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341.
东海浮游动物量的分布特征   总被引:7,自引:5,他引:7  
浮游动物生物量属于海洋次级生产力的范畴,在海洋食物链中是极其重要的环节。对其生产力大小的探讨,可以评价海洋渔业资源的潜力和开发远景,由此可以看出浮游动物生物量,是渔场调查中必要的基础资料。东海是我国海洋渔业十分重要的开发区域。这里有鲐鲹等中上层鱼类;有带鱼、大黄鱼、小黄鱼等底层鱼类。这些鱼类都有比较广泛的食性[2,3],在它们发育早期或者直到成年阶段,必须有依赖浮游动物为食的时期。因此浮游动物的数量分布与经济鱼类的幼鱼或成鱼的数量分布都有密切的关系。本文根据为1971年7月至1974年6月,共历时4年,在北纬27°—32°、东经127°以西海区所进行的35个航次,1577个测站的调查资料。采集系用大型浮游动物网(口径80厘米,网目每厘米15个)由底到表垂直拖网。  相似文献   
342.
本文采用PD、GPY、YES、SYE、GPM5种不同培养基培养海藻真菌菌株PT2,并对其在不同培养基中的生长情况、代谢产物的形成及抗肿瘤活性进行分析,旨在了解不同培养基对菌株生长和活性物质合成的影响.结果显示,PT2菌株在不同培养基上的培养特征及生长速率有所不同,液体培养基发酵液抽提物的抗肿瘤活性也有较大差别,其中SYE发酵液抽提物活性最强,对KB、Raji和Hela 3种肿瘤细胞的IC50分别为7.6μg/cm^3、2.4μg/cm^3和3.3μg/cm^3.采用HPLC法对不同抽提物进行分析,发现它们之间的组成成分有显著差异.本文的实验结果表明,不同培养基对该菌株的生长及活性代谢产物的合成具有显著的影响。  相似文献   
343.
Abstract-Heat content of the upper layer above the 20℃ isotherm in the tropical Pacific Ocean isestimated by using the sea temperature data set with a resolution 2°latitude×5°longitude (1980~1993)for the water depths (every 10 m) from 0 m to 400 m, and its temporal and spatial variabilities are an-alyzed. (1) The temporal variability indicates that the total heat in the upper layer of the equatorial Pa-cific Ocean is charcterized by the interannual variability. The time series of the equatorial heat anomaly5 months lead that of the El Nino index at the best positive lag correlation between the two, and theformer 13 months lag behind the latter at their best negative lag correlation. Therefore the equatorialheat content can be used as a better predictor than the El Nino index for a warm or cold event. In addi-tion, it is also found that less heat anomaly in the equator corresponds to the stronger warm events inthe period (1980~1993) and much more heat was accumulated in the 4 years including 1992/1  相似文献   
344.
本文利用收集到的实测双峰谱型海浪过程资料,把这些资料以波高和周期的相关系数为参数分成5组,讨论每组双峰谱型下被高、周期的统计分布.并探讨了相关系数对波高分布和周期分布的影响。  相似文献   
345.
西太平洋暖池区海—气通量计算分析   总被引:4,自引:0,他引:4  
用J.Launiaimen和T.Vihma提出的近地面层湍流通量计算方法,对我国在1992年11月至1993年2月TOGA—COARE—IOP实验中所获资料计算处理。得出所在站位的海一气间显效、潜热及动量通量。指出西大平洋暖池海区游热通量与显效通量之比为10.14:1;风速大于8m/s后各通量随风速的变化率明显增加;动量与热量的块体通量系数Cd和Ce,h随风速变化有相似的规律;Monin—Obukhov大气稳定度参数Z/L与△T/U_(10)之间有较好的统计关系。  相似文献   
346.
本文以粤西水东湾表层沉积物样品的粒度分布为基本数据,使用对应分析方法并结合地形与波流特征,分析了海湾动力沉积环境。分析结果表明,海湾现代沉积环境可划分为4个动力沉积区。  相似文献   
347.
