Sedimentary architecture and growth pattern of turbidite systems in distal part of a median fan; example of the Upper Miocene sedimentary sequence of the Lower Congo basin

The understanding of deep-water turbidite systems implies a preliminary detailed analysis of the architectural elements which compose them. Using 3D seismic data, three architectural elements are recognized including a new one: the “meandering erosional nested channels”. The spatial organisation and the relative stratigraphic position of these “elementary bricks” allow to define four stages which form the sedimentary history of the distal part of a upper Miocene turbidite system of the Lower Congo basin: 1, depositional stage with frontal splay development; 2, erosional channel and prograding system; 3, depositional stage with vertical aggradation of the channel and 4, abandonment phase with channel avulsion.     

深海热液区化能自养菌Caminibacter profundus氢酶对环境因子的响应特点

以深海热液区化能自养菌Caminibacter profundus为对象,采用扫描电镜和化学能谱分析,研究了菌株表面形态和矿物元素沉积;同时研究了菌株生长、甲基紫精(MV)还原的氢酶活性及膜结合的类型I NiFe氢酶基因(hynL)表达对盐度、pH和温度几种环境因子变化的响应特点。结果表明,菌株表面被Si、Ca、S和Fe等多种元素组成的矿物质层所包裹。不同条件下,菌株生长、MV还原的氢酶活性和hynL的表达趋势相一致,其最适条件为盐度30、pH5.5和55℃培养温度。研究结果表明,在环境改变时,C.profundus通过调控hynL的表达,以调整菌株的能量代谢,维系菌株的生长繁殖。     

Gap size effect on the tribological characteristics of the roller for deep-sea mining robot

To design the deep-sea mining robot, it is essential to analyze the tribological characteristics of its roller. In this study, we introduced the dynamic simulation model to analyze the tribological characteristics of the roller for deep-sea mining robot, considering the temperature, viscosity, viscous damping force, and gap size between the inner and outer rib seals. Effective viscosity changes with gap size in micro/nanoscale while the effective viscosity is equal to the kinematic viscosity in macroscale. For the stable operation of the roller, the effective viscosity must be less than the critical viscosity. As the gap size decreases, the effective viscosity increases while the critical viscosity decreases. This study shows that the gap size between the inner and outer rib seals of roller is the most dominant factor in designing the roller for deep-sea mining robot to use at relatively low temperatures that are found in the deep-sea environments.     

The Characteristic of Deep Sea Hydrothermal Ecosystem and Their Impact on the Extreme Microorganism

Deep-sea is one of the most important extreme environments on the earth. Numerous and diverse extremophiles thrive in this extreme environment, presenting distinctive physiological structure, metabolic mechanism and symbiosis relations, which provide new methods to study the origin of life and extraterrestrial life. Despite extensive studies on deep-sea extremophiles from the point of view of biology, the impacts of deep-sea hydrothermal activity on the evolution of extremophiles remain largely unknown. On the basis of summarizing features of the deep-sea ziphysicochemical and geological environment, the distribution and formation mechanism of submarine hydrothermal vents were analyzed, respectively. Hydrothermal vents have great effect on the distribution and succession of communities. Our discussion focused on the extreme life forms of microorganisms surviving in the hydrothermal ecosystem and their important significance for the nutrient cycling and ecosystem evolution. However, the research of life processes in extreme environments is still in the primary stage and more work is needed on the in-situ detection technique, molecular biology and interdisciplinary research.     

Practical engineering approaches and infrastructure to address the problem of marine debris in Korea

As a solution to the problem of persistent solid marine debris, a nationwide project began in Korea in 1999 to develop and popularize fundamental changes to the infrastructure. The ten year project, called “A Practical Integrated System for Marine Debris,” consists of four linked types of technology: prevention, deep-water survey, removal and treatment (recycling). These reflect the characteristics of marine debris, which though widespread, vary by location and time of generation. Each technical component has each representative outcome that has been outreached the local governments and marine debris-related associations. The in situ infrastructures lead to enhance the retrieval of the marine debris and create direct and indirect benefits to industry. Both end-of-pipe technology improvement and the introduction of front-of-pipe technology should be considered as we strive to reduce the generation of marine debris in Korean coastal areas.     

