Intra-archipelago moult dispersion of southern elephant seals at the Prince Edward Islands,southern Indian Ocean

During three summer surveys at Prince Edward Island (PEI), southern Indian Ocean (2001, 2004 and 2008), 416 southern elephant seals Mirounga leonina were inspected for identification tags. In all, 42 seals that had been tagged as weaned pups at their natal site were found on Marion Island (MI), 38 of which could be individually identified by resighting their tag numbers. The majority of the MI-tagged seals were yearlings or subadults, and all but one were hauled out at PEI for the annual moult. The attendance rate of the known individuals at their natal island during the annual moult was only 40%, based on their resighting histories. This was significantly lower than the 77 ± 6% moult attendance rate estimated for a random MI population sample drawn from the same cohorts (based on 10 000 replications). Annual resight probabilities (considering all haulout phases) was 58% per annum for the MI seals seen at PEI, and 80 ± 4% for the simulation. Seasonal and annual absences of seals from MI violate the ‘homogeneity of capture’ assumption of mark-recapture models. When multiple sightings during any year are treated as a single sighting, resights during other haulouts (e.g. breeding) compensate only partially for absences during the moult. Therefore, mark-recapture studies undertaken in archipelagos should ideally include both marking and resighting of individuals on all islands which will allow discrimination between mortality and local migration.     

优化采样策略下长江口潮间带大型底栖生物物种丰富度的估算

在异质性潮间带湿地中通过野外采样估算大型底栖动物物种丰富度,面临的挑战是统计上精确性的要求与实际采样难度之间的矛盾。为了解决这个问题,本研究通过对采样策略整个过程的三个主要部分进行优化设计（优化采样方法、确定最少采样效力、探索最佳的采样间距）,以期在中国长江河口典型的潮间带湿地中获得一个优化、有效和实用的大型底栖动物采样策略。本研究选取了横断面采样方法,并根据典型栖息地类型（潮滩、潮沟、盐沼植被）进行分层优化采样,这种类型的采样也称为横断面分层抽样。最少采样效力和最佳的采样间距由两个数学方法确定：蒙特·卡洛模拟和物种累积曲线。结果表明,根据典型栖息地类型优化的横断面分层采样,在大为减少采样效力和劳动力的情况下,还能采集样地81%物种,优化效果明显。同时,还分别确定了三类栖息地的最佳采样间隔和最小采样效力：在盐沼植被中,采样效力需要超过1.8 m2,最佳采样间隔为10 m;在潮滩中,最小采样效力2 m2,最佳采样间隔为10 m;在潮沟中,采样效力为3 m2,间隔为1 m。不同栖息地类型之间最小采样效力和最佳采样间隔的差异可能受到优势物种的迁移范围和栖息地的物理差异（例如潮汐水文、底泥、植被覆盖）的影响。本研究所采用的优化采样策略在平衡采样效力的情况下,为大型底栖动物丰富度估算提供良好的精度。此外,在河口湿地进行大型底栖动物调查之时,本研究的结论能提供采样策略参考。本研究所采用的采样策略设计注重采样的三个关键部分,具有良好的采样效果,可作为栖息地管理或生态系统评估的野外实地采样指南。     

Assessment of the effectiveness of POLYMODE data assimilation by a numerical barotropic model for synoptic motions

This paper considers the results of numerical experiments involving POLYMODE data assimilation by a barotropic model for synoptic ocean dynamics. The model's response the data assimilation for various space-time discretenesses of assimilation is studied. Results derived from the application of optimal interpolation algorithms and modified optimal filtration algorithms are compared. Qualitative similarity to the calculations carried out through the simulation modelling technique is noted. Optimal assimilation algorithms are determined, depending on the space-time discreteness used. An optimal sampling discreteness for the POLYMODE conditions is suggested.Translated by Vladimir A. Puchkin.     

