Population Structure and Secondary Production of the Mediterranean Octocoral Lophogorgia ceratophyta (L. 1758)     

M. Mistri 《Marine Ecology》1995,16(3):181-188

Abstract. The gorgonian Lophogorgia ceratophyta thrives in turbid water at Tinetto Rock, La Spezia Gulf, Ligurian Sea. Its age structure suggests that the population is in a steady state; nevertheless, it is difficult to discern whether the main factors controlling this population are biological or event-related. Secondary production was estimated by means of an increment-summation method and yielded 0.54 g ash-free dry weight (AFDW)*m^-1 a^-1. This estimate does not take into account biomass losses due to reproductive output and non-lethal predation. Standing stock biomass was 5.44 g AFDW e m^-2. The annual P/B ratio was 0.10 and turnover time about 10a  相似文献   

黄海地质构造与油气资源   总被引：13，自引：4，他引：13  

李廷栋  莫杰 《海洋地质前沿》2002,18(11):4-7

概述了南，北黄海盆地地质构造特征，盆地的形成与演化，分析研究了油气地质特征与成藏条件；对黄海各盆地和隆起区可能具有找油气远景的新领域，新层位和新类型，提出一些探讨性的认识。  相似文献   

Modelling morphological processes in the vicinity of shore-parallel breakwaters     

Julio A. Zyserman  Hakeem K. Johnson 《Coastal Engineering》2002,45(3-4)

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渤海南部表层沉积的相特征   总被引：1，自引：0，他引：1  

王琦  赵其渊  杨作升  周莉  沈渭铨  周伟  李平 《中国海洋大学学报(自然科学版)》1989,(1)

通过海上调查及实验室分析,查明渤海南部表层沉积物在结构类型、矿物组合、生物组分及沉积构造等相特征方面具有明显的分区性。渤海南部存在五种沉积相:黄河水下三角洲相、陆架盆地相、海湾相、潮流浅滩相及古滨岸相。黄河水下三角洲相从河口延至水深15—20米处,沉积速率很高,沉积物富含碎屑云母及CaCo_3。陆架盆地相的沉积为粉砂质粘土,具有生物扰动构造。  相似文献   

烟台市污水处理深海排放工程设计方案研究与选择   总被引：2，自引：0，他引：2  

王文喜  李明基 《海岸工程》1997,16(1):30-35

沿海城市污水处理深海排放工程在我国起步较晚，烟台市污水处理深海排放工程我国目前规模最大的同类工程，且已进入施工阶段，本文详细阐述了该工程及水工设计方案，在我国城市污水２深海排放工程领域作了积极有益的探索。  相似文献   

9012号热带气旋维持的卫星云图和垂直结构特征分析   总被引：2，自引：0，他引：2  

严光华  吴志伟等 《台湾海峡》1995,14(2):174-180

本文根据卫星云图的演变和常规天气分析相结合，对9012号热带气旋登陆后维持水消的成因进行了分析。指出该热带气旋经久不消的重要原因为其西南侧对流云团和东北侧高空槽前对流云带与热带气旋云系相衔接在中低层东北气流引导下卷入，热带气旋内部的两条云带的维持，以及利有的环流条件。  相似文献   

The trophic spectrum: theory and application as an ecosystem indicator     

Gascuel  Didier; Bozec  Yves-Marie; Chassot  Emmanuel; Colomb  Audrey; Laurans  Martial 《ICES Journal of Marine Science》2005,62(3):443-452

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2000年夏季莱州湾生态环境要素的分布特征   总被引：1，自引：0，他引：1  

