The Würm in NW Iberia, a pollen record from Area Longa (Galicia)

The pollen record at Area Longa is the westernmost sequence available for investigation of the last glaciation in continental Europe. It is located in a region, NW Iberia, for which data from times earlier than the late glacial period are scarce. It comprises a series of exposed limnetic levels that lie above an Eemian (Oxygen Isotope Stage [OIS] 5e) beach and are separated by inorganic layers. The oldest limnetic level (Level I), attributed to the early glacial period (OIS 5a to OIS 5d), shows a dominance of woodland with high proportions of Fagus pollen and is tentatively identified with St. Germain I. The lower pleniglacial (OIS 4) Level II records a stadial landscape of grassland and shrub. Level III, from the pleniglacial interstade (OIS 3), reflects a complex period in which three warmer woodland phases alternated with periods of more open vegetation. This cyclical behavior correlates with the ice core isotope record and with the general tendencies observed in other Würmian pollen records, but the composition of our pollen profiles differs from those observed in these other records. In NW Iberia, the dominant trees were deciduous taxa, not conifers. Of particular note is the presence of lowland Fagus woodlands during the pre-Würm, and the occurrence of Carpinus considerably farther west than the boundary of its current distribution in the Iberian Peninsula.     

Application of a vessel monitoring system to advance sustainable fisheries management—Benefits received in Taiwan

Vessel monitoring systems (VMS) are considered important instruments for fisheries monitoring, control and surveillance (MCS) to reverse the current depressed state of the world’s fisheries, and have been mandated worldwide by fishery management agencies. The essential function of the system is to provide near-real time vessel position; the potential applications could, however, be more than that. This study explores the additional benefits, with practical examples, that Taiwan has received from implementing the system: in improving the quantity and quality of logbooks recovered, obtaining access to fishery-independent fishing effort estimates and prompt catch/effort reporting, enabling the possibility of regional management and understanding of both fleet dynamics and vessel behavior, and increasing efficiency of vessel safety protection. For other distant-water fishing nations, Taiwan’s experiences serve to demonstrate how the application of VMS technology can advance sustainable fisheries management.     

利用自然电位与自然伽马测井曲线划分沉积相带及储层分布

自然电位、自然伽马测井曲线形态和特征与沉积相带及其储集砂体关系密切,它们对不同岩性地层特征响应十分敏感.利用自然伽马、自然电位同步减小的较大幅度评价识别渗砂层,指示划分水下分流河道主体沉积微相带;利用自然伽马、自然电位减小的幅度差评价识别低渗砂、致密砂层,指示划分水下分流河道堤泛(侧翼)沉积微相带;并以自然电位比自然伽马减小幅度的相对细小差异识别油水层.在安塞油田沿河湾地区长6自然伽马、自然电位曲线划分沉积相带及储层的应用中,建立了自然伽马、自然电位划分储层的下限标准,有效地评价了特低渗透储层沉积微相带及储层类型,提高和扩大了测井曲线的应用及效果.     

Trend detection in river flow series: 1. Annual maximum flow / Détection de tendance dans des séries de débit fluvial: 1. Débit maximum annuel

Abstract

Results of a study on change detection in hydrological time series of annual maximum river flow are presented. Out of more than a thousand long time series made available by the Global Runoff Data Centre (GRDC) in Koblenz, Germany, a worldwide data set consisting of 195 long series of daily mean flow records was selected, based on such criteria as length of series, currency, lack of gaps and missing values, adequate geographical distribution, and priority to smaller catchments. The analysis of annual maximum flows does not support the hypothesis of ubiquitous growth of high flows. Although 27 cases of strong, statistically significant increase were identified by the Mann-Kendall test, there are 31 decreases as well, and most (137) time series do not show any significant changes (at the 10% level). Caution is advised in interpreting these results as flooding is a complex phenomenon, caused by a number of factors that can be associated with local, regional, and hemispheric climatic processes. Moreover, river flow has strong natural variability and exhibits long-term persistence which can confound the results of trend and significance tests.     

黄河口减沙与流路稳定

黄河口的减沙与水资源利用是稳定黄河流路的重要措施。入海流路的选择是确保油田开发、港口建设和防灾的重要工作。加强河口港湾和河口治理工程的研究是解决黄河口治理的关键工程。     

Northern Adriatic phytoplankton response to short Po River discharge pulses during summer stratified conditions

A 275‐km‐long transversel Northern Adriatic profile from the mouth of the Po River (Italian Adriatic coast) to the Kvarner region (Croatian coastal island area) was investigated in three successive case studies in August 2008, 2009 and 2010. The short Po River pulses in August result in the surface advection of riverine water, nutrients and phytoplankton from the western to the eastern side of the Adriatic. This surface spreading exhibits inter‐annual variability depending on the riverine discharge in the preceding period. The Po River discharge pulse in August 2010 in particular resulted in an extraordinary tongue‐like advection of riverine water, nutrients, and phytoplankton towards the Eastern Adriatic coast. The phenomenon was detected using both satellite imagery and classical oceanographic measurements. In the advective water, toxic dinoflagellates were most abundant in August 2010, when the influence of the Po was greatest.     

