巢湖微囊藻和浮游甲壳动物昼夜垂直迁移的初步研究

2002年10月进行了巢湖微囊藻和几种优势浮游甲壳动物的昼夜垂直变化的研究,结果表明:微囊藻具有明显的昼夜垂直变化现象。白天上层水中的微囊藻密度显著高于下层水中,夜晚逐渐下沉使得下层水中的密度相对高于上层水。微囊藻与叶绿素a、水温、溶解氧和pH等均呈显著的正相关(p<0.01)。几种优势浮游甲壳动物的昼夜垂直迁移存在较大的差异。短尾秀体溞和角突网纹溞白天在下层水(1.5m和2.5m)中的密度较高,夜晚则倾向于在上层水(0m和0.5m)中活动。相反,卵形盘肠溞白天在上层水中密度较高,象鼻溞则在11:00和15:00时各水层中的密度显著高于夜晚。汤匙华哲水蚤和广布中剑水蚤白天倾向于在下层水中活动,夜晚则逐渐迁移到上层水中。许水蚤在夜晚和凌晨3:00时各水层中的密度显著高于白天。中华窄腹剑水蚤昼夜垂直变化不明显。微囊藻与短尾秀体溞密度呈显著的负相关,而与象鼻溞和卵形盘肠溞呈显著的正相关(p<0.01)。     

夏季南黄海浮游动物的垂直分布与昼夜垂直移动

对 2 0 0 1年 8月南黄海青岛外海至济州岛断面 ,浮游动物的日垂直变化、断面垂直分布及其与海区水文特征的关系进行了研究。共鉴定浮游动物 40种。断面浮游动物的平均丰度为 13 62 ind/ m 3 ;种类丰富度与暖水种数呈正相关 ,分布趋势为测区东部高、西部低 ;优势种为中华哲水蚤 (Calanus sinicus)、小拟哲水蚤 (Paracalanus parvus)、拟长腹剑水蚤 (Oithona similis)、强壮箭虫 (Sagitta crassa)、近缘大眼剑水蚤 (Corycaeus affinis)。在不同水层 ,浮游动物丰度分布不同 ,随水深增加而减少 ,表层丰度最高 (3 2 2 1ind/ m3) ,温跃层和底层分别为 743 ind/ m3、43 8ind/ m3;种类组成也不相同 ,表层数量最多的种类为鸟喙尖头(Penilia avirostris)、温跃层及其以下水体为中华哲水蚤 ,其它主要种类亦表现不同水层取向。在连续观测站 ,根据浮游动物主要种类的昼夜垂直移动与温跃层关系 ,将之分为表层分布 ,近温跃层分布 ,底层分布及全水层分布 4种类型     

太湖梅梁湾大型控藻围栏对浮游甲壳动物群落结构的影响

2005年对太湖梅梁湾大型鲢、鳙控藻围栏内外浮游甲壳动物群落结构的季节变化进行了监测.结果表明:围栏内外的环境因子、浮游植物生物量、浮游甲壳动物种类组成无显著差异.但鲢、鳙放养对浮游甲壳动物的生物量产生了较大的影响,围栏内浮游甲壳动物的总生物量和枝角类的生物量显著低于围栏外.总体上,枝角类各种类的生物量受鲢、鳙放养的影响程度大于桡足类的种类.太湖梅梁湾浮游甲壳动物的季节演替明显,大部分种类只是季节性出现.冬季和春季以溞(Daphnia sp.)和近邻剑水蚤(Cyclops vicnus)等大型种类为主,夏季和秋季以象鼻溞(Bosmina sp.)、角突网纹溞(Ceriodaphnia cornuta)和中华窄腹剑水蚤(Limnoithona sinensis)等小型种类为主.典范对应分析表明,透明度、温度和浮游植物的生物量是影响浮游甲壳动物季节变化的主要因素.     

