胶州湾李村河口沉积物中酸可溶硫化物与活性金属分布特征

对胶州湾李村河口9个短柱状样沉积物中活性金属、AVS和有机质含量等参数进行了分析.其中AVS含量:198.4～0.4 μmol/g,平均35.8μmol/g.大部分样品活性金属含量具有 Fe > Zn > Cu > Cr >V > Ni > Pb > Co > Cd 的顺序.活性重金属 Zn, Cu, Cr, V, Ni, Pb, Co, Cd 含量之和 ( ΣM ) 为:0.53～17.39 μmol/g.通过对所测数据分析发现,大多数活性金属间具有较好的相关性,反映了它们具有相同的来源或相似的早期成岩地球化学特征.近河口区沉积物的地球化学特征与远河口区差异明显:近河口区底层水为还原环境,AVS 形成的制约因素是活性铁的可获得性,而活性重金属的分布受到AVS的控制并主要以金属硫化物或硫化物吸附态的形式存在,AVS 仍具有较大的吸附重金属的潜力,同时硫化物中重金属再次释放造成二次污染的潜在性也较大;而在离河口稍远的海域,沉积物中 AVS 形成的控制因素是有机质的供给和环境氧化还原状态的变化,活性重金属主要以铁氧化物结合态存在,表层沉积物中重金属的环境敏感性及生物有效性都较高.     

底边界层水沙观测系统和应用

利用现代先进的光学和声学测量仪器(ADP、PC-ADP、ADV、OBS等),组制四角架观测系统用于底边界层的水沙观测.此观测系统既可获取垂向流速场,更可获取常规水文观测难以获取的高分辨率的近底流速、近底单点紊动过程、近底温盐沙和波浪过程.利用此观测系统于2007年8月在长江口北槽最大浑浊带内进行了实地观测.分析四角架观测数据与同步船测底部数据表明,四角架观测系统在近底(特别是底部明显分层)观测时表现出明显优势.常规水文观测测得底部含沙量一般只相当于距底70～120 cm高度含沙量;船测底部最大含沙量为5.8 kg/m 3,而架测距底30 cm处最大含沙量有25 kg/m 3;近底含沙量较高时往往出现强分层,强分层时实测距底30 cm处含沙量可达距底120 cm处含沙量的5倍;船测底部流速比架测距底30 cm处流速平均偏大45%;但距底30 cm处最大流速仍可达1.2 m/s.船测数据也验证了四角架观测数据的正确性.     

磨刀门拦门沙区域近期地貌演变和航道整治研究

应用近几年的水文和地形实测资料,研究了磨刀门拦门沙区域近期的动力和地貌演变特点.近期地貌演变的主要特点为:深槽外移扩展,一主一支分汊明显;拦门沙内坡冲刷外移,外坡变化不大,纵向宽度变窄;拦门沙西区淤积,拦门沙中心区和拦门沙东区冲刷;地貌轴线总体向南和西南方向偏转.从水动力和地貌演变的角度来看,磨刀门拦门沙区域航道整治应关注下列问题:1)注意河口性质的变化,着重解决径流输沙,波流共同输沙这两个主要问题;2)在工程布置中,应与口门外动力场的特点和地貌演变的总体趋势相适应,以建设双导堤为宜;3)西汊、东汊均是可选择的航线,从综合因素考虑宜选择西汊;4)注重河口分汊的自然规律,注意保护东支汊;5)注意稳定拦门沙中心区.     

河口三维流动数学模型研究进展

回顾了近年来国内外河口与海岸三维水动力学数学模型研究的新进展,着重讨论了三维水动力学数学模型研究中的若干基本问题。对河口三维潮流和密度流问题而言,其基本方程已经基本解决,但是在风暴侵袭期间,多种尺度的动力因素同时存在,建立其合理的流动模型是一项重要的基础性工作;尽管已有一些成功的河口三维流动数学模型,但是寻求基于并行计算技术的数值模拟系统将是值得努力的方向。此外,河口大规模动边界和漫滩水流的模拟仍有待作进一步研究。     

河口海岸水动力模拟技术研究的进展

本文在回顾河口海岸水动力数值模拟研究进展的基础上，对其新技术数字河口动力模型的基本内涵、科学意义和河口模型四维资料同化的作用及其发展前景进行了探讨，并最终认为数字信息技术与四维同化技术将变革河口海岸科学研究的手段，从而促使河口海岸数值模拟技术有更加广阔的发展前景。     

珠江口外海水声速经验正交函数分析

利用珠江口外海多年的水文观测资料,采用经验正交函数(EOF)法分别对该海域表层及21°N垂向断面的声速及其距平值进行了分析.结果表明该海域表层声速自西北向东南增大,21°N垂向断面声速随水深的增加而减小.EOF法分析声速及其距平值得出的第一个特征分量在该区域表层和21°N垂向断面上都是最重要的.声速季节变化显著:自上一年的10月开始减小,2或3月减到最小值后开始增大,7~9月增至最大值,有显著的年变化周期.声速也似有年际变化:1981年冬季声速开始减小,一直持续到1982年秋季,1982年冬季开始呈增大的趋势.声速的年际变化强度随着水深的增加而减弱.     