Dynamic simulation of tropical coral reef ecosystem being disturbed by multiple situations

In consideration of the rapid degradation of coral reef ecosystems, the establishment of models is helpful to comprehend the degradation mechanism of coral reef ecosystems and predict the development process of coral reef communities. According to the characteristics of complex ecosystem of tropical coral reefs in China, the coral reef functional group is the core level variable; combined with the multiple feedback effects of coral reef functional groups and environmental changes, the study presents a coral reef ecosystem dynamics model with hermatypic corals as the core. Based on the simulation of the assumed initial value and the internal feedback of the system, the results show that in the basic simulation(relative health conditions), the coverage area of live corals and coral reefs generally decreased first and then increased, and increased by 4.67% and 6.38% between2010 and 2050, respectively. Based on the calibration model and the current situation of the studied area, the multi-factor disturbance effects of coral reef communities were simulated and explored by setting up three scenarios involving fishing policy, terrestrial deposition, and inorganic nitrogen emissions. Among them, in the single factor disturbance, the fishing policy exerts the most direct impact on the community decline; and the succession phenomenon is obvious; the terrestrial sedimentation has a faster and more integrated effect on the community decline; the effect of inorganic nitrogen emission on the community decline is relatively slow. In the double/multi-factor disturbance, the superimposed disturbance will aggravate the multi-source feedback effect of the coral reef communities development, accelerate the community decay rate, and make its development trajectory more complicated and diverse. This method provides a scientific and feasible method for simulating the damage of long-term coral reef community and exploring the development law and adaptive management of coral reef ecosystems. In the future, it can be further studied in the ecological restoration process and decisionmaking direction of coral reefs.     

软悬挂状态下隔水管动力特性分析

建立了软悬挂状态下隔水管动力分析模型,采用有限单元法对模型进行离散,结合Newmark-β法对动态方程求解,并对模型进行验证,最后选取南海某口深水井实际参数,对软悬挂状态下隔水管动力特性进行分析。研究结果表明:软悬挂状态下隔水管底端横向位移最大,顶部铰接处弯矩最大。软悬挂状态下,隔水管横向位移与弯矩随着海底隔水管总成(LMRP)重量增加而减小,随着平台运动速度、平台航向与海流方向夹角增大而增大;回收隔水管减小悬挂长度有利于减小最大横向位移,但会造成弯矩轻微增加;采用旋转刚度适当较大的挠性接头则有利于减小隔水管挠性接头以下整体位移与弯矩。研究成果为钻井平台避台撤离时隔水管的安全提供理论指导。     

Life cycle and population dynamics of Idotea balthica basteri (Pallas, 1772), Isopoda Valvifera from the Bizerte lagoon (Southern Mediterranean Sea – Tunisia)

The population dynamics and life cycle of Idotea balthica basteri (Pallas, 1772) were studied at the Menzel Jemil (lagoon of Bizerte, Tunisia) based on monthly samples taken from October 2009 to September 2011. The presence of juveniles and gravid females throughout the sampling period showed that this species exhibits continuous reproduction. Sexual differentiation occurs in approximately 43–59 days. Females took 88–160 days (3–5.5 months) to reach sexual maturation, and males took 102 days (3.5 months). The fecundity and fertility values exhibited a great variation in the number of eggs and embryos or mancae inside the marsupium which was correlated with the length of the gravid females. The sex ratio underwent fluctuations throughout the sampling period but was always in favour of females. Size frequency distributions were analysed recognizing 24 cohorts during the sampling period. Six cohorts were identified in October 2009 and 18 cohorts in November 2009–September 2011. Among these latter cohorts, nine were tracked till they disappeared. The minimum average size of new cohorts ranged from 1.92 ± 0.31 to 2.97 ± 0.26 mm and the maximum values ranged from 12.83 ± 0.96 to 19.23 ± 0.56 mm. Life span was estimated at 10–14 months. I. balthica basteri, in the lagoon of Bizerte, is a semi‐annual species with iteroparous females, and a bivoltine life cycle that produces two generations per year.     

Numerical simulation of water flooding into a damaged vessel’s compartment by the volume of fluid method

When a vessel is damaged, seawater floods into the damaged compartments and subsequently influences the motion of the vessel. Furthermore, the vessel’s behaviour affects the floodwater motion. In this paper, a Navier-Stokes (NS) solver with a free surface capturing technique, i.e., the volume of fluid (VOF) method, was developed to numerically simulate water flooding into a damaged vessel. To verify the developed solver, a 2-D and a 3-D dam break problems were tested. The numerical results coincide well with the experimental results and with the published numerical results. Additionally, it was used to solve the problems of linear and non-linear liquid sloshing in a hexahedral tank. The numerical results are satisfactory in comparison with the experimental results and analytical solutions. Finally, the phenomenon of water flooding into a damaged compartment of a Ro-Ro ferry was simulated numerically. The computed results are in good agreement with the experimental data.