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1.
The study of contourite drifts is an increasingly used tool for understanding the climate history of the oceans. In this paper we analyse two contourite drifts along the continental margin west of Spitsbergen, just south of the Fram Strait where significant water mass exchanges impact the Arctic climate. We detail the internal geometry and the morphologic characteristics of the two drifts on the base of multichannel seismic reflection data, sub-bottom profiles and bathymetry. These mounded features, that we propose to name Isfjorden and Bellsund drifts, are located on the continental slope between 1200 and 1800 m depth, whereas the upper slope is characterized by reduced- or non-deposition. The more distinct Isfjorden Drift is about 25 km wide and 45 km long, and over 200 ms TWT thick. We revise the 13 years-long time series of velocity, temperature, and salinity obtained from a mooring array across the Fram Strait. Two distinct current cores are visible in the long-term average. The shallower current core has an average northward velocity of about 20 cm/s, while the deeper bottom current core at about 1450 m depth has an average northward velocity of about 9 cm/s. We consider Norwegian Sea Deep Water episodically ventilated by relatively dense and turbid shelf water from the Barents Sea responsible for the accumulation of the contourites. The onset of the drift growth west of Spitsbergen is inferred to be about 1.3 Ma and related to the Early Pleistocene glacial expansion recorded in the area. The lack of mounded contouritic deposits on the continental slope of the Storfjorden is related to consecutive erosion by glacigenic debris flows. The Isfjorden and Bellsund drifts are inferred to contain the record of the regional palaeoceanography and glacial history and may constitute an excellent target of future scientific drilling.  相似文献   

2.
俄罗斯沿岸海洋更新统的地层和岩性—岩相多样性是由不同的原因造成的:如沿岸和陆架构造机制特点,陆上的冰川均衡作用和海洋的冰川海平面升降运动,气候—水文机制等,并且经常彼此之间毫无联系。在这种条件下,考虑到极其不同的沉积物研究程度,建立基于某一特征的俄罗斯沿岸海洋更新统统一的内容可靠的地层表,  相似文献   

3.
Ocean Science Journal - This study sought to examine the characteristics and patterns of marine algae community changes in Wangdol-cho in order to establish a theoretical basis for the development...  相似文献   

4.
于2006-05-07采用同站位多介质同时采样的方法获得了表层沉积物样20件,底层水20件,沉积物间隙水17件,生物样27件,系统分析了各介质中痕量金属浓度的分布特征、相关关系及生物体对痕量金属的富集状况.对于不同介质来说,表层沉积物中痕量金属浓度最高,生物体和间隙水次之,底层水最低;然而与各介质的国家标准相比较,沉积物中痕量金属浓度基本无超标,底层水中痕量金属Cu,Pb,Zn的平均浓度大大超过国家海水水质一级标准,生物体中痕量金属Zn和Cu在各类生物体内的平均浓度远远超过国家海洋生物质量一级标准,根据澳大利亚国家卫生和医学研究理事会制定的人体消费卫生标准,As和Cd的浓度则严重超过人体消费标准;各类生物对痕量金属的富集系数均大于20,最高可达10 000以上;相关分析表明,沉积物、底层水及间隙水之间均存在正相关关系(R>0.6),生物体中多数痕量金属与其它介质中痕量金属的相关性不明显,仅元素Cu和Pb与沉积物中的Cu和Pb有相关性(R分别为0.547和-0.523,P值均小于0.05).  相似文献   

5.
Abstract. Hg, Cd, Pb and Zn concentrations were determined in sediment and in tissues of five species of soft-bottom marine macrophytes ( Posidonia oceanica, Cymodocea nodosa, Zostera noltii, Ruppia cirrhosa and Caulerpa prolifera ) along the Spanish Mediterranean coast. Levels of metals were low in most of the sampling stations and similar to those found by other authors in uncontaminated zones. Certain locations, however, showed some degree of contamination (Cambrils, Almassora, Alacant, Mar Menor and El Portús). In Santa Pola we found high contents of metals in one sample of sediment due to the high proportion of the fine fraction (particules < 63µm) and organic matter, but not in the seagrass species. Mercury and zinc concentrations in the sediment are correlated to those in at least some anatomic fractions of Posidonia oceanica, Cymodocea nodosa and Caulerpa prolifera , suggesting that these species reflect the levels of these metals in the environment. Lead contents in the alga Caulerpa prolifera are also correlated to those in the sediment, while no significant correlations were obtained for cadmium. Among the species studied, Posidonia oceanica and Cymodocea nodosa seem to be better biomonitors than Caulerpa prolifera .  相似文献   

