渤海自由生活海洋线虫多样性的研究

首先介绍Warwick和Clarke(1995)提出的等级生物多样性指数以及在自由生活海洋线虫中的应用,重点以1998年9～10月和1999年4～5月两个航次的沉积物样品,用物种数目(S)、Margalef物种丰富度指数(d)、优势度Simpson指数(λ)、多样性Shannon-Wiener指数(H')、Pielou的均匀度指数(J)、Hill多样性系列指数(N₁,N₂和N_+∞)、分类多样性指数(△)、分类差异指数(△*)、等级多样性指数(△+)对渤海自由生活海洋线虫的多样性进行了研究。结果表明,黄河输入的泥沙对渤海自由生活海洋线虫多样性的变化有一定的作用,距离黄河口越近的站位,群落具有的物种多样性和均匀性越低,优势度越高;距离黄河口越远的站位,群落具有的物种多样性和均匀性越高,优势度越低。     

厦门岛东南海滩自由生活海洋线虫一新种

本文报道厦门岛东南海滩自由生活海洋线虫单宫线虫目希阿利线虫科新种-厦门吻腔线虫（Rhynchomema xiamenensis sp.nov)。对新种形态特征进行了详细描述并与近似种作了比较。     

东海大陆架自由生活海洋线虫一新种:镰刀光皮线虫(线虫:色矛科)

于东海陆架沉积物中发现并描述一自由生活海洋线虫新种：镰刀光皮线虫Actinonema falciforme sp.nov.镰刀光皮线虫的主要鉴定特征为：六根外唇刚毛和四根头刚毛成一圈;表皮具复杂而前后不同的装饰和侧分化;大而明显的化感器椭圆形,中间具一横裂口;单前精巢,反折;前后双卵巢,反折;缺失交接刺和引带,仅具有镰刀形引带侧件。在光皮线虫属中,只有镰刀光皮线虫和长尾光皮线虫A.longicaudatum缺失交接刺和引带,而仅具有引带侧件。镰刀光皮线虫可根据较短的体长、镰刀形引带侧件和较短的尾部而区别于长尾光皮线虫。     

中国福建省红树林湿地中自由生活海洋线虫(联体线虫科)的2个新种

本文描述了中国福建省红树林湿地中自由生活海洋线虫的2个新种。Sabatieria conicoseta sp.nov.的主要特征是：具有短的锥形体刚毛、12-15个管状的肛前附器以及长度为12-15 μm的直的引带突起。Dorylaimopsis papilla sp.nov.的主要特征是：交接器中部具有角质化带状隔膜,近端头状具一小钩,其长度为肛门所在位置体直径的1.5–1.8倍,具有长度为37-40μm的背尾指向的引带突起。泄殖孔前具16-18个微型乳突状的肛前附器。     

广西北海金海湾红树林保护区自由生活海洋线虫联体线虫属（Comesoma）两个新记录种

在2021年春季对广西北海金海湾红树林保护区的自由生活海洋线虫进行分类和多样性研究中发现联体线虫属（Comesoma）国内2个新记录种,分别为百慕大联体线虫（Comesoma bermudense）和赫尔曼联体线虫（Comesoma hermani）,并对其特征进行了描述与图示。百慕大联体线虫主要特征为：4根头刚毛,长度为21~31 μm,4根亚头刚毛,长度为5~7 μm;虫体表皮具横排的侧分化点纹,颈部有不规则排列的颈刚毛;口腔前部膨大,底部角质化;螺旋状化感器,2.5圈;两条细长的交接器,弧长189~200 μm,引带没有突起,肛前附器乳突状;金海湾标本交接器弦长与尾长之比为0.7~0.9,大于其模式种的0.4~0.6。赫尔曼联体线虫主要特征为：口腔前部呈杯状,基部加厚,后部狭窄;螺旋状化感器,2.5圈;两条细长的交接器,弧长187~192 μm,引带没有突起;金海湾标本雄性体长约为2.2~2.4 mm,大于模式种的1.7~2.1 mm。该属物种在红树林湿地为首次报道。     

南海北部自由生活海洋线虫的群落结构和生物多样性

A quantitative study on the community structure and biodiversity of free-living marine nematodes and their relationship with environmental factors in the northern South China Sea were carried out based...     

