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21.
选取长白山火山碎屑喷出物(火山灰)和熔岩(浮岩、碱流岩、黑曜岩),对其进行岩石地球化学分析以确定其源区、演化过程和构造环境。研究表明,长白山火山碎屑喷出物和熔岩属于钾玄岩系列和高钾钙碱性系列,富K_2O+Na_2O,并具有高K_2O以及较高的Fe_2O_3含量,低CaO、MgO、TiO_2、P_2O_5和MnO含量,Mg#值变化范围为0.02~0.10,A/CNK的平均值为0.82,属于偏铝质岩石,稀土元素(REE)相对富集,轻重稀土分异强烈、轻稀土(LREE)相对富集、重稀土(HREE)亏损,铕负异常[δ(Eu)=0.04~0.15],大离子亲石元素(LILE) K、Sr、Ba等相对亏损,高场强元素(HFSE) Th、U、Ta、Nb、Hf相对富集,P、Ti等强烈亏损,Rb/Sr比值为3.23~93.33,在岩浆岩成因类型判别图上,所有样品均落在A型花岗岩区域内,说明其具有A型花岗岩成分特征。根据前人研究成果和本文所述的地球化学分析结果,可以说明长白山火山碎屑喷出物和熔岩可能起源于幔源岩浆的分异演化,在上侵时混染了地壳组分。长白山火山碎屑喷出物和熔岩形成于非造山板内拉张环境。  相似文献   
22.
In 2008,a green tide broke out before the sailing competition of the 29th Olympic Games in Qingdao.The causative species was determined to be Enteromorpha prolifera (Ulva prolifera O.F.Müller),a familiar green macroalga along the coastline of China.Rapid accumulation of a large biomass of floating U.prolifera prompted research on different aspects of this species.In this study,we constructed a nonnormalized cDNA library from the thalli of U.prolifera and acquired 10 072 high-quality expressed sequence tags ...  相似文献   
23.
The distribution and abundance of euphausiid larvae and salps was studied from samples collected in 2002 and 2006 from Prydz Bay, Antarctica.Larvae of Thysanoessa macrura and Euphausia superba were mainly distributed in the north of the continental shelf. T. macrura was more abundant and had a relatively wider distribution. In 2006, with ice having retreated and higher seawater temperatures and chlorophyll a levels, E. superba and T. macrura occurred in higher abundances and at more mature developmental stages. Euphausia crystallorophias was mainly distributed in the neritic region. In 2002, with severe ice conditions in the neritic region, abundance of E. crystallorophias was consisted of metanauplius (MN) and calyptopis I (CI). Salps, mostly Salpa thompsoni, had a low abundance in Prydz Bay. In 2002, S. thompsoni was only m)-3. In 2006, S. thompsoni was found at three stations located near the contimental factors, such as the timing of ice melt, polynya formation and food concentration appear to have a marked effect on the distribution and abundance of euphausiid larvae and salps.  相似文献   
24.
黄海中华哲水蚤C5发育期油脂积累初步研究   总被引:3,自引:2,他引:1       下载免费PDF全文
根据9个黄海调查航次的数据,研究了黄海中华哲水蚤C5发育期油脂积累的区域、季节变化,并探讨了中华哲水蚤油脂积累对其生理、生活史的可能作用。在黄海近岸海域,中华哲水蚤C5期油囊体积常年较小;而在陆架海域则表现出明显的季节差异。在陆架区,C5期的油囊体积与度夏过程联系密切:最大油囊体积(可占前体部体积的30%以上)出现于度...  相似文献   
25.
