Spatio-Temporal Distribution of Algal and Animal Communities in a Posidonia oceanica Meadow     

Lucia MaZzella  Maria Beatrice Scipione  Maria Cristina Buia 《Marine Ecology》1989,10(2):107-129

Abstract. Investigations were carried out in a Posidonia oceanica meadow at Ischia (Gulf of Naples) along a depth gradient from 1 to 32 m in November 1979 and May 1981.
In these two months, different discontinuities were found at the sampling stations (1, 5, 10, 20, 30 m) at 10 m for leaf features, between 1 and 5 m for the algal community and the vagile fauna. The leaf features (length, surface, and biomass) along the transects show a delay in leaf production toward the deeper stations, below the thermocline.
The algal community shows in both seasons and in all stations a persistence of an encrusting layer, mostly represented by Corallinaceae and the brown alga Myrionema orbiculare , while at the shallowest station (1 m) the community is characterized by a more developed upright layer.
The vagile fauna of the leaf stratum, mostly represented by Polychaeta, Mollusca , and Crustacea (Peracarida and Decapoda) , shows a consistent zonation in both seasons along the transect. A superficial community at I m, characterized by a low number of species and individuals and specialized for high environmental energy levels, and a deeper community, persistent in time and more strictly related to the Posidonia oceanica meadows, are identified.
The influence of environmental factors and the importance of meadow structure for the zonation of the algal and animal communities are discussed.  相似文献   

Seabird numbers and prey consumption in the North Atlantic   总被引：1，自引：0，他引：1  

Barrett  Robert T.; Chapdelaine  Gilles; Anker-Nilssen  Tycho; Mosbech  Anders; Montevecchi  William A.; Reid  James B.; Veit  Richard R. 《ICES Journal of Marine Science》2006,63(6):1145-1158

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Development of fouling communities on vertical structures in the Baltic Sea   总被引：6，自引：2，他引：6  

Susanne Qvarfordt  Hans Kautsky  Torleif Malm 《Estuarine, Coastal and Shelf Science》2006,67(4):618-628

The pillars of the bridge connecting the Island of Öland with the Swedish mainland were rebuilt between 1990 and 2000. The renovation produced pristine vertical concrete substrates, which became submerged in known years and seasons. The fouling communities on the pillars were examined in 2001 to determine whether the community structure could be explained in terms of either orderly successional development or of seasonal variation in the settlement of benthic organisms. As well, the communities on the pillars were compared to communities on the vertical surfaces of boulders in the area. The results indicated that an annual species composition is the final stage in the succession on the observed, vertical constructions. The few perennial species add to the variation between pillars as they increase in biomass (Polysiphonia fucoides) or become out-competed (Balanus improvisus). Also, observed seasonal differences in the biomass of these perennial species indicated that the time of year free space becomes available might be an important determinant of the future structure of the community. Comparison between the pillar and boulder communities showed that the artificial structures were not surrogates for the natural hard substrate: pillar communities differed in that they lacked most perennial algal species and had a high biomass of B. improvisus.  相似文献   

4D seismic time-lapse monitoring of an active cold vent,northern Cascadia margin   总被引：1，自引：1，他引：1  

Michael Riedel 《Marine Geophysical Researches》2007,28(4):355-371

Two single-channel seismic (SCS) data sets collected in 2000 and 2005 were used for a four-dimensional (4D) time-lapse analysis of an active cold vent (Bullseye Vent). The data set acquired in 2000 serves as a reference in the applied processing sequence. The 4D processing sequence utilizes time- and phase-matching, gain adjustments and shaping filters to transform the 2005 data set so that it is most comparable to the conditions under which the 2000 data were acquired. The cold vent is characterized by seismic blanking, which is a result of the presence of gas hydrate in the subsurface either within coarser-grained turbidite sands or in fractures, as well as free gas trapped in these fracture systems. The area of blanking was defined using the seismic attributes instantaneous amplitude and similarity. Several areas were identified where blanking was reduced in 2005 relative to 2000. But most of the centre of Bullseye Vent and the area around it were seen to be characterized by intensified blanking in 2005. Tracing these areas of intensified blanking through the three-dimensional (3D) seismic volume defined several apparent new flow pathways that were not seen in the 2000 data, which are interpreted as newly generated fractures/faults for upward fluid migration. Intensified blanking is interpreted as a result of new formation of gas hydrate in the subsurface along new fracture pathways. Areas with reduced blanking may be zones where formerly plugged fractures that had trapped some free gas may have been opened and free gas was liberated.  相似文献   

Distribution of population-based indicators across multiple taxa to assess the status of Gulf of Alaska and Bering Sea groundfish communities     