6.
Abstract. Marine turtles harbour a variety of epizoa, some of which are specific to these hosts, but shelled gastropod and bivalve mollusks were previously unrecorded on marine turtles. Thousands of turtles of five species from all major oceans were examined. Loggerheads, Caretta caretta , from Greece and the states of Georgia and Florida, USA, were the most remarkable hosts to mollusks. At least 15 species of bivalves and 5 species of gastropods were found on turtles. Many turtles hosting mollusks carried only one species and few individuals. Edible oysters, the most common molluscan epizoan on Grecian Loggerheads, may grow to more than 10cm in diameter, so in some cases the mollusks may survive for several years on the turtle. Large epizoan bivalves may in turn serve themselves as substrates for epizoa, molluscan or otherwise. There are no known obligate relationships between turtles and mollusks, although there may be a parasitic relationship between the Loggerhead turtle, a spirorchid blood fluke, and a gastropod intermediate host. It is unknown if turtles carrying mollusks are at a disadvantage.  相似文献   

7.
为研究百年人类活动对广西防城江口沉积物的影响,依据2014-08取得的广西防城江口HSL柱的210Pb、粒度、常量元素、重金属元素数据,建立210Pb年代序列,对其重金属环境背景进行构建,对HSL柱的重金属元素富集系数进行计算,对人类活动影响下的重金属元素进行潜在生态危害评价。结果表明,HSL柱210Pb年代拟合系数在0.9以上,该柱沉积速率约为0.37 cm/a。以沉积物粒度中<32μm体积分数为参比元素构建的防城江口的重金属环境背景显示:HSL柱20 cm以深为"清洁样品";10 cm(约1990年)以浅开始显著受人类活动影响;5 cm(约2000年)以浅各重金属富集系数均显著受工业活动影响,Cd单因子危害系数达到强生态危害程度,Hg达到中等生态危害程度,潜在生态危害指数也达到强生态危害程度。受防城港市产业结构调整的影响,2010年之后潜在生态危害指数有所降低,但部分重金属(Cd和Hg)的潜在生态危害依然较为严峻。  相似文献   

8.
海洋文化遗产是指具有经济、文化、政治或社会方面价值的涉海历史遗存物,是海洋文化的重要载体,在沿海社会文化中发挥重要作用。与以欧盟为代表的发达国家相比,我国海洋文化遗产保护存在基础薄弱、认识不足、制度缺失等问题。将海洋文化遗产保护纳入海洋保护区管理范围,依托保护区管理体制开展信息普查、完善评估工具、健全管理制度,能够尽快建立起有效的管理保护体系。以青岛西海岸新区为例,提出了海洋文化遗产保护区域示范的思路和措施。  相似文献   

9.
Beach debris abundance was estimated from surveys on 10 beaches of the Turkish Western Black Sea Coast. Debris was collected from 20 m long transects during four different seasons; sorted and categorized by type, usage and origin. Litter density varied from 0.085 to 5.058 items m−2. Debris was mainly composed of unidentifiable small size (2–7 cm) plastic pieces and beverage-related litter such as bottles and bottle caps. About half of the labeled litter was of foreign origin, including 25 different countries, 23% of which are in the Black Sea region.The south-western Black Sea Coast seems to receive foreign litter from two main sources: land-based debris from the neighboring countries and seaborne debris due to international shipping. Standardized methodology and indicators need to be designated all over the Black Sea basin in order to quantify and qualify coastal litter pollution, monitor compliance with MARPOL and develop regionally effective mitigation measures.  相似文献   

10.
黄海西部底栖海藻记录的评论   总被引:1,自引:0,他引:1  
黄海西部是指北起鸭绿江口,南至长江口(包括渤海)的中国沿岸。这一带的海藻研究,迄今将近百年,目前已掌握的海藻分类研究文献共有45篇。我们在研究和分析这些文献后,把这些海藻记录归的为3类。(1)可以接受的记录:根据我们十多年来在黄海沿岸的调查采集经验证实所记录的产生于黄海西部的海藻,或虽尚未采到,但就目前的资料分析,估计该项记录可能是正确的。(2)待证实的记录:有些海藻记录无法肯定其鉴定是否正确,需待重新检查其原标本后始能确定的。(3)不能接受的记录:这类记录中,有些是已被藻类学家所否定,有些经检查原定名标本后证实是错误的,有些则根据地理分布观点,被认为是不可能生长在这个海区的种类。 根据黄海西部的海藻研究的发展情况,我们把过去的工作划分为两个历史阶段。  相似文献   