厦门凤林红树林湿地自由生活海洋线虫群落的研究

2004年冬季在集美凤林类似底质类型、盐度和潮位的海湾地段4个断面,就不同红树植物林中的小型底栖动物数量和自由生活海洋线虫群落进行了研究。结果表明:海洋线虫是凤林红树林中小型底栖动物中的绝对优势类群,占到小型底栖动物的76.1%~96.3%;从丰度来看,旧区白骨壤(Avicennia marina)林中小型底栖动物的数量较少,有污水流过的光滩数量较大;4个断面共鉴定出海洋线虫37种(分类实体单元),其中新区秋茄(Kandelia candel)林中的生物多样性指数较低,旧区白骨壤林中群落具有较高的物种多样性;从出现的物种来看,新区秋茄林、旧区白骨壤林和光滩上出现的优势种和摄食功能群的类型各不相同。从4个断面13个站位进行的聚类分析和MDS标序分析结果推断自由生活海洋线虫的群落结构与不同的红树植物形成的沉积物有关。     

中国南海自由生活海洋线虫Sabatieria Rouville,1903的三个新纪录种

对首次发现于我国南海海域SabatieriaRouville,1903的三个种进行了描述。其中,弯刺萨巴线虫Sabatieria curvispiculata Gagarin.2013主要特征为:头刚毛较短(3μm),角皮具有不规则的侧装饰点,交接刺细长且双弯曲,雄体具有15个小的乳突状肛前辅器。锥尾萨巴线虫Sabatieria conicaudaVitiello,1970主要特征为:具有短的锥状尾,角皮具有侧装饰点,交接刺弯曲,前半部分较宽,中间有角质化的隔膜,后半部较窄且没有隔膜,雄体具有9个小孔状的肛前辅器。迁徙萨巴线虫Sabatieria migrans JensenGerlach 1977主要特征为:头刚毛较长(22μm),交接刺细长且弯曲,近端具有中间隔膜,雄体具有23个小的肛前辅器。     

渤海自由生活海洋线虫两个新纪录种

在对渤海滨州贝壳堤岛的自由生活海洋线虫进行分类和多样性研究中,发现2个我国新纪录种并进行了描述。其中,澳洲深咽线虫Bathylaimus australis Cobb,1894主要特征为:头刚毛长约20μm,分为4节,顶端膨大;前口腔大,无齿,后口腔小,具小齿;化感器双环形,位于口腔中部位置;交接刺细长,稍向腹面弯曲,近端膨大呈头状,长32-37μm;引带宽大,肾形,长36-40μm,末端角质化,渐尖。古氏努朵拉线虫Nudora gourbaultae Vincx,1989主要特征为:体表具12列纵向排列的V型装饰;第二体环较宽,头刚毛11-15μm(为头颈的67%-81%);化感器圆形,直径4-6μm(为相应体径的29%-38%),位于第二体环上;具双咽球;交接刺细长,弯曲呈S型,长为肛径的1.3-1.5倍;引带等于或长于交接刺,镰刀型,无肛前辅器。     

海洋自由生活线虫群落和环境的关系研究

以2007年春季在渤海湾近岸海域进行的调查为基础,分析了海洋自由生活线虫的群落组成和环境之间的关系.以等级聚类(Cluster)、非度量多维标度(MDS)和生物-环境分析(BIO-ENV)等多元统计方法为主,采用 PRIMER 5.2软件进行数据处理和分析.在测定的约30个环境因素中,有10个因素对底栖线虫群落产生了重要影响,包括水体的 pH、硝酸盐、悬浮物、活性硅酸盐、温度、盐度、溶解氧和沉积物的脱镁色素、叶绿素 a、平均粒径等因素.一些沉积物因素和水环境因素组合后较好地解释了底栖线虫群落结构情况,这反映了水环境和沉积环境的关联性,今后的底栖生物研究中应注意水体和沉积物环境的耦合.     

