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1.
1989年8月,从大亚湾短吻鲾Leiognathus brevirosiris的胆囊中发现粘孢子虫拟单囊虫属一新种,定名为鲾拟单囊虫Coccomyxa leiognatha sp.nov.,该种孢子前部较宽大,中后部窄小,外观似手榴弹状,体前部具一棒状或椭圆形极囊。  相似文献   

2.
Abstract. Two new genera of Tantulocarida are described from the Ligurian deep sea (Western Mediterranean) off Corsica. Xenalytus scotophilia is referred to the Microdajidae and differs from Microdajus GREVE in thoracopodal segmentation as well as in the presence of coupling spines on thoracopod 6 and longitudinal lamellae on the cephalic shield. Aphotocentor styx is placed in the Deoterthridae and holds an intermediate position between Deoterthron BRADFORD & HEWITT and Boreotantulus HI/YS & BOXSHALL. Some aspects of cephalon internal structure are described for the first time and give a possible explanation for the mechanism of stylet protrusion. The external structures of the oral disc are described using SEM. The discovery of well-developed muscles in the trunk and thoracopods is discussed in the light of the benthic phase the tantulus passes through. The boundary between the thorax and abdomen in the tantulus is reinterpreted, corroborating the 5–7-5 bodyplan of the hypothetical urmaxillopodan as found in the Upper Cambrian Skaracarida and possibly also Dala peilertae MOLLER. Some aspects related to dispersal, infection, and feeding are reinterpreted or approached from a different perspective. SEM of Microdajus langi GREVE gives evidence that the tantuli hatch via a conspicuous slit located at the posterior end of the female trunk sac. A worldwide key to the tantulocaridan families and genera is given, and distributional records are compiled. It is suggested that Tantulocarida might be common representatives of the temporary meiobenthos and that their present species number represents only the tip of the iceberg.  相似文献   

3.
采用2010年1~9月采自北部湾及邻近海域流刺网渔获的54尾金线鱼(Nemipterus virgatus( Houttuyn,1782))、71尾深水金线鱼(Nemi pterus bath ybius Snyder,1911)和65尾日本金线鱼(Nemi pterus ja ponicus (Bloch,1791))耳石样本,进行了椭圆傅立叶分析.耳石轮廓经图像处理后进行灰阶转换和二值化处理,消除噪点,然后解析为椭圆傅立叶标码( EFDs).采用77个EFD系数进行主成分分析和判别分析来区分3种金线鱼的耳石.结果表明,日本金线鱼幼鱼和成鱼耳石在性成熟前后存在显著的体长效应(P<0.05),金线鱼和深水金线鱼则体长效应不显著(P>0.05).因此在耳石椭圆傅立叶分析中,日本金线鱼采用性成熟个体样本,金线鱼和深水金线鱼采用全部样本.主成分分析中,第1、第2和第3主成分,分别解释了总变异的65.1%,15.3%和5.3%,可以将3种金线鱼耳石区分开来.EFD系数的逐步判别分析中,3种鱼的平均正判率达98.6%;交互验证结果显示,3种鱼的平均正判率达97.9%,这表明耳石椭圆傅立叶分析可以作为鱼种识别的有效工具.  相似文献   

4.
Macoma inquinata, a detritus feeding clam, was exposed for 60 days to coarse-grained, and Abarenicola pacifica, a burrowing polychaete, to fine-grained, sediment. Each sediment contained 14-C-labelled phenanthrene, chrysene or benzo(a)pyrene. Over 70% of the chrysene and benzo(a)pyrene, but only 8% of the phenanthrene, remained in the coarse sediment during the exposure. Essentially all of the chrysene and benzo(a)pyrene and 70% of the phenanthrene remained in the fine sediment. The concentrations of chrysene and benzo(a)pyrene in the clams rose steadily, reaching levels 11·6 and 5·2 times as high as those in the sediment. The tissue phenanthrene concentration rose for 3 days, then fell to one-eighth of the initial concentration. The concentrations of each of the aromatic hydrocarbons in Abarenicola tissue increased for 2 weeks to four to six times the sediment levels. The tissue concentration of chrysene remained constant thereafter, but the levels of phenanthrene and benzo(a)pyrene fell to three-quarters of their peak values. No intermediate degradation products of any of the hydrocarbons were identified in extracts of sediment from either exposure system, or in solvent extracts of tissue or of tissue digestates.Significant 14C-activity, associated with non-solvent extractable compounds, remained in tissue digestates of individuals of both species exposed to phenanthrene.  相似文献   

