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21.
采用浅水Ⅰ型浮游生物网,分别于2017年春、夏、秋和冬季在渤海湾海域采集浮游动物,基于网采样品数据分析了桡足类群落的组成种类、生物多样性和丰度分布特征及环境因子与桡足类群落特征之间的关系。结果如下:调查海域共出现桡足类20种,其中秋季种类最多达到13种,春季和冬季分别为12种和9种,夏季最少为8种。渤海湾海域桡足类丰度的平均值在春季最高,达到了882.5 ind/m3。夏季和秋季分别为84.0 ind/m3和48.4 ind/m3。冬季最低,为11.8 ind/m3。桡足类在秋季时,其香农-威纳指数和物种丰富度指数的平均值达到了最高,夏季时桡足类的香农-威纳指数平均值达到了最低,桡足类在春季时,其物种丰富度指数的平均值达到了最低。通过分析环境因子与桡足类丰度间的相关性,结果显示:温度、盐度、溶解氧、磷酸盐、硅酸盐、pH和浊度等环境因子会对渤海湾海域桡足类群落结构的季节变化产生显著影响。春季桡足类丰度的总体分布趋势与叶绿素水平分布的趋势相似;夏季和冬季桡足类丰度的总体分布趋势与温度水平分布的趋势相似;秋季桡足类丰度的总体分布趋势与温度水平分布的趋势相反。  相似文献   
22.
海山区浮游生态学研究   总被引:10,自引:7,他引:3  
本文综述了海山浮游生态学研究的现状。海山是大洋中常见的地形单元,在有的海山附近鱼类和底栖生物的生物量比周围大洋中要多,针对这些鱼类和底栖生物的饵料来源提出了三种假说,第一种假说认为海山区特殊的物理环境导致初级生产力较高(经典假说),第二种假说认为海山区的饵料不是本地生产的,地形和流场使得外来的浮游生物在海山区富集或通量加大(外来营养补充假说),第三种假说认为海山上部的颗粒有机物营养较高,是鱼类和底栖生物的营养来源之一(颗粒有机物补充假说)。对海山浮游生态学的研究基本围绕这几个假说进行。目前只在9座海山进行了浮游生态学研究,这些研究表明单个假说并不能解释海山附近鱼类生物量较大的现象,海山鱼类和底栖生物的营养来源可能有很多,这些假说阐述的机制并不互相矛盾,海山生物之间的营养关系也比原来想象的复杂得多。已有研究都是针对其中某个假说进行验证研究,建议我国即将进行的海山浮游生态学研究针对三种假说进行海上调查,以提供完备的数据支持。  相似文献   
23.
The identification of scallop larvae is essential to understand the population structure and community dynamics and to assess the potential environmental impacts caused by scallop larvae released or escaped. However, the larvae identification by morphological characteristics is notoriously difficult, mainly due to the small size (usually being less than 150 μm) and vague morphological characteristics among different scallop species. A simple and accurate molecular method was developed to identify four economically farmed scallop species, the Zhikong scallop Chlamys farreri, the noble scallop C. nobilis, the bay scallop Argopecten irradians and the Yesso scallop Mizuhopecten yessoensis. The tests used the high degree of species-specific microsatellite markers, which was specified by transferability analyses, assessed by reference individuals and evaluated by BLAST searches. The sensitivity test indicated that the species-specific microsatellites were sensitive enough for the detection of 1% -2% larvae in mixed plankton samples. Larvae collected from scallop hatcheries and their effluents and from the artificially controlled crosses were well identified to the species/hybrid level. The results demonstrated that the one-step PCR-based assay was technically simple, inexpensive and robust in identification analyses, and also less sensitive to initial quality of template DNA extracted from the ethanol-preserved samples for several years.  相似文献   
24.
使用标准化壳体重量法和传统壳体重量法分别对中国南海(South China Sea,简称SCS)站表层沉积物和MD06-3052岩心沉积物样品进行了测试,获得了浮游有孔虫种属Globigerinoides ruber(G. ruber)的标准化壳体重量和传统壳体重量.通过对SCS站表层沉积物中G. ruber标准化壳体重量与传统壳体重量的比较,认为在该海域使用标准化壳体重量替代性指标能够更好的排除壳体粒径的干扰.通过对MD06-3052岩心中G. ruber标准化壳体重量与南极Vostok冰心的CO2浓度(pCO2)曲线进行对比,认为标准化壳体重量方法能够较好的反映出表层海水[CO32-]的变化.标准化壳体重量方法快速简便,指示性好,在探讨晚更新世以来表层海水在全球碳循环的重要作用中,是一个很有潜力的指标.   相似文献   
25.
