The hydrodynamics and salinity regime of a coastal lagoon – The Coorong,Australia – Seasonal to multi-decadal timescales     

Ian T. Webster 《Estuarine, Coastal and Shelf Science》2010

The Coorong is a choked coastal lagoon in South Australia that forms part of the terminal lake system at the end of the River Murray, Australia’s major river. It is an inverse estuary with a constricted channel connection to the sea at one end and extends parallel to the coast for more than 100 km away from this inlet. The present paper considers the physical dynamics of the Coorong, particularly its ecologically important salinity and water level regimes, and how these respond to connectedness with the ocean, barrage flows and meteorological conditions. The approach combines hydrodynamic modelling with measurements and considers temporal variation in the system ranging from seasonal to multi-decadal timescales.  相似文献   

环礁潟湖沉积物重建南沙群岛小冰期以来的热带气旋活动     

杨红强  谭飞  徐辉龙  张喜洋  施祺  陶士臣 《热带海洋学报》2022,41(6):171-182

热带气旋活动以及由此产生的风暴潮和强降雨对南海及周边沿海地区社会经济构成巨大威胁。对器测记录之前全新世热带气旋的研究有助于准确预测全球变暖背景下热带气旋活动的变化趋势。本文利用南沙群岛安乐礁潟湖沉积物重建了小冰期以来准年分辨率的热带气旋活动,共识别28个风暴事件层。研究表明,小冰期以来,南沙群岛安乐礁热带气旋活动在年代际到百年尺度上频繁变化,发育两个主要的风暴活跃期。在小冰期早期(AD1471—1620)经历了最为强烈的风暴活跃期,另一个风暴活跃期位于现代暖期的AD 1930—1960,风暴活动虽有所加强,但明显低于小冰期早期。与同期永暑礁重建结果的对比表明,热带气旋活动存在明显的时空差异性,更多来自相近区域的高分辨率风暴记录可有效降低古风暴活动重建的不确定性,提高重建记录的准确度。  相似文献   

Human-induced sedimentological changes in Manzala Lagoon, Nile Delta, Egypt   总被引：1，自引：0，他引：1  

G. Randazzo  D. J. Stanley  S. I. Di Geronimo  C. Amore 《Environmental Geology》1998,36(3-4):235-258

 The Manzala Lagoon in Egypt's Nile Delta has become a sediment sink of reduced area and depth, with increased contaminant levels. Loss of much-needed fresh to brackish water reserves and decreased fish catches have serious ramifications. Herein, maps of temporal and regional sediment distributions in Manzala incorporate petrological and statistical analyses of 200 surficial and short core samples. These provide baseline information needed to help implement protection measures for this vital wetland. Four periods are considered: 1920s, 1940s, ∼1965, and 1990. Important depositional changes between 1940s and ∼1965 resulted from anthropogenic effects on this quasi-closed lagoon system, including industrial buildup, wetland conversion to agricultural land, and irrigation waterway development. Further modification from ∼1965 to 1990 is associated with closure of the Aswan High Dam, continued construction of waterways that discharge waste water into lagoon margins, and marine incursion into the northern lagoon. If current practices continue, the lagoon could be reduced to about one-third of its present area by 2050 AD. Received: 2 October 1997 · Accepted: 13 January 1998  相似文献   

Fish Larvae Abundance and Distribution in the Coastal Zone off Terminos Lagoon, Campeche (Southern Gulf of Mexico)     

L. Snchez-Velasco  C. Flores-Coto  B. Shirasago 《Estuarine, Coastal and Shelf Science》1996,43(6):707-721

Fish larvae abundance and distribution in the coastal zone off Terminos Lagoon and their relation to the environmental features of the Lagoon inlets were analysed (1986–87). The sampling grid consisted of 24 stations extending between 0·5 and 10 km off the Lagoon, including both Terminos Lagoon Inlets; El Carmen and Puerto Real. A total of 23 families and 43 species were identified. Highest larval abundance was registered during the rainy period (July and September) when the fluvial discharges favoured the planktonic development. The lowest larval abundance was recorded in the period of northern cold wind (January–March) when the fluvial discharges decreased. Bray-Curtis index defined two groups of stations, corresponding to each of the lagoon inlets, persisting throughout the year. The first one, ‘ El Carmen ’, was characterized by larvae of Engraulidae and Gobiidae; estuarine-dependent inhabitants. This group could be considered as a functional extension of the Lagoon to the sea. The second group, ‘ Puerto Real ’, was characterized by highest larval abundance of marine dwellers (e.g.Opisthonema oglinumandHarengula jaguana). This situation suggests that the Puerto Real Inlet could be the main entrance of marine fishes into the Lagoon. These results indicate that the coastal zone off Terminos Lagoon constitutes an important nursery area both for species spending part of their life cycle linked to this estuarine system, and for marine species that migrate towards the Lagoon, carried by local currents.  相似文献   

Spatial versus temporal patterns in fish assemblages of a tropical estuarine coastal lake: The Ebrié Lagoon (Ivory Coast)     

