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《Oceanologica Acta》2003,26(5-6):645-655
The Medusae of Tunis Gulf (25 species) are qualitatively the third zooplanktonic group after Tintinnids and Copepods. Anthomedusae (eight species), Trachymedusae (five species) and Leptomedusae (four species) represent the major part among the 20 species of Hydromedusae identified during our study (December 1993–November 1995). However, the Limnomedusae (two species) and the Narcomedusae (one species) are poorly represented. In the Bay of Tunis, Obelia spp., the most common and dominant species, command the quantitative fluctuations of Hydromedusae and reach exceptionally the density of 25 800 ind. m–3. Within the Scyphomedusae (five species), Pelagia noctiluca is the most common species which outbreaks in winter and autumn. Tunis Gulf seems to be composed of two jellyfish communities; the first one is composed of endogenous species showing a constant period of blooming like Olindias, Cladonema, Aurelia, Cotylorhiza and Rhizostoma and sometimes permanent like Obelia spp. and Clytia spp.; the second is represented by exogenous species considered as “visitors” like Velella, Sminthea or Pelagia whose presence on the coast is dependent on local and particular winds and currents. 相似文献
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《Oceanologica Acta》1998,21(5):631-644
The fine-grained sediments of the West Gironde mud patch derive mainly from materials supplied via the Gironde estuary. Between 1500 and 1200/1300 years BP and 300/400 years BP and the present day, the Sr isotopic and chemical compositions of the estuarine silty clay inputs are the same. In contrast, these compositions were different during the period 1200/1300 to 300/400 years BP. These variations probably reflect anthropogenic activities including cultivation and agriculture, in the Garonne and Dordogne drainage basins during the medieval period. Modem silty clay sedimentation in the mud flats of the Marennes-Oleron basin and Perthuis Breton is characterised by the occurrence of important quantities (between 40 and 90 % of the total) of detritus that issues from the Gironde estuary. The autochthonous silty clays derived from outcrops of Jurassic green marls and Flandrian deposits are mixed with estuarine allochthonous clays delivered by coastal surface currents. In the Anse de l'Aiguillon, the muds are mainly composed of these autochthonous silty clays. The silty clay infilling of these mud flats has been highly influenced by the development of the oyster and shellfish aquaculture. 相似文献
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《Oceanologica Acta》1998,21(6):767-782
An estimation of the annual productivity in the Gulf of Lions has been made in the 0–100 m layer using a Let-Go system, with monthly measurements at a fixed station. A value of 140 to 150 g m−2 a−1 of C is found, of which around 75 % occurs in the upper 50 m. The seasonal production is described according to three distinct patterns during the two hydrological seasons: (1) variable production in winter; (2) surface bloom in late winter; (3) homogeneous and mean production in summer with a clear Deep Chlorophyll Maximum. The hydrological winter phase represented 60 % of total annual production. The seasonal duality of the hydrodynamic system and the mesoscale variations of the Northern Mediterranean Current account for the variability and the evolution of the three production patterns. 相似文献
