密西西比现代被动边缘海底扇与古活动边缘海底扇两者浊积相组合之比较     

Shaum.  G 守玉 《海洋地质译丛》1989,(6):25-31

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Macrofauna impact on Ulva rigida C. Ag. production and relationship with environmental variables in the lagoon of Venice   总被引：2，自引：0，他引：2  

Balducci C  Sfriso A  Pavoni B 《Marine environmental research》2001,52(1):27-49

The grazing pressure of the macrofaunal invertebrates associated with the biomass of Ulva rigida in the Venice lagoon, their species composition and relationship with environmental variables have been studied. Fifteen sampling campaigns were carried out during different seasons both in the central basin of the lagoon, dominated by macroalgae (especially U. rigida C. Ag.) and in the southern basin, prevalently populated by seagrasses (especially Zostera marina L.). Replicate experiments were conducted in the field by exposing Ulva fronds in net cages of 10 and 1 mm (control) mesh-sizes to allow or prevent grazer entrance. The grazing pressure was determined as Ulva growth rate difference in the cages. In the absence of invertebrate herbivores, Ulva exhibited per cent relative growth rates (%RGRs) ranging from 1.5 to 9.5% day(-1), whereas in their presence the %RGRs were significantly lower (from -2.5 to 3.4% day(-1)) and frequently negative, especially in the station dominated by macroalgae. In this area, peak grazing rates and macrofauna biomasses of up to 8.6% day(-1) and 1,480 g m(-2) fwt (84.4 ash-free dry weight), respectively, were found. On the whole, during in field experiments in the Ulva-dominated station, herbivores removed an amount of biomass whose percentage ranged from 59 to 165% (mean: 103%) of the biomass yield (grazers excluded) found in the cages. These results suggest the possibility that grazers could act as an important factor affecting Ulva production in the Venice lagoon. Macrofauna populations were analysed by means of multivaliate techniques applied to biological variables only and biological and environmental variables together. Data of individual abundance, after a log(x + 1) transformation and the calculation of the Bray-Curtis matrix, were classified using the Cluster Analysis and ordinated by means of the Non-Metric Multidimensional Scaling (MDS) technique, in accordance with the strategies used in the study of multispecies distributions. Finally, biological and environmental variables were analysed together by means of correlation matrices and the Principal Component Analysis.  相似文献   

泛大陆的具有两种机制的两阶段分裂作用     

Hynes  A 朱起煌 《海洋地质译丛》1991,(1):37-41

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洋脊的岩浆房有多大？     

Nicol.  A 陶鲁 《海洋地质译丛》1993,(3):75-78

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Measurement of DNA single-strand breaks in gill and hemolymph cells of mussels, Mytilus sp., collected on the French Atlantic Coast     

Akcha F  Tanguy A  Leday G  Pelluhet L  Budzinski H  Chiffoleau JF 《Marine environmental research》2004,58(2-5):753-756

DNA single-strand breaks were measured by the comet assay in both gill and hemolymph cells of mussels collected in 3 sampling areas of the French coast (Pointe du Castelli, Pen Bron and Saint-Nazaire Harbour). Whole mussel tissue samples were also collected for the chemical determination of PAH, PCB and heavy metal concentrations. In mussel, a higher level of DNA strand breaks was measured in gill than in hemolymph cells (p < 0.01). Despite a factor of contamination from 2 to 3 between sites, no difference in the extent of mussel DNA strand breaks was shown between sampling locations (p > 0.05), questioning the sensitivity of the assays used in biomonitoring studies.  相似文献   

海洋微生物学的主要任务     

A.E.科利斯 《海洋与湖沼》1958,1(2):337-343

海——微生物栖息的特殊环境。特殊的盐类成分,低温,高压,低浓度的有机物质,植物及动物区系的稀少等组成了微生物生命活动的广阔海洋区域一些主要生态特征。 海洋中最初的微生物学研究,早在上一世纪就已进行了,但足它们局限于较狭小的任务——  相似文献   

A NEW MODEL FOR PEBBLE BEACH TRACER DISPERSAL     

A. T. WILLIAMS 《海洋学报(英文版)》1987,6(2):229-234

A series of eight tracer experiments were carried out over one year (1983) on a low energy, macro-tidal beach in South Wales, UK. Tracer movement was monitored and 30 pebbles adjacent to coloured tracer pebbles were measured. Measurements were of the A, B, and C axes, roundness, Maximum Projection Sphericity and Oblate-Prolate indices. Analysis shows that through time, the percentage rejection of these properties increased. It is theorised that the surface tracers are 'misfits' or 'rejects' which have not found their equilibrium position in the pebble facies.  相似文献   

Oxidative stress in ecotoxicology: from the analysis of individual antioxidants to a more integrated approach     

Regoli F  Gorbi S  Frenzilli G  Nigro M  Corsi I  Focardi S  Winston GW 《Marine environmental research》2002,54(3-5):419-423

An integrate approach will be discussed for investigations on oxidative stress in xenobiotic toxicity. While the analysis of individual antioxidants is useful for their sensitivity and to understand the mode of action of a stressor, the integration with the analysis of the total antioxidant capacity provides a more holistic assessment of the overall biological significance of such variations. TOSC has a greater predictive value on the health condition of the organisms and allows to discriminate the different role of specific ROS in oxidative stress syndrome.  相似文献   

西南太平洋彭林海盆表层和埋藏锰结核成分和生长史     

A．Usui单连芳  刘季花 《海洋地质前沿》1994,(9):11-13

本文所研究的样品由《Hakurei—maru》号科学考察船进行的GH80—1和GH83—3两个航次所采集．这两次航行的目的是作为日本“中太平洋锰结核调查”五年计划(1979—1983)任务的一部分，在威克-塔希提横断层上进行地质调查(GSJ)。  相似文献   

南极威德尔海陆缘固冰区叶绿素a及硅藻的分布     

陈兴群  G.迪克曼 《海洋学报》1989,11(4):501-509

本文描述了1985年1月-2月联邦德国“极星”号极地考察船沿威德尔海陆缘固冰区调查期间所获得的冰柱状样内叶绿素a以及硅藻的分布,对三个不同区域柱状样的分析结果表明,底部10-30cm的海冰多呈褐色,其内由大量藻类,特别是由硅藻细胞的富集而形成,丰度变化大.在融化的底部冰样中,细胞数高达10⁸个/l,叶绿素a浓度高达2220mg/m³,中部常见到大量小型的失去色素乃至死亡的硅藻细胞.初步鉴定出26种硅藻,其多数隶属于茧形藻属(Amphiprora),斜纹,藻属(Pleurosigma),菱形藻属(Nitzschia),盒形藻属(Biddulphia),角刺藻属(Corethron),海毛藻属(Thalassiothrix),海链藻属(Thalassiosira),以及脆杆藻属(Fragilaria)等,本文还记录了两种不同的底部生态群落:寡种和多种集群的生态类型,并对硅藻的富集和分布成因作了一些讨论.  相似文献