Phylogenetic position and systematics of the wood‐associate limpet genus Caymanabyssia and implications for ecological radiation into deep‐sea organic substrates by lepetelloid gastropods

The gastropod superfamily Lepetelloidea represents an extremely diverse lineage in terms of their utilization of different deep‐sea organic substrates that include sunken wood, leaves, whale and fish bones, egg cases of sharks and rays, annelid tubes and detrital cephalopod beaks among others. They also inhabit cold seeps and hydrothermal vents, thus presenting an interesting case for the evaluation of such organic substrates as ‘stepping stones’ into these chemosynthetically nourished environments. Here we show the first molecular phylogeny of the Pseudococculinidae, a primarily wood‐dwelling family and the most speciose in Lepetelloidea. Special emphasis is placed on the genus Caymanabyssia, for which the only subfamily Caymanabyssiinae has been established, and a new species Caymanabyssia solis is described herein and compared with previously known taxa in order to reconsider the morphological characteristics of lepetelloids on wood. Bayesian and likelihood trees reconstructed using four‐gene sequences reveal that Pseudococculinidae sensu auctt. is a polyphyletic taxon that is grouped by shared plesiomorphic conditions of characters including the radula, a digestive organ, the morphology of which is often governed strongly by diet and feeding ecology. The newly reinterpreted families Pseudococculinidae and Caymanabyssiidae represent reciprocal sister clades as a basal radiation in Lepetelloidea. Sunken wood might thus have served as an ancestral habitat from which species on other substrates and vent and seep taxa were derived.     

Diversity of faunal assemblages associated with ribbed mussel beds along the South American coast: relative roles of biogeography and bioengineering

Benthic organisms are among the most diverse and abundant in the marine realm, and some species are a key factor in studies related to bioengineering. However, their importance has not been well noted in biogeographic studies. Macrofaunal assemblages associated with subtidal beds of the ribbed mussel (Aulacomya atra) along South America were studied to assess the relationship between their diversity patterns and the proposed biogeographic provinces in the Southeastern Pacific and Southwestern Atlantic Oceans. Samples from ribbed mussel beds were obtained from 10 sites distributed from the Peruvian coast (17°S) to the Argentinean coast (41°S). The sampling included eight beds in the Pacific and two in the Atlantic and the collections were carried out using five 0.04 m² quadrants per site. Faunal assemblages were assessed through classification analyses using binary and log‐transformed abundance data. Variation in the size and density of mussels, and in the species richness, abundance and structure of their faunal assemblages were tested using a permutational multivariate analysis of variance. Faunal assemblages showed a north–south latitudinal gradient along both the Pacific and Atlantic coasts. Binary and abundance data showed a difference in the resulting clustering arrangement of Pacific sites between 40°S and 44°S, indicating a pattern of continuity in the species distribution associated with biological substrates. At a regional scale, the distribution of species along the South American coast matched the general provincial pattern shown by prior studies, which show two biogeographic units on the Pacific coast separated by an intermediate (probably transitional) zone and a single province on the Atlantic coast extending up to Northern Argentina. Biological substrates such as ribbed mussel beds play an important ecological role by making a similar habitat type available on a large scale for a variety of invertebrate species. Despite such habitat homogeneity, however, the associated fauna exhibit marked distribution breaks, suggesting strong constraints on dispersal. This therefore suggests that macrofaunal assemblages could possibly be used as biogeographic indicators.     

Influence of habitat and host morphology on macrofaunal assemblages associated with the sponge Halichondria melanadocia in an estuarine system of the southern Gulf of Mexico

Sponges are inhabited by a wide variety of organisms and have been regarded as one of the richest biotopes in tropical seas. The aim of this study was to assess the influence of the host morphology and selected environmental conditions on macrofaunal assemblages associated with the sponge Halichondria melanadocia in an estuarine system of the southern Gulf of Mexico. This sponge exhibits different growth forms when it inhabits mangrove prop roots of Rhizophora mangle (thickly encrusting form) and adjacent seagrass beds (massive, amorphous or ramose form). From a total of 50 sponge specimens collected in each habitat, a total of eight taxa (of epi‐ and endobionts) was found associated with this sponge, with polychaetes, echinoderms and crustaceans the most abundant groups. In both morphotypes (thickly‐encrusting and massive‐ramose forms), taxon richness was positively related to sponge volume and oscular diameter. The overall mean abundance of associated fauna was also positively related to sponge volume in both morphotypes and with the oscular diameter (in the seagrass morphotype only). These findings suggest that H. melanadocia constitutes an important microhabitat for a wide variety of fauna, independent of its morphology and habitat type. However, when comparing the two morphotypes, the mangrove individuals, despite having smaller sizes, smaller oscular diameter and less structural complexity, displayed an overall mean abundance of fauna 17 times higher [0.36 ± 0.18 individuals (ind.)·ml·sponge^?1] than that recorded in the seagrass individuals (0.021 ± 0.01 ind.·ml·sponge^?1). There were also marked differences in the proportions of the major taxonomic groups; in fact, some of them were found exclusively in one morphotype. The variability recorded in the composition and abundance of associated fauna between the morphotypes seems to be influenced by differences in sponge morphology, environmental conditions (e.g. sedimentation rate and light intensity), substrate orientation and the fauna inhabiting the surrounding area.     

