海洋沉积物病毒荧光计数法的优化     

维妙  徐奎栋 《海洋与湖沼》2017,48(3):516-526

病毒在海洋生态系统的物质循环和能流中起着重要作用,对其进行有效定量是研究其数量变动和生态功能的前提。现行的海洋沉积物病毒定量主要采用荧光染色计数法,但对技术流程中一些处理方法的定量效能尚待验证。本研究利用不同类型海洋沉积物对荧光计数法进行了效能评估和条件优化。结果表明:将沉积物采样后染色封片直接计数或-20°C保存为最佳,保存3个月后未见丰度降低。而不同类型的沉积物经液氮闪冻后于-80°C冷冻保存后的定量效能不同:沙质沉积物保存1个月后病毒丰度下降1个数量级;泥沙质沉积物保存1个月后丰度降低了约27%,2个月后则下降了60%。对焦磷酸钠最优终浓度实验结果显示,使用3mmol/L终浓度获得的病毒计数定量效能优于目前普遍使用的5mmol/L终浓度。水浴超声分离在常温下的定量效果更优,在水浴中添加冰块导致获取的沙质沉积物中的病毒丰度下降约37%。研究发现:处理中用稀释替代离心不仅可降低沉积物颗粒的干扰,而且定量效能更高;离心处理获取的沙质和泥沙质沉积物中的病毒丰度较稀释处理低约40%。对海洋沉积物中原核生物的定量效能与病毒有相似的结果。据此,本文提出了改进的沉积物病毒荧光计数法的操作流程。  相似文献   

The proposed introduction of the large‐mouth black bass micropterus salmoides (lacepede) into New Zealand     

R. M. McDowall 《新西兰海洋与淡水研究杂志》2013,47(2):149-161

Known characteristics of the largemouth black bass, Micropterus salmoides (Lacépède), in its natural habitats in North America and as an introduction in other areas are discussed in relation to the suggestion that the fish should be introduced into New Zealand. It is concluded that much more research on the New Zealand ecosystems is necessary before a realistic assessment can be made of the likely effects of the predatory bass on indigenous fish and on trout fisheries.  相似文献   

The distribution and morphology of tintinnids (ciliate protozoans) from the coastal waters around New Zealand     

D. A. Burns 《新西兰海洋与淡水研究杂志》2013,47(4):387-406

Tintinnids from the surface plankton of New Zealand coastal waters are illustrated with scanning electron micrographs. Brief notes are given on their taxonomy, and their use of silica grains, diatom valves, and coccoliths in construction of the lorica is discussed. Distributional data are given for each species and these are related to the hydrological regime.  相似文献   

Anatomical and ultrastructural comparison of the eyes of two species of aquatic,pulmonate gastropods: The bioluminescent Latia neritoides and the non‐luminescent Ancylus fluviatilis     

V. Benno Meyer‐Rochow  Marina V. Bobkova 《新西兰海洋与淡水研究杂志》2013,47(4):739-750

Light‐adapted eyes of two freshwater gastropods with similar habitat preferences (Latia neritoides (Gray 1850) and Ancylus fluviatilis (Müller 1774)) were compared with each other in relation to optics, anatomy, and ultrastructure. Individuals of L. neritoides not only possess significantly larger eyes than similarly sized A. fluviatilis, they also have a more voluminous layer of photorecep‐tive membranes and appear capable of discerning at least some crude shapes. The eye of A. fluviatilis, on the other hand, has a very shallow retina which is so closely apposed to the lens that it can be little more than an indicator of light and darkness. Both types of eye are generously endowed with screening pigment granules and exhibit no signs of light‐induced damage. Although the lenticular F‐values for L. neritoides (1.78) and A. fluviatilis (1.74) alone are hardly indicative of an adaptation to a dark environment, the greater amount of photic vesicles and the substantial development of muscle fibres in the eye of L. neritoides suggest that the latter can adjust its vision more rapidly to changing light levels than that of A. fluviatilis. Since L. neritoides (but not A. fluviatilis) has the ability to secrete a bright green luminescent mucus, a faster accommodation system would serve the species well. There is, however, no proof that in Latia bioluminescence alone has been responsible for the development of a more capable eye. Most of the differences between the eyes of L. neritoides and A. fluviatilis can be explained by the distinctly greater nocturnal activity of L. neritoides in combination with the ability to produce bright light in the latter species.  相似文献   

栉江珧精子超微结构的电镜观察     

顾向飞  边平江  周小龙  林志华  董迎辉 《海洋科学》2013,37(8):67-71

为了给栉江珧(Atrina pectinata)受精机理提供细胞学依据,利用透射电镜对栉江珧精子的超微结构进行了详细观察。结果显示,栉江珧成熟精子为典型的原生型,包括头部、中段与尾部三部分。头部为卵圆形,由顶体和细胞核组成。顶体纵切面为倒“V”字形,顶体腔内电子密度不均匀,近顶体外膜有一电子密度较高的弧状带,其余部分电子密度较低。核内有高度浓缩的染色质,其中有不规则的电子密度较低的核泡存在。无核后窝,有核前窝和植入窝。中段由2个相互垂直的中心粒及周围5个呈辐射状排列的线粒体组成。线粒体近卵圆形,由内外膜组成。尾部鞭毛由轴丝和质膜组成。结果表明栉江珧精子超微结构与典型的双壳贝类精子结构类似,在一定程度上反映了栉江珧的生殖进化及受精机理。  相似文献   

Climate deterioration in the Eastern Mediterranean as revealed by ion microprobe analysis of a speleothem that grew from 2.2 to 0.9 ka in Soreq Cave, Israel   总被引：2，自引：0，他引：2  