高会旺  吴德星  白洁  石金辉  李正炎  江文胜 《中国海洋大学学报(自然科学版)》2003,33(2):185-191

论文依据 2 0 0 0年夏季 8月 2 9日至 9月 2日莱州湾的 1次综合性生态环境调查资料 ,给出了表、中、底 3层的平均温度、盐度、主要营养盐浓度及其比例和叶绿素 a浓度 ,分析了莱州湾的温盐结构、主要营养盐和叶绿素 a的分布特征。由于莱州湾的水深较浅 ,各要素的垂直分布都比较均匀。生态环境要素的水平分布表现为小清河口为高温、低盐、高营养盐和高叶绿素 a浓度区 ,小清河口东测的湾顶区域为高温、高盐、相对低的营养盐和叶绿素 a浓度区。此次观测到的盐度较 1997年以前有明显升高。莱州湾各层平均的 N/ P和 Si/ N分别为 16.73和 1.67,都比 1998～ 1999年渤海中部的值大 ,但 N/ P比 1992 ,1995和 1996年莱州湾的 N/ P明显偏低。叶绿素 a浓度与硅酸盐浓度之间有较好的相关关系 (α=0 .0 1) ,表、中、底 3层叶绿素 a浓度同硅酸盐浓度的线性相关系数分别为 :0 .5 4 ,0 .68和 0 .67  相似文献   

Design of a 3D Chirp Sub-bottom Imaging System     

Jonathan M. Bull  Martin Gutowski  Justin K. Dix  Timothy J. Henstock  Peter Hogarth  Timothy G. Leighton  Paul R. White 《Marine Geophysical Researches》2005,26(2-4):157-169

Chirp sub-bottom profilers are marine acoustic devices that use a known and repeatable source signature (1–24 kHz) to produce decimetre vertical resolution cross-sections of the sub-seabed. Here the design and development of the first true 3D Chirp system is described. When developing the design, critical factors that had to be considered included spatial aliasing, and precise positioning of sources and receivers. Full 3D numerical modelling of the combined source and receiver directivity was completed to determine optimal source and receiver geometries. The design incorporates four source transducers (1.5–13 kHz) that can be arranged into different configurations, including Maltese Cross, a square and two separated pairs. The receive array comprises 240 hydrophones in 60 groups whose group-centres are separated by 25 cm in both horizontal directions, with each hydrophone group containing four individual elements and a pre-amplifier. After careful consideration, it was concluded that the only way to determine with sufficient accuracy the source–receiver geometry, was to fix the sources and receivers within a rigid array. Positional information for the array is given by a Real Time Kinematic GPS and attitude system incorporating four antennas to give position, heading, pitch and roll. It is shown that this system offers vertical positioning accuracy with a root-mean-square (rms) error less than 2.6 cm, while the horizontal positioning rms error was less than 2.0 cm. The system is configured so that the Chirp source signature can be chosen by software aboard the acquisition vessel. The complete system is described and initial navigational and seismic data results are presented. These data demonstrate that the approach of using fixed source-receiver geometry combined with RTK navigation can provide complete 3D imaging of the sub-surface.  相似文献   

Variability of organic δC and C/N in the Mersey Estuary, U.K. and its implications for sea-level reconstruction studies     

Graham P. Wilson  Angela L. Lamb  Melanie J. Leng  Silvia Gonzalez  David Huddart 《Estuarine, Coastal and Shelf Science》2005,64(4):685-698

Microfossil analysis (e.g. diatoms, foraminifera and pollen) represents the cornerstone of Holocene relative sea-level (RSL) reconstruction because their distribution in the contemporary inter-tidal zone is principally controlled by ground elevation within the tidal frame. A combination of poor microfossil preservation and a limited range in the sediment record may severely restrict the accuracy of resulting RSL reconstructions. Organic δ¹³C and C/N analysis of inter-tidal sediments have shown some potential as coastal palaeoenvironmental proxies. Here we assess their viability for reconstructing RSL change by examining patterns of organic δ¹³C and C/N values in a modern estuarine environment. δ¹³C and C/N analysis of bulk organic inter-tidal sediments and vegetation, as well as suspended and bedload organic sediments of the Mersey Estuary, U.K., demonstrate that the two main sources of organic carbon to surface saltmarsh sediments (terrestrial vegetation and tidal-derived particulate organic matter) have distinctive δ¹³C and C/N signatures. The resulting relationship between ground elevation within the tidal frame and surface sediment δ¹³C and C/N is unaffected by decompositional changes. The potential of this technique for RSL reconstruction is demonstrated by the analysis of part of an early Holocene sediment core from the Mersey Estuary. Organic δ¹³C and C/N analysis is less time consuming than microfossil analysis and is likely to provide continuous records of RSL change.  相似文献