富营养化对小型湖泊浮游甲壳动物群落结构及多样性的影响

2017年3月到2018年2月研究了临涣湖浮游甲壳动物群落结构的季节变化。临涣湖共记录浮游甲壳动物13种,其中枝角类8属8种,桡足类5属5种。短尾秀体溞(Diaphanosoma brachyurum)、广布中剑水蚤(Mesocyclops leuckarti)和象鼻溞(Bosmina sp.)等小型富营养种类是温暖季节的优势种,而近邻剑水蚤(Cyclops vicinus)是冬季的优势种。盔形溞(Daphnia galeata)等大型种类仅在少数月份中被观察到。临涣湖浮游甲壳动物的年平均密度和生物量分别为28.3个/L和0.33 mg/L。营养状态指数(TSI_M)的年平均值为62.6。浮游甲壳动物的Shannon指数、Pielou指数和Simpson指数的年平均值分别为0.86、0.74和0.49,且3种多样性指数均具有显著的季节差异。营养盐水平、营养状态指数和物种多样性指数均表明,临涣湖水体处于富营养化状态。冗余分析结果表明,水温、总磷浓度和叶绿素a浓度是影响临涣湖浮游甲壳动物群落结构变化的上行效应因子。鲢、鳙鱼的捕食压力是临涣湖浮游甲壳动物群落结构小型化的下行效应因子。     

惠州西湖生态修复对浮游甲壳动物群落结构的影响

为研究湖泊生态修复对浮游动物群落结构的影响,该文于2010年1-12月份对惠州西湖未修复的子湖-平湖及已实施生态修复后的子湖-元妙观湖、南南湖的浮游甲壳动物群落结构进行了调查。结果表明:龟状笔纹溞、卵型盘肠溞、矩形尖额溞和右突新镖水蚤仅出现在修复后的元妙观湖与南南湖,而颈沟基和溞与平直溞仅在平湖中检出;元妙观湖和南南湖浮游甲壳动物种属数、丰度及多样性指数均高于平湖。冗余分析结果表明:哲水蚤、剑水蚤和枝角类丰度与透明度呈正相关,哲水蚤密度与营养盐呈负相关。研究显示,湖泊生态修复对浮游动物群落结构有重要的影响。     

鄱阳湖浮游甲壳动物群落结构特征

鄱阳湖是中国第一大淡水湖,具有"丰水为湖,枯水为河"的独特特点。为探讨鄱阳湖浮游甲壳动物群落结构及其时空分布的特征,于2009年全年采集其不同季节、不同水位期的浮游甲壳动物样品进行定量分析。结果显示,鄱阳湖浮游甲壳动物群落结构总体与河流浮游甲壳群落具有相似性。无节幼体、象鼻溞、剑水蚤等河流优势类群在鄱阳湖浮游甲壳动物中占优势;而哲水蚤和溞属仅在低水位季节占优势,枝角类丰度仅在高温、高水位、流速缓的季节高过桡足类。丰水期浮游甲壳动物平均丰度和生物量远远高于枯水期,可达枯水期的50倍,差异极其显著(P0.01)。温度和水位变化引起的环境因子改变是导致鄱阳湖浮游甲壳动物发生季节演替的主要原因;而营养盐对浮游甲壳动物的影响并不显著。空间上浮游甲壳动物群落构成明显不同,年均丰度最高和最低的点均出现在河口地区。因此:对于换水周期短,水交换速率快的水体,应该充分考虑水文条件对生物的影响。     