Jean-Marc Ecoutin  Emilie Richard  Monique Simier  Jean-Jacques Albaret 《Estuarine, Coastal and Shelf Science》2005,64(4):623-635

The fish assemblages of the Ebrié lagoon (Ivory Coast) were sampled by experimental fishing over the entire lagoon using a purse seine net. The sampling was conducted in the two main hydroclimatic seasons for this ecosystem, i.e. in the dry season (March–April) and in the wet season (August–September). The results obtained showed a fish assemblage organized around a consistently occurring group of twenty species. When analysed in terms of ecological categories, the seasonal influence led to a cycle in the assemblages from freshwater to marine around this permanent species pool, with a seasonal renewal of the assemblage. At the scale of the lagoon, there were variations in the composition of the assemblages that clearly distinguished the western part from the eastern one. The limit was situated at the Vridi canal, a wide artificial channel permanently connecting the lagoon to the sea. To the west, the assemblage was characterised by a strong spatial uniformity and low seasonal variability. To the east, the assemblage formed two different entities; one assemblage with pronounced freshwater affinities occurring in a side arm and the other assemblage with great seasonal variability under the alternating influence of seawater in the dry season and freshwater in the wet season. This part of the lagoon functioned somewhat like a typical estuary.  相似文献   

Integration of High and Very High-resolution Seismic Reflection Profiles to Study Upper Quaternary Deposits of a Coastal Area in the Western Gulf of Lions, SW France     

Caroline Labaune  Michel Tesson  Bernard Gensous 《Marine Geophysical Researches》2005,26(2-4):109-122

High resolution (HR – sparker) and very high resolution (VHR – boomer) seismic reflection data acquired in shallow water environments of the Roussillon coastal area are integrated to provide an accurate image of the stratigraphic architecture of the Quaternary deposits. The complementary use of the two systems is shown to be of benefit for studies of shallow water environments. The HR sparker data improved the landward part of a general model of Quaternary stratigraphy previously established offshore. They document an incised valley complex interpreted as the record of successive late Quaternary relative sea-level cycles. The complex is capped by a polygenetic erosional surface developed during the last glacial period (>18 ky) and variably reworked by wave ravinement during the subsequent post-glacial transgression. The overlying transgressive systems tract is partly preserved and presents a varying configuration along the Roussillon coastal plain. The VHR boomer data provide information on the architecture of the uppermost deposits, both in the near-shore area and in the lagoon. These deposits overlie a maximum flooding surface at the top of the transgressive systems tract and constitute a highstand systems tract composed of two different architectural elements. In the near-shore area, a sandy coastal wedge is subdivided into a lower unit and an upper unit in equilibrium with present day dynamics. In the Salses-Leucate lagoon area, the sedimentary architecture is highly complex due to the closure of a former embayment and the formation of the present beach barrier.  相似文献   

海南岛小海沙坝-泻湖-潮汐通道体系自动调整及恶化   总被引：5，自引：0，他引：5  

王世俊  李春初  田向平 《台湾海峡》2003,22(2):248-253

本文运用历史地图对比方法，结合现场考察及水文泥沙测量资料，分析海南岛小海口门近40a来的变化过程，找出小海口门在人为作用下的演变规律．结果表明，小海沙坝—泻湖—潮汐通道体系曾是一个稳定的系统，它通过口门断面、地形调整以适应在人类活动作用下口门动力的变化并保持相对平衡．三大人为活动的综合影响，尤其是盐墩三岛的围垦及冈箱养殖，破坏了口门维持的最后动力(潮汐动力)，使小海沙坝—泻湖—潮汐通道体系失去了调整作用，直接导致了口门的迅速缩小．因此小海综合治理的首要任务是小海口门的治理。  相似文献   

Biology of Ethmalosa fimbriata (Bowdich) and fish diversity in the Ebrie Lagoon (Ivory Coast), a multipolluted environment     

Guyonnet  B; Aliaume  C; Albaret  J.-J; Casellas  C; Zerbi  A; Lasserre  G; Do Chi  T 《ICES Journal of Marine Science》2003,60(2):259-267

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Population Ecology of the Amphipod caprella equilibra Say in a Lagoon Estuary (Northern Adriatic Sea, Italy)     

R. Sconfietti  P. Lupari 《Marine Ecology》1995,16(1):1-11

Abstract. The population ecology and dynamics of Cuprella equilibra were studied in a lagoon estuary of the Northern Adriatic Sea during 1985 to 1986. The breeding activity showed peaks in April and September and a decrease in summer due both to high temperatures and a dystrophic crisis; breeding stops in winter. Females produced more than one brood per year.  相似文献   

粤东后江湾沙坝—泻湖海岸系统的演变及动力分析   总被引：1，自引：2，他引：1  

戴志军  韩丽  施伟勇 《台湾海峡》2001,20(2):142-146

本文根据钻孔资料及海图对比，对粤东后江湾沙坝－泻湖海岸系统的形成和发展过程进行了初步探讨，在此基础上，分析了该系统近代演变的动力作用及泥沙运动。  相似文献