Geomorphological and seismostratigraphic evidence for multidirectional polyphase glaciation of the northern Celtic Sea     

Zsuzsanna Tóth  Stephen McCarron  Andrew J. Wheeler  Stefan Wenau  Stephen Davis  Aaron Lim  Volkhard Spiess 《第四纪科学杂志》2020,35(3):465-478

High-resolution seismic and bathymetric data offshore southeast Ireland and LIDaR data in County Waterford are presented that partially overlap previous studies. The observed Quaternary stratigraphic succession offshore southeast Ireland (between Dungarvan and Kilmore Quay) records a sequence of depositional and erosional events that supports regional glacial models derived from nearby coastal sediment stratigraphies and landforms. A regionally widespread, acoustically massive facies interpreted as the ‘Irish Sea Till’ infills an uneven, channelized bedrock surface overlying irregular mounds and deposits in bedrock lows that are probably earlier Pleistocene diamicts. The till is truncated and overlain by a thin, stratified facies, suggesting the development of a regional palaeolake following ice recession of the Irish Sea Ice Stream. A north–south oriented seabed ridge to the north is interpreted as an esker, representing southward flowing subglacial drainage associated with a restricted ice sheet advance of the Irish Ice Sheet onto the Celtic Sea shelf. Onshore topographic data reveal streamlined bedforms that corroborate a southerly advance of ice onto the shelf across County Waterford. The combined evidence supports previous palaeoglaciological models. Significantly, for the first time, this study defines a southern limit for a Late Midlandian Irish Ice Sheet advance onto the Celtic Sea shelf. © 2020 John Wiley & Sons, Ltd.  相似文献   

北欧海微微型真核浮游生物的多样性和群落结构及其与环境因子的关系     

韩郁烨  郭萃  段雪萍  管旭冉  姜勇  邵红兵  矫玉田  汪岷 《海洋与湖沼》2019,50(6):1263-1270

为探究北欧海微微型真核浮游生物多样性和群落结构的分布特征,本研究于2017年6月采集北欧海一个典型断面的表层海水,利用标靶(18SrRNA基因V4区)扩增结合高通量测序技术研究了水体中微微型真核浮游生物的多样性及群落结构,并探讨了群落结构、优势类群与环境因子之间的关系。结果表明:微微型真核浮游生物群落的主导类群为囊泡虫类(54.61%),主要由甲藻纲(18.42%)和海洋囊泡虫新类群I (23.01%)组成;后鞭毛类占21.55%,其中真菌在各站中都有较高的相对丰度,为18.86%;此外,不等鞭毛类中的硅鞭藻和囊泡虫类中的甲藻在温度较低的站位中分布较多,而海洋囊泡虫新类群I则在温度较高的站位中分布较多。典型相关分析结果表明,温度对微微型真核浮游生物的群落结构有重要的影响。北欧海的水文特征复杂,寒暖流在此交汇,造成了微微型真核浮游生物的群落结构有明显的区域差异。  相似文献   

东南沿海台风风暴潮增水过程中非线性机制和地形的作用研究:以1509号台风"灿鸿"为例   总被引：4，自引：0，他引：4  

张西琳  楚栋栋  张继才  车助镁  李春雁 《海洋与湖沼》2020,51(6):1320-1331

本文基于FVCOM（Finite Volume Community Ocean Model）构建了一个覆盖中国渤海、黄海和东海的数值模型，采用NCEP-CFSR风场数据对1509号台风“灿鸿”产生的风暴潮进行模拟，与实测水位数据的对比表明该模型可靠、模拟结果合理。基于此模型，本文对非线性作用和地形在风暴潮增水过程中的作用进行了研究。首先，重点分析了增水过程中潮汐与风暴潮的非线性作用，结果表明：高潮时非线性作用使增水值降低；低潮时非线性作用使增水值升高。另外，开边界处分别只添加M₂、S₂和K₁分潮，分析天文潮的潮高和周期对非线性作用的影响，结果表明：潮高越高，非线性作用越明显；半日潮的非线性作用较全日潮更明显；并且，增水极值附近出现的半日周期的波动也与非线性作用有关。其次，除了非线性作用，地形对风暴潮的增水也有一定影响，本文改变地形的实验结果表明：坡度越大，增水极值越小。琉球群岛的存在使得东南沿海出现风暴潮增水的面积减小，但使得风暴潮增水的高值区域扩大。  相似文献   

