初始缺陷对深海载人潜水器耐压球壳塑性稳定性影响

载人深潜器耐压球壳是中厚度壳结构,当结构发生失稳时,球壳结构的局部部位因为材料达到屈服极限而发生了塑性变形.将有限元分析与经典理论相结合,研究弹性屈曲模态缺陷、局部缺陷以及球壳整体圆度和厚度偏差对中厚度球壳结构的塑性稳定性的影响.计算结果表明中厚度球壳结构对初始缺陷并不很敏感,对球壳结构当局部缺陷范围刚好达到临界弧长时结构的承载力最弱.通过缺陷结构和完善结构的极限承载力比较,提供了初始缺陷影响曲线.     

难浸硫化金矿的微生物氧化预处理

实际生产中,由于金被包裹以及碳质物和金属硫化物的影响,常规浸出工艺往往不能直 接将矿石中的金顺利提取出来。微生物氧化预处理是一种卓有成效的处理这种难浸金矿石的方 法,它通过微生物的催化作用,使那些包裹金颗粒的金属硫化物溶解,达到暴露金的目的。此外, 此工艺流程简单、投资少、生产成本低且不污染环境,采用此工艺能大大提高矿山的社会效益和 经济效益。     

Distributions of fatty acids in a stalagmite related to paleoclimate change at Qingjiang in Hubei,southern China

~~Distributions of fatty acids in a stalagmite related to paleoclimate change at Qingjiang in Hubei,southern China1. Dorale, J. A., Edward, R. L., Ito, E. et al., Climate and vegetation history of mid-continent from 75 to 25 ka: A speleothem record from Crevice Cave, Missouri, USA, Science, 1998, 282(5395): 1871-1874. 2. Li, B., Yuan, D., Qin, J. et al., Oxygen and carbon isotopic char- acteristics of rainwater, drip water and present speleofhems in a cave in Guilin area, and thei…     

世界海底多金属结核调查与研究进展

随着全球经济的发展,世界各国都面临着严峻的资源危机,而开发利用深海固体矿产资源已成为许多国家的重要选择。人们越来越意识到,海洋已经成为实现新世纪人类社会经济可持续发展的重要空间。随着中国大洋调查的进展,有必要系统梳理世界国际海域深海多金属结核资源调查历程、研究现状及进展。深海多金属结核资源作为可能是海底分布最广、储量最大的金属资源,历来得到国际和国内学者的广泛关注。近几十年的调查和估算表明,全球海洋中大约覆盖了54×106km2的多金属结核,有商业开采潜力的资源量达75×109t。但是很多海域涉及到具体区域性的资源调查工作还有待开展,同时在新的理论认识如热液成因和生物化学作用在多金属结核形成过程中的影响以及如何使金属提取过程更加绿色环保和科学高效等学科已经逐渐成为各国学者关注的新方向。中国应该合理有效开展具有针对性的多金属结核调查,争取使中国在深海海域矿产资源的调查和开发工作中走在国际前列。     

深海热液真菌Fusarium sp. SCSIO 06196中抗病毒聚酮类化学成分研究

从西太平洋深海热液沉积物来源的镰刀菌SCSIO 06196中分离鉴定了6个色原酮类化合物(1~6), 通过核磁共振光谱、质谱及旋光等多种分析测试方法确定了色原酮类化合物的结构。抗病毒活性筛选发现, 化合物1~3展示出显著的抗肠道病毒EV-71活性, IC₅₀分别达到26.7μmol•L^-1、19.8μmol•L^-1和22.0μmol•L^-1 (阳性对照药物利巴韦林为177μmol•L^-1)。此外, 化合物1还显示出弱的抗流感病毒H3N2活性, IC₅₀为8.6μmol•L^-1 (阳性对照药物达菲为18.5nmol•L^-1)。     

西南印度洋龙旂热液区神盾螺共附生微生物多样性分析

深海热液区的极端环境促使热液区生物形成了独特的生存机制,即与微生物的共附生关系。本文利用高通量测序技术分析了与西南印度洋龙旂热液区神盾螺（Gigantopelta aegis）共附生微生物的种类及功能。基于16S rRNA基因 V3-V4区扩增子测序结果发现：①神盾螺共附生菌中99.99%都属于细菌域,丰度最高的是变形菌门γ-,ε-,和α-变形菌纲;②神盾螺个体Ga1和Ga3的共附生菌群落中以γ-变形菌为主,个体Ga2 中以ε-变形菌为主,表明在同一热液区生活的不同个体间其共附生菌种类也存在较大差异;③宏转录组测序结果与扩增子测序结果基本一致,即神盾螺共附生细菌中变形菌门相对丰度最高,同时发现了高丰度的硫代谢、氢代谢、甲烷代谢以及环境胁迫应答基因。神盾螺共附生微生物的研究将有助于探究深海热液喷口生物的生存和适应策略,为进一步研究奠定基础。     

A data processing method for MAPR hydrothermal plume turbidity data and its application in the Precious Stone Mountain hydrothermal field

Hydrothermal plume is an important constituent of seabed hydrothermal circulation and is also one of the characteristics of active hydrothermal vents. Portable Miniature Autonomous Plume Recorders （MAPR） attached to a towed deep-sea instrument was used to search for hydrothermal plumes and hydrothermal vents. We introduced the basic principle of MAPR based on deep towing technology to detect plumes, then analyzed the factors affecting the quality of the MAPR data and presented a data correction method for MAPR, including instrument location correction, noise reduction processing, system error elimination and seawater background reduction. Finally we applied the method to analyze MAPR data obtained during the Chinese DY115-21 cruise on R/VDayang Iin the “Precious Stone Mountain” hydrothermal field on the Gala-pagos Microplate. The results provided a better understanding of the distribution of the hydrothermal activ-ity in this field, indicating the presence of a new hydrothermal vent.     