2011 年夏季胶州湾三种大型水母的种群动态研究   总被引:1,自引:3,他引:1  
2011年8月1日-9月30日,对胶州湾三种大型水母沙海蛰(Nemopilema nomurai)、白色霞水母(Cyanea nozakii)、海月水母(Aurelia aurita)的种群数量变动及空间分布情况开展了目测调查,同步获得了气象、水温、盐度、叶绿素a、浮游动物丰度、种类组成等数据,调查频率为每周2次。调查期间,海月水母表现出逐渐降低的趋势,沙海蛰与白色霞水母种群均于8月11日达到数量高峰,8月底及9月中旬之后依次衰落,至9月底,三种水母基本消失。三种水母的种群平均丰度变化范围分别为:沙海蛰0-230.8ind/km2;霞水母0-150.2ind/km2;海月水母0-123.4ind/km2。从分布区域来看,海月水母主要位于近岸区,沙海蜇主要分布于湾口和中部深水区,而白色霞水母则在高峰期和次高峰期分别集中于深水区和近岸区。结合往年资料,作者认为,海月水母种群能够在胶州湾内进行自我补充并完成其生活史,而胶州湾沙海蛰与霞水母的种群补充则可能主要依赖于湾外种群。另外,目测方法的准确性可能受到气象条件的影响。  相似文献   
26.
胶州湾毛颚类生态学研究   总被引:4,自引:0,他引:4  
王倩  孙松  霍元子  杨波 《海洋与湖沼》2010,41(4):639-644
根据2006年9月—2007年8月胶州湾浅水Ⅰ型浮游生物网的调查资料,分析了胶州湾毛颚类的种类组成、数量分布、摄食、生物量、生产力情况。结果表明,本次调查共出现毛颚类3种:强壮箭虫(Sagitta crassa)、拿卡箭虫(Sagitta nagae)和百陶箭虫(Sagitta bedoti)。其中强壮箭虫全年出现,在数量上占有绝对优势,年平均密度达到45.3ind/m3;拿卡箭虫和百陶箭虫在秋、冬、春季出现,年平均密度分别为0.17ind/m3和0.35ind/m3。通过推算得到胶州湾毛颚类年平均生物量为107.92mg/m2,年平均生产力为1.47mgC/(m2·d),占浮游动物总生产力的11.6%。毛颚类对浮游动物生物量和生产力的摄食压力在冬季达到全年最大值,分别为5.71%和83.47%,在春季、夏季、秋季毛颚类对浮游动物生物量的摄食压力分别为0.67%、0.08%、6.48%,对生产力的摄食压力分别为27.00%、2.48%和48.88%。由此可见,在冬季毛颚类的摄食对浮游动物群落结构等可能会产生重要影响。  相似文献   
27.
本文依据 1 989/1 990和 1 990 /1 991夏季 ,“极地”号考察船在普里兹湾邻近海域 (南大洋的印度洋区 )的拖网样品 ,对大磷虾的性腺发育和生殖群体的年龄结构等 ,进行了分析研究。大磷虾的生殖开始于 1月 ,一直持续到 3月。高峰期出现在 2月中旬 ,比大西洋区相比迟了一个月。生殖群体主要包括两个年龄组 ,即 3 + 龄和 4+ 龄。换句话说 ,绝大部分个体是三年性成熟 ,一生可生殖两次 ,不排除少数个体两年性成熟 ,或第三次性成熟的可能 ,但比例非常小。在 5 91 6尾能区分性别的个体中 ,雄性个体只占 3 4 .1 %。雄性比随体长的增加而降低。体长大于 5 0 mm的个体中雄性仅占 2 2 .9%。  相似文献   
28.