北欧海大气低空辐合辐散的东西振荡模态及其相应的大气遥相关异常环流     

张书萌  黄菲 《中国海洋大学学报(自然科学版)》2021,(4)

北欧海作为连接北冰洋和北大西洋的重要海域,其由热效应产生的辐合场值得关注。本文利用NECP/NCAR的速度势函数(Velocity Potential,VP)数据表征北欧海辐合辐散场,发现在秋冬季北欧海上空大气低层存在一个独立的辐合区域。经验正交函数分解结果表明,北欧海上空的VP显示出除了表征北极涛动的全区一致型模态外,还表现出一个东西向辐合辐散反位相的东西振荡型模态。该模态与一支连接北大西洋涛动(NAO)和欧亚遥相关(EU)的复合型大气遥相关波列有关,北欧海表层潜热和感热异常加热通过影响低空大气的异常辐合辐散,与北大西洋偶极子型海温异常加热共同作用,加强了NAO异常环流;同时高空急流波导作用加强了从北欧海到东亚的EU波列,使得位于NAO和EU之间的北欧海成为连接NAO和EU大气遥相关波列的“中继站”,进而通过这种复合型大气遥相关波列将北大西洋与东亚大气环流联系起来,形成对东亚地区天气气候的远程影响。  相似文献   

中国海汇螺科Potamididae的分类学研究II．拟蟹守螺属、锥蟹守螺属、望远蟹守螺属及笋光螺属     

孙启梦  张素萍 《海洋科学》2022,46(10):13-23

继中国沿海汇螺科Potamididae分类学研究I后,又完成了汇螺科的分类学研究II。本文主要论述了汇螺科中拟蟹守螺属Cerithidea、锥蟹守螺属Cerithideopsis、望远蟹守螺属Telescopium及笋光螺属Terebralia共4属9种,其中1个中国新纪录种为邱氏拟蟹守螺Cerithideaquoyii(Hombron&Jacquinot,1848)。文中对其形态特征、生活习性和地理分布等进行了研究论述,并对以往鉴定有误和使用混乱的种名进行了修订。目前为止,共整理分类出中国沿海汇螺科5属18种。为了解中国汇螺资源情况、生物多样性和生态学研究提供基础资料。  相似文献   

The Convention on Biological Diversity's Ecologically or Biologically Significant Areas: Origins,development, and current status     

《Marine Policy》2014

In 2008, the Convention on Biological Diversity (CBD) adopted seven criteria to identify Ecologically or Biologically Significant Areas (EBSAs) “…in need of protection, in open ocean waters and deep sea habitats”. This paper reviews the history of the development of the “EBSA process”, which was originally driven by the commitment to establish marine protected areas in areas beyond national jurisdiction, but which has since broadened to encompass the possibility of informing marine spatial planning and other activities, both within and beyond national jurisdiction. Additionally, the paper summarizes ongoing efforts through CBD regional workshops to describe EBSAs and the development of the EBSA Repository, where information on these areas is to be stored. The overlap between the EBSA criteria and biodiversity criteria suites used by various authorities in areas beyond national jurisdiction is illustrated. The EBSA process has reached a critical juncture, whereby a large percentage of the global ocean has been considered by the regional workshops, but the procedure by which these areas can be incorporated into formal management structures has not yet been fully developed. Emerging difficulties regarding the mandate to describe, identify, endorse, or adopt EBSAs, are discussed.  相似文献   