Relationship of Sediment-Biochemistry,Bacterial Morphology,and Activity to Geotechnical Properties in the Central Indian Basin

Distribution of biochemical properties, morphological and functional characteristics of bacteria in the extreme sedimentary environment of the Central Indian Basin (CIB) was examined in relation to geotechnical properties and sediment texture. Interrelationships between these parameters in siliceous northern sediments were compared to southern pelagic clay to understand relationships and to appreciate mining implications. Clay impacted lipids negatively and silt positively in the south. Geotechnical properties had the opposite influence on the distribution of coccoidal and rod forms of bacteria. Rods were affected negatively by water content/porosity and positively by wet bulk density in the north suggesting their preference for deeper niches. Shear strength affected coccoidal distribution negatively in the south. Competition for labile substrates by coccoidal forms in the surface layers could also have restricted the rods to the deeper regions. Principal component analysis (PCA) further strengthened our inference that the distribution of rod forms increased with depth. Enzymatic properties of bacterial isolates also showed that the rods were able to degrade substrates like gelatin and DNA. These observations suggest that they are capable of degrading relatively more recalcitrant compounds in the deeper layers. The minor components, like the rod morphotypes and sand content, could wield a large influence on the variability of other parameters.     

Restoration of Deep-Sea Macrofauna after Simulated Benthic Disturbance in the Central Indian Basin

ABSTRACT

Macrofaunal communities of the Central Indian Basin (CIB) were sampled with a spade before (June 1997), and immediately after (August 1997), and 44 months (April 2001) after a simulated benthic disturbance for polymetallic nodule mining. The average density recorded down to a sediment depth of 40 cm ranged from 89 to 799 ind·m^?2 (mean: 373 ± 221 SD; n = 12) and 178–1066 ind·m^?2 (mean: 507 ± 489 SD; n = 3) in the test and reference area, respectively. Most of the macrobenthic animals (64%) were concentrated in the upper 0 to 2 cm sediment layers, whereas, sizeable fauna (6%) inhabited the 20–40 cm sediment section and the deepest 5 cm section from 35–40 cm contributed only about 2% to the total population density. The fauna, comprised of 12 groups, were dominated by the nematodes, which constituted 54% of the total population. The macrofaunal density in the test site showed a significant increase (x:400 ind·m^?2) in the 44 months postdisturbance sampling (x:320 ind·m^?2). The population of nematodes and oligochaetes was nearly restored after 44 months, but the polychaetes and crustaceans did not reach the baseline populations measured in June 1997. The top 0–2 cm sediment layer was severely affected by the disturber, and the study suggests that physically disturbed deep-sea macrofauna may require a longer period for restoration and resettlement than normally believed.     

Characteristics of Seafloor Morphology and Ferromanganese Nodule Occurrence in the Korea Deep-sea Environmental Study (KODES) Area,NE Equatorial Pacific

Abstract

Seafloor morphology and ferromanganese nodule occurrence were studied using a multibeam side scan sonar (SeaBeam, 2000) and a deep-sea camera system in the Korea Deep-sea Environmental Study (KODES) area, northeast equatorial Pacific. Seafloor morphology and nodule abundance are highly variable even in this small study area. The NNE-SSW oriented hills are parallel and about 100–200 m high. Valleys are very flat-floored, while hilltops are rugged with depressions of tens of meters. Cliffs to about 100 m bound the valleys and the hills. The study area can be classified into three types based both on nodule occurrence and seafloor morphology, mostly G- and B-types and some M-type. G-type is characterized by high nodule abundance, ubiquitous bioturbation, and flat seafloor morphology, while B-type is characterized by irregular-shaped nodules, variable nodule abundance, occurrence of giant nodules and sediment lumps, rugged bottom morphology with depressions, and white calcareous surface sediments. Medium nodule abundance and a generally flat seafloor characterize M-type. G-type occurs mostly in the valley regions, while B-type is on the hilltop areas. M-type is located between the hilltop and the valley. Tectonic movement of the Pacific plate resulted in the elongated abyssal hills and cliffs. The rugged morphology on hilltops resulted from erosion and redistribution of surface siliceous sediments on hilltops by bottom currents, outcropping of underlying calcareous sediments, and dissolution of the carbonate sediments by corrosive bottom water undersaturated with CaCO₃. Sediment eroded from the hills, which is relatively young and organic-rich, is deposited in the valleys, and diagenetic metal supply to manganese nodules in the valley area is more active than on the hills. We suggest that tectonic movement ultimately constrains morphology, surface sediment facies, bottom currents and sediment redistribution, bioturbation, thickness of the sedimentary layer, and other conditions, which are all interrelated and control nodule occurrence. The best potential area for mining in the study area is the G-type valley zones with about 3–4 km width and NNW-SSE orientation.