysed. Only a small computer need be available to the user.  相似文献   
439.
Drift was collected over 24‐h periods in five rivers in South Island, New Zealand, to determine whether diel periodicity was consistent across a range of river types, and whether the pattern was similar for different life stages/sizes of selected taxa. Total drift density (numbers per 100 m3 ) of aquatic invertebrates was greater at night than during the day in all rivers; peak abundance occurred shortly after sunset in clear water rivers and shortly before sunrise in a turbid, glacier‐fed river. Densities of drifting Deleatidium spp., Nesameletus spp. (both Ephemeroptera), Aoteapsyche spp., and Hydrobiosidae (both Trichoptera), were generally greater at night than during the day. However, the timing of peak abundance in the drift for other common taxa varied between rivers. Larger Deleatidium spp. larvae (> 1.00 mm head width) were more common in the drift at night than during the day in all rivers. However, this was not apparent for Aoteapsyche spp. and Hydrobiosidae, for which diel differences in the size of drifting animals were not consistent even within the same river. The propensity for some aquatic invertebrates to drift at night may influence fish feeding behaviour, particularly with respect to the timing of feeding and the species or life history stages of their prey.  相似文献   
440.
Inanga (Galaxias maculatus Jenyns) are the basis of an important recreational and commercial freshwater fishery that has declined over the past 100 years, probably because of habitat degradation in developed areas. Maintenance of suitable stream flows for inanga is one means of protecting the fishery. Observations of habitat use by drift‐feeding inanga were made in three streams. Most feeding inanga were stationary in the current taking food items from the drift and sometimes from the surface. Drift‐feeding locations were related to current patterns and water velocity, with inanga feeding at locations where the current concentrated food, and where water velocities were sufficiently low to allow the fish to hold position. The mean feeding velocity did not vary significantly between streams, although the range of velocities used did. Optimum feeding velocities were 0.03–0.07 m s‐1, and were comparable with brown trout (Salmo trutta) feeding velocities, when adjusted for the differences in fish size. Depth use was very different between streams and this was attributed to the variation in available habitat. Depths greater than 0.3 m were optimum, with some use of depths between 0.1 and 0.3 m. It is suggested that inanga suitability criteria are dictated by biological factors, such as swimming ability and bio‐energetic requirements, rather than the river the fish is living in and that it is necessary to collect habitat use and availability data in a wide range of stream types to define optimal habitat and suitability criteria for generalised application.  相似文献   
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