大沙河水库浮游甲壳类动物群落特征

于2010 年1 月至12 月对广东大沙河水库的三个典型水域(河流区、过渡区和湖泊区)进行逐月采样, 共检出浮游甲壳类动物15 种, 其中枝角类10 种, 桡足类5 种, 多为广温性和嗜暖性种类。全年出现的种类有: 象鼻溞(Bosmina spp.), 微型裸腹溞(Moina micrura)、角突网纹溞(Ceriodaphnia cornuta)、温中剑水蚤(Mesocyclops thermocyclopoides)、博平近剑水蚤(Tropocyclops bopingi)和右突新镖水蚤(Neodiaptomus schmackeri)。在丰度上无节幼体占优势, 枝角类的优势种以小型种类(象鼻溞、微型裸腹溞、角突网纹溞)为主, 枯水期的优势种为象鼻溞, 在丰水期优势种为角突网纹溞, 形成象鼻溞(1-4 月)-角突网纹溞(5-9 月)-象鼻溞(10-12 月)的季节更替结构。浮游甲壳类总丰度和总生物量的变化范围分别是58.73-231.89 ind·L–1 和224.36-986.03 μg·L–1, 季节波动都比较明显, 丰水期浮游甲壳类的丰度和生物量明显高于枯水期; 高峰值均出现在捕食压力相对较低而生长期开始的丰水早期(4 月)。浮游甲壳类的丰度和生物量在三个采样水域之间的时空差异性不明显, 群落结构主要受水库的水温、营养水平和浮游植物种类组成的影响。     

梁子湖浮游甲壳动物的生物多样性

基于2006年8月至2008年3月对梁子湖浮游甲壳动物的采样调查,记录了该湖区浮游甲壳动物22种,隶属9科18属,其中枝角类(Cladocera)16种,桡足类(Copepoda)6种,包括9属新记录.物种多样性季节性动态变化明显:枝角类优势种在春、夏和秋冬季依次为透明溞(Daphnia hyalina,优势度Y = 0.80±0.01),小栉溞(Daphnia cristata,Y = 0.50±0.03)和长额象鼻溞(Bosmina longirostris,Y = 0.58±0.04);而桡足类优势种在夏、秋和冬春季依次为长江新镖水蚤(Neodiaptomus yangtsekiangensis,Y = 0.41±0.01)、近邻剑水蚤(Cyclops vicinus,Y = 0.46)和特异荡镖水蚤(Neutrodiaptomus incongruens,Y = 0.65±0.18).浮游甲壳类个体密度以春季最高((292±85) ind/L),夏、秋、冬季渐低(依次为(169±104)、(140±53)、(120±0) ind/L).物种多样性冬春季较低(物种数S≤12,丰富度指数D = 0.77和0.71,香农-威纳指数H = 1.79和1.45),夏秋季较高(S≥17,D = 0.98和0.88,H = 1.78和1.83).梁子湖浮游甲壳类动物多样性年际差异不显著,表明湖区环境条件较为优越、稳定.     

苏州工业园区水体浮游甲壳动物群落特征及其与环境因子的关系

于2012年6月至2013年5月,对苏州工业园区湖泊和河流水体的浮游甲壳动物组成及群落结构进行了研究,分析了浮游甲壳动物的密度和生物量的年度变化,探讨其分布与水体理化因子间的关系.结果表明：园区水体有枝角类6科12属24种,桡足类7科13属18种,其中短尾秀体溞、长额象鼻溞、汤匙华哲水蚤及近邻剑水蚤在不同水体中不同季节均为优势种.在湖泊水体和河流水体中,浮游甲壳动物的密度和生物量表现为夏、秋季较高,冬、春季较低,且在夏、秋季分别具有2个峰值.枝角类平均密度和生物量在河流水体中均高于湖泊水体,两者间均具有显著差异;桡足类的平均密度在河流水体和湖泊水体间差异不显著,而平均生物量要显著高于湖泊水体.湖泊水体和河流水体在溶解氧、pH、透明度、总溶解固体、盐度、总磷、总氮及铵氮含量上均存在显著差异;冗余分析表明无论是湖泊水体还是河流水体,多数浮游甲壳动物的分布与水温、盐度、化学需氧量(COD_Mn)和总磷等指数呈正相关,只有枝角类中的溞属、船卵溞属种类的分布与水体溶解氧、pH值及透明度呈正相关.     