深水随机波列中畸形波统计特征的研究

本文基于Longuet-Higgins随机波浪模型和JONSWAP谱,进行了大量深水随机波的模拟,获取了畸形波发生概率稳定的随机波列,并对随机波列中的畸形波进行了分析。结果表明,畸形波发生的概率小于基于Rayleigh分布预测结果,且随谱宽的减小而增大。在固定时间段内,畸形波发生的频次服从泊松分布,时间间隔服从指数分布,且随着谱宽的增大,畸形波的发生频次减小,相邻畸形波的发生时间间隔增加。通过小波变换方法分离随机波中的波群,研究了出现畸形波的波群特征,发现一个波群中最多会出现4个畸形波,但是在发生畸形波的波群中,单个畸形波的概率最大。随着谱宽减小,一个波群中包含多个畸形波的概率增加。另外,出现畸形波的波群时间长度服从广义极值分布,随着谱宽减小,畸形波波群的时间跨度增加。     

Growth marks in eyestalks of Portunus trituberculatus:A development of technique and evidence of molting

The analysis of growth bands in the eyestalk has been increasingly used for estimating crustacean ageing and molting. In this study, we developed an effective method to process and observe the eyestalk microstructure of the swimming crab(Portunus trituberculatus). We found that dark pigmentation as a result of boiling has an influence on the observation of the eyestalk microstructure. Choosing an unboiled eyestalk, this study compared the cross section and longitudinal section, and concluded that the cross section is suitable for the observation of growth increments with 6.1% CV(coefficient of variation), and growth bands are suitable for the observation of the longitudinal section with 5.4% CV. The width of growth increments near the edge of the endocuticle is small, and the width of growth increments of the middle part of the endocuticle is large. Relationship of number of growth bands to molting time was fitted to a linear function with the slope not significantly different from 1, indicating that growth bands are formed associated with molting. Periodicity of growth increment formation was calculated as 3.7 d, however was not verified. Our results provide a new improved technique for identification of crustacean molting and growth.     

西北太平洋柔鱼角质颚微结构及其生长纹周期性研究

本文分析了采集于北太平洋海域的35尾柔鱼(Ommastrephes bartramii)角质颚的微结构,并对其生长纹的周期性进行了验证。研究结果显示:上颚喙部截面由头盖和脊突两部分组成,周期性的生长带明显,每条生长带由明、暗相间的两条生长纹组成。头盖部的生长纹明显比脊突部的清晰,两者交汇于内轴成""形。喙部顶端以及后端常有明显的标记轮,其形成与个体发育期的特殊事件以及外界的突发事件有关。角质颚生长纹数目与耳石日龄相当(P0.05),证明柔鱼角质颚生长纹的沉积为"一日一纹"。根据角质颚生长纹估算柔鱼的生命周期小于1年,样本胴长、体重和角质颚喙长与日龄呈显著的逻辑斯蒂关系。研究结果不仅为柔鱼类年龄鉴定和生长估算提供新方法,而且为我国头足类学者开展相关研究提供重要基础。     

Juvenile nursery colonization patterns for the European flounder (Platichthys flesus): A latitudinal approach

In this work, we analysed the latitudinal trends in the nursery habitat colonization processes of the European flounder (Platichthys flesus). This was accomplished by estimating the duration of the pelagic and metamorphic stages, as well as the duration of the spawning period, in several nursery areas across its geographical distribution range in the European Atlantic Coast: Mondego estuary (Portugal), Vilaine estuary (France), Slack estuary (France), Wadden Sea (Netherlands) and the Sørfjord (Norway). All juvenile flounders were captured with beam trawls in June/July 2010, and otolith microstructure was used to determine the duration of each stage by means of daily growth increments. The pelagic and metamorphic stages were longer at the middle of the distribution range, and lasted in total up to two months after hatching. The spawning period occurred between mid-January and early-July over the species' distribution range, with a time lapse of nearly two months between the Mondego estuary and the Sørfjord, as a consequence of warmer water temperature earlier in the season in southern areas. In general, total length of the captured fish showed a latitudinal cline between the northernmost and southernmost sampling sites, with higher values at the middle of the distribution range. The results also suggested the existence of a countergradient growth compensation mechanism in the northernmost populations. Apart from temperature, which sets the general metabolic pace of organisms, differences between sites were also related with local features, such as the extension of the continental platform and adaptations to transport and retention mechanisms.     