中国渤海的微口线虫属(线虫动物门)一新种

描述了中国渤海自由生活海洋线虫一新种,奥氏微口线虫Tershellingia austenae sp.nov ,奥氏微口线虫与同属相近种马尔代夫微口线虫的区别特征是:体长(前者为770～950μm,后者为2370μm)、亚头刚毛的位置(前者位于化感器的两边,后者位于化感器之后)及长度(前者明显长于后者),化感器宽度与相应体直径的比例在新种中也更大一些(50～60 vs 45).提供了一个表格式检索表,以助鉴定和比较该属缺乏明显界定食道后球的一个种组.模式标本存放于英国伦敦自然历史博物馆.     

海洋浮游甲壳类分子系统学研究进展

回顾海洋浮游甲壳类系统学研究的基础上，综述了生化水平和DNA(mtDNA和核DNA)水平的分子系统学研究现状。分子标记中DNA序列分析最为常用，其次是RFLP和RAPD分析，mtDNA主要应用于分类学、群体遗传学、种间分子进化和系统发育重建研究，而核DNA则应用于科以上较高阶元的系统发育和种内、近缘种间的遗传结构和遗传分化研究。最后对存在的问题和应用前景进行了展望。     

渤海小型底栖动物生物量的初步研究

主要以线虫、桡足类、双壳类、多毛类和动吻5个类群对渤海小型底栖动物的生物量进行了估算,并对其水平分布进行了研究.结果表明,3个航次平均,渤海小型底栖动物年生物量为(干重)0.404g/(m2·a);1998年9～10月和1999年4～5月2个航次中小型底栖动物生物量的水平分布主要表现为渤海中东部和海峡口站位的生物量明显高于其他站位,但在1999年航次,海峡口靠近海岸的站位生物量下降,位于莱洲湾B1站位生物量明显上升.依据小型底栖动物的年生产力P=9B,估算渤海小型底栖动物的年平均生产力为(干重)3.636g/(m2·a).还对渤海小型底栖动物生物量与世界其他海域的进行了比较,认为渤海小型底栖动物生物量的数值与其他海域生物量的数值接近,但略偏低.就不同学者研究所得的线虫平均个体干重进行了比较研究.     

联体线虫科(线虫动物门)系统分类研究进展

联体线虫科是自由生活海洋线虫中种类多样性较高的一个科,广泛分布于潮间带、浅海甚至超过6 000 m的深渊海底。联体线虫科目前已记录有19个属239个有效种(另有4个属由于原始描述较简单,被认为是疑似属),是当前海洋线虫分类学研究最为活跃的一个科。本文简述了联体线虫科的系统分类研究历史,回顾了这一类群的国内外系统分类学研究进展,对3个亚科的分类进一步做了梳理,并列出了各个属的种类检索表。     

Abundance and biomass of meiobenthos in the spawning ground of anchovy (Engraulis japanicus) in the southern Huanghai Sea

1 Introduction Meiofauna is an important group in benthic small food web energetically due to their small size, high abundance and fast turnover rates. The production of meiofauna is equal to or higher than that of macrofau- na in estuaries, shallow waters and deep sea (Gerlach, 1971; Platt and Warwick, 1980; Heip et al., 1985; Zhang et al., 2004). A role of meiofauna may be the recycling of nutrients. Marine nematodes may keep the bacterial colonies on sand grains in active phase of growth …     

Diversity patterns of free‐living marine nematodes in the southwest continental shelf off Bay of Bengal and their link to abiotic variables

Marine sediments in continental shelf ecosystems harbor a rich biodiversity of benthic communities. In this study, the spatial and temporal diversity and community assemblages of free‐living marine nematodes were studied by sampling at six depths and over 3 years from the southwest continental shelf off Bay of Bengal, one of the least explored tropical shelf ecosystems. The dominant marine nematode species were related with abiotic variables as part of this study. The effects of sediment granulometry generally decreased with increasing depth and the highest nematode density and species diversity were recorded on coarse sand (shallower depths). Multivariate analysis of the nematode community data showed that community structure differed significantly among depths as well as among years. Statistical analyses showed significant correlations between the nematode community and abiotic variables. Sediment texture, organic matter, water pressure and depth profile were crucial factors for determining diversity, vertical profile and feeding types of the nematode community. Other environmental factors, including anthropogenic pressure, did not have an effect on nematode diversity except for the presence of some tolerant species (Metachromadora spp., Sabatieria spp. and Siplophorella sp.). This study represents a baseline of knowledge of free‐living marine nematode communities that can be used in the future to compare nematode assemblages from temperate shelf ecosystems.     