三种中华鳋的扫描电镜观察

桡足类隶属节肢动物门(Arthropoda)甲壳动物亚门(Crustacea)颚足纲(Maxillopoda)桡足亚纲(Copepoda), 其中既有剑水溞和镖水溞等自由生活的类群, 也有营寄生生活的杯口水蚤种类1。杯口水蚤目(Poecilostomatoida)鳋科(Ergasilidae)种类的幼虫及雄性成虫完全营自由生活, 只有雌性成虫寄生在鱼体上, 因此被认为可能是由自由生活向寄生生活演化的过渡类群2。       

Vertical mammaplasty

Current criticisms regarding vertical mammaplasty include problems with poor immediate postoperative appearance, nipple-areola complex malposition, and excessive lower pole length. These problems can be avoided by proper patient selection, by utilizing correct concepts of skin design, and by observing correct glandular resection and closure concepts. Vertical mammaplasty also can result in other problems, such as hypertrophic circumareolar scars and lower pole deformities, including notching, boxy shape, infra-areolar depression, and flatness. These problems are also largely avoidable by using correct technique. Several basic concepts described previously have not proven necessary to achieve good results. Abandoning some of these principles has contributed to the ability to establish an aesthetically ideal breast shape intraoperatively as well as to a decrease in morbidity. This includes eliminating liposuction as a major integral component of the procedure, eliminating suturing the gland to the pectoralis muscle, not undermining the lower pole skin, and avoiding overly wide skin resection and tight wound closure that produces significant lower pole distortion in the early postoperative period. An important concept that has proven reliable is to use a "closed" design that does not predetermine the areolar opening whenever circumstances permit. When this is not possible, a modification that utilizes the smallest possible circumference as an open design is better than a large "mosque." These alternatives allow greater flexibility in determining final nipple position and also reduce the risk of hypertrophic circumareolar scars. Important glandular resection concepts include creating pillars that are attached to both the skin and the chest wall; making them of adequate dimension to avoid postoperative lower pole shape problems, such as flattening; resecting closer to the skin lateral to the pillars to avoid a boxy breast shape; and using a drain both to assist in accurately determining the endpoint of resection and to avoid postoperative seromas. Key closure concepts include approximation of the superior surfaces of the pillars at their base to maintain vertical height and thereby prevent lower pole flattening; approximation of the inferior surfaces of the pillars to the base of the breast to prevent notching; and proper management of the vertical incision by restricting the purse-string suture effect to only the inferior portion of the incision, where there may be skin excess present. Inclusion of these concepts leads to predictable and improved aesthetic results in vertical mammaplasty. This allows full realization of the purported advantages of vertical mammaplasty and allows this method to be utilized with a level of confidence similar to that seen with inverted-T techniques.     

Vertical migration of copepods

Diel vertical migration (DVM) by herbivorous copepods is a nearlyuniversal feature of pelagic ecosystems. The ecosystem consequencesof this behavior are less well understood. A simulation of copepodlife cycles in the northern North Sea examines migration interms of reproductive success at diapause. Different patternsof vertical migration appear to be less important than mixedstrategies for onset of diapause to cope with interannual variabilityin the physical environment.     

The Subjective Visual Vertical and the Subjective Haptic Vertical Access Different Gravity Estimates

The subjective visual vertical (SVV) and the subjective haptic vertical (SHV) both claim to probe the underlying perception of gravity. However, when the body is roll tilted these two measures evoke different patterns of errors with SVV generally becoming biased towards the body (A-effect, named for its discoverer, Hermann Rudolph Aubert) and SHV remaining accurate or becoming biased away from the body (E-effect, short for Entgegengesetzt-effect, meaning “opposite”, i.e., opposite to the A-effect). We compared the two methods in a series of five experiments and provide evidence that the two measures access two different but related estimates of gravitational vertical. Experiment 1 compared SVV and SHV across three levels of whole-body tilt and found that SVV showed an A-effect at larger tilts while SHV was accurate. Experiment 2 found that tilting either the head or the trunk independently produced an A-effect in SVV while SHV remained accurate when the head was tilted on an upright body but showed an A-effect when the body was tilted below an upright head. Experiment 3 repeated these head/body configurations in the presence of vestibular noise induced by using disruptive galvanic vestibular stimulation (dGVS). dGVS abolished both SVV and SHV A-effects while evoking a massive E-effect in the SHV head tilt condition. Experiments 4 and 5 show that SVV and SHV do not combine in an optimally statistical fashion, but when vibration is applied to the dorsal neck muscles, integration becomes optimal. Overall our results suggest that SVV and SHV access distinct underlying gravity percepts based primarily on head and body position information respectively, consistent with a model proposed by Clemens and colleagues.     

