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1.
对墨西哥湾北部水深2200m的Alaminos Canyon645区块（AC645区）和水深540m的Green Canyon185区块（GC185区）冷泉碳酸盐岩的有机质进行了研究，结果显示深水和浅水区冷泉碳酸盐岩的有机质丰度和烷烃组成差别较大，下陆坡深水AC区样品有机质含量低，正构烷烃、萜烷、甾烷各组分的含量相对较高，正构烷烃以低碳数占绝对优势，并含有种类丰富的三环萜烷和五环三萜烷，且以17a（H），21B（H）-藿烷为主峰碳，反映了深水区冷泉碳酸盐岩的有机质来源于细菌和低等藻类，有少量的深部油气藏有机质的渗漏输入，并受微弱的微生物作用改造。上陆坡浅水GC区样品有机质含量较高，其中正构烷烃含量较低，并且以难以分开的复杂混合物（UCM）为主，同样含有种类丰富的以17α（H），21β（H）-降藿烷为主峰碳的三环萜烷和五环三萜烷，表明有机质主要来源于深部油气藏渗漏的有机质，并遭受了强烈的微生物降解。本文系统地研究了冷泉碳酸盐岩中正构烷烃、萜烷、甾烷的组成和分布特征，并探讨了有机质来源和冷泉渗漏的关系。 相似文献
2.
正构烷烃及单体碳同位素的古植被与古气候意义 总被引：11，自引：1，他引：11
与古植被、古气候变化密切相关的正构烷烃分子化石及其单体碳同位素的研究是近年来最为引人注目和关切的环境科学问题之一，这一研究在国际上已取得了一定的成果。在详细综述国际上正构烷烃及其单体碳同位素在古植被与古气候方面研究进展的同时，着重叙述了他们在生物输入源的识别，古植被、古温度的重建以及古大气飘尘源区气候变化的响应等方面的研究动态，分析并讨论了目前存在的问题及其发展趋势。指出随着测试分析技术的发展，正构烷烃分子化石及其单体碳同位素将成为重现古环境变迁和现代环境信息变化的一个强有力的工具。 相似文献
3.
利用气相色谱-质谱联用仪(GC-MS)对湖北麻城金罗家遗址古文化层样品进行了系统分析,检测出丰富的类脂物分子,包括正构烷烃、一元正脂肪酸、一元正脂肪醇和α-正构脂肪酮等,主要讨论正构烷烃类脂物的分布特征。正构烷烃的分布在各文化层不同,其中,在生土层以C17为主峰;西周文化层F2和F4两样品以C17和C31为双主峰,F3样品以C17为主峰;东周文化层主要以C17和C31为双主峰,而F 7以C31为主峰,F9以C17为主峰;唐宋文化层以C17和C31为双主峰;明清文化层以C31为主峰,现代耕植土层以C29为主峰。而正构烷烃高碳数C27/C31比值的变化反映出遗址域中木本植物与草本植物的相对变化,正构烷烃高碳数ACL值反映遗址域中的草本植物与木本植物之间的转变,有机δ13C表现为C3和C4植物,它们在本剖面上表现出多阶段的变化。因此,正构烷烃在不同的人类古文化层具有不同的分布特征,除了反映当时的微生物活动、植物属种的相互取代或分子沉积后的改造作用外,还可能蕴藏着当时的气候变化和古人类活动的信息,有待进一步研究。 相似文献
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5.
采用气相色谱/质谱方法(GC/MS)对7 种常见润滑油中的生物标志化合物(正构烷烃、姥鲛烷、植烷、甾烷、萜烷、多环芳烃)进行定性分析, 并基于其生物标志化合物指纹信息进行了多元统计分析。结果表明, 润滑油的气相色谱图中不可分辨的混合物(UCM)具有明显优势; 润滑油中含有丰富的甾、萜烷类稠环生物标志化合物, 仅含有非常少量的饱和链烷烃(正构烷烃、姥鲛烷、植烷)和多环芳烃类(目标多环芳烃、烷基化多环芳烃、二苯并噻吩同系物)生物标志化合物; 基于甾、萜烷类生物标志化合物指纹信息的主成分分析与聚类分析所得的结果高度一致, 均可用于有一定差异的润滑油的鉴别分析。 相似文献
6.
