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991.
本文通过对不同水深区沉积物中组分、生物面貌、矿物、CaCO3含量和碳酸钙溶解率等特征的分析和对比,把本区碳酸钙溶解深度带划分为碳酸钙溶跃面(小于3700m)、弱溶带(3700~4800m)、强溶带(4800~5200m)和全溶带(大于5200m)。提出本海域碳酸钙补偿深度界面约在5200m。文中还阐述了不同碳酸钙溶解带及其沉积物特征,认为造成这种特征的主要原因是随着水深变化碳酸钙溶解程度不同以及与南极底层流等因素的影响有关。 相似文献
992.
As an important part of the Bohai economic rim, the Laizhou Bay has been stressed by serious eco-environmental problems in recent years. In this study, the Shannon-Wiener index(H′), AZTI's marine biotic index(AMBI) and the multivariate AMBI(M-AMBI) were used to assess the ecological quality status(EQS) of the Laizhou Bay according to macrobenthos data collected annually in August 2011–2014. The results showed that the overall benthic habitat quality in the Laizhou Bay was assessed as "Good". However, 25% of the samples were classified as"Moderate", "Bad" or "Poor" status under degraded conditions. Ecological group Ⅲ(EGⅢ) species which had a certain tolerance to environmental disturbances had a higher proportion in each station, and most of them had appeared the pollution indicator species Capitella capitata. This indicated that the benthic habitat in the Laizhou Bay had been disturbed and polluted to some extent. The comparison of the three indices evaluation result and the RDA analysis showed that the H′ and M-AMBI were more suitable when the relative abundance of the single species was high and the macrobenthic community was significantly imbalanced; when the relative abundance of opportunistic species(EGIV and EGV) was high, the AMBI and M-AMBI could reflected the EQS objectively; in an undisturbed and polluted environment, all the three indices could indicate the benthic habitats quality. In summary, the better correlation between the three indices and environmental factors showed that they were well responsive to the tendency of the benthic habitats quality in the Laizhou Bay. 相似文献
993.
内流对海底管线涡致振动与疲劳寿命的影响 总被引:2,自引:0,他引:2
在复杂的海洋环境条件下,管道的动力学特性受到内外部流体的作用而呈现出新的特点。本文通过对处在海底平稳流动作用下的悬跨管道的涡致振动进行分析,特别地考虑到管道内部流动的作用,给出了内流速度对管道响应幅度的影响,进而指出其对管道疲劳的意义。 相似文献
994.
995.
Relationship between deep-sea fish distributions and oceanic conditions of the East China Sea 总被引:2,自引:0,他引:2
Shen Jin''ao 《海洋学报(英文版)》1994,13(4):535-550
Relationshipbetweendeep-seafishdistributionsandoceanicconditionsoftheEastChinaSea¥ShenJin'ao(ReceivedNovember17,1993;accepted... 相似文献
996.
Based on the time-dependent mild slope equation including the effect of wave energy dissipation, an expression for the energy dissipation factor is derived in conjunction with the wave energy balance equation. The wave height of regular and irregular waves is numerically simulated by use of the parabolic mild slope equation considering the energy dissipation due to wave breaking. Comparison of numerical results with experimental data shows that the expression for the energy dissipation factor is reasonable. The effects of the wave breaking coefficient on the breaking point and the distribution of wave height after breaking are discussed through the study of a specific experimental topography. 相似文献
997.
- The ultimate strength analysis of offshore jacket platforms is a research project which has been developed in recent years. With the rapid development of marine oil industry, the departments of design and IMR (Inspection, Maintenance and Repair) in the offshore engineering have attached great importance to this project. The research procedure applies to both the stress check of new design platforms and the whole safety assessment of existing platforms. In this paper, we combine the pseudo non-linear technique with the linear analysis program and successfully analyze the ultimate strength of the space frame structure subject to the concentrated load and a real jacket platform subject to the dead load and environmental load. 相似文献
998.
999.
On the deep sea demersal fish communities of the East China Sea 总被引:1,自引:0,他引:1
Cluster analysis of data on the species similarity index offish samples taken at various sampling stations of different depths by the R /V " Dongfang " of the East China Sea Fisheries Research Institute, Chinese Academy of Fisheries Science, during the deep sea demersal fish resources survey in May - November, 1981, showed deep sea demersal fish fauna of the western part of the East China Sea can be grouped into the following communities :1)The outer continental shelf community ,2)The continental slope community, and3)The western Okinawa Trough community .The authors found that not only the species diversity index, but also the species similarity index are important criteria to reflect the structure of biotic community. 相似文献
1000.
江汉平原水质性缺水问题日益突出,识别江汉平原地下水流系统分布模式,对地下水资源的合理利用与保护具有重要意义.选取江汉平原典型区域,综合水文地质条件、水动力场及水化学同位素指标深入分析地下水补给过程、水岩作用及滞留时间.得出由于碳酸盐岩的溶解,研究区的地下水化学类型属于HCO3-Ca (Mg)型.地下水中典型离子随深度增加逐渐降低,同位素随深度增加逐渐偏负,表现出地下水流系统呈局部与区域水流系统的特点,系统深度界限在10~20m.独立而复杂的局部水流系统在平枯水期地下水向河渠地表水排泄.根据3H的含量,局部水流为现代水,水循环交替迅速.受地形控制,中深层地下水总体由西和西北向东和东南径流,汇入汉江和长江,为区域水流系统.由于补给源的高程效应,区域水流的18O值存在明显分区,指示不同的补给来源与水流路径.山前丘陵区基本为现代水,向平原腹地纵深至汉江和长江排泄区,地下水年龄在几百年至6000a不等,水循环交替缓慢.研究发现江汉平原低洼排泄区存在区域水流的顶托补给,可为原生劣质水的分布与聚集研究提供依据. 相似文献