Abstracts Species abundance and seasonal succession of copepods in saline-alkaline ponds were studied in Zhaodian Fish Farm, Gaoqing County, Shandong Province, from 5 April 1997 to 1 September 1998. The results indicated that in the conditions of salinity ranging from 1.36 to 20 g/L, total alkalinity changing from 2.4 to 7.2 mmol/L and pH 8-9, zooplankton in saline-alkaline ponds was composed of freshwater salt-tolerated species or halophile species, some of which are halobiont species and usually occurs in freshwater. In our study, copepods were predominant in many fish-culture ponds and all control ponds without fishes in spring, late autumn and early winter. Dominant species of copepods were Sinocalanus tenellus, Cyclops vicinus, Thermocyclops taihokuensis. The biomass of copepods in the control ponds without fishes was higher than that of the fish-culture ponds.  相似文献   
26.
Northward flowing coastal currents along the western margin of India during winter–spring advect low-salinity Bay of Bengal water in to the Eastern Arabian Sea producing a distinct low-salinity tongue, the strength of which is largely governed by the freshwater flux to the bay during summer monsoons. Utilizing the sedimentary records of δ18OG. sacculifer, we reconstructed the past salinity-gradient within that low-salinity tongue, which serves as a proxy for the variation in freshwater flux to the Bay of Bengal and hence summer monsoon intensity.The north–south contrast in the sea level corrected (residual)-δ18OG. sacculifer can be interpreted as a measure of surface salinity-contrast between those two locations because the modern sea surface temperature and its past variation in the study region is nearly uniform. The core-top residual-δ18OG. sacculifer contrast of 0.45‰ between the two cores is assumed to reflect the modern surface salinity difference of 1 psu and serves as a calibration for past variations.The residual-δ18OG. sacculifer contrast varies between 0.2‰ at 75 ky B.P. (i.e., late-Marine Isotope Stage 5) and 0.7‰ at 20 ky B.P. (i.e., Last Glacial Maximum), suggesting that the overall salinity difference between the northern- and southern-end of the low-salinity tongue has varied between 0.6 and 1.6 psu. Considerably reduced difference during the former period than the modern suggests substantially intensified and northward-extended low-salinity tongue due to intense summer monsoons than today. On the other hand, larger difference (1.6 psu) during the latter period indicates that the low-salinity tongue was significantly weakened or withdrawn due to weaker summer monsoons. Thus, the salinity-gradient in the eastern Arabian Sea low-salinity tongue can be used to understand the past variations in the Indian summer monsoons.  相似文献   
27.
文章以南海北部ODP1146站沉积物岩芯为研究材料,利用浮游有孔虫次表层水种Pulleniatina obliquiloculata壳体的氧、碳稳定同位素,结合该站位浮游及底栖有孔虫氧碳同位素数据,分析中更新世以来南海北部上层水体结构的演化。1.2 Ma以来ODP1146站P.obliquiloculata壳体δ^18O的变化可分3个阶段:1)1.2~0.9 Ma,冰期-间冰期变化幅度较小、主导周期为41 ka斜率周期;2)0.9~0.6 Ma,冰期旋回变化幅度逐渐增强、100 ka偏心率周期开始强化;3)0.6 Ma以来,冰期旋回呈现稳定且幅度较大的100 ka周期变化。0.9 Ma以来南海北部上层海水δ^18O的冰期旋回变幅增强,可能反映东亚冬季风在0.9 Ma之后显著强化。其中,表层水体δ^18O只在冰期变幅增强,P.obliquiloculata所反映的次表层水体δ^18O的变化幅度在冰期和间冰期都显著增强。约0.9 Ma浮游和底栖有孔虫δ^18O的100 ka周期几乎同时显现;但在0.9~0.6 Ma时期P.obliquiloculata的δ^18O偏心率周期更为显著、斜率周期的强度也更高。因此,冰期旋回周期转型及幅度变化两方面的证据共同反映温跃层结构演化在南海北部中更新世转型(MPT)气候转变过程中的特殊性。1.2 Ma以来ODP1146站P.obliquiloculata的δ^13C在0.02 Ma、0.49 Ma和0.99 Ma左右呈明显的碳重值,同时表层种-次表层种之间的δ^13C差值减小到近于0,可以解读为碳重值事件期间南海北部生产力相对减弱。  相似文献   
28.