Symbiotic Relations of Sediment-Agglutinating Nematodes and Bacteria in Detrital Habitats: The Enzyme-Sharing Concept

Abstract. A new concept (‘enzyme sharing’) concerning the interaction of marine nematodes and microbes in the degradation of sedimentary detritus is presented. Elements of this concept are (1) the notorious tendency of many aquatic nematodes to agglutinate detrital particles by mucus secretions, (2) new observations on the stimulation of microbial growth by nematodes in agar plates, and (3) literature data on limited endogenous proteolytic capacities of aquatic nematodes.
Observations on nematode‐microbe associations in agar plates prompted the conceptual synthesis. In agar medium without the addition of any nutrients a spectacular growth of bacteria was visible on the sinusoidal crawling trails of nematodes only 2 – 3 days after introduction of the worms (species of Adoncholaimus, Anoplostoma and Sabatieria). Juveniles of Anoplostoma that hatched in the agar cultures left their minute trails in the medium and these were rapidly occupied by bacteria. The nematodes repeatedly visited their bacterial trails, which persisted as a peculiar biotic structure for more than one year and survived the nematodes.
In sterile agar preparations containing the fluorogenic methylumbelliferyl‐β‐glucoside in the presence of the nematode Adoncholaimus, an enhanced fluorescence of the medium was visible, indicating β‐glucosidase activity. We therefore assume that oncholaimid nematodes discharge enzymes that alone, or in concert with microbial activities, contribute to the hydrolytic cleavage of refractory polysaccharides containing β‐glucosidic bonds such as agar components and cellulose. The sugars thus produced may then be taken up by the nematodes and concomitantly support the conspicuous growth of microbes. Since we did not observe any feeding of the nematodes on the associated microbes in agar plates, we question the nutritive potential of intact microbial cells for a number of nematodes abounding in detrital habitats, and call attention to the significance of ambient dissolved or adsorbed organic monomeric nutrients.
Consequently, we perceive the puzzling perpetual accretion of detrital organic particles to sediment agglutinations by nematodes as an adaptation for operating an ‘enzymatic reactor’ for the production of dissolved nutrients. We hypothesise a relationship of mutual commensalism of nematodes and heterotrophic microbes in detrital habitats and propose the term ‘enzyme sharing’ for this relationship. Both parties invest in a common enzyme pool that decomposes organic detritus for their nutrition. We present here evidence that nematodes contribute β‐glucosidase, which is involved in the cellulase system. Data from the literature suggest that microbial enzymatic processing of detrital proteins yields amino acids available to nematodes, which apparently have no efficient proteolytic enzyme system in their intestines.     

Tackling the Sulfide Gradient: A Novel Strategy Involving Marine Nematodes and Chemoautotrophic Ectosymbionts

Abstract. The Stilbonemutinue (marine free-living nematodes) arc remarkable for cctosymbiotic bacteria, which cover the greatest part of their body in a highly ordered and species specific pattern. Using SEM we describe the main types of symbiotic cover and give evidence for the role of the bacteria in the nutrition of their host on the basis of stable carbon isotope ratios. In experimental systems the worms migrated repeatedly across a sulfide gradient during 12 h when sulfide concentrations were low, but stayed above the sulfide maximum at high concentrations. The migration across the chemocline exposes the symbionts alternately to reduced sulfur compounds and oxygen; this constitutes an alternative strategy to the ventilation/circulation systems in symbiotic macrofauna from sulfidic habitats.     

Pattern of Nematode Species Diversity in Temperate and Tropical Subtidal Sediments

Abstract. Revision of published data on species diversity of marine nematode assemblages indicated significantly higher values in temperate coastal sediments than in tropical open sea and lagoonal sublittoral sediments of similar depth. The influence of sample size, mean grain size, latitude. degree of isolation and stability of the system arc discussed for 112 temperate samples and 85 tropical samples from 23 localities around the world.     

遗传标记技术在海洋桡足类生物多样性和系统发生研究中的应用

研究回顾遗传标记技术的发展及其在海洋桡足类分类学、群体遗传学、系统发育和分子进化研究等方面的应用情况。