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331.
对虾养殖生态系中有机碳的初步研究本研究由 总被引:1,自引:0,他引:1
对于围隔养殖对虾生态系中有机碳的变动进行了研究 ,结果表明 :溶解有机碳 (DOC)含量波动在 5 .2 99~ 13.39mg/ L之间 ,平均为 8.5 3mg/ L± 2 .2 5 mg/ L;颗粒有机碳 (POC)含量波动在0 .6 5~ 6 .6 3mg/ L之间 ,平均为 3.2 5 mg/ L± 1.76 mg/ L;总有机碳 (TOC)含量波动在 6 .92~ 2 0 .0 2mg/ L之间 ,平均为 11.78mg/ L± 3.82 mg/ L ;其中 DOC∶ POC∶ TOC为 0 .72∶ 0 .2 8∶ 1。各种有机碳组分的含量明显高于自然海水中各种有机碳的含量 ;各种有机碳组分的含量在养殖期间总体上呈上升的趋势 ;其变化与 DCOD的变化呈显著线性正相关的关系。 相似文献
332.
本文在总结和比较中国现有黄海、东海海域漫衰减系数反演算法的基础上,利用水色测量数据分析得到漫衰减系数Kd(532)与Kd(490)之间的关系,为激光测深系统(以CZMIL为例)的性能评估提供了基础。利用MODIS二级数据产品评估了中国黄海、东海海域在CZMIL海道测量模式下最大可测水深的空间分布。研究结果表明CZMIL在黄海、东海海域可测水深基本在0—50 m,该区域的面积占研究区域面积的比例为76.2%,为浅海海域开展激光测深作业提供了测深能力评估的依据和方法。 相似文献
333.
334.
Study of zooplankton ecology in Zhejiang coastal upwelling system-Zooplankton biomass and abundance of major groups 总被引:1,自引:0,他引:1
He Dehu Yang Guanming Fang Shaojin Shen Weilin Liu Hongbin Gao Aigen Huang Shuxin 《海洋学报(英文版)》1988,7(4):607-620
The studied area is a shallow water area that belongs to the East China Sea continent shelf. The distribution of zooplankton biomass is higher inshore than offshore. The maximum abundance is in the inshore edge of the centre of upwelling, which is the superposed area of the salinity front and temperature front, due to the fact that the mixture of three different waters has brought about a concentration of nutrients. The herbivorous Euphausia, Copepoda and Tunicata are the major groups of the abundant area. Tunicata possess the possibility to compete against other kinds of herbivorous zooplankton. This means that there is negative correlation between the distribution of Tunicata and that of Copepoda and Euphausia. The positions of maximum areas of zooplankton biomass, phytoplankton individual and the concentration of phosphates and chlorophyll-a overlap one another. In the centre of upwelling, zooplankton can not adapt itself to the environment of lower temperature and less oxygen even with rich nutrient 相似文献
335.
Storm surges pose significant danger and havoc to the coastal residents' safety, property, and lives, particularly at offshore locations with shallow water levels. Predictions of storm surges with hours of warning time are important for evacuation measures in low-lying regions and coastal management plans. In addition to experienced predictions and numerical models, artificial intelligence (AI) techniques are also being used widely for short-term storm surge prediction owing to their merits in good level of prediction accuracy and rapid computations. Convolutional neural network (CNN) and long short-term memory (LSTM) are two of the most important models among AI techniques. However, they have been scarcely utilised for surge level (SL) forecasting, and combinations of the two models are even rarer. This study applied CNN and LSTM both individually and in combination towards multi-step ahead short-term storm surge level prediction using observed SL and wind information. The architectures of the CNN, LSTM, and two sequential techniques of combining the models (LSTM–CNN and CNN–LSTM) were constructed via a trial-and-error approach and knowledge obtained from previous studies. As a case study, 11 a of hourly observed SL and wind data of the Xiuying Station, Hainan Province, China, were organised as inputs for training to verify the feasibility and superiority of the proposed models. The results show that CNN and LSTM had evident advantages over support vector regression (SVR) and multilayer perceptron (MLP), and the combined models outperformed the individual models (CNN and LSTM), mostly by 4%–6%. However, on comparing the model computed predictions during two severe typhoons that resulted in extreme storm surges, the accuracy was found to improve by over 10% at all forecasting steps. 相似文献
336.
大气边界层(Atmospheric Boundary Layer,ABL)是自由大气和地球表面(陆地和海洋)的连接层,它对于降水的发生发展有重要影响。ABL高度是ABL的一个重要参数,主要应用于大气数值天气(或气候)模式中的ABL过程的参数化,获取准确的ABL高度数据对于提高数值天气预报模式、空气污染物预报模式等的预报精度具有重要作用。概述了利用常规探空资料、卫星遥感资料、气溶胶后向散射资料、全球导航卫星系统GNSS (Global Navigation Satellite System)掩星探测资料等数据估计ABL高度的主要方法及进展情况,提出在同时具有多种观测资料时如何处理ABL高度的三个基本原则,并以目前广泛应用的数值天气预报模式WRF (Weather Research and Forecasting)为例重点介绍ABL高度数据在数值天气(或气候)预报模式中的应用,对相关的发展情况进行了总结展望。
相似文献337.