本文提出河流携带入海的沉积物或沿岸剥蚀物中矿物的分布及再组合是受多种因素控制的。为了确定控制鲁南两城河至白马河沉积物样品中矿物分布及再组合的主要因素,作者对该区109个沉积物样品的重矿物资料进行了Q型和R型因子分析。研究指出,在诸多的河流中,白马河和两城河是控制该区沉积物分布的最上要的河流;矿物的化学稳定性是决定该区矿物再组合的主要因素。  相似文献   
348.
High precision geoid models HKGEOID-2000 for Hong Kong and SZGEOID-2000 for Shenzhen, China, have been developed with a hybrid approach of so-called sequential processing, using high precision GPS/leveling data, land and sea gravity anomalies, and digital terrain models. These two local geoid models have the same 1-km resolution. The estimated accuracy (external accuracy) is better than 1.7 cm for HKGEOID-2000 and 1.4 cm for SZGEOID-2000. Some common areas are covered by HKGEOID-2000 and SZGEOID-2000. So these two geoid models, along with high quality GPS/leveling data collected on the overlapping areas, can be used to detect the systematic bias between HKGEOID-2000 and SZGEOID-2000, as well as the difference between Hong Kong Principal Datum and 1956 yellow sea height datum of China, yielding RMS errors of 1.011 m and 1,003 m, respectively. Moreover, HKGEOID-2000, along with GPS ellipsoidal heights, is employed to determine the errors of the “orthometric heights” from purely trigonometric heighting, yielding an RMS error of 0.102 m. The combination of SZGEOID-2000 and GPS ellipsoidal heights has been used to replace the traditional spirit leveling and mapping, called GPS mapping.  相似文献   
349.
Diagnosis of iridovirus in large yellow croaker by PCR   总被引:1,自引:0,他引:1  
A rapid and sensitive PCR-based method for the detection of the large yellow croaker iridovirus(LYCIV) is described,which involves the amplification of a 295 bp fragment of the LYCIV ATPase gene from DNA isolated from naturally infected fish spleen.Sequencing of LYCIV ATPase gene fragment showed it shared 100% nucleotide sequence homology with the corresponding region of the ATPase gene of red sea bream iridovirus(RSIV) and sea bass iridovirus(SBIV),suggesting that LYCIV was homologous with RSIV and SBIV at least in part of the gemone.The specificity and sensitivity of the PCR procedure were tested on the iridovirus-infected fishes,the expected fragment was detected from spleen DNA samples of infected fishes,whereas no fragments were amplified from healthy fish spleen DNA,white spot syndrome baculoviruses(WSBV) DNA and pseudorabies virus(PRV) DNA.Detection limit of this method was 10-7 ng positive plasmid DNA containing target sequence,equal to about 100 virions.In the infected experiment,first positive detection(1/4) appeared at Day 3 post-infection,all fish(4/4) tested positive at Day 7,however obvious symptoms were observed at Day 8,so LYCIV infection could be detected prior to the appearance of obvious symptoms.These results indicate that this PCR method could be used for early,rapid and specific detection of LYCIV infection.  相似文献   
350.
The effects of scattering and resonance on the energy dissipation of an internal tide were investigated using a two-dimensional model which is a reassembled version of the theoretical generation model devised by Rattray et al. (1969) for internal tide. The basic character of the scattering process at the step bottom was first investigated with a wide shelf model. When the internal wave incited from a deep region (Region II) into the shallow shelf region (Region I), a passing wave into the shallow region, a reflected wave into the deep region, and a beam-like wave, i.e. a scattered wave (SW), emanated at the step bottom. The SW, which consists of the superposition of numerous internal modes, propagated upward/downward into both regions. The general properties of the SW were well expressed around the shelf edge, even in the present model with viscosity effect. The amplitude of the SW decreased dramatically when the depth of the velocity maximum of the incident internal wave in Region II corresponded with the depth of the shelf edge. In the narrow shelf model, where the decay distance of the internal wave in Region I is longer than the shelf width, the incident internal wave reflected at the coast to form a standing wave. When the internal wave in Region I is enhanced by the resonance, the energy of the SW in Region II is also intensified. Furthermore, the energy of the modes in Region II predominated when the velocity maximum is identical to that of the dominant mode in Region I. These results suggest that the spatial scale of shelf region is a very important factor governing the energy dissipation of the internal tide through reflection and scattering in a narrow shelf.  相似文献   
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