鳌山湾水域水文设计参数分析

根据青岛大港验潮站的长期实测资料和鳌山湾连续一年的历时潮住资料,利用PearsonⅢ型曲线法和同步相关方法分析获得了鳌山湾极值水位及鳌山湾水域的设计水位。在此基础上,计算得到了深水和近岸波要素。所得水文设计参数为鳌山湾的后续开发提供了科学依据。     

养马岛西南海域泥沙运移及近岸演化态势研究

养马岛西南海域近30年来发生普遍淤积,海域海底淤积速率平均为1．5cm／a,局部可达10cm／a。鱼鸟河以东岸线向海推进速度约1～6m／a。海域表层沉积物有整体细化的趋势,该海域的快速淤积与海岛的屏蔽消能以及海堤的拦截作用有关。海底淤积对取水口的设计方案有明显影响,分析了工程海域动力、泥沙、海岸及近岸演化态势,并对取水口设计方案进行了论证。     

Nitrogen loadings to two small estuaries,Prince Edward Island,Canada: a 2‐year investigation of precipitation,surface water and groundwater contributions

In this research the dissolved inorganic nitrogen (DIN) loadings from direct precipitation, stream flow and groundwater discharge to two small estuaries located in Prince Edward Island (PEI), Canada, were quantified over a 2‐year period. The two estuaries, like many around the world, exhibit deteriorating conditions that are believed to be related to excessive nitrogen transport from adjacent catchments. The significance of the groundwater transport pathway and the temporal variability of the loadings have not been previously investigated. The wet fraction of the atmospheric loading was quantified using available precipitation and DIN concentration records. Stream water entering the estuaries and the discharge from numerous shoreline springs, the predominate form of groundwater discharge, were monitored periodically during the study. The annual DIN loads delivered to both estuaries were dominated by streams, although groundwater discharge provided significant contributions of approximately 15–18%. Temporal variability of DIN loading was large, with monthly loads varying by a factor of 5; this variability was found to be primarily related to the variability of freshwater discharge. Concentrations of nitrate in stream water discharging to the estuaries and shoreline groundwater springs were similar in each catchment, suggesting that there was minimal differential attenuation during transport via these two pathways. The McIntyre Creek estuary had one of the highest normalized loads reported in the literature (1700 kg NO₃‐N/ha estuary/year), more than four‐fold that of the Trout River estuary, and this result appears to be related to the larger percentage of land area used for potato production in the catchment. This study demonstrates that direct groundwater discharge to estuaries in PEI should not be ignored and that seasonal variations in loading may be important for managing DIN delivery to such estuaries. Copyright © 2010 John Wiley & Sons, Ltd.     

The nearshore current along a high-rainfall,trade-wind coast-Nicaragua

Runoff from abundant rainfall on the watersheds along the east coast of Nicaragua results in a well-defined nearshore current, extending 20–40 km out from the coast. Important terms in the controlling dynamical balance are the Coriolis forces, and eddy frictional forces. Calculations of the diabathic surface slope 0(10^?5) show a smooth setup of 4–5 cm from the outer edge of the current to the shoreline. A longshore surface slope of 0(10^?8) appears to be set up by the longshore wind stress, and further computations allow an estimate of ～ 6 gr cm^?1 s^?1 for the dynamic eddy viscosity. An analytical expression including diabathic surface slope and density gradient, parabathic surface slope, wind stress, and quadratic bottom friction reproduces the salient observed features of the nearshore current. These include the pronounced maximum in the parabathic (along-shelf) current about 10 km off the coast, a complex diabathic velocity structure, and a shelf countercurrent just seaward of the outer edge. Further calculations suggest that the dominant driving arises from the freshwater-induced density gradients, accounting for upward of 80% of the flow velocity. As suggested by Royer (1982), the prevailing trade wind exerts an onshore wind stress that serves the important role of maintaining the integrity of the density gradients via the convergence of a surface Ekman layer toward the coast.     

Quantification of nearshore morphology based on video imaging

The Argus network is a series of video cameras with aerial views of beaches around the world. Intensity contrasts in time exposure images reveal areas of preferential breaking, which are closely tied to underlying bed morphology. This relationship was further investigated, including the effect of tidal elevation and wave height on the presence of wave breaking and its cross-shore position over sand bars. Computerized methods of objectively extracting shoreline and sand bar locations were developed, allowing the vast quantity of data generated by Argus to be more effectively examined. Once features were identified in the images, daily alongshore mean values were taken to create time series of shoreline and sand bar location, which were analyzed for annual cycles and cross-correlated with wave data to investigate environmental forcing and response.These data extraction techniques were applied to images from four of the Argus camera sites. A relationship between wave height and shoreline location was found in which increased wave heights resulted in more landward shoreline positions; given the short lag times over which this correlation was significant, and that the strong annual signal in wave height was not replicated in the shoreline time series, it is likely that this relationship is a result of set-up during periods of large waves. Wave height was also found to have an effect on sand bar location, whereby an increase in wave height resulted in offshore bar migration. This correlation was significant over much longer time lags than the relationship between wave height and shoreline location, and a strong annual signal was found in the location of almost all observed bars, indicating that the sand bars are migrating with changes in wave height. In the case of the site with multiple sand bars, the offshore bars responded more significantly to changes in wave height, whereas the innermost bar seemed to be shielded from incident wave energy by breaking over the other bars. A relationship was also found between a site's mean wave height and inner sand bar location; sites with the highest wave heights tended to have sand bars farther from shore than those with relatively low wave heights.     