泸沽湖沉积物正构烷烃分布特征及其古植被意义 总被引：1，自引：0，他引：1
利用气相色谱-质谱联用仪从泸沽湖沉积物中检测出丰富的正构烷烃系列分子化石,泸沽湖沉积物正构烷烃分布特征可归纳为双峰前峰型和双峰后峰型,说明泸沽湖沉积有机质母质来源为混源。较高丰度的中等长度正构烷烃及Paq和(C15+C17+C19)/(C27+C29+C31)比值等指标指示挺水植物及沉水/漂浮植物等水生植物贡献量较大,同时,也说明较大的内源输入可能是泸沽湖TOC含量较高的原因之一。主峰碳及正构烷烃代用指标(C27+C29)/(C31+C33)比值和ACL指示泸沽湖沉积有机质木本植物输入量占优势,这与现今泸沽湖流域植被类型特征相符。纵向上,(C27+C29)/(C31+C33)比值和ACL没有明显的阶段性和趋势性变化,反映出正构烷烃记录的泸沽湖流域草本植被与木本植被相对变化不明显。不同沉积时期正构烷烃分布特征有所不同。3万年以来泸沽湖流域植被演化特征可以分为3个阶段:30~20cal.kaBP气候偏干冷,沉积有机质母质主要为低等水生生物和藻类,沉水和漂浮植物也有较大贡献;20~5cal.kaBP为相对暖湿的气候环境,陆源高等植被对泸沽湖沉积有机质的贡献增加;5~0cal.kaBP(对应剖面205~0cm)气候有变冷干的趋势,沉积有机质物源以低等水生生物和藻类为主,同时,具有较多高等植物和沉水/漂浮植物输入。泸沽湖流域12kaBP为干冷气候时期,这在时间与气候特征上与YD事件相符,可能是西南季风对YD事件的响应。 相似文献
7.
正构烷烃气相色谱指纹法鉴别海面溢油源一事例研究 总被引：5，自引：0，他引：5
通过对厦门海域一个具体海面溢油事例的研究，探讨了鉴别海面溢油源的正构烷烃气相色谱指纹法及其可行性和有效性，结果令人满意。该方法包括样品的前处理、GC测定和数据分析。其整个操作流程短，且较简便易行，尤其是选择正十七烷（n－C17）、正十八烷（n－C18）、姥鲛烷（pri）、植烷（phy）和正二十烷（n-C20）等特征烷烃作为判据，可信度大，对于经历一定风化作用的海面溢油仍可进行有效的鉴别。 相似文献
8.
长江、黄河河口沉积物中生物标志化合物组成的初步研究 总被引：5，自引：1，他引：5
该文对长江口、黄河口以及废黄河口现代沉积物中生物标志化合物组成进行分析。结果表明 :长江与黄河沉积物中的生物标志化合物组成有较大的差别 ,长江沉积物中具明显奇偶优势的高碳数正构烷烃以及 C2 9甾烷的相对含量较高 ,Pr/Ph值较大 ,受陆生高等植物的影响明显 ;黄河低碳数正构烷烃和 C2 7甾烷的相对含量较高 ,Pr/Ph值较小 ,受陆生高等植物的影响较弱。甾烷、萜烷的成熟度指数显示长江高于黄河、现代黄河高于废黄河。这些差异主要受流域环境背景和流域内人文过程两大不同因素的影响 相似文献
9.