Ian J. Orland  Miryam Bar-Matthews  Avner Ayalon  John W. Valley 《Quaternary Research》2009,71(1):27-35

Analysis of oxygen isotope ratios (δ¹⁸O) by ion microprobe resolves a sub-annual climate record for the Eastern Mediterranean from a Soreq Cave stalagmite that grew between 2.2 and 0.9 ka. In contrast to conventional drill-sampling methods that yield a total variation of 1.0‰ in δ¹⁸O_calcite values across our sample, the methods described here reveal up to 2.15‰ variation within single annual growth bands. Values of δ¹⁸O measured by ion microprobe vary in a regular saw-tooth pattern that correlates with annual, fluorescent growth banding where calcite grades from light to dark fluorescence. Modern records of precipitation and of cave dripwater indicate that variable δ¹⁸O_calcite values record regular seasonal differences in δ¹⁸O_rainfall modified by mixing in the vadose zone. Large differences in δ¹⁸O values measured across a single band (i.e., between the dark and light fluorescent calcite, or Δ¹⁸O_dark-light) are interpreted to indicate wetter years, while smaller differences represent drier years. Oxygen isotopes record: 1) month-scale growth increments, 2) changes in Δ¹⁸O_dark-light that represent seasonality, 3) a systematic, long-term decrease in maximum Δ¹⁸O_dark-light values, and 4) an overall increase in average δ¹⁸O_calcite values through time. These results suggest a drying of regional climate that coincides with the decline of the Roman and Byzantine Empires in the Levant region.  相似文献   

Deformation Field around the Stress Induced Crack Area in Sandstone by the Digital Speckle Correlation Method   总被引：1，自引：0，他引：1  

ZHAO Yonghong  MA Shaopeng 《《地质学报》英文版》2009,83(3):661-672

Abstract: The deformation field around sub-cracks was calculated using the digital speckle correlation method. First, the uni-axial compression tests on sandstone samples containing a pre-fabricated fracture were made. Photomicrographs showing the characteristics of the sub-crack development were taken using a scanning electron microscope (SEM). From these photomicrographs, the real-time images showing the initiation, growth and coalescence of sub-cracks and micro-cracks in the sandstone specimens were obtained and the effects of loading level as well as grain boundaries on the development of cracks were analyzed. Second, the intensity images of the sandstone specimen surface were captured from the observations of the SEM corresponding to different loading levels. Then correlation computation was carried out for the sequential pairs of intensity images to evaluate the displacement components, as well as the strain field. The results show that the deformation varies in different areas separated by sub-cracks during rock damage processes.  相似文献   

和田软玉的化学成分和显微结构研究     

李举子  ;吴瑞华  ;凌潇潇  ;李青会 《地质科学译丛》2009,(4):9-14

采用场发射扫描电子显微镜（FE-SEM）系统对产自新疆和田的软玉样品的主要矿物组成、化学成分、显微结构等进行了较详细的研究,并与产自中国青海、辽宁、河南及韩国的软玉样品进行了比较。结果表明,各产地软玉样品的矿物组成、化学成分和显微结构有一定的差异。和田软玉样品中含有镁质绿泥石,而辽宁软玉样品中含有较多的闪锌矿,青海软玉样品中有含Zr元素矿物的颗粒,河南软玉样品中有含La与Ce元素较高矿物的颗粒;对纯度较高的软玉样品,仅依靠主成分很难区分其产地,但依靠其微量元素成分却能起到较好的鉴别作用;和田软玉样品中透闪石的显微结构较致密,纤维尺寸要小于其它产地软玉样品的。以上信息对确定软玉的产地具有较好的参考意义。  相似文献   

古代盐盆找钾中扫描电子显微镜技术应用   总被引：2，自引：1，他引：1  

宣之强  刘成林  王弭力 《化工矿产地质》2009,31(3):183-186,192

通过用电子显微镜对新疆库车盆地第三系含钾岩屑进行形貌及能谱元素成分分析研究,发现该盆地2400～3600m间累计含钾岩层厚度约100m。分上下两大含钾类型层,下层主要为硫酸盐钾芒硝类型,上层为钾石盐（光卤石）类型。  相似文献   

腐植酸改性强化磁铁矿吸附水体中铅镉的实验研究     

邵坤  赵改红  赵朝辉 《岩矿测试》2019,38(6):715-723

磁铁矿是一种绿色廉价的矿物材料,对水体中重金属离子具有良好的吸附性,但吸附容量低,选择性差,易团聚,通过改性可以克服该缺点并提高其吸附性能。本文以腐植酸为改性剂,采用常温水相反应制备了腐植酸改性磁铁矿吸附材料。通过傅里叶红外光谱(FTIR)、扫描电镜(SEM)和X射线光电子能谱(XPS)表征研究其表面形貌和微观结构。采用静态平衡实验考察了pH、吸附时间等因素对铅、镉吸附性能的影响,探讨了吸附动力学规律,拟合了吸附等温线。结果表明:腐植酸上的羧基、羟基被成功地接枝到了磁铁矿表面。在室温下,溶液初始pH对Pb~(2+)的吸附率几乎无影响,对Cd~(2+)的影响较大,当pH=7时,Pb~(2+)和Cd~(2+)吸附率均达到了95%。对初始质量浓度为10mg/L的Pb~(2+)、Cd~(2+)最佳吸附平衡时间为360min,吸附过程符合准二级动力学方程。吸附等温线实验得到的竞争吸附顺序为Pb~(2+)Cd~(2+),由Langmuir等温吸附模型得到Pb~(2+)、Cd~(2+)饱和吸附容量分别为39.27mg/g、28.95mg/g,显著大于磁铁矿的饱和吸附容量,表明磁铁矿经腐植酸改性后增强了对水中铅镉的吸附能力。  相似文献