Numerical experiments with data assimilation in the simplest dynamic-stochastic model for the ocean's synoptic variability closed at the level of the second moments

The results of numerical experiments with data assimilation in a non-linear model of the synoptic dynamics of the world's oceans are reported. The model's response to the data assimilation is studied at different values of the relative error in determining the initial fields and assimilation discreteness. The results of application of the algorithms of optimum filtration and optimum interpolation are compared. The advantages of the filtration algorithm employed are discussed only for the case of small errors in determining the initial fields and low assimilation discreteness. The possibility of deterioration of the prediction estimates in data assimilation with discreteness less than the typical time of variability of the average fields is noted.Translated by Mikhail M. Trufanov.     

Effectiveness of data assimilation using probabilistic techniques in a model for synoptic velocity field evolution

The results of numerical experiments involving data assimilation by linear and non-linear models for synoptic ocean dynamics are presented. This paper considers the model's response to data assimilation at diverse values of the relative error in the determination of the initial fields and space-time discreteness of data assimilation. The data obtained using the optimal filtering are compared with those provided by the optimal interpolation (OI). A qualitative difference in the response of the linear and non-linear models to data assimilation is noted. The limiting values of the time-space discreteness of observations assimilation are determined, which allow correct application of OI.Translated by Vladimir A. Puchkin.     

不同采样设计对估计鱼类空间格局指数的影响

查明渔业种群空间格局可为渔业资源的合理利用和管理提供参考依据.在渔业资源调查中,采样设计会影响调查分析结果的准确性和适用性.为查明采样设计对分析种群空间格局的影响,本文根据2016年10月、2017年2月、5月、8月在山东南部近海调查获得的数据,以星康吉鳗(Conger myri-aster)、方氏云鳚(Enedria...     

High-frequency variability of vertical distribution of suspended sediment concentration under irregular waves

Based on the data of a field experiment in a storm environment, we examined the specific features of the variability of the vertical profiles of the concentration of suspended sand sediments at a discreteness shorter than the wave period. Physical mechanisms that determine the processes of suspension and shape the types of vertical distributions of sediments are considered. A mathematical model for the prediction of vertical distributions of the suspended sediments governed by irregular wave forcing is developed. The model is verified from data of field and laboratory experiments.     

作用于平台桩腿的海冰屈曲破坏冰压力随机过程模型及其参数确定

冰对结构的作用过程是典型的随机过程。本文在冰压力过程为平稳过程的假设下，从渤海海冰对平台桩腿作用的大量实测冰压力数据中，选取了２１条冰屈曲破坏时的冰压力时程曲线，对它们进行谱分析后，得到了单点冰屈曲破坏的压力随机过程的谱密度，并确定了谱参数及其跟环境要素的关系，依据文献［１］中冰压力沿圆柱面的空间分布，建立了绕桩腿的冰压力随机场模型，并得到了作用于桩腿的总冰力随机过程及其谱密度。本文的研究成果为平台结构冰激随机振动和疲劳累积损伤分析提供了荷载基础     

Assessment of coral health in the coastal areas of the Persian Gulf

In this study, Zooxanthellae density, chlorophyll a concentration, and mitotic index (MI) were measured in the coral Porites compressa obtained from coastal areas of the Persian Gulf in early February to September 2008. During the summer, zooxanthellae density declined by approximately 30% compared to the winter peak (3,607,849 ± 229,894, n = 15) and reached a minimum of 2,536,732 ± 169,776, n = 15. The highest value of chlorophyll a (0.828 ± 0.043 μg/cm²) was recorded in the south while the lowest (0.604 ± 0.048 μg/cm²) was measured in the north sampling site at the cold season. There was a higher level of MI in the warm season followed by cold > and temperate seasons. The MI were significantly higher (p < 0.05) in the warm and cold seasons in comparison with the temperate season. Differences in response may be attributed to the drastic seasonal temperature changes. However, the significant decline found in the north sampling site indicates that anthropogenic stressors may adversely affect coral P. compressa. These results imply that there were negative impacts on coral P. compressa in our study site.     