11.
南海北部陆坡神狐海域HS-373PC岩心表层沉积物古菌多样性   总被引:3,自引:0,他引:3  
利用分子生物学技术分析南海北部神狐海域天然气水合物潜力区HS-373PC岩心表层沉积物中古菌多样性,从沉积物中提取总DNA并扩增古菌16SrRNA基因序列,对克隆文库进行系统发育分析。结果显示所有古菌序列均属于泉古菌(Crenarchaeota)和广古菌(Euryarchaeota)。其中泉古菌以C3为主要类群,另有少量序列属于Marine Benthic Group(MBG)-B,MBG-C,Marine Crenarchaeotic Group I(MGI),Marine Hydrothermal VentGroup(MHVG)和Novel Group of Crenarchaea(NGC);广古菌以MBG-D为主,其它序列分别属于UnclassifiedEuryarchaeotic Clusters-1/2(UEC-1/2)。  相似文献   

12.
本文对常用的染料亚甲基蓝(MB)在海洋沉积物上的吸附行为进行了研究,发现它的吸附机理主要是在沉积物上的表面吸附和微孔作用,吸附与黏土矿物的含量有一定的相关性.在实验浓度范围内,MB在3种不同处理方式沉积物上的吸附行为都可以用Freundlich等温式来描述.通过改变吸附条件发现,随着盐度的增加,吸附能力减小,而温度的改变,对吸附能力的影响并不明显.此外,通过向体系中加入不同表面活性剂来模拟双溶质体系的方法,对MB与表面活性剂的竞争吸附行为进行了研究.结果发现在2种介质中,吐温20(Tween20)的加入对吸附的影响均不大;十六烷基三甲基溴化铵(CTAB)的加入使MB的吸附能力减弱,在蒸馏水中抑制作用更加明显;在海水中,十二烷基苯磺酸钠(SDBS)对吸附有抑制作用,而在蒸馏水中,SDBS却对吸附起到促进作用.  相似文献   

13.
研究非离子表面活性剂Tween20在海洋沉积物上的吸附行为.发现沉积物中有机质和粘土矿物的含量对其吸附起主要作用.在实验浓度范围内,Tween20在HCl和H2O处理沉积物上的吸附行为可用线性等温式描述,而在H2O2处理样上的吸附行为可用Freundlich等温式来描述.海水的离子强度和温度都影响其吸附行为:离子强度增加,温度降低,会使沉积物的吸附能力增加.根据热力学函数关系计算出吸附焓ΔHθ为-32.98 kJ/mol,吉布斯自由能ΔGθ为-16.01~-16.99 kJ/mol,吸附熵ΔSθ<0.Tween20在海洋沉积物上的吸附是一自发放热的过程.  相似文献   

14.
本文对常用的染料亚甲基蓝(MB)在海洋沉积物上的吸附行为进行了研究,发现它的吸附机理主要是在沉积物上的表面吸附和微孔作用,吸附与黏土矿物的含量有一定的相关性。在实验浓度范围内,MB在3种不同处理方式沉积物上的吸附行为都可以用Freundlich等温式来描述。通过改变吸附条件发现,随着盐度的增加,吸附能力减小,而温度的改变,对吸附能力的影响并不明显。此外,通过向体系中加入不同表面活性剂来模拟双溶质体系的方法,对MB与表面活性剂的竞争吸附行为进行了研究。结果发现在2种介质中,吐温20(Tween20)的加入对吸附的影响均不大;十六烷基三甲基溴化铵(CTAB)的加入使MB的吸附能力减弱,在蒸馏水中抑制作用更加明显;在海水中,十二烷基苯磺酸钠(SDBS)对吸附有抑制作用,而在蒸馏水中,SDBS却对吸附起到促进作用。  相似文献   

15.
本文对常用塑料增塑剂邻苯二甲酸二丁酯( DBP)在海洋沉积物上的吸附行为进行研究,发现它的吸附机理主要是在沉积物上的有机质间分配及表面吸附和微孔作用,吸附与有机质含量和黏土矿物的含量有一定的相关性.在实验浓度范围内,DBP在3种不同处理方式沉积物上的吸附行为分别可以用Linear和Freundlich等温式来描述.通过改变吸附条件发现,随着盐度减小、温度的增加,吸附能力减小;而随酸度的升高,吸附能力先升高后下降.此外,通过向体系中加入不同表面活性剂来模拟双溶质体系的方法,对DBP与表面活性剂的竞争吸附行为进行了研究.结果发现,十六烷基三甲基溴化铵(CTAB)和吐温80(Tween80)的加入使DBP的吸附能力增强;十二烷基苯磺酸钠(SDBS)的加入使DBP的吸附能力降低.  相似文献   