基于脂肪酸标记的长江口海区浮游动物常见种食性分析   总被引:5,自引:0,他引:5  
金鑫  李超伦  孙松  刘梦坛 《海洋与湖沼》2012,43(6):1083-1090
脂肪酸不仅是浮游动物的重要组分,也被作为生物标记来指示动物的食物组成及其之间的营养关系。本文运用脂肪酸标记法对长江口附近海区6个浮游动物常见种的食性进行了分析。研究结果表明,中华哲水蚤(Calanus sinicus)雌体和桡足幼体都表现出明显的植食性。但雌体中16:1ω7的含量要明显高于18:4ω3,表明雌体对硅藻的摄食较多;桡足幼体的18:4ω3要高于雌体,说明桡足幼体对甲藻的摄食较多。磷虾(Euphausia spp.)的多不饱和脂肪酸(PUFA)和ω3系列脂肪酸的含量很高,说明其作为饵料可以给摄食者提供较多的脂类营养物质。中华哲水蚤和磷虾较低的22:6ω3/20:5ω3比值说明他们的营养地位较低。箭虫(Sagitta spp.)的20:1和22:1脂肪酸含量很高,指示了其对植食性桡足类的摄食。蝶水母(Ocyropsis crystallina)、瓜水母(Bero cucumis)和四叶小舌水母(Liriopetetraphylla)的20:1+22:1脂肪酸所占比例较高,指示了其对植食性桡足类的摄食,但是水母类的总脂肪酸含量都很低。几种水母和箭虫的22:6ω3的含量要明显高于20:5ω3的含量,说明它们在浮游食物网中具有较高的营养地位。  相似文献   
29.
We used long term monitoring data to evaluate changes in abundance and species dominance of small-jellyfish (collected with zooplankton net whose bell diameter was less than 5 cm) between 1991 and 2009 in the Jiaozhou Bay, China. Zooplankton samples were vertically towed with conical plankton net from near-bottom to surface, identified microscopically, and mapped in time-space using Grapher 7.0 and Surfer 8.0. Results show that the abundance of small-jellyfish throughout the bay had been increasing during 2001-2009 on average of 15.2 ind./m 3 , almost 5 times higher than that between 1991 and 2000. The occurrence of peak abundance shifted from spring to summer after 2000, and two peaks appeared in spring and summer, respectively, after 2005. Both the abundance and the frequency of blooms of small-jellyfish increased after 2000 in the bay. In addition, the biodiversity of jellyfish has increased significantly in recent years with a change in dominant species. Several new dominant species appeared after 2000, including Rathkae octopunctata in winter, Phialidium hemisphaericum in spring, summer, and autumn, Phialucium carolinae in spring, and Pleurobrachia globosa in summer and autumn, while some previous dominant species throughout the 1990s (Eirene ceylonensis, Zanclea costata, Lovenella assimilis, and Muggiaea atlantica) were no longer dominant after 2000. The abundance of small-jellyfish was positively correlated with the density of dinoflagellates, and the abundance of zooplankton. We believe that the changes in smalljellyfish abundance and species composition were the result of eutrophication, aquaculture and coastal construction activities around the bay. Concurrently, seawater warming and salinity decrease in recent decades promoted the growth and reproduction of small-jellyfish in the bay.  相似文献   
30.
Zooplankton abundance, biovolume and taxonomic composition in Jiaozhou Bay and the adjacent coastal Yellow Sea were evaluated using ZooScan measurement of samples collected by net towing every August from 2005 to 2012. Zooplankton abundance and biovolume ranged from 1 938.5 to 24 800 ind./m~3 and 70.8 to 1 480.1 mm~3/m~3 in Jiaozhou Bay and 73.1 to 16 814.3 ind./m~3 and 19.6 to 640.7 mm~3/m~3 in the coastal Yellow Sea. Copepods were the most abundant group in both regions, followed by N octiluca scintillans and appendicularians in Jiaohzou Bay, and chaetognaths and N octiluca scintillans in adjacent coastal Yellow Sea. Over the study period, the most conspicuous hydrographic change was an increase in water temperature. Meanwhile, a general decrease in zooplankton abundance was observed, particularly in copepod populations. Based on redundancy analysis(RDA), the warming trend was the key environmental factor influencing to decrease of copepod abundance. The proportion of small-sized copepods increased while the mean size of all copepods decreased, in significant correlation with water temperature. Our results indicate that zooplankton, particularly copepods, are highly sensitive to change in water temperature, which is consistent with predicted impacts of warming on aquatic ectotherms. Due to their dominance in the zooplankton, the decline in copepod size and abundance could lead to an unfavourable decrease in energy availability for predators, particularly planktivorous fish.  相似文献   
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