北欧海主要海盆海面热通量的多年变化   总被引：2，自引：0，他引：2  

赵进平  Ken Drinkwater 《中国海洋大学学报(自然科学版)》2014,44(10):9-19

北欧海有暖流和寒流注入,又发生大量回流,水团特性异常复杂。由于北欧海的环流受地形控制,其水团的分布与4个海盆的分布有密切的关系。本文研究各个海盆热通量变化的差异,以研究获取对北欧海海气相互作用区域差异的认识。北欧海的热量夏季以太阳短波辐射为主,冬季以来自海洋的长波辐射、感热和潜热通量为主。海盆间的差异主要体现在格陵兰海,其变化幅度短波辐射高出50%,长波辐射高出大约40%,潜热高出大约60%,感热高出近4倍。可能的原因是,格陵兰海强烈的感热和潜热释放导致海温降低,气温也受北极冷空气的影响,形成与暖流区迥异的自然环境。过去30年发生了2次显著的热量减少事件。其中,1987年的事件很可能与冰岛的火山喷发有关,火山喷发对短波辐射的影响长达一年之久,导致感热和潜热也同步减少。1998年格陵兰海的潜热和感热明显减少,与北极海冰输出导致的海温偏低有显著关系。文章分析了4个主要海盆热通量的变化与北极涛动(AO)指数的关系。结果表明,发生在冰岛海的向下短波辐射和发生在格陵兰海的感热和潜热与AO相关度较高,体现了与AO的密切关系。这些热通量与AO指数的滑动相关系数表明,1992年以前冰岛海的短波辐射与AO的相关性非常高,而格陵兰海的感热和潜热在1993年后与AO高度相关,是值得深入研究的现象。本文的结果支持以下观点:北欧海对北极涛动的贡献主要是格陵兰海的感热和潜热释放通过冰岛低压区的上升气流影响冰岛低压的云量,从而影响到达的太阳辐射而导致大气环流的变化。  相似文献   

沉积分异作用与河口海洋沉积     

李玉中 《江苏地质》2014,38(4):556-560

沉积分异作用在解释表层沉积现象时具有重要意义。在水流辐聚或辐散区域,表层沉积物将因辐聚和辐散运移而分别呈细化和粗化状态。河口区细颗粒沉积区的形成,是因为河口区存在底层余流辐聚的滞流区现象;东中国海涡旋区泥质沉积现象的形成,是因为涡旋区存在指向涡旋中心的底层辐聚流;浙闽沿岸泥质沉积现象是近岸的浙闽沿岸流和远岸的台湾暖流之间存在余流辐聚带;英吉利海峡宽度最窄处的沉积物粗化现象,是因该处沉积物在水流作用下呈分离运移趋势所引起。  相似文献   

INTERNAL TIDES, SOLITARY WAVES AND BORES IN SHALLOW SEAS     

王涛  高天赋 《中国海洋湖沼学报》2001,19(2):103-111

Remote sensing and in situ observations of internal tides, solitary waves and bores in shallow water are briefly reviewed in this paper. The emphasis is laid on interpreting SAR images based on oceanographic measurements, and analyzing characteristics of internal waves in the China Seas. Direc-tions for future research are discussed.  相似文献   

UPWELLING AND SEDIMENTATION DYNAMICS Ⅲ：COINCIDENCE OF UPWELLING AREAS WITH MUD PATCHES IN NORTH HEMISPHERE SHELF SEAS   总被引：1，自引：0，他引：1  

庞重光  胡敦欣 《中国海洋湖沼学报》2002,20(2):101-106

The determinant role of upwelling in fine sediment patches is examined from the view-points of physical process and biological process respectively. It is pointed out that physical and biologicalprocesses are usually coexistent and interact with each other during the sedimentation of suspended mat-ters. This study used available figures showing the circulation pattern and surface sediment distribution inthe whole China Seas, the Gulf of Maine, the Irish Sea and the North Sea, and additional data to verifythat wherever upwelling exists on the continental shelf, mud must occur; and that wherever dowrtwellingoccurs, coarse sediment substitutes for mud.  相似文献