Habitat selection of stone and starry flounders in an estuary in relation to feeding and survival

Juveniles of both stone flounder Platichthys bicoloratus and starry flounder Platichthys stellatus utilize estuaries as nursery grounds. To understand their habitat selection and the functions of habitats such as food supply, we defined the seasonal distribution of recently settled fish of these species in shallow nursery areas and investigated their feeding habits in the Natori River estuary, Japan. Distribution of stone flounder was limited to the lower estuary (<3 km upriver from the mouth) and stone flounder were most abundant near the mouth. Recently settled starry flounder were first detected further upstream in areas characterized by low salinity <10 and by the absence of the predatory sand shrimp Crangon uritai. Early juvenile stone and starry flounders consumed mainly siphons of the bivalve Nuttallia olivacea and the mysid Neomysis awatschensis, respectively; however, 1- and 2-yr-old fish of both stone and starry flounders fed mainly on the bivalve siphons. These results indicate that habitat selections of juvenile stone and starry flounders enable utilization of preferred prey and predator avoidance, respectively, and that non-overlap of these species' habitats results in avoidance of inter-specific competition for food between these two species.     

Landsat-8 OLI卫星数据的大气校正检验及其应用

本文检验了Vanhellemont和Ruddick算法在浑浊的海洋沿岸水体中的适用性。采用基于Vanhellemont和Ruddick算法对2013—2015年黄河口水体的landsat-8 OLI数据进行大气校正,该算法得到的OLI反射率与黄河口高光谱实测反射率较一致, R为0.95,在483 nm(蓝)、561 nm(绿)、655 nm(红)波段处平均相对误差为16.4%、17.3%和25.7%。MODIS和Landsat-8 OLI数据获取的悬浮物浓度之间一致性较好, R为0.85,平均相对误差为20.5%,表明该算法适用于黄河口水体。基于时间序列OLI数据,得到了悬浮物浓度时空分布特征。黄河口悬浮物浓度变化差异主要由风速和输沙量引起的,风速和输沙量对悬浮物浓度的影响存在一定的时间滞后现象。     

Hydrodynamic forcing on salt-marsh development: Distinguishing the relative importance of waves and tidal flows

To unravel the relation between hydrodynamic forcing and the dynamics of the tidal flat–salt-marsh ecosystem, we compared hydrodynamic forcing in terms of proxies relevant to bed sediment motion for four tidal flat–salt-marsh ecosystems that were contrasting in terms of wind exposure (sheltered vs. exposed) and lateral development (shrinking vs. expanding). Wave and current field measurements on these four contrasting tidal flat and salt-marsh ecosystems indicated that the hydrodynamic forcing on the bottom sediment (bed shear stress) was strongly influenced by wind-generated waves, more so than by tidal- or wind-drive currents. The measurements further showed that the hydrodynamic forcing decreased considerably landward of the marsh cliff, highlighting a transition from vigorous (tidal flat and pioneer zone) to sluggish (mature marsh) fluid forcing. Spatial wave modeling using measured wind, revealed that the time-integrated wave forcing on the intertidal mudflat in front of the marsh (i.e., the potential bed sediment pickup) was a factor two higher for salt marshes that are laterally shrinking than for laterally expanding marshes, regardless of whether these marshes were exposed to or sheltered from the wind. The same result could not be obtained from a straightforward wind speed and fetch length approach for estimating wave forcing. This confirmed that wave force estimates required spatial modeling to be consistent with the sites trends of shrinking or expanding marshes and wind exposure is not enough to characterize the wave forcing at these sites.     

Empirical relationship between eelgrass extent and predicted watershed-derived nitrogen loading for shallow New England estuaries

Seagrasses provide important ecological services that directly or indirectly benefit human well-being and the environment. Excess nitrogen inputs are a major cause of eelgrass loss in the marine environment. Here we describe the results of a study aimed at quantifying the extent of eelgrass as a function of predicted watershed-derived nitrogen loading for small-to-medium-sized shallow estuaries in New England. Findings confirm that reduced extent of eelgrass corresponds to increased loading of nitrogen to this class of estuary. At lower levels of nitrogen loading (≤50 Kg ha⁻¹ yr⁻¹), eelgrass extent is variable and is likely controlled by other ecosystem factors unrelated to water quality. At higher loading rates, eelgrass coverage decreases markedly, with essentially no eelgrass at loading levels ≥100 Kg ha⁻¹ yr⁻¹.