Diversity of symbiotic algae of the genus Symbiodinium in scleractinian corals of the Xisha Islands in the South China Sea

Symbiotic algae （Symbiodinium sp.） in scleractinian corals are important in understanding how coral reefs will respond to global climate change. The present paper reports on the diversity of Symbiodinium sp. in 48 scleractinian coral species from 25 genera and 10 families sampled from the Xisha Islands in the South China Sea, which were identified with the use of restriction fragment length polymorphism （RFLP） of the nuclear ribosomal DNA large subunit gene （rDNA）. The results showed that： （i） Symbiodinium Clade C was the dominant zooxanthellae in scleractinian corals in the Xisha Islands; （ii） Symbiodinium Clade D was found in the corals Montipora aequituberculata, Galaxea fascicularis, and Plerogyra sinuosa; and （iii） both Symbiodinium Clades C and D were found simultaneously in Montipora digitata, Psammocora contigua, and Galaxeafascicularis. A poor capacity for symbiosis polymorphism, as uncovered by RFLP, in the Xisha Islands indicates that the scleractinian corals have low adaptability to environmental changes. Further studies are needed to investigate zooxanthellae diversity using other molecular markers.     

西沙群岛西琛一井中新世地层,古生物群和古环境研究

根据壳状珊瑚藻、海相底栖介形类和有孔虫资料,西琛一井井深３４６．９２－８０２．１７ｍ的地层分别被归为下中新统西沙组下段（井深５５０－８０２．１７ｍ）和上段（４３１－５５０ｍ）,中中新统宣德组（３５３．４０－４３１ｍ）。西沙组下段包括３个介形类组合,自下而上为：①Ａｕｒｉｌａ ｘｉｓｈａｅｎｓｉｓ－Ｔｅｎｅｄｏｃｙｔｈｅｒｅ ｘｉｓｈａｅｎｓｉｓ,②Ｔｅｎｅｄｏｃｙｔｈｅｒｅ ｘｉｓｈａｅｎｓｉｓ－     

中国南中国海海岸湿地的保护和管理

中国南中国海湿地是中国各类生态系统中生物多样性最为丰富的地区之一,也是中国人口稠密、经济发达的地区。范围包括广东省、香港特别行政区、澳门特别行政区、广西壮族自治区和海南省等5个行政区。该区海岸湿地总面积约为1.54×104km2。海岸湿地处于海陆的交错地带,是脆弱的生态敏感区。由于受人口增加和经济发展的巨大压力,中国南中国海湿地破坏严重,退化趋势明显。本文在对中国南中国海地区海岸湿地的现状、类型及湿地退化的主要原因进行分析的基础上,提出中国南中国海地区海岸湿地资源保护与管理的建议,以便切实保护中国南中国海沿海多样化的湿地类型,持续发挥其生态服务功能。     

深圳湾表层沉积物中甲藻孢囊的垂直分布

采集了深圳湾3个采样点约20cm的表层沉积物样品,研究了甲藻孢囊的垂直分布。共分析鉴定出孢囊类型37种,其中5种为我国沿海未报道的新记录类型,原多甲藻类孢囊是该海域种类最丰富的孢囊类型。除上表层沉积物外,深圳湾甲藻孢囊密度较低,孢囊密度大多在500cysts／gDWt以下,总孢囊密度变化范围为83～4036cysts／gDWt之间。锥状斯氏藻是深圳湾甲藻孢囊的优势种类,上表层沉积物中该孢囊密度的急剧上升证实了2000年附近海域所发生的该藻赤潮。而裸甲藻类孢囊含量明显比南海其他海域高。孢囊的香农-威弗种类多样性指数为1．50～3．96之间,并且在非养殖区、离岸海域及较深层次沉积物中较高,而孢囊密度则呈相反的变化趋势。种类多样性的下降及孢囊密度的上升在一定程度上说明深圳湾污染的变化趋势,富营养化程度非养殖区大于养殖区,近岸海域大于离岸海域,并且近年来污染逐渐加剧。     

南中国海五种新纪录纤毛虫的形态学研究(原生动物,纤毛门)

从活体形态及纤毛图式水平,对采自广东大亚湾潮间带的5个南海新纪录种纤毛虫,即德卢偏体虫Dysteria derouxi,斜带齿管虫Chamydodon obliquus,恩茨伸颈虫Trachelotractus entzi,异佛氏全列虫Holosticha heterofoissneri和美丽原腹柱虫Protogastrostyla pulchra行了形态学研究,其中对德卢偏体虫银线系统、恩茨伸颈虫皮层颗粒、异佛氏全列虫的皮层颗粒和大核等进行了补足性描述.     