Reliability analysis of submarine slope considering the spatial variability of the sediment strength using random fields

The properties of marine sediments vary spatially, and the undrained shear strength of marine clay increases linearly with depth because of depositional processes and the effective overburden pressure. To evaluate the stability of submarine slope considering the spatial variability of soil strength, the random field discretized by the Karhunen-Loève expansion is combined with the limit equilibrium method to conduct reliability analysis. For simplicity, our physical model does not include many complexities such as the effects of excess pore water pressure on the stability of submarine slopes. Stability estimates of the infinite slope model, under both static and seismic loading, are made with three types of one-dimensional stationary or non-stationary random fields. The two-dimensional slope model is also analyzed, where the shear strength varies with the positions of the strips because of the discrete random-field function for the soil material. In submarine slope reliability analysis, the non-stationary random field of the linearly increasing soil strength is used, instead of the commonly used stationary one. To obtain the failure probability through Monte Carlo simulations, a novel response surface method based on Gaussian process regression is introduced to build the surrogate model. The computational efficiency is significantly increased, because there is a considerable reduction of calls of the deterministic analysis. Therefore, the proposed method makes the prediction of submarine landslides which are usually rare events with very small probabilities more efficient.     

Measurement and evaluation of the hydrodynamics and secondary currents in and near a strait connecting large water bodies—A field study

The straits connect two large water bodies show highly strong and stratified currents related to meteorological, morphological and hydrodynamic conditions. In some cases, spatial and temporal changes of the stratified currents and their thickness, direction and magnitude are so complex. This complexity directly affects the circulation pattern in the region, water exchange between both ends of the straits and migration of fish species. In order to understand general characteristics of this kind of straits and identifying the complexity of the hydrodynamics of the region and evaluate the secondary currents and recirculation need long term, intensive, field work and measurement studies. As an example of this kind of hydrodynamically complex straits, Bosphorus strait is selected for a field study. The Bosphorus strait has a strongly stratified two-layer system and a unique case of the maximal exchange regime typical of strait flows, which is largely determined by conditions at the Black Sea. Although the Bosphorus strait has distinct two-layer stratification with an associated two-layer system exchange, no continuous current measurements have been made so far, previous measurements all having been random sampling.In this paper, a detailed measurement program has been applied to Bosphorus strait. In the measurement program, a short-term current profile measurement at selected locations at southern part of the strait has been conveyed. Additionally a long-term measurement of current profile has been performed at a selected critical location (in front of the Dolmabahçe Palace) where a recirculation flow exists in the strait. The scope of this paper is to present the techniques and the results of analysis of measurement data. In the measurements the current profile (magnitude and direction) has been determined at every 1 m depth intervals from the surface to the sea bottom at 3 min duration at every hour. Measurements provide that lower-layer flows in northward direction from the Sea of Marmara towards the Black Sea, whereas the upper-layer flow comes from the Black Sea and flows towards the Sea of Marmara in the opposite direction of lower layer. The Bosphorus strait exhibits distinctive features associated with variations in its width and depth. The meandering features of Bosphorus also cause recirculation flows. These results of measurements are presented, discussed and compared with previous studies.     

In Situ Time-Series Measurements of Subseafloor Sediment Properties

The capabilities and diversity of subsurface sediment sensors lags significantly from what is available for the water column, thereby limiting progress in understanding time-dependent seabed exchange and high-frequency acoustics. To help redress this imbalance, a new instrument, the autonomous sediment profiler (ASP), is described herein. ASP consists of a four-electrode, Wenner-type resistivity probe and a thermistor that log data at 0.1-cm vertical intervals over a 58-cm vertical profile. To avoid resampling the same spot on the seafloor, the probes are moved horizontally within a 20 times 100-cm^-2 area in one of three preselected patterns. Memory and power capacities permit sampling at hourly intervals for up to 3-mo duration. The system was tested in a laboratory tank and shown to be able to resolve high-frequency sediment consolidation, as well as changes in sediment roughness. In a field test off the southern coast of France, the system collected resistivity and temperature data at hourly intervals for 16 d. Coupled with environmental data collected on waves, currents, and suspended sediment, the ASP is shown to be useful for understanding temporal evolution of subsurface sediment porosity, although no large depositional or erosional events occurred during the deployment. Following a rapid decrease in bottom-water temperature, the evolution of the subsurface temperature field was consistent with the 1-D thermal diffusion equation coupled with advection in the upper 3-4 cm. Collectively, the laboratory and field tests yielded promising results on time-dependent seabed change.     