昆虫共生菌的垂直传播

共生菌普遍存在于昆虫体内,它们能够为宿主昆虫提供生长发育所必需的氨基酸、固醇类等营养物质,还能提高昆虫适应高温、寄生虫、病毒等不利环境因素的能力,昆虫则为共生菌提供稳定的生存环境和营养物质,昆虫与共生菌相互依存。多数情况下,共生菌通过垂直传播在宿主代次间进行传播,即共生菌由母代传递给子代。结合最近几年相关研究,本文综述了不同昆虫共生菌的垂直传播模式。除极少数肠道共生菌通过污染卵壳被宿主幼虫取食得以垂直传播外,垂直传播的共生菌多为经卵传播。根据侵染时期的不同,共生菌经卵传播模式多数可分为以下4种：侵染宿主昆虫幼虫中的生殖干细胞、侵染宿主昆虫年轻雌成虫中的生殖干细胞、侵染宿主昆虫雌成虫中的成熟卵母细胞以及侵染宿主昆虫囊胚期胚胎。其中,有些共生菌是以共生菌菌胞整体侵染的方式进入到宿主卵巢。另外,少数肠道共生菌也通过卵巢进行垂直传播,此类共生菌先侵染卵巢侧输卵管并在侧输卵管聚集,待卵排放至侧输卵管时再进入到卵中。在文中,我们也探讨了昆虫共生菌垂直传播过程中的细胞机制和免疫机制,包括共生菌避开宿主免疫反应、共生菌通过内吞作用进入卵巢以及不同共生菌间的协同作用等。     

Vertical Dispersal of Steinernema scapterisci

When infective juveniles ofSteinernema scapterisci Nguyen &Smart were released on the soil surface in the field and in the laboratory, some of them moved downward through the soil at least 10 cm in 5 days and infected and killed mole crickets. When released 2 cm below the soil surface, most of the juveniles moved into the upper 2 cm layer of soil, but some moved downward 10 cm. When placed at the center of a 16-cm soil column, infective juveniles moved in both directions with three times more moving downward than upward. Infective juveniles were more efficient in killing mole crickets in the field than in the laboratory.     

Vertical asymmetries in orb webs

In almost all vertical orb webs the hub is above the geometric centre and consequently, the extent of the capture area is larger below the hub than above. In addition to this vertical web‐extent asymmetry, orb webs show vertical asymmetries in number of spiral loops, mesh widths, and angles between radii. However, it was unknown whether these asymmetries are adaptations to the web‐extent asymmetry or whether they are linked to gravity in a different way than through web‐extent asymmetry. We reviewed known vertical asymmetries of orb webs, and we analysed the asymmetries of webs built by four different Cyclosa species, which show large intra‐ and inter‐specific variation in web‐extent asymmetry. We found all analysed structural asymmetries to be linked both to web‐extent asymmetry and to gravity: Larger web extents below the hub and gravity both led to more sticky‐spiral loops and to smaller angles between radii below the hub, whereas web‐extent asymmetry and gravity had opposing effects on mesh width (mean and peripheral). Independent of web‐extent asymmetry, almost all analysed webs had narrower peripheral meshes and smaller angles between radii below the hub than above. We interpret the narrow peripheral meshes along the web's lower edge as an adaptation to prevent tumbling prey from escaping, and the small angles between radii as an adaptation to prevent the sticky‐spiral lines in these narrow meshes to come into contact with each other. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 114 , 659–672.