16.
Offshore geotechnical surveys form part of an integrated investigation to rejuvenate a decrepit minor port at Badagara, Kerala on the southwestern coast of India. The sediments typify a fluvio-marine milieu ranging from silty clay, sand, silty sand, sandy silt and clayey silt. Geotechnical and sedimentological studies of shallow cores reveal the geotechnical aspects besides the depositional history of the sediments. Downcore geotechnical variations and regressive coefficients based on their inter-relationships highlight diverse factorial inferences. X-Ray Diffraction data indicate the prominent clay type.

A comparative evaluation of the geotechnical characteristics of clayey sediments off Badagara, with similar studies along various sectors of the Kerala coast, both on land as well as in the near shore, is broadly attempted. Geotechnical studies carried out earlier on the uplifted Cochin marine clays provide comparative data for evaluating the possible variations between present day marine clayey sediments occurring along the Kerala coast and uplifted marine clays which, besides their gross variations in levels with respect to the present sea-level, also obviously relate to a much older depositional environment and provenance during probable Holocene times.  相似文献   

17.
海洋沉积物中硝化和反硝化过程研究进展   总被引:3,自引:0,他引:3  
硝化和反硝化过程是氮循环的中心环节。水生态环境中氮的转化受诸多因素的制约,了解这些控制要素的作用机理,对预防和消除水体富营养化或缓解初级生产的氮限制有重要意义。综述了硝化和反硝化的研究现状,着重介绍了硝化-反硝化影响因素及测量方法的研究进展,并预测了进一步研究重点。  相似文献   

18.
海洋沉积物取样测量会改变沉积物的温度、压力等参数,取样测量所得到的数据会与沉积物的真实参数有所差距。针对上述问题本文开展了海洋沉积物热、电、声探测技术研究,并设计了一款适用于深潜器的海洋沉积物原位热、电、声多参数探针。探针使用时差法测量沉积物中的声速、声衰减系数,使用温纳法测量沉积物的电导率参数,使用NTC热敏电阻作为温度传感器测量沉积物温度。在探针校准并对沙质沉积物进行测量。实验结果表明探针测量电导率标准误差小于2.8 %。温度测量误差小于0.28 ℃,温度测量时间不小于120 s,此次获取泥沙样品的声速为1 737.5 m/s,声衰减系数2.5 dB/m。实验结果显示该探针能够准确、快速的测量海洋沉积物的热、电、声参数。  相似文献   

19.
渤海湾西岸潮间带沉积物粒度分布特征   总被引:2,自引:1,他引:2  
根据2003年12月在渤海湾西岸海河口南缘至歧口间岸段采集的4个柱状沉积物样品和6个表层样品的粒度分析结果,探讨了渤海湾西岸潮间带的粒度分布特征和沉积作用。结果表明,由北向南,表层沉积物逐渐变细,分选性变差。海河口南缘至独流减河之间的表层沉积物为分选良好的细砂,至歧口附近变为粉砂质粘土。在垂直方向上,表层以下一定深度内沉积物的平均粒径都存在一均匀层,层内沉积物为分选良好的细砂,此深度以下沉积物中的粘土含量增加。说明由于60年代之后的自然变化和人类活动,入海泥沙量减少,改变了潮间带沉积物原有的输沙与海滩发育模式,导致独流减河以北的砂质沉积物出现粗化现象。  相似文献   

20.
Jan Kavan 《Marine Geodesy》2020,43(3):234-247
Abstract

Changes in the position of the shore in the vicinity of Kapp Napier in central Svalbard was described. The overall advance of the shore was probably related to high input of the sediment material originating from erosion of the coastal areas south of the Kapp Napier locality and high input of material from adjacent glacifluvial system of Nordenskiöld glacier with its marginal water streams. Fast evolution of glacier retreat related processes after the Little Ice Age was a secondary driver of the dynamic changes in the central Svalbard coastal areas especially in the first half of the 20th century. The highly dynamic longshore currents in the area altogether with still ongoing glacio-isostatic uplift played an important role in the process as well. The most active parts of the shore experienced advance of almost 100 m since 1908 to 2009. On the other hand, a small part of the coast retreated of about 20 m. Most of the study area experienced aggradation (65%), 30% of the coast was stable and about 5% of the coast has undergone minor retreat. The maximum aggradation rate of 0.96?m/year corresponds well with similar sites in the vicinity.  相似文献   

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