《海洋湖沼通报》2015,(3)
以实际溢油案例中出现的4种油品为对象,利用GC/MS分析手段研究了不同油品之间的正构烷烃、多环芳烃和甾烷萜烷的分布特征和特征比值的一致性。结果表明:(1)不同油品指纹的正构烷烃特征比值CPI,萜烷类特征比值C31αβ(S/(S+R))、C32αβ(S/(S+R))、C33αβ(S/(S+R))、C34αβ(S/(S+R))和甾烷类特征比值C29甾ααα(S/(S+R))差异性不明显,可能会出现一致性;(2)不同油品指纹的多环芳烃特征比值存在明显差异,基本不存在一致性问题;(3)在油指纹鉴别过程中,要考虑到特征比值参数的稳定性,同时考虑不同油品指纹特征比值可能出现的一致性问题。 相似文献
10.
利用GC-MS对红原泥炭样品中的分子化石进行了系统检测,获得了一系列正构烯烃,碳数分布范围为C18—C28,主峰碳为C27,次主峰为C23或C25,与同一深度处的正构烷烃分布模式完全不同。泥炭中正构烯烃的轻重组分∑C21-/∑C2 1、正构烯烃与相应碳数的正构烷烃比值呈有意义的阶段性变化。其中∑C21-/∑C21 与正构烷烃L/H的变化趋势大体一致;而C24:1/C24:0和C23:1/C23:0比值却与之相反。这可能与正构烯烃,特别是这些中碳数化合物因气候如温度的变化在厌氧条件下发生微生物的氢化作用有关,很可能记录了青藏高原东北部地区全新世以来的温度信号。(C26 C27 C28)/(C23 C24 C25)正构烯烃比值,与该区植被分布具有一定的对应关系,说明这些正构烯烃可能除了与植被有关外,也与不同植被类型的组织具有不同抗微生物降解能力相关。这些指标记录的气候信息与前期报道的分子化石记录的气候演化基本一致,说明正构烯烃可以作为古气候的替代性指标。 相似文献
11.
Arne Schnack-Friedrichsen Angela M. Davis Jim D. Bennell Dei G. Huws 《Marine Georesources & Geotechnology》2001,19(4):221-243
The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths. 相似文献
12.
Shigehisa Nakamura 《Marine Geodesy》2000,23(1):55-61
Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone. 相似文献
13.
The effect of different fixation and storage protocols on the flow cytometric (FCM) simultaneous analysis of bacterioplankton and phytoplankton in coastal seawater samples (Mediterranean coastal lagoons) was investigated. FCM measurements (cell number, fluorescence and scatter characteristics) were obtained through DAPI staining. Three fixatives [glutaraldehyde (GA), formaldehyde (FA) and paraformaldehyde (PFA)] and two storage (3 months duration) methods (5 °C and −196 °C) were tested. Two dominant populations were detected in studied samples: bacteria and eukaryotic picophytoplankton. Adding fixatives (2% final concentration) appears necessary to obtain FCM exhaustive counts of all the bacteria and phytoplanktonic cells. This was related to the permeation effect of fixatives which allowed a better DAPI staining of the cells. Maximum fluorescence, i.e. optimal staining of the cells was obtained with FA or PFA, and significant lower fluorescences with GA. Fixed samples stored at 5 °C induced rapid cell loss. Only storage in liquid nitrogen of samples fixed with FA or PFA, allows mid-term (≥4 months) preservation of bacteria or picophytoplankton cell numbers, and limited evolution of DAPI-induced fluorescence and scatter characteristics. 相似文献
14.
Coastal inundation associated with extreme sea levels is the main factor which leads to the loss of life and property whenever a severe tropical cyclonic storm hits the Indian coasts. The Andhra and Orissa coasts are most vulnerable for coastal inundation due to extreme rise in sea levels associated with tropical cyclones. Loss of life may be minimized if extreme sea levels and associated coastal flooding is predicted well in advance. Keeping this in view, location specific coastal inundation models are developed and applied for the Andhra and Orissa coasts of India. Several numerical experiments are carried out using the data of past severe cyclones that struck these regions. The simulated inland inundation distances are found to be in general agreement with the reported flooding. 相似文献
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《海洋学报(英文版)》2014,(9):F0003-F0003
<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology, 相似文献
17.