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6.
The generation of tidal asymmetries is clarified via numerical integration of the one-dimensional equations for channel geometries characteristic of shallow estuaries. Channels without tidal flats develop a time asymmetry characterized by a longer falling than rising tide. This behavior is enhanced by strong friction and large channel cross-sectional area variability over a tidal cycle. Resulting tidal currents have a shorter, intense flood and a longer, weak ebb (flood-dominant). Addition of tidal flats to the channels can produce a longer rising tide and stronger ebb currents (ebb-dominant), if the area of tidal flats is large enough to overcome the effects of time-variable channel geometry. Weaker friction with flats can also produce this asymmetry.Despite the physical complexity of these systems, essential features of estuarine tidal response can be recovered from one-dimensional models. Shallow estuaries are shown to have a system response leading to stable, uniform senses of tidal asymmetry (either flood- or ebb-dominated, due to phase-locking of forced tidal constituents), with down-channel development in magnitude of asymmetry. These concepts are illustrated by modeling idealized representations of tidal channels at Nauset Inlet, MA, and Wachapreague Inlet, VA, which have flood- and ebb-dominance, respectively.  相似文献   

7.
Proper control sites for nematode abundance, patch size and patch dispersion could not be defined prior to a manipulative oil pollution experiment despite the apparent physical similarity and proximity of two locations. Comparisons of abundance and patch size demonstrated that neither site could serve as a control for the other. Spectral analysis was not useful, in this case, in resolving patch dispersion in the range of 1·2 to 60 cm. These data indicated that in circumstances where a posteriori studies comparing two areas cannot be avoided, it is only with great caution that a single factor should be interpreted as causative of observed densities or distribution of organisms.  相似文献   

8.
基于生态系统的海洋综合管理是海洋管理的新理念和新模式,其倡导从海洋生态系统角度开展环境资源保护,并以促进海洋生态系统与人类开发活动的协调可持续发展为终极目标。美国大沼泽湿地项目是基于生态系统的海洋综合管理的经典范例。基于生态系统的海洋综合管理的核心理念是将整个生态系统纳入海洋综合管理范畴,颠覆传统的单一对象保护理念,实现海洋生态保护与人类生存发展协调可持续。美国大沼泽湿地项目采用了基于生态系统的海洋综合管理理念,将整个大沼泽湿地视为一个整体生态系统,实现联邦政府、州政府和社会组织协作,合力促进大沼泽湿地的绿色生态可持续发展。美国大沼泽湿地项目全面贯彻基于生态系统的海洋综合管理理念,采用联合管理模式,重视水资源环境治理取得一定成效,但也暴露出管理模式有待改进、公众宣传参与不到位、区域间联系不紧密等问题。  相似文献   

9.
应用蛋白银染色法对采自大亚湾水域的拟急游虫进行形态学研究,并与文献报道的种类进行比较发现:该种拟急游虫在个体大小以及体纤毛的数量上与同属的其他相似种有着极明显的差异,定为拟急游虫属的一个新种,命名为大拟急游虫Strombidinopsisgrandissp.nov.。  相似文献   