中国海粗毛猛水蚤科一新记录属和新种记述

通过对南海采集的沉积物进行分析,发现一新种奇足威伦狭腹猛水蚤,这也是首次在中国海报道威伦狭腹猛水蚤属。新种奇足威伦狭腹猛水蚤与同属其它种的主要区别特征是：身体表面除尾节有小刺外,其余各节表面均光滑;第四胸足外肢第三节内侧具两根刚毛;雌性第五胸足內肢具4根刚毛和刺,外肢顶端具一根尖刺,尾叉长约为宽的六倍。     

Sponges boring into precious corals: an overview with description of a new species of Alectona (Demospongiae, Alectonidae) and a worldwide identification key for the genus

Precious corals represent peculiar substrata for several species of boring sponges that exploit their carbonatic scleraxis, strongly decreasing their commercial value. Here we describe a new species of the genus Alectona from Japan recorded in a colony of Paracorallium japonicum (Kishinouye, 1903). The spicular complement of the new species consists of diactinal spicules covered by mushroom-like tubercles, often modified into styloid forms, and fusiform amphiasters with two or sometimes four verticils, each generally made up of six short tubercled rays. A complete survey of the literature on boring sponges recorded in precious corals in the Mediterranean Sea and Pacific Ocean indicates that the species of the family Alectonidae are the most strictly associated to this kind of substratum. Their world distribution, in fact, partially or totally overlap that of their coral hosts.     

热带太平洋活性微生物菌株的筛选和鉴定

从热带太平洋的生物、海水、沉积物样品中分离到细菌、酵母和霉菌共475株．选择8个指示菌并采用圆形纸片法对分离菌株的发酵液进行抗菌和抗肿瘤活性筛选，获得20个具有抗菌和／或抗肿瘤活性的微生物菌株．细菌、酵母和霉菌活性菌株的筛选得率都比较低，分别为5．4％、2．2％和3．4％，其原因可能与纸片的发酵液的添加量较少和菌株发酵条件的控制有关．同时采用分子生物学方法鉴定了活性菌株，除4株未有结果外，其余菌株分归为9个属，其中芽孢杆菌属7株、占活性菌株的35％，盐单胞菌属2株、占10％，其它菌属各1株、占5％．抑菌谱分析表明，大多数活性菌株对革兰氏阳性细菌具有抑制作用，而来源于鱼体的菌株抑菌谱较广，对细菌、真菌均有拮抗作用，另外还发现一株酵母（Rhodosporidium toruloides）可抑制金黄色葡萄球菌．作者提出“活性指示（activity index）”参数，对活性菌株的抗菌谱和活性强度进行综合评估，也表明源于鱼体的菌株的活性指示值较高．这4株芽孢杆菌尤其是DY-Y-11A1A菌株，具有潜在的后续开发价值．     

北极黄河站地区不同基底中真菌的分离培养及初步鉴定

为了探索北极陆域真菌的多样性,进一步揭示其生态学角色,本研究对中国第5次北极科学考察采集自黄河站区附近的24份样品进行了真菌的分离培养及鉴定,样品涂布划线后共分离得到60株真菌,其中腐殖质样品中分离到的真菌种类和数量最多;对选取的28株代表菌株进行了真菌ITS区序列鉴定,结果表明它们分属于4个纲,12个属,分别为散囊菌纲、粪壳菌纲、座囊菌纲和微藻菌纲,其中地丝霉属为优势类群。该结果表明北极地区具有丰富的真菌物种多样性。通过对代表土壤理化性质的测定,探究了真菌多样性和土壤理化参数的相关性,其中有机碳氮及可溶性营养盐含量是影响北极土壤真菌多样性的重要指标。     

