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Beginning June of 1993 suites of 13 water samples have been collected at Oyster Landing, North Inlet (SC), every 20 days covering two consecutive tidal cycles at 2.07 h intervals. In order to ascertain whether this large (and still growing) water chemistry data set can be used to determine tidal fluxes of nutrients and sediments, we coupled measured concentrations to estimates of instantaneous tidal discharge based on a basin water storage curve and hindcast tides. The mean advective fluxes of all constituents, including salt, showed statistically significant exports. This result, however, is largely due to an ebb bias in the sampling protocol, which resulted in 52% of the samples being collected on ebb tide versus a theoretical percentage of 48%. When this bias was corrected by reducing the mean discharge (−610 l s−1) to a value (−125 l s−1) that produced a balance between the mean advective and dispersive salt fluxes, the advective fluxes of the other constituents were reduced to values that are not significantly different from zero. In addition to a statistically significant dispersive influx of salt, significant dispersive exports were found for DON, NH4, DOP, PO4 and DOC. All particulate constituents (PN, PP, ISS and OSS) yielded dispersive fluxes that were not significantly different from zero. Annual material budgets for the Oyster Landing basin based on the dispersive fluxes of all constituents (except salt) are generally similar in magnitude and direction to those measured by [Dame, R.F., Spurrier, J.D., Williams, T.M., Kjerfve, B., Zingmark, R.G., Wolaver, T.G., Chrzanowski, T.H., McKeller, H.N., Vernberg, F.J., 1991. Annual material processing by a salt marsh-estuarine basin in South Carolina, USA. Marine Ecology Progress Series 72, 153–166.] in the nearby and ecologically similar Bly Creek basin, indicating that the dispersive fluxes determined in this study are realistic. We offer suggestions for improving the reliability and usefulness of future Oyster Landing water quality data. 相似文献
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L.A. Cifuentes R.B. Coffin L. Solorzano W. Cardenas J. Espinoza R.R. Twilley 《Estuarine, Coastal and Shelf Science》1996,43(6):781-800
Variations in elemental and isotopic ratios of suspended particulate matter (SPM) were investigated in the Guayas River Estuary Ecosystem (GREE) that empties into the Gulf of Guayaquil, Ecuador. Detritus in the system was identified on the basis of extremely high carbon:chlorophyll aratios (>1000). This material had mean δ13C of −26·4±0·3, δ15N of +4·8±0·2, and (C:N)atomicof 14·1±0·9. The isotopic data were comparable to measurements reported for fresh and degrading mangrove leaves, whereas the elemental ratio was comparatively enriched in nitrogen. Isotope measurements of SPM throughout the GREE were more similar to values for riverine material and detritus compared with that for the coastal end-member. Values indicative ofin situproduced algae, sewage and shrimp pond effluent were only found at selected sites. Bacterial bioassays, which were used to document potential sources of dissolved organic matter in the GREE, were isotopically similar to SPM. This correspondence coupled with the relatively low (C:N)aof SPM could be explained by bacterial immobolization of nitrogen onto detritus. Finally, tidal variations of (C:N)aand δ13C at a brackish mangrove site were similar in magnitude to spatial variations encountered throughout the GREE. Based on these results, the authors caution that care must be taken when samples are taken for food-web studies in these systems. 相似文献
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Fluctuations of peak energy and peak frequency o local wavelet energy spectrum for wind wavesTXFluctuationsofpeakenergyandpeak... 相似文献
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减少航道外波浪集聚对策研究 总被引:3,自引:0,他引:3
进港航道开挖引起波能重新分布 ,导致航道外近区域波能聚集 ,波高增大 ,从而影响防波堤稳定及港内泊稳条件。文章介绍了 Boussinesq方程的推导过程和发展过程 ,基于深水和缓变地形的色散关系 ,建立了波浪数学模型。该模型可用于研究深水和浅水地区波浪的浅水变形、折射、绕射和反射。并提出了减少波能聚集、降低堤前波高的多种措施。结合大窑湾港实际工程 ,经过多方面的数物模比选 ,利用数学模型优化出一种可行的喇叭口航道开挖方案并付诸实施 ,降低了防波堤的堤前波高 ,满足了预期的设计要求。 相似文献
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福建深沪湾潮间带全新世有孔虫及其环境意义 总被引:2,自引:1,他引:2
本文对深沪湾西部潮间带表层沉积物和两个钻孔岩芯共30个样品的有孔虫组成进行了定性和定量分析。结果表明,表层沉积物中有孔虫群分布规律明显,随着离岸向海越远,水深越大,有孔虫娄量从1倍数上升到5位数,种数为9-69种,多变度V31-44,复合分异度H(s)3.25-3.25。从钻孔岩芯中的全新世有孔虫群特征可看出,中全新世以来海面升降和海洋环境可分为2个阶段:(1)海水初到钻孔位置,有孔虫数量和种数较少,分异度不高,海相性程度较低。(2)后期(埋深1.8m和2.0m以浅),海面有所升高,变为潮间带(高潮位→中潮位→低潮位)环境。 相似文献
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本文通过对实测海平面高度的对比,发现龙口平均海平面从1991年起有明显的升高趋势。作者猜测此乃龙口在码头扩建后有系统下沉所致。 相似文献