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A juvenile (26 mm) specimen of the New Zealand turbot Colistium nudipinnis (Waite) is figured and described. Differences between the juvenile and adult forms, and characters distinguishing juvenile C. nudipinnis from the young of other New Zealand species of flatfish, are noted.  相似文献   

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北方春季时期印度次大陆和西藏高原的差异性增热吸引了印度洋的潮湿空气穿越印度大陆,产生了世界上最显著的西南印度夏季季风(ISM)体系(Webster,1987)。世界上大约25%的人口受到这种季节降雨的影响。20世纪60年代末期,印度约150万人死于连续3年的季风失常(重大灾害数据库,2005)  相似文献   

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本文对1987~1988年在山东省部分海岛底栖生物调查时发现的异毛虫科5个种进行了详细的描述并配有插图,其中一种为新亚种,另有3个种在我国为首次记录。  相似文献   

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Halosaurus pectoralis McCulloch is recorded from off Gisborne, New Zealand, and from south‐east of Lord Howe Island, thus adding a second species of the order Heteromi to the New Zealand fauna.  相似文献   

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Variations in the calcite compensation depth (CCD) in the East Sea (Sea of Japan) since the early middle Miocene were inferred from data on age-depth relationships, sediment carbonate, and benthic foraminifers from ODP sites 794, 795, and 797. The CCD remained relatively shallow during much of the middle Miocene–Pliocene, and deepened sharply at the beginning of the Pleistocene. Since then it has fluctuated rapidly, possibly in relation to the onset of the northern hemisphere glacial cycles in the late Pliocene. The average CCD has deepened since at least the early middle Miocene, coinciding with the long-term drop in eustatic sea level. Received: 5 November 1998 / Revision accepted: 2 February 2000  相似文献   

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The identification of boundaries of genetic demes is one of the major goals for fishery management, and few Mediterranean commercial species have not been studied from a genetic point of view yet. The deep-water rose shrimp Parapenaeus longirostris (Lucas, 1846) is one of the most important components of commercial landings in Mediterranean, its fishery aspects have received much attention, regrettably without any concern for the genetic architecture of its populations. The population structure in the central and eastern Mediterranean Sea (captures from six Italian and two Greek landings) has been analysed on the basis of surveys carried out with mitochondrial and AFLP markers. Data revealed the presence of a gradual discrepancy along a west–east axis. This species, occurring mainly at a depth of between 100 and 400 m, is not strongly confined in isolated demes, but it demonstrates an ‘Isolation By Distance’ model, within the Mediterranean Sea, which includes geographical areas with a some degree of isolation. The role of hydrodynamic forces, such as currents, water fronts, is discussed; and a further evidence of the ‘Levantine isolation’ within Mediterranean basin is shown.  相似文献   

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The Mediterranean endemic Cladocora caespitosa (Linnaeus, 1767) is a colonial scleractinian coral belonging to the family Faviidae and the only zooxanthellate coral from Mediterranean whose colonies may fuse in reef‐like structures (hermatypic). Recent surveys are focused on three locations where banks occur in the Adriatic Sea (Croatia): near Prvi? Island in the northern Adriatic, near Pag Island in the central Adriatic and in Veliko jezero (Mljet National Park) in the southern Adriatic. The C. caespitosa bank in Veliko jezero covers an area more than 650 m2 and is thus the largest bank of C. caespitosa found to date. The strong sea currents, which occur as a result of tidal exchange in the channel, appear to favour the growth of the bank. The goal of the study was to present the influence of major environmental factors upon the build‐up process of the coral bank. Biometrical parameters in the C. caespitosa colonies like diameter of the calyces, polyp ash free dry weight (AFDW), corallite linear growth rate and index of sphericity were investigated and compared from these three locations. The morphology of coral banks from the Adriatic Sea and the disposition of the biometrical values are affected by the sea currents, temperature and sedimentation.  相似文献   

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2011年,1117号强台风“纳沙”和1119号强台风“尼格”分别在海南岛沿岸登陆,在海南岛沿岸造成不同程度的风暴潮,部分岸段最高潮位超过当地警戒潮位,给海南省造成严重的经济损失.本文分别从热带气旋特征、增水特征、灾害损失等方面进行分析,对这两次风暴潮增水过程的特征进行比较,以便为以后的风暴潮预报积累经验,更好地为我省海洋减灾防灾服务.  相似文献   

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The origin and evolution history of the Curonian Spit in the Baltic Sea are discussed based on geological and geomorphologic data. Evidence of the correlation between the spit formation stages and the Holocene sea level oscillations is presented. The ledges of moraine basement and marine accumulative features formed a single barrier. Its subsequent transformation occurred under the influence of the wave-related lithodynamic and eolian processes.  相似文献   