浅谈沿海滩涂开发中的测量问题

沿海滩涂大部分为淤泥质平原海岸带,滩地比较开阔,分布集中,但滩涂地形,地貌,自然植被等具有特殊性,所以其测量也不同于一般的地面测量。本文介绍了沿海滩开发中 水准测计算方法和渠道施工测量,并提出了滩涂水准测量中值得注意的几个问题,对指导当前沿海滩涂开发测量有参考价值。     

东海近岸带鱼(Trichiurus japonicus)线粒体控制区序列的群体遗传变异研究

带鱼(Trichiurusjaponicus)是广泛分布于东亚大陆架海域的暖温性近底层经济鱼类,也是东海区最重要的海洋渔业捕捞对象。然而,目前的研究报道对东海近岸带鱼群体遗传变异特性认识不足,不利于其种群的遗传资源保护和管理。本研究利用线粒体控制区序列对东海近岸带鱼6个群体191个个体的遗传多样性、遗传分化和历史动态进行分析。在577 bp长的控制区序列中共检测到70个多态位点,定义了121个单倍型。群体总的单倍型多样性较高(0.9911),但总的核苷酸多样性较低(0.0092),群体间遗传多样性水平差异较小。单倍型遗传学关系、Fst值和分子方差分析结果均表明群体间的遗传分化不显著,存在广泛的基因交流。历史动态分析结果表明东海近岸带鱼群体在更新世中晚期可能经历了瓶颈效应和随后的群体快速扩张,这是导致群体遗传多样性较低的主要原因。带鱼较强的扩散能力、洄游行为、海洋环流以及近期的群体扩张可能是造成东海近岸带鱼缺乏显著的系统地理种群结构的原因。研究结果提示,在线粒体DNA水平上,东海近岸带鱼群体是一个随机交配的种群,在遗传资源管理上可作为一个单元进行管理。     

Investigation of wave characteristics in a semi-enclosed bay based on SWAN model validated with buoys and ADP-observed currents

In this study, the simulating waves nearshore (SWAN) model with a locally refined curvilinear grid system was constructed to simulate waves in Jervis Bay and the neighbouring ocean of Australia, with the aim of examining the wave characteristics in an area with special topography and practical importance. This model was verified by field observations from buoys and acoustic Doppler profilers (ADPs). The model precisions were validated for both wind-generated waves and open-ocean swells. We present an approach with which to convert ADP-observed current data from near the bottom into the significant wave height. Our approach is deduced from the Fourier transform technique and the linear wave theory. The results illustrate that the location of the bay entrance is important because it allows the swells in the dominant direction to propagate into the bay despite the narrowness of the bay entrance. The wave period T p is also strongly related to the wave direction in the semi-enclosed bay. The Tp is great enough along the entire propagating direction from the bay entrance to the top of the bay, and the largest Tp appears along the north-west coast, which is the end tip of the swells’ propagation.     

近岸水体中海洋雪对细颗粒微塑料沉降过程影响的实验研究

海洋微塑料是全球共同面对的环境问题和挑战,然而目前海洋微塑料从源到汇的输运和沉积过程及影响机制尚不明确。已有研究发现微塑料颗粒的垂向沉降过程受到海洋雪等水体悬浮物质的影响,但是目前相关研究只局限于定性的观察分析。在实验室中模拟含有海洋雪的近岸水体环境,使细颗粒微塑料(PS微球、PVC颗粒)与海洋雪产生碰撞、聚集,观测微塑料或微塑料-海洋雪聚集体的沉降过程。研究结果表明,水体中含有海洋雪时,一方面海洋雪会促进微塑料颗粒自身的聚集,形成更大的聚集体;另一方面由于海洋雪包裹微塑料形成松散的聚集体,导致平均沉速减小。50 μm以下的微塑料其沉降过程受海洋雪的影响较大,平均沉速减小35%以上;微塑料密度越大,受海洋雪的影响越小,平均沉速减小10%以下。沉降速率的减缓,意味着微塑料在水柱中的停留时间增加,处于不同深度的水生生物可能有更多时间和概率与微塑料接触,增加了鱼类等水生生物摄入微塑料的风险。