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Gilbert Bellaiche 《Marine Geology》1975,19(2):M1-M6
The interpretation of sedimentological and geochronological results lead us to the conclusion that the sedimentary levees flanking the deep-sea channels of the Rhône deep-sea fan are made up of various kinds of turbidites originating from different coastal areas and were deposited during the Quaternary glacial epochs. 相似文献
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近岸沉积物对~(90)Sr(~(85)Sr),~(137)CS,~(60)CO及~(106)Ru的吸附性能 总被引:2,自引:0,他引:2
本文应用同位素示踪和γ能谱分析方法,就近岸沉积物对放射性同位素~(90)Sr((~85)Sr),~(137)Cs,~60Co及~(106)Ru的吸附性能进行了研究。对同种类型的沉积物,吸附分配系数Kd值的变化顺序大致为~(137)Cs>~(60)Co>~(106)Ru>~(90)Sr;对同种放射性同位素,吸附分配系数Kd值与沉积物的粒度系数(Mdφ)存在正相关关系;在低活度示踪条件下,Kd值不变。实验结果与相应海区的实际调查结果相符,沿岸核企业在设计排污方案时,亦应考虑沉积物对放射性同位素的吸附及其污染影响。 相似文献
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<正>"13146-K,目标350米。感应雷达自动关闭。"领航员3号报告。"13146-J,目标350米。感应雷达自动关闭。"领航员3号继续报告,十分轻松。"1313 9-I,目标3 5 0米。感应雷达自动关闭。"领航员5号报告,揉揉疲惫的眼睛,继续跟踪下一个目标讯息。面前的显示屏上,代表13139-g的亮点却一动不动。"13139-g,13139-g,13139-g?"领航员5号睁大眼睛,连声呼唤,不断按动鼠标,那亮点却像粘牢在屏幕中了一样,领航员5号拍打键盘。显示屏一分为二,出现13139-g的视野,画面来自13139-g携带的水下摄影仪。视野中尽是混浊黑暗近乎 相似文献
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本文应用同位素示踪和γ能谱测定方法,就海水对近岸沉积物中放射性同位素~(90)Sr(~(85)Sr)、~(137)Cs、~(60)Co及~(106)Ru的解吸性能进行了初步研究。海水对沉积物中四种同位素解吸性能的变化顺序为~(90)Sr(~(85)Sr)>~(106)Ru>~(60)Co>~(137)Cs,沉积物吸附的~(90)Sr(~(85)Sr)易被海水解吸,而~(137)Cs和~(60)Co则易被沉积物吸附固定。 相似文献
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本工作使用一次培养法初步研究了Cr(VI)对菱形硅藻和隐藻的毒性,实验结果表明,当Cr(VI)浓度大于16ppb时,则对其生长率产生抑制作用,其72小时EC_(50)值分别为260ppb和230ppb.根据活性点位模式计算了Cr(VI)与藻体的结合常数,约为2×10~5藻体中Cr含量与培养液中Cr浓度有关,两者近似指数关系,根据藻体中Cr含量和溶液中Cr的浓度,估计每个硅藻细胞与Cr最大结合容量约为5×10~(-17)mol/cell. 相似文献
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鱼类摄取的蛋白质,首先用于维持体重,其次才用于增加体重。只用体重增加量表示的是蛋白质效率,把维持体重也同时考虑在內的 相似文献
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刘安国 《中国海洋大学学报(自然科学版)》1996,(3)
莫恩,H(HenrikMohn,1835515-1916.9.12)挪威气象学家、海洋学家。1835年5月15日生于卑尔根,1916年9月12日逝世于奥斯陆。1861年在克里斯蒂安尼亚(Christiania,今奥斯陆)天文台工作。1866-1913年任奥斯陆大学教授、挪威气象台台长,任期长达47年。在气象学上,积极组建挪威气象站网,主要研究挪威气候、天气学、动力气象学和大气中声的传播,以及研究大西洋海洋与气象。在海洋学方面,1876-1878年参加北极探险。曾根据美国北极探险家德朗(G.W.DeLong,1844-1881)指挥的《珍尼特号》(Jeannette)在西伯利亚群岛东北海域… 相似文献
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刘安国 《中国海洋大学学报(自然科学版)》1996,(3)
约翰逊,M.W.(MartinWiggoJohnson,1893.9.30~?)美国海洋生物学家。1893年9月30日出生于南达科他州的昌巴。1924年获华盛顿大学理学土学位。1930年获理学硕士学位、1931年获动物学博士学位。历任华盛顿大学弗拉德港实验室主任(1924~1929)、华盛顿大学教师(1932~1933),1934年后一直在斯克里普斯海洋研究所任职。其在海洋研究上的贡献是:1.在海洋学名著《海洋》(TheOcean)中撰写海洋生物学,从而与H.U.SverdruP和R.H.Fleming共同闻名于海洋界;2第二次世界大战早期,提出水下不寻常的背景噪声乃是由于许多虾蟹… 相似文献
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《中国海洋大学学报(自然科学版)》1996,(1)
威尔克斯,Ch(CharlsWikes,17984.3~18772.8美国南极探险家。1798年4月3日生于纽约,1877年2月8日抿于华盛顿。1818年进入海军。1838~1842年率探险队进行环球航行,进入南极区,发现威尔克斯地(100°~142°20′E),途中对大洋洲波里尼西亚的约260个岛屿,其中包括菲尼克斯群岛和托克劳群岛中三个以前没有查明的岛屿。探险队员中有后来成为著名的美国地质学家J.D.达纳(JamesDwightDana,1813~1895)。1844~1861年撰写考察报告,亲自写了19卷中的7卷。1866年晋升为海军少将。著有《美国探险队纪事》(5卷,1845);《美国西… 相似文献