印度洋深海沉积物样品纯培养细菌的分离鉴定

为探索印度洋深海沉积物中纯培养细菌的多样性,本文对采自印度洋12个沉积物样品进行细菌纯培养分离,共获得343株细菌。所有细菌采用16S rRNA 基因进行比对分析,鉴定为4个门：厚壁菌门（Firmicutes）、变形菌门（Proteobacteria）、放线菌门（Actinobacteria）和拟杆菌门（Bacteroidetes）,5个纲,13个目,26个科,39个属下的121个种。分离出的优势类群为链霉菌属（Streptomyces,分离率为16.53%）和芽孢杆菌属（Bacillus,分离率为8.26%）,其中可能有12个潜在的新分类单元。研究结果表明,印度洋深海沉积环境中纯培养细菌资源丰富,潜在新物种较多;其次,分离培养方法与从海洋沉积物中获得的细菌物种多样性直接相关。     

Effects of epibionts on Sabellaria alveolata (L.) biogenic reefs and their associated fauna in the Bay of Mont Saint-Michel

Biogenic structures built by ecosystem engineers such as corals, bivalves, polychaetes, and sea grasses provide habitat for benthic vertebrates and invertebrates. The polychaete Sabellaria alveolata is an important foundation species whose reef structure adds topographic complexity and high levels of biodiversity to the otherwise low-relief, low diversity, soft-bottom environments in the Bay of Mont Saint-Michel, France, where the largest such reef formations in Europe are found. In this bay, reefs are being increasingly colonised by oysters (Crassostrea gigas) from local aquaculture operations and by green algae (Ulva sp.) due to the increasing inputs of nitrates from terrestrial origin. The purpose of this study was to investigate the possible impacts of epibiotic oysters and green algae on the S. alveolata population and reef community structure in the Bay of Mont Saint-Michel, France. Univariate and multivariate comparisons of macrofauna were conducted for five reef types: controls (no epibionts), low oyster density, high oyster density, green algae, and oyster and green algae. Results showed that all the three reef types with oysters had significantly higher species richness and diversity values than control and algae-only reef types. Pairwise ANOSIM and SIMPER comparisons of controls versus the four reef types with epibionts revealed that all three of the reef types with oysters were significantly different from controls, but there was no significant difference between controls and algae-only reef types. A striking feature of the reef comparisons is that no single species in this species-rich system contributed more than 8.86% to the dissimilarity between the reef types. Thus, k-dominance curves for species abundances were not effective in revealing differences among the reef types. Our results demonstrate that recent anthropogenic inputs of oysters affect the reef species assemblage more strongly than algal epibionts. In addition, epibionts, especially green algae, alter S. alveolata population structure, causing a reduction in new recruits that over the long run may cause significant damage to the reef structure itself. These results are a first step towards understanding anthropogenic threats to S. alveolata reefs and may be useful in the development of strategies for their protection and management.     

福建九龙江和东屿地区全新世微型硅藻的初步研究

利用透射电镜研究了九龙江口现代潮间带表层沉积物、九龙江地区中全新世剖面和东屿中-晚全新世剖面的微型硅藻(细胞大小为2～20μm)的组成和丰度.共计硅藻12属26种(包括变种).对每个种的生态分布作了描述,并提供了相应的壳面电镜照片.Thalassionema nitzschioides是九龙江口现代潮间带表层沉积物中的优势种;九龙江中全新世地层的优势种为Navicula climacospheniae,Thalassionema nitzschioides;东屿中-晚全新世地层中,Cyclotella striata,Thalassionema nitzschioides是优势种.微型硅藻在各个样品中所占比例都相对较高,最高可达86.7%,表明微型硅藻在沉积硅藻中占有重要的地位.     

养殖大菱鲆细菌性红体病病原菌的分离与鉴定

从患有红体病的养殖大菱鲆(Scophthalmus maximus)的肌肉中分离得到一株优势菌并记为H1.经人工注射感染证实H1即为引起养殖大菱鲆红体病的病原菌,其半致死量LD50为2.82×105CFU/mL,而低浓度(1.41×103 CFU/mL)没有造成死亡,但注射部位有脓肿现象,注射相同体积1.5%无菌生理盐水的对照组没有明显的症状,注射部位也无异常.革兰氏染色显示该菌为革兰氏阴性,菌体呈杆状,周生鞭毛.综合该菌的形态、常规生理生化特征和API32E鉴定结果,发现H1与迟钝爱德华氏菌的表性特征非常相似,相似率迭到99.9%.在分子水平上对其16SRNA基因序列的测定,同源性分析,结果表明H1与迟钝爱德华氏菌的亲缘关系最近,相似度达到99%.综合上述研究结果,将该菌株初步鉴定为迟钝爱德华氏茵(Edwardsiella tarda).     