Hoi-Soo Jung Kap-Sik Jeong Yong-Shik Chu Sung-Hyun Park Ki-Hyune Kim 《Marine Georesources & Geotechnology》2001,19(3):181-195
Grain size and water content in box-core sediments from the Clarion-Clipperton fracture zone (C-C zone) in the northeast equatorial Pacific were analyzed in detail to understand the downcore variations across a hiatus between Quaternary and Tertiary layers. Grain-size distributions in the topmost core sediments show two modes: a coarse mode (peaked at 50 μm) and a fine mode (at 2-25 μm). The coarse mode disappears gradually with depth accompanied by the dissolution of siliceous fossil tests, whereas the fine mode coarsens due to the formation of authigenic minerals. Water content increases abruptly across a color boundary between an upper pale brown layer and a lower dark brown layer that is the hiatus between Quaternary and Tertiary layers. Abundant smectites and microvoid molds, which are created by the prolonged fossil dissolution in the underlying sediment, are attributed for the abrupt downcore variation of water content. Overall variations in grain size and water content in the topmost core sediments in the western C-C zone are possibly constrained by the dissolution of biogenic siliceous fossils. Variations in geotechnical properties related to these changes must be considered in the design of nodule collectors. 相似文献
18.
Shigehisa Nakamura 《Marine Geodesy》2001,24(1):27-33
This article concerns an interrelation between the sea levels and the western boundary flow near a tectonic boundary in a local zone in the Northwestern Pacific. In this zone, sea level variations at stations located on the coast facing the Pacific are studied to find the interrelation between variations of the Kurosio flow as an index of the distance of the flow axis off a specific coast. The result is discussed after data processing of the monthly means of the sea levels, and a notice is taken of variations caused by active crustal upheavals during a seismic event, a local earthquake. 相似文献
19.
This study tests the hypothesis that the in situ void ratio of surficial marine sediments may be predicted from shear wave velocity-depth data with a reliability equal to that of other methods currently available. Shear wave velocity is fundamentally controlled by the number of grain-to-grain contacts per unit volume of material and by the effective stress across those contacts. In this study, three previously established empirical formulae are used to predict void ratio from velocity-depth data. Field data were acquired along a transect off the northern Californian coast across which water depth increased from 35 to 70 m and seafloor sediment type varied from sand to silty-sand, respectively. A towed seafloor sled device was used to collect shear wave refraction data, and a marked, systematic decrease in velocity was observed along the line, ranging from 35-70 m/s for the coarse, near-shore material to 25-40 m/s for the finer, offshore deposits. Void ratios predicted from these velocities were compared with data measured directly from box-core samples. Of the formulae used for prediction, two agree remarkably well with the control data. Both predicted and control values increase from 0.6-0.8 for the sandy material to 1.1-1.5 for the silty-sand. Thus, this study does not disprove the hypothesis set and demonstrates the potential of field shear wave velocity-depth data as a means of delineating spatial variation in void ratio for surficial marine sediments in a remote, nondestructive manner. 相似文献
20.
Particulate samples were collected from the Changjiang river system during a flood period, in May 1997, and POC, stable isotope and lipids associated with particles were examined. Results showed the decrease (0.84% ～ 1.88%) of organic carbon content from the upper reaches to the estuary.δ13C values of particulate organic carbon was in the range of -24.9×10-3 to -26.6×10-3, which were close to the isotopic signature of continental C3 vegetation. Total particulate n-alkanes concentrations varied from 1.4 to 10.1μg/dm3,or from 23.7 to 107μg/g of total suspended matter. Fatty acids were present in all the samples, from 1.4 to 5.4μg/dm3, with saturated and unsaturated straight-chain and branched compounds in the carbon number range from C12 to C30. Both δ13C and the ratio of carbon content to nitrogen content indicate the predominance of terrestrial inputs (soil organic matter) among the particles. The biomarker approach has been used to identify the relative portion of terrigenous and autochthonous fraction in the particulate samples. The distribution of fatty acids suggests a striking phytoplanktonic and microbial signal in most particle samples. The terrestrial alkanes are used to estimate the contribution of terrestrial inputs along the mainstream. 相似文献