10.
The non-ideality of commercially available glass pH electrode normally used for alkalinity determination by the Gran-type titration has been examined and its effect on the accuracy of the estimated alkalinity evaluated. It is found that slope errors of the glass electrode could be a limiting factor to the accuracy that can be obtained. This error source could be eliminated altogether by applying the proposed ‘slope correction’ algorithm which uses the titration data for in situ slope calibration of the glass electrode. Application of the proposed method eliminates the need for calibration of the glass electrode and the requirement for thermostating the test solution.  相似文献   

11.
The annual loads of nutrients (TOxN equal to nitrate+nitrite; ammonium, phosphate, silicate) to all the estuaries on the mainland of the United Kingdom were estimated from data on water flow through gauging stations at the tidal limits of estuaries, and from concentration measurements under the Harmonised Monitoring Scheme of nutrient concentrations in water samples from these stations. The annual loads of nutrients showed distinct regional variations, with estuaries along the west coast of Wales and northern Scotland having much smaller loads than those along the east coast of England. The largest nitrogen loads were of TOxN, and ammonium loads were usually small in comparison. The Severn, Mersey, Humber and Thames had the highest loads, although these were small in relation to the larger continental European estuaries. Loads of TOxN per unit of catchment area were surprisingly constant (about 105 moles N km−2 y−1). The nutrient loads showed that most U.K. catchments were influenced by human activity, the majority being in the ‘ moderately influenced ’ category. Nutrient loads were also normalized for the area of each estuary, as a measure of the relative influence of nutrients on the receiving estuaries. The ratios of N:P, N:Si and P:Si in the annual loads suggested that most estuaries were likely to be, if anything, P limited rather than N or Si limited. However, crude annual loads may conceal significant seasonal variations.The spring maximum chlorophylla concentrations in coastal waters adjacent to each estuary were significantly correlated with the log total annual loads of TOxN, ammonium and phosphate (but not silicate) for each estuary, providing a direct link between a measure of the degree of biological response in coastal waters and the nutrient load through the estuaries. There were no significant correlations between spring maximum chlorophyll a concentrations and either catchment-normalized or estuary-normalized nutrient loads. There was significant correlation between catchment area-normalized loads of phosphate and an urbanization index for the catchments, but not with the catchment area-normalized loads of the other nutrients.  相似文献   

12.
13.
The eutrophication of Langstone Harbour, a large tidal basin, has been studied by statistically designed nutrient surveys. Rates of input of nutrients from the sea, from effluent discharges and from other sources, have been estimated. Sediment/water interactions have been shown to be important in the phosphate budget of the basin, but they are less important in the nitrogen budget. Deductions were made about the relative importance of the various inputs and processes affecting concentrations of nutrients in the water column.It is concluded that ecologically or aesthetically detrimental growths of macroalgae are unlikely to occur in Langstone Harbour in the foreseeable future and that the removal of nutrient inputs, formerly thought to be necessary, will not, in fact, be required.The principles of the experimental design and of interpreting the data are of general applicability to tidal waters where the ratio of natural to man-made inputs needs to be known, where eutrophication is, or is expected to become, a problem, or where the progressive accumulation of nutrients by recycling is suspected.  相似文献   

14.
Protothaca staminea and Macoma inquinata were exposed to sediment contaminated with 1237 ppm Prudhoe Bay crude oil in the field. Eighty-five per cent of the Protothaca and 17% of the Macoma survived 54 days' exposure. Body burdens of saturated and di- and tri-aromatic hydrocarbons were less than 2 ppm and quite variable. The condition index of Protothaca was reduced by 6% by exposure to oil. The level of free glycine in the mantle, gills and adductor muscle did not change significantly, but the taurine level fell, leading to a decrease in the taurine:glycine ratio. It was concluded that Protothaca, a filter feeder, is affected less severely by oil pollution than Macoma, a detritivore, perhaps because the feeding activity of filter feeders is less inhibited.  相似文献   