Isolation and identification of a marine killer yeast strain YF07b and cloning of the gene encoding killer toxin from the yeast

It was found that the marine yeast strain YF07b could secrete a large amount of killer toxin against a pathogenic yeast strain WCY which could cause milky disease in Portunus trituberculatus.The marine yeast strain YF07b was identified to be Pichia anomala according to the results of routine yeast identification and 18S rDNA and ITS sequences.The gene encoding killer toxin in the marine yeast strain YF07b was amplified by PCR technology.After sequencing,the results show that an open reading frame,consisting of 1 281 bp,encoded a presumed protein of 427 amino acids.The sequence of the cloned gene was found to have 99% match with that of the gene encoding killer toxin in Pichia anomalas strain K.A signal peptide including 17 amino acids appeared in the N-terminal domain of the killer toxin.Therefore,the mature protein consisted of 410 amino acids,its molecular mass was estimated to be 47.4 ku and its isoelctronic point was 4.5.     

中国南麂列岛产海洋底栖硅藻新种-南麂侧链藻(Pleurosira nanjiensis sp. nov.)的形态与分子系统学研究

本文描述了采自南麂列岛小柴屿岩相潮间带的一海洋底栖硅藻新种,南麂侧链藻（Pleurosira nanjiensis sp.nov.）。本研究使用光学显微镜和扫描电子显微镜对该种进行了形态学观察,并基于SSU rRNA和rbcL基因重建了其系统发育关系。南麂侧链藻具有壳面橄榄形、椭圆形或圆形,壳面隆起,单眼突出于壳表面,2–3个唇状突（rimportulae）,放射排列的线纹等特征,区别于其他侧链藻。     

Genetic and morphological description of Eucalanus spinifer T. Scott, 1894 (Calanoida: Eucalanidae), a circumglobal sister species of the copepod E. hyalinus s.s. (Claus, 1866)

A distinct genetic form of the eucalanid calanoid copepod Eucalanus hyalinus s.l. was identified in subtropical and temperate waters of the Pacific, Atlantic, and Indian Oceans. Results from mitochondrial (16S rRNA, COI) and nuclear (ITS2) genetic markers suggest that the two E. hyalinus forms are reproductively isolated. Eucalanus spinifer T. Scott is taken out of synonymy with E. hyalinus and is applied to the smaller of the two genetic forms, increasing the number of species in the genus Eucalanus to a total of six. Adult females of the sister species E. hyalinus s.s. and E. spinifer can be distinguished morphologically by the shape of the anterior portion of the head in lateral and ventral views, asymmetry in the length of antennule segments 22 and 23, length ratios of 22/5 and 23/5 of the longer of the antennules, the length of the caudal rami, and total body size, as measured by total length or prosome length. We illustrate and describe both adult females and males of E. spinifer, and discuss aspects of sexual dimorphism. The sister species are sympatric throughout much of their circumglobal biogeographic distributions, but appear to have centers of abundance in slightly different water mass types.     

A survey on Anthomedusae(Hydrozoa: Hydroidomedusae) from the Taiwan Strait with description of new species and new combinations

New data on Anthomedusae are included. Seven new species and 2 new combinations are described. An additional Teissiera polypofera Xu, Huang and Chen, 1991 is redescribed and its position of taxonomy is discussed. Other lists of species on Anthomedusae are summarized.     

An analysis of the radar backscatter from oil-covered sea surfaces using moment method and Monte-Carlo simulation: preliminary results

An analysis of the radar backscattering from the ocean surface covered by oil spill is presented using a microwave scattering model and Monte-Carlo simulation. In the analysis, a one-dimensional rough sea surface is numerically generated with an ocean waveheight spectrum for a given wind velocity. A two-layered medium is then generated by adding a thin oil layer on the simulated rough sea surface. The electric fields backscattered from the sea surface with two-layered medium are computed with the method of moments (MoM), and the backscattering coefficients are statistically obtained with N independent samples for each oil-spilled surface using the Monte-Carlo technique for various conditions of surface roughness, oil-layer thickness, frequency, polarization and incidence angle. The numerical simulation results are compared with theoretical models for clean sea surfaces and SAR images of an oil-spilled sea surface caused by the Hebei (Hebei province, China) Spirit oil tanker in 2007. Further, conditions for better oil spill extraction are sought by the numerical simulation on the effects of wind speed and oil-layer thickness at different incidence angles on the backscattering coefficients.