海浪对ASCAT散射计反演风场的影响研究

To improve retrieval accuracy, this paper studies wave effects on retrieved wind field from a scatterometer. First, the advanced scatterometer(ASCAT) data and buoy data of the National Data Buoy Center(NDBC) are collocated. Buoy wind speed is converted into neutral wind at 10 m height. Then, ASCAT data are compared with the buoy data for the wind speed and direction. Subsequently, the errors between the ASCAT and the buoy wind as a function of each wave parameter are used to analyze the wave effects. Wave parameters include dominant wave period(dpd), significant wave height(swh), average wave period(apd) and the angle between the dominant wave direction(dwd) and the wind direction. Collocated data are divided into sub-datasets according to the different intervals of each wave parameter. A root mean square error(RMSE) for the wind speed and a mean absolute error(MAE) for the wind direction are calculated from the sub-datasets, which are considered as the function of wave parameters. Finally, optimal wave conditions on wind retrieved from the ASCAT are determined based on the error analyses. The results show the ocean wave parameters have correlative relationships with the RMSE of the retrieved wind speed and the MAE of the retrieved wind direction. The optimal wave conditions are presented in terms of dpd, swh, apd and angle.     

Temporal sampling and discharge asymmetry in salt marsh creeks

Studies of tidal flows in salt marsh creeks have shown velocity pulses on certain tides, although these have often been overlooked in considering temporal sampling designs for the measurement of discharge asymmetry. Velocity measurements for both spring and neap tides were taken at 5-min intervals at Bridge Creek in south-east Essex. The importance of temporal sampling interval in determining measured discharge asymmetry is examined using these data, integrating at intervals of between 5 and 30 min. The results indicate that sampling at 30-min intervals can underestimate discharge when velocity pulses on spring tides are not accurately monitored. Both under- and over-estimation of discharge on neap tides suggests that temporal sampling is also an important consideration when velocity pulses do not occur.     

Short‐term temporal variation in gelatinous zooplankton populations over 48 hours in a coral reef at Redang Island,Malaysia

Gelatinous zooplankton abundance and species composition were investigated at 3‐h intervals for a 48‐h period at a fringing reef in Malaysia. A total of 20 gelatinous zooplankton species were observed; the community was dominated by the calycophoran siphonophore Diphyes chamissonis (79.9%), followed by the trachymedusdae Aglaura hemistoma (5.6%) and Liriope tetraphylla (4.8%). The gelatinous zooplankton were not collected in the water column during most of the daytime hours (1200, 1500 and 1800 h) but were common during the night. However, an abrupt peak in abundance was found at 0900 h on the second day. The times of appearance at night were different depending on the species, and the number of species was also different depending on the hour of sampling. Sampling at 3‐h intervals over a 48‐h period revealed that the temporal variation (or sampling availability) was large in this study. Careful consideration should be given to the sampling variability in handling the gelatinous zooplankton samples in coral reef areas.     

Optimum sampling interval for evaluating ferromanganese nodule resources in the central Indian Ocean

A study to estimate manganese nodule abundance (weight of nodules in kg/m²) was carried out in a small area of the abyssal plains covering a one-degree square block in the central Indian Basin. Abundance was assessed at various intervals by progressively reducing the grid spacing. Sampling the corners of the 1° survey block (approximately110-km spacing), i.e., four stations with 5-7 free-fall operations (sampling locations) in each case, indicated a nodule abundance of 3.50 kg/m². By reducing the sampling spacing to four grid units (0.5° survey blocks) and sampling the entire block at eight stations (25 locations), the average abundance of the block was 3.36 kg/m². Further reduction of the grid to 0.25° survey blocks and sampling in 16 grid units (70 sampling locations) increased the abundance to 4.41 kg/m². For 64 grid units in the one-degree block (sampling in 0.125° survey blocks), a substantially higher value was recorded, i.e., 5.31 kg/m² or about 1.5 times the abundance obtained at a 1° spacing. Adding 25 more stations in 0.0625° survey blocks (intervals of sampling locations approximately 500 m) resulted in a negligible change in abundance, the average value of the one-degree block being 5.23 kg/m². These data demonstrate that, for estimating nodule resources in the region, it is important to adopt a close-grid sampling strategy, so that areas with lower abundance can be relinquished and areas with higher abundance can be confidently identified. To ascertain exact nodule abundance for mine-track selection, it may be sufficient to restrict detailed grid surveys to areas with marked variations in topography and nodule abundance, rather than carrying out such detailed (albeit less cost effective) surveys at a very narrow spacing (0.0625°) over the entire pioneer area.