广东大亚湾七种腹毛类纤毛虫(原生动物,纤毛门)的形态学研究

利用活体观察和蛋白银染色技术对采自广东大亚湾沿岸水体的7个南海新纪录种:紧缩全列虫Holosticha diademata(Rees,1883)Kahl,1932、缩颈半腹柱虫Hemigastrostyla enigmatica(Dragesco & Dragesco-Kernéis,1986)Song&Wilbert,1997、念珠腹棘虫Gastrocirrhus monilifer(Ozaki & Yagiu,1942)Curds & Wu,1983、四核舍太虫Certesia quadrinudeata Fabre-Domergue,1885、斯特后尾柱虫Metaurostylopsis struederkypkeae Shao et al.,2008、盐尖毛虫Oxytricha saltans(Cohn,1866)Kahl,1932、小心毛虫Caryotricha minuta(Xu et al.,2008)Miao et al.,2009等腹毛类纤毛虫进行了形态学再研究,补充了有关活体形态学、纤毛图式以及性状变异等分类学新信息.结果显示,该7种的南海种群与我国北方海域种群之间存在不同程度的形态学差异.     

广东大亚湾六种海洋刺钩类纤毛虫的形态学研究

利用活体观察及银染法首次对采自广东大亚湾沿岸的盐菲阿虫Phialina salinarum Kahl,1928,海洋长吻虫Lacrymaria marina Kahl,1933,惊扰伪颈毛虫Pseudotrachelocerca trepida(Kahl,1928)Song,1990,贪食纤口虫Chaenea vorax Quennerstedt,1867,柱核柱毛虫Cyclotrichium cyclokaryon Meunier,1907和加冈栉毛虫Didinium gargantua Meunier,1910六种刺钩类纤毛虫进行了形态学研究,补充了活体形态学以及纤毛图式等分类学新信息。首次观察到了海洋长吻虫体纤毛基部的皮层颗粒和柱核柱毛虫大亚湾种群较青岛种群具有更多的体动基列等若干新信息。研究表明,刺钩类纤毛虫在大亚湾近岸水域具有较高的物种多样性。     

慢原甲藻——南海热带附生甲藻新记录

从海南陵水新村港分离出1株附生原甲藻,在光学显微镜和扫描电子显微镜下进行形态学特征分析,并结合核糖体18S rRNA基因序列分析,鉴定为慢原甲藻(Prorocentrum rhathymum),为国内首次报道.国内曾将该种与墨西哥原甲藻(Prorocentrum mexicanum)归为同种异名.     

南中国海地区主要生态系统的退化现状与保育对策

南中国海是一个具有重要全球生物多样性意义的地区.由于长期不合理的开发利用,该区域生态系统显著退化,生物多样性严重丧失.南中国海沿岸各国红树林的年均损失率为0.5%～3.5%,海草床有20%～50%遭到破坏,珊瑚礁中有82%呈退化趋势.在对上述生态系统的利用现状、退化原因以及环境问题的跨境影响进行分析的基础上,提出了有效保护和管理南中国海的对策和建议,以期在双边或区域的层面上共同协作,采取适当措施扭转南中国海地区的生态系统退化趋势.     

Characterization of a novel α4/4-conotoxin,Qcl.2, from vermivorous Conus quercinus

As part of continuing studies of the identification of gene organization and cloning of novel α-conotoxins, the first α4/4-conotoxin identified in a vermivorous Conus species, designated Qcl.2, was originally obtained by cDNA and genomic DNA cloning from Conus quercinus collected in the South China Sea. The predicted mature toxin of Qc1.2 contains 14 amino acid residues with two disulfide bonds （Ⅰ-Ⅲ, Ⅱ-Ⅳ connectivity） in a native globular configuration. The mature peptide of Qcl.2 is supposed to contain an N-terminal post-translationally processed pyroglutamate residue and a free carboxyl C-terminus. This peptide was chemically synthesized and refolded for further characterization of its functional properties. The synthetic Qcl.2 has two interconvertible conformations in aqueous solution, which may be due to the cis-trans isomerization of the two successive Pro residues in its first Cys loop. Using the Xenopus oocyte heterologous expression system, Qcl.2 was shown to selectively inhibit both rat neuronal α3β2 and α3β4 subtypes of nicotinic acetylcholine receptors with low potency. A block of -63% and 37% of the ACh-evoked currents was observed, respectively, and the toxin dissociated rapidly from the receptors. Compared with other characterized α-conotoxin members, the unusual structural features in Qcl.2 that confer to its receptor recognition profile are addressed.