日本西南部四国增生复合体中的锰矿分布

Bedded manganese ore deposits occur in many localities within the accretionary belts of the Shikoku region, SW Japan. The deposits occur mostly in bedded chert or its metamorphosed equivalent. These chert-hosted manganese deposits are considered to have been manganese nodule/crust-bearing siliceous sediments on deep-sea floor and have been converted to manganese ores by low-grade metamorphism through subduction-accretion process. The mineral assemblages of the ores reflect the metamorphic grade of the accretionary complexes. On the other hand, iron-manganese deposits and some manganese deposits occurring directly over basalt are considered to have been the hydrothermal precipitates associated with submarine volcanism.     

Day and Nighttime Changes in Species Composition of Deep-Sea Demersal Fishes

Species compositions of deep-sea demersal fishes were compared during the day and at night in two cruises of KT-01-8 and KT-02-5. A total of 742 individuals belonging to 28 species were collected in four day and four night hauls in KT-01-8, and in KT-02- 5 128 individuals belonging to 33 species were sampled in three night and four day hauls. Principal Component Analysis (PCA) revealed that there were two distinct groups corresponding to sampling time in both cruises, although in KT-02-5 the species composition from the first haul sampled after sunrise was similar to those found in night hauls. This suggests that the species composition of deep-sea demersal fishes changes between day and night. The existence of a time lag between the sea surface and the sea floor was also suggested, lag being 2–4 hr at 500 m depths in the study area. There may be two possible explanations for the change in deep-sea demersal fish composition between daytime and nighttime: the artificial effect of successive sampling design, and actual fish migration. Since the artificial effect would not be sufficient to explain the change of demersal fish composition, the vertical or horizontal movements of deep-sea demersal fishes would contribute to the faunal change between daytime and nighttime in the study areas.     

Geotechnical characteristics of deep-sea sediments from the North Atlantic and North Pacific oceans

Geotechnical properties from a series of deep-sea sites in the North Atlantic and North Pacific oceans are examined to evaluate overall trends and to compare with similar fine-grained soils found on land. The study areas encompass a range of sedimentary environments dominated by combinations of turbidite and pelagic deposits. Carbonate content in excess of 20% is seen to result in a decrease in liquid limit and compressibility. Vertical profiles of geotechnical properties in the North Pacific show broader changes in down-core geotechnical properties compared to the North Atlantic and reflect the effects of long-term climatic changes and seafloor spreading. Sediments in the North Atlantic indicate significant differences depending on location, which is attributed to variability in turbidite deposition, water depth, distance from sediment sources, and the effects of bottom currents. Compared to equivalent fine-grained soils on land, deep-sea sediments are generally softer, more compressible and have higher friction angles at comparable Atterberg limits. Deeper and older sediments in the North Pacific are characterized by unusually large plastic limits, which are attributed to the presence of volcanic fractions. Empirical relationships for compression index and friction angle are discussed for sediments from both oceans.     

An overview of cold-water coral protection on the high seas: The Hatton bank (NE Atlantic)—A case study

The present paper provides an overview of cold-water corals protection in the Hatton Bank deep-water fisheries through the implementation of the United Nations General Assembly resolution 61/105. The methodology and scientific evidence used to propose protection of cold-water coral ecosystems in the high seas (∼16,000 km²) are briefly summarised. The role of international agents and importance of interdisciplinary research for making management decisions are furthermore described. Implementation was slow because (i) of scarce initial scientific knowledge, (ii) research on the high seas was difficult and expensive, (iii) there were several international interests at stake, (iv) agreement from a number of agents was needed, and (v) international advisory and decision making processes were quite slow. Some lessons learned are also discussed since these may help to increase protection efficiency of deep-sea vulnerable marine ecosystems in the high seas.     

深海热液口化能合成共生作用的研究进展

海洋无脊椎动物和细菌间的化能合成共生作用的发现,改变了人们对深海热液口初级生产力主要来源的认知.近年的研究表明,营化能合成共生的动物隶属于纤毛门、软体动物门、环节动物门和节肢动物门;其中无脊椎动物作为宿主在与共生菌的长期共生过程中,伴随着部分器官和功能的退化或消失,逐渐形成和演化出了与此相适应的形态结构,并产生了一些特殊的行为;在深海热液口发现的所有化能合成共生菌都属于革兰氏阴性菌,它们的宿主大致可以分为2个群体;通过16 SrRNA基因编码分析,不同代谢类型的共生菌在系统发育中通常处于不同分支,形态也有所差异;共生菌独特的传播方式和进化模式也使其更加适应共生生活;由无脊椎动物和化能合成细菌构成的共生体系与环境相互作用,影响了深海热液口生态系统的演化.对共生菌蛋白质及代谢组学的研究,以及对宿主生理和代谢机制的研究将成为未来热液口化能合成共生作用研究的新热点.