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21.
Rita Borges Radhouan Ben-Hamadou M. Alexandra Chícharo Pedro R Emanuel J. Gonalves 《Estuarine, Coastal and Shelf Science》2007,71(3-4):412-428
There have been no previous studies of the composition of nearshore larval fish assemblages along the coast of Portugal. We aimed to describe the composition and horizontal distribution patterns of larval fish assemblages and their temporal dynamics near a rocky reef at depths shallower than 13 m (inshore) and at two miles (3.70 km) from shore (offshore), as well as along transects perpendicular to the shoreline, from the reef to 10 miles offshore (18.52 km). Samples were taken using 5 min sub-surface trawls at the rocky shore of the Arrábida Marine Park (W Portugal). A total of 1021 larvae were collected, belonging to 61 taxa inshore and to 29 taxa offshore. Along transects, 626 larvae of 52 taxa were collected. Most larvae belonged to coastal species associated with rocky reefs. Total larval abundance and diversity were higher from May to July, which is consistent with the spawning activity of adults. Diversity and total larval abundance decreased significantly with increasing distance from shore, both in the inshore/offshore comparison and in the transects, where this decrease was evident at a very small spatial scale (within the first mile from the reef). Species assemblages differed in the pattern of distribution, with most species clearly associated to the extreme nearshore. The distribution patterns obtained were independent of the spawning mode of species. Results are discussed in the light of the possible physical mechanisms that can potentially act at the Arrábida Marine Park to facilitate larvae retention and the role of larval behaviour. 相似文献
22.
To the first order in a Stokes expansion, the pressure force exerted by a sea state on a large horizontal cylinder represents a stationary random Gaussian process. A relationship is obtained between the spectrum of this process and the wave spectrum. As a consequence, the basic statistical properties of the height and period of the individual waves of the force-process are also obtained. It is proven that these statistical properties agree very well with the data from a small scale field experiment. 相似文献
23.
晋江河口及泉州湾湿地生物分布特点 总被引:3,自引:0,他引:3
泉州湾受晋江河口径流影响很大,导致湿地生物的水平分布与盐度的分布紧密相关.大致分为湾外和外湾种、内湾低盐种、感潮河段咸淡水种.长腕和尚蟹、扁平蛛网海胆和文昌鱼仅分布在外湾或湾外的砂质海底.3种红树植物、互花米草、招潮蟹、弹涂鱼是内湾泥滩的优势种.咸水草是感潮河段咸淡水指标种.河蚬虽是淡水种,也分布在低盐河段. 相似文献
24.
Shinya Magome Tomohiro Yamashita Takeshi Kohama Atsushi Kaneda Yuichi Hayami Satoru Takahashi Hidetaka Takeoka 《Journal of Oceanography》2007,63(5):761-773
Jellyfish patch formation is investigated by conducting a drifter experiment combined with aerial photography of a sustained
patch of the moon jellyfish in Hokezu Bay, Japan. Jellyfish patches are aggregations of individuals that are caused by a combination
of swimming (active influence) and advection by currents (passive influence). The drifter experiment involved the injection
of 49 drifters around a distinct surface patch of jellyfish within an area of approximately 300 m × 300 m. The drifters’ motion,
caused only by the passive influence, was recorded in a series of 38 aerial photographs taken over approximately 1 h. The
ambient uniform current field larger than the patch scale was estimated from the movement of the centroid position of drifters,
while the distribution of horizontal divergence and relative vorticity around the patch was estimated from the time-derivative
in areas of triangles formed by the drifters. The centroid positions of both drifters and patches moved stably toward the
bay head at different speeds. The difference vector between the patch and drifter centroids was directed to the sun, and was
opposite to the ambient current. The distributions of vorticity and divergence around patches exhibited inhomogeneity within
the patch scale, and the drifters in this nonuniform current field aggregated near the convergence area within 1 h. The results
suggest that horizontal patch formation is predominantly influenced by passive factors at the surface of Hokezu Bay. Furthermore,
the upward swimming against downwelling may make sustained patch in surface layer. 相似文献
25.
Climatic effects on plankton and productivity on the Faroe Shelf 总被引:1,自引:0,他引:1
Hansen Bogi; Eliasen Solva K.; Gaard Eilif; Larsen Karin M.H. 《ICES Journal of Marine Science》2005,62(7):1224-1232
26.
水平井含水率上升影响因素 总被引:1,自引:1,他引:0
利用塔里木油田塔中4油田(TZ4)底水油藏相关的地质、流体数据建立数值模型。在所建模型的基础上,应用数值模拟计算的累积产油、产水和产液量回归俞启泰水驱特征曲线,以反映水平井见水特征的参数b。以参数b为研究对象,采用正交试验的方法研究不同因素对b值的影响,筛选影响水平井见水特征的主要因素,认为原油粘度、油层厚度、非均质性及水平井水平段在油藏中的位置是影响水平井含水上升趋势的主要指标。最后建立主要因素与b值的关系式,结合俞启泰曲线b值图版,提出预测水平井见水规律的公式——图版法(F-b法)。应用F-b法对塔里木水平井含水率进行预测,并与其他相关方法及实际生产数据对比,认为F-b法可作为预测塔里木油田水平井含水率、估算可采储量的一种有效方法。 相似文献
27.
通过对塔东地区古城4井上寒武统和中、上奥陶统碳酸盐岩围岩及充填物的碳、氧、锶同位素地球化学和流体包裹体成分的对比研究表明,充填于中、上奥陶统和上寒武统的流体分属于2个不同来源的流体体系。充填于中、上奥陶统灰岩裂缝中方解石脉的w(87Sr)/w(86Sr)介于0.7084~0.7088,它与早奥陶世海水的w(87Sr)/w(86Sr)相近;流体体系为CH4-H2O体系;充填物与围岩间具有明显的碳、氧同位素差异,表明上部流体体系中的流体来自于奥陶系地层本身。上寒武统白云岩裂缝中方解石脉的w(87Sr)/w(86Sr)为0.7138,明显地高于同时代海水的锶同位素值;流体体系为CO2-H2O体系;下部流体体系中的流体为外来富锶流体。上、下流体体系间互不连通暗示着上寒武统地层具有相对较好的保存条件。 相似文献
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