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Living (Rose Bengal stained) benthic foraminifera were investigated at 18 deep-sea stations sampled in the Whittard Canyon area (NE Atlantic). The stations were positioned along 4 bathymetric transects ranging from 300 to 3000 m depth: two along the main canyon axes (Western and Eastern branches) and two along adjacent open slopes (Western and Eastern slopes). The aim of this study was to assess changes of foraminiferal standing stock, composition and microhabitat in relation to the physico-chemical conditions prevailing at and below the sediment-water interface in various canyon and open-slope environments. Minimal oxygen penetration depths and maximal diffusive oxygen uptakes were recorded at upper canyon stations, suggesting a high mineralisation rate. This is confirmed by the high phytopigment concentrations measured in the sediment of the upper canyon axes. Foraminiferal abundance was positively correlated with diffusive oxygen uptake and phytopigment concentration in the sediment. This suggests a control of organic matter fluxes on the foraminiferal communities. Foraminiferal abundance was generally higher along the canyon axis compared to open-slope sites at comparable water depths. The species composition varied with water depth along all four transects, but was also different between canyon branches and adjacent slopes. The silty/sandy intercalations at many of the deeper canyon stations may have been rapidly deposited by fairly recent gravity flows. At station 51WB (3002 m), the faunal characteristics (strong dominance, shallow infaunal microhabitats) suggest that the foraminiferal community is in an early state of ecosystem colonisation after these recent sedimentation events, which would have supplied the important amounts of phytopigments.  相似文献   

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The life cycle of a brackish water population of Marphysa sanguinea (Polychaeta Eunicidae), from the Venice Lagoon (Italy), was investigated from April 1993 to August 1994. Marphysa sanguinea is a large‐sized gonochoric species with annual iteroparous strategy and synchronous spawning at population level. The sex‐ratio was close to 1:1. There were no morphological differences between males and females and spawning occurred without epitokal metamorphosis. The gonadial activity was maximum during summer period in both sexes. From May to September in the females, the greater number of immature oocytes could be observed; starting from November immature oocytes decreased and progressively those with a wider diameter increased in number. Spawning took place in April–May and generally not all eggs were spawned, a small proportion being kept as a reserve material for the following gamete production. The pelagic phase (trochophore and metatrochophore stages) was short (2–3 days). The reduction in the dispersal phase, together with the development of a strong anterior musculature, brought to an early acquisition of the benthic habit, which was attained with the construction of the mucous tube inside of which the larva lived. The results highlighted that colonization of brackish environments took place thanks to morphological and physiological features that allow this species to live in a sediment layer characterized by the stability of the physical and chemical characteristics of the substratum.  相似文献   

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Estuarine ecosystem has greatly changed in the recent decades due to anthropogenic perturbations in the Changjiang Estuary. Change patterns and impact factors were analyzed based on the continuous data...  相似文献   

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锯缘青蟹视神经节免疫细胞化学研究   总被引:2,自引:0,他引:2  
采用兔抗哺乳类血清,应用链霉菌抗生物素蛋白-过氧化物酶免疫细胞化学技术,观察了锯缘青蟹视神经节中5羟色胺、胰高血糖素、神经肽Y和生长抑素免疫阳性细胞和神经纤维的形态和分布,结果发现,视神经节的4个神经髓均有5羟色胺免疫阳性细胞,除X器检出1个较大型阳性细胞外,其余均为小型细胞.视外髓、视内髓和视端髓都具有胰高血糖素免疫阳性细胞,视端髓的神经髓质阳性染色深,X器中阳性细胞成群分布,窦腺免疫阳性反应强.神经肽Y免疫阳性细胞在视神经层和视外髓为小型阳性细胞,在视内髓和视端髓检出较大型阳性细胞,另有小型阳性细胞散布于X器中.生长抑素免疫阳性细胞分布于4个神经髓,数量少.4种免疫阳性物的特异性分布模式,可为其不同的神经生理作用提供形态学证据.  相似文献   

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Siderophores play an important role in biological iron acquisition in iron-limited aquatic systems. While it is widely accepted that the solubilization of iron-bearing mineral phases is a key function of siderophores, the mechanism of siderophore-promoted mineral dissolution in aquatic systems is largely unknown. In this study, we investigated the effect of siderophores (desferrioxamine B (DFOB) and aerobactin) on light-induced dissolution of goethite and lepidocrocite in the presence or absence of oxalate in aerated and deaerated suspensions at pH 6. For the irradiated two-ligand system (oxalate/siderophore), the experimental results suggest that oxalate acts as the electron donor for the formation of surface Fe(II), and the siderophore acts as an efficient shuttle for the transfer of surface Fe(II) into solution. Furthermore, even in the absence of an electron donor such as oxalate, both DFOB and aerobactin accelerated the light-induced dissolution of lepidocrocite as compared to the thermal dissolution. Experiments with dissolved Fe(III)–DFOB and Fe(III)–aerobactin complexes suggest that this enhancing effect is not due to photolysis of corresponding surface complexes but to efficient transfer of reduced surface Fe(II) into solution, where surface Fe(II) may be formed, e.g., through photolysis of surface Fe(III)–hydroxo groups. Based on this study, we conclude that the interplay of light and siderophores may play a key role in the dissolution of colloidal iron(III) (hydr)oxides in marine systems, particularly in the presence of efficient electron donors.  相似文献   

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The main objective of this study was to apply a set of sensitive non-lethal biomarkers in skin biopsies of fin whales (Balaenoptera physalus) to evaluate the toxicological status of this mysticete in the Pelagos Sanctuary (Mediterranean Sea) and in the Gulf of California (Sea of Cortez-Mexico). We developed a “multi-trial diagnostic tool” (based on field and in vitro studies), combining molecular biomarkers (western blot of CYP1A1, CYP2B) and gene expression (qRT-PCR of HSP70, ERα, AHR, E2F-1) with the analysis of OCs, PAHs and PBDEs. The study revealed a higher level of toxicological stress in the Mediterranean fin whales.  相似文献   

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