Mueter  Franz J.; Megrey  Bernard A. 《ICES Journal of Marine Science》2005,62(3):344-352

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The effects of fishing on sharks, rays, and chimaeras (chondrichthyans), and the implications for marine ecosystems   总被引：16，自引：4，他引：16  

Stevens  J. D.; Bonfil  R.; Dulvy  N. K.; Walker  P. A. 《ICES Journal of Marine Science》2000,57(3):476-494

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凡纳滨对虾咸淡水养殖系统内细菌群落组成的PCR-DGGE分析   总被引：16，自引：0，他引：16  

罗鹏  胡超群  谢珍玉  张吕平  任春华  许尤厚 《热带海洋学报》2006,25(2):49-53

采用PCR(polym erase chain reaction)-DGGE(denaturing grad ient gel electrophoresis)及传统的微生物培养方法对凡纳滨对虾Litopenaeus vannam ei咸淡水养殖系统内各种环境的细菌群落组成进行了比较研究。传统的微生物培养计数表明,从海湾水、养殖池水到对虾粪样,细菌和弧菌的数量表现出依次增加的趋势,粪样及肠壁中弧菌的数量高出外界水环境1—4个数量级。相对于外界水环境,粪样中有很高的芽孢杆菌孢子含量,但是肠壁定植细菌中不存在芽孢杆菌(孢子)。PCR-DGGE及聚类分析结果表明,从海湾沿岸、养殖池、对虾粪便到对虾肠壁,细菌群落的多样性由高到低,无论是在哪种环境,群落的优势种都十分明显,且只有2—4种。来自同一环境各样品间的细菌群落组成非常相似,来自不同环境的样品,其细菌群落组成差别较大。聚类图上各簇的排列顺序反映了样品在取样空间分布上的毗邻次序和它们的相似程度。  相似文献   

渔业社区管理在中国的实施探讨   总被引：4，自引：0，他引：4  

唐建业  黄硕琳 《海洋通报》2006,25(4):63-68

传统的渔业管理强调了政府的直接控制管理,忽视了渔区在其中的作用。渔业社区管理是随着市场经济和政府管理的发展而被作为一种解决传统渔业管理困境的途径提出。为此,首先总结了渔业社区管理的概念,并对目前有关各国的实践进行分类。在此基础上,利用制度经济学的理论分析该管理制度的作用机制及实施条件。然后,分析该管理制度在我国实施的必要性和可行性,渔业社区管理是解决目前我国渔业管理中存在诸多问题的一种合适方案,且当前国家政策和渔区实际也为其提供良好的实施环境。最后,提出从政府管理者和渔民或与渔业相关的利害人两个方面创造实施渔业社区管理的条件。  相似文献   

Elemental geochemical records of seafloor hydrothermal activities in the sediments from the Okinawa Trough     

ZHAI Shikui  YU Zenghui  DU Tongjun 《海洋学报(英文版)》2007,26(4):53-62

The major and minor element contents in the sediment core H9 from the hydrothermal fields of the Okinawa Trough show a sharp change at the depth of 80 cm. The elements enriched in the upper 80 cm core are those enriched in the hydrothermal deposits and in the surface sediments recovered from the hydrothermal fields in the trough, which indicates the input of hydrothermal materials. Comparing with other hydrothermal sediments from Mid-ocean Ridges or the Lau Basin, the degree of the enrichment of elements iron, copper,cobalt, and nickel is relatively low. However, the enrichment of elements manganese, lead, arsenic, antimony and mercury is remarkable. The average contents of these elements in the upper 80 cm core sediments are three to six times those in the lower section, and 3~12 times those in the surface sediments which are not influenced by hydrothermal activities. Hydrothermal activities have contributed significant manganese, lead, arsenic, antimony and mercury to the sediments, and these elements are distinct indicators for the hydrothermal activity in the Okinawa Trough. The significant enrichment of these elements in Core H9 upward from the depth 80 cm indicates the start or the significant enhancing of the hydrothermal activity in this area at about 5 740 aB.P. The average accumulation rate of manganese during this period is about 40 461 μg/(cm2·ka), which is similar to the hydrothermal sediments in the Lau Basin or the East Pacific Rise.  相似文献   

Organic enrichment and structure of the macrozoobenthic community in the northern Adriatic Sea in an area facing Adige and Po mouths   总被引：1，自引：0，他引：1  

Simonini  R.; Ansaloni  I.; Bonvicini Pagliai  A.M.; Prevedelli  D. 《ICES Journal of Marine Science》2004,61(6):871-881

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