The B/Ca ratio of planktonic foraminifer shells has been used as a proxy for reconstructing past ocean carbonate chemistry. However, recent studies have revealed significant uncertainties associated with this proxy, such as whether seawater temperature or [ CO_3~(2-)] is the dominant control on the partition coefficient(K_D) of planktonic foraminiferal B/Ca. To address these uncertainties and thus improve our understanding of the planktonic foraminiferal B/Ca proxy, we analysed B/Ca ratios in the tests of Neogloboquadrina dutertrei(300–355 μm) and Pulleniatina obliquiloculata(355–400 μm) in surface sediment samples from the tropical western Pacific and South China Sea. The relationship between these B/Ca ratios and bottom water calcite saturation states(Δ[ CO_3~(2-)]) is weak, thus suggesting only a small dissolution effect on the B/Ca of the two species. The correlation coefficients(R~2) between the B/Ca ratios of N. dutertrei and P. obliquiloculata and environmental parameters(e.g., temperature, salinity, phosphate, DIC and ALK) in the tropical western Pacific and South China Sea are not high enough to justify using B/Ca ratios as a palaeoenvironmental proxy in the study areas. The significant correlation between K_D values of N. dutertrei and P. obliquiloculata and carbonate system parameters(e.g.,[ CO_3~(2-)], DIC, ALK, pH and [ HCO_3~-]) in the study area reflect chemical links between the K_D denominator and these variables. Based on our surface sediment calibration, an empirical relationship between the K_D of N.dutertrei and temperature is proposed in the tropical western Pacific. We also generated a record of B/Ca ratios in N. dutertrei(300–355 μm) from Core MD06-3052 in the tropical western Pacific over the past 24 ka to evaluate the application of the revised B/Ca proxy method. Based on the reconstructed empirical relationship for B/Ca and subsurface seawater ALK, we estimated subsurface seawater carbonate system parameters in the tropical western Pacific since 24 ka. In general, the estimated subsurface seawater pH and [ CO_3~(2-)] show an increase with time, and the record of subsurface seawater pCO_2 shows a decrease with time, in the tropical western Pacific over the past 24 ka. The consistent trends in subsurface seawater pCO_2 and opal flux during deglaciation may imply that the reported increase in subsurface water pCO_2 in the study area was promoted by enhanced upwelling in the Southern Ocean.  相似文献   
29.
在对台湾以北海域浮游桡足类生物海洋学特征进行数量分布方面的研究后的续篇,重点对本海区浮游挠足类的群落结构和群落性质以及与栖区环境条件间的关系作了分析探讨.结果表明,本区桡足类群落结构种类组成复杂,出现种类共237种,但周年共有种比例仅占32%.桡足类群落的多样度和均匀度年均值各为3.714和0.690,在平面分布上呈外部海区高于近岸海区的大体趋势.本区群落可划分为5个生态类群,其中暖水性外海高温偏低盐类群和热带大洋高温高盐类群可分别指示台湾海峡水和黑潮表层水的季节消长过程.从不同侧面的计算分析均表明,冬季在环境条件上均有异于其他3季.在春、夏、秋季,以普通波水蚤最具优势,盐度是影响群落特征值的主导因子,群落的性质是以暖水性外海种类为主、热带大洋种也占相当比例的亚热带-热带群落结构的特点;在冬季,主要优势种是海洋真刺水蚤,温度是群落特征值的主要制约因子,群落呈现以热带大洋种占支配地位的热带大洋群落结构属性.  相似文献   
30.
对西太平洋暖池核心区MD01—2386柱状样最上部5m进行了高分辨率的浮游有孔虫Globigerinoides ruber和Pulleniatina obliquiloculata的氧、碳稳定同位素分析,结合AMS^14C测年,研究表明其属于末次盛冰期-全新世的沉积。赤道西太平洋海区末次盛冰期以来δ^18O值显著降低,但有几次回返事件。表层浮游有孔虫G.ruber比次表层温跃层属种P.obliquiloculata对于环境变化的响应要快,但后者变化的幅度较大。这两个种的氧、碳同位素差值反映出温跃层深度自末次盛冰期以来逐渐加深,并存在周期性的回返事件,说明西太平洋暖池晚第四纪冰期旋回存在气候不稳定性。  相似文献   
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