东海大陆架异养细菌的生态分布 总被引:4,自引:0,他引:4
从海洋物质循环的观点来看,异养细菌在分解有机物质和无机化过程中起着极重要的作用。从海洋食物链的角度来看,分解各种类型有机物而得以增殖的异养细菌自身也是海洋原生动物、浮游动物及底栖动物的营养源。异养细菌在海洋生态系中占有极重要的位置。对海洋中某些细菌的代谢活动与其他海洋生物之间的相互关系的研究日益受到普遍的重视。
海洋异养细菌的生态分布资料已有不少报道。但至今尚未有人发表过东海大陆架海域海洋微生物生态调查的报告。东海大陆架海域江河交汇人海,大陆对海洋的影响极为突出,水文和底质情况复杂,水产资源丰富,因而特别富有多样化的有机物来源。调查和了解这一海域中异养细薗生态分布规律,并研究其参与物质转化过程的特异性,不仅有助于深入研究海洋生态学问题,而且对于阐述东海大陆架的特点也极有价值。本文着重讨论异养细菌在东海大陆架的生态分布特征及菌群组成的特点。 相似文献
338.
Geochronology and geochemistry of leucosomes in the North Dabie Terrane, East China: implication for post-UHPM crustal melting during exhumation 总被引:1,自引:0,他引:1
Shui-Jiong Wang Shu-Guang Li Li-Juan Chen Yong-Sheng He Shi-Chao An Ji Shen 《Contributions to Mineralogy and Petrology》2013,165(5):1009-1029
Migmatites are widespread in the North Dabie ultrahigh-pressure metamorphic terrane (NDT) of Dabie orogen, East China. Idiomorphic and poikilitic amphibole grains in both leucosome and melanosome contain inclusions of plagioclase, quartz and biotite, suggesting formation of leucosome by fluid-present melting of biotite + plagioclase + quartz-bearing protoliths at P = 5–7 kbar, T = 700–800 °C. Precise SIMS zircon U–Pb dating indicates that migmatization of Dabie orogen initiated at ~140 Ma and lasted for ~10 Ma, coeval with the formation of low-Mg# adakitic intrusions in Dabie orogen. Based on mineralogical, petrographic and geochemical data, leucosomes in NDT can be subdivided into three groups. (1) High La/Yb(N)–Medium Sr/Y group (Group I), whose high Dy/Yb(N) but medium Sr/Y ratios are caused by amphibole and plagioclase residual during partial melting of dioritic to granodioritic gneisses. (2) Low La/Yb(N)–Low Sr/Y group (Group II), whose flat HREE patterns are produced by entrainment of peritectic amphiboles into melts derived from partial melting of dioritic gneiss. (3) High La/Yb(N)–High Sr/Y and Eu# group (Group III), whose extremely high Sr and Eu but low other REE concentrations are caused by accumulation of plagioclase and quartz. Although Group I and III fall in the adakitic fields on La/Yb(N)–Yb(N) and Sr/Y–Y diagrams, they are chemically distinct from contemporary high-pressure adakitic intrusions in Dabie orogen in a series of geochemical indexes, for example, lower Dy/Yb(N) and/or Sr/Y ratios at given La/Yb(N) ratio, lower Sr/CaO ratios, lower Rb concentration but higher K/Rb ratios. Therefore, leucosomes are produced by anatexis of the exhumed ultrahigh-pressure metamorphic rocks at middle crustal level, instead of partial melting of thickened lower crust with garnet-rich and plagioclase-poor residual. The coeval occurrence of migmatites and high-pressure adakitic intrusions in Dabie orogen indicates large-scale partial melting of middle to thickened lower crustal column in the early Cretaceous. The required heat source may be the mantle heat conducting through the lithospheric mantle whose lower parts have been convectively removed. 相似文献
339.
本文对菲尔德斯半岛群的划分提出了一个新的方案 ,时代从晚白垩世一直延续到中新世早期 ;新建立的半三角组系湖相沉积 ,孢粉及同位素年龄数据 (71 .3 +0 .3 Ma)均指示属晚白垩世后期 ,是目前所知菲尔德斯半岛出露最早的岩层 ,也是南极仅知的晚白垩世陆相沉积地层 ;据岩层区域分布、岩相及含古生物组分的差别 ,始新统化石山组可进而划分为上、下两部分 ,层型剖面仅代表该组下部地层 ,上部在别林斯高晋站油库附近出露较好 ;文中命名“苏菲尔角火山岩”以表示菲尔德斯半岛更新时代的火山活动 ,但尚需深入研究。 相似文献
340.