15.
Bernhard  Riegl Andrea  Riegl 《Marine Ecology》1996,17(1-3):399-410
Abstract. Africa's southernmost coral reefs are situated in Natal Province, South Africa. The Natal coast is exposed to open Ocean swells and episodic storm swell conditions. Benthic communities on these reefs differentiated into three community types: shallow reefs (8–18 m) were dominated by alcyonacean corals and low-growing, massive Scleractinia; intermediate reefs (18–25 m) were dominated chiefly by branching and tabular Scleractinia of the genus Acropora (A. austera, A. clathrata); deep reefs were not dominated by corals but by sponges. Breakage and recovery experiments indicated that the difference in Acropora dominance between shallow and intermediate sites was caused by breakage in high swell conditions. Survival of experimentally produced A. austera fragments was significantly higher in intermediate than in shallow sites, where higher surge made re-attachment and regeneration unlikely. Also, colony morphology was adapted to differential surge conditions: colonies on the shallow reefs were smaller with shorter branches, while on intermediate reefs they were much bigger with long, widely spreading branches. Episodic breakage and low fragment survival due to high water-motion thus excluded branching corals from shallow reef sites.  相似文献   

16.
Abstract. The burrows of Squilla mantis are described from polyester resin casts taken at two Adriatic sites near Ancona. Typically, burrows had two openings, one of which was larger than the other, and were basically U-shaped. An interesting association with the little-known caridean shrimp Athanas amazone was observed. The sediments occupied by S. mantis were silty sands and sandy muds. Field observations of S. mantis and other species on the same grounds are presented and some information on burrow density is given, derived from burrow counts using underwater television. Burrowing behaviour is described from observations of animals transferred to laboratory aquaria.  相似文献   

17.
StudyontheisozymesintwospeciesofprawnsLiTaiwu,SuXiurong,ZhangJian,YinHongying,XieMingjie,NingShuxiang(ReceivedJune25,1997;acc...  相似文献   

18.
浮游介形类是海洋生态系统中极为丰富的一类小型甲壳动物,是海洋浮游动物的重要组成部分。吸海萤科是介形纲吸海萤目下的一大类群,其中,浮萤族已记述21属的生物。本文报道和描述了新近采自南海中部的一个浮萤族新属新种--复合多腺浮萤。该新物种与相关属和种可通过综合相关特征进行区分:位于右不对称腺体上方的侧角腺开口于近后缘;沿其壳腹缘具有一列排列密集的边缘腺;其前器官形状的综合特点与族内其他属物种均不同;第一触角的e刚毛不具有毛或刺;第二触角内肢乳状突表现为一具有腹面中央凹的椭圆隆起,第一外肢具有一根小背前缘刺,第一与第二外肢愈合,第三与第四外肢不具有刚毛或刺;大颚的第一内肢具一根长腹侧刚毛,第二内肢具一根腹侧刚毛;小颚第一内肢具两根基部刚毛;第五肢的第一外肢仅具一根腹侧刚毛;第六肢的第一与第二外肢不具有腹侧刚毛。其壳上主要腺体及开口位置与其他已记录属种的显著区别是该新属的主要特征。  相似文献   

19.
文章描述了采自青岛胶州湾潮下带沉积物中自由生活线虫Wieseria属的两个新种。新种Wieseria sinica sp.nov.特征为具有短的唇刚毛和头刚毛,且指向后方;具有椭圆形双边化感器;弓形的交接刺具有翼膜;环状的引带以及棒状尾。新种Wieseria tenuisa sp.nov.特征为具有大的德曼值(133.6);长的唇刚毛指向前方;交接刺具有翼膜,近端呈钩状;引带呈棒状;具有相当长的棒状尾(长度相当于7.9倍泄殖腔相应体径)。它区别于新种Wieseria sinica sp.nov.主要在于更长的唇刚毛,且指向前方;交接刺相对较直且具有钩状近端,身体更加细小(德曼“a”值较大)。文章更新完善了的Wieseria属的二岐检索表。  相似文献   

20.
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