共查询到19条相似文献，搜索用时 805 毫秒
1.
通过对湛江湖光岩玛珥湖现代环境介质(水体和表层沉积物)中的长链烷基二醇类化合物的定性和定量分析,检测出了一系列的长链烷基二醇化合物,包括1,13-C28、1,13-C30、1,14-C30、1,15-C30和1,15-C32.表层水体中1,14-C30相对含量最高,中层水体中1,15-C30相对含量最高,而底层水体中1,13-C30相对含量最高.推测1,14-C30主要来源于硅藻,但也不排除异鞭藻来源.1,13-C28可能同时具有黄绿藻和硅藻来源.1,13-C30、1,15-C30和1,15-C32长链化合物主要来源于黄绿藻(Eustigmatophytes),但也存在其他藻类来源.表层沉积物中长链烷基二醇化合物的分布与中层水体颗粒物各二醇类化合物的分布相似,表明湖光岩玛珥湖沉积物中长链烷基二醇类化合物主要来源于浮游藻类.湖泊水体颗粒物中二醇指数(DIX)同实测的湖泊水体温度具有很强的线性相关性,而表层沉积物中DIX一致,表明湖光岩玛珥湖中二醇指数能够用来作为水体温度的替代性指标.此研究结果为长链烷基二醇类化合物在湖泊古环境重建应用中提供了现代过程证据. 相似文献
2.
珠江口盆地Site4B沉积物中（65~300 cm）检出了1,15-C30（ω16）和1,15-C32（ω18）烷基二醇和酮醇,总的长链烷基二醇和酮醇含量分别为0.026～4.373 μg/g干沉积物和0.005～1.549 μg/g干沉积物。沉积物剖面上检测到的1,15-C30烷基二醇（-26.6‰±0.9‰）相对于来自陆源高等植物的C30直链烷基醇（-32.8‰±1.5‰）较正的碳同位素特征反映了这类化合物可能不是来自陆源高等植物;同时沉积物中未检出在黄绿藻中相对长链烷基二醇和酮醇更丰富的甾醇,且沉积物浅表层中（0~65 cm）未检出长链烷基二醇和酮醇类化合物,表明现今沉积物中几乎没有黄绿藻的贡献,和沉积物所处的寡营养盐（不适宜藻类生长发育）的陆坡位置相吻合。沉积物中1,15-C30烷基二醇（-24.6‰～-28.4‰）和海洋细菌来源的短链脂肪酸 (-25.5‰～-28.6‰)具有相似的碳同位素组成,表明了海洋细菌是其可靠来源。Site4B沉积物中1,15-C30和1,15-C32烷基酮醇和二醇具有非常好的相关性,表明了它们可能来自相同的生物来源或者来自相关性较好的不同生源,而不是通过对应的二醇氧化生成,因为在65~95 cm的氧化环境中酮醇比例没有明显增高。Site4B沉积物中二醇参数和酮醇参数的变化非常相似,结合含量分布特征反映了古海水温度以及淡水入侵的双重影响,即较高的二醇参数及较高的二醇含量和较低的二醇参数及较低的二醇含量都可能反映了古海水温度是主要影响因素;而较低的二醇参数及较高的二醇含量则可能反映了淡水的侵入是主要影响因素。 相似文献
3.
甘油二烷基链甘油四醚是一类结构稳定、来源广泛、对气候环境响应敏感的微生物标志物,也是古气候与古环境重建的重要工具。相对于其他地区,青藏高原极端微生物对环境因子的响应机理复杂,不同载体中甘油二烷基链甘油四醚的分布特征不同,这给青藏高原古气候和古环境定量重建研究带来了不确定性,限制了甘油二烷基链甘油四醚在青藏高原研究中的充分应用。首先,总结了青藏高原不同载体中甘油二烷基链甘油四醚的分布特征、来源及影响因素;其次,概述了甘油二烷基链甘油四醚指标在青藏高原古气候环境重建中的应用,重点阐述了甘油二烷基链甘油四醚在青藏高原应用中的不确定性来源及其成因解释;最后,结合青藏高原多圈层相互作用对甘油二烷基链甘油四醚的影响机理,对青藏高原各载体中甘油二烷基链甘油四醚的研究进行了讨论和展望。 相似文献
4.
《地球科学进展》2019,(9)
异形胞蓝细菌是重要的固氮微生物,广泛分布于淡水与海洋环境,其细胞壁内侧含有由糖苷基连接长链二醇、三醇、酮醇或酮二醇烷基而形成的糖脂,被称为异形胞糖脂(Heterocyst Glycolipids,HGs)。HGs是异形胞蓝细菌独特的生标化合物,其结构较为稳定,在淡水、海洋、微生物席及沉积物中均被检测到。对HGs生物地球化学研究起步较晚,但近年来进展较快,发现它们在异形胞蓝细菌的生物分类和环境示踪方面具有很大潜力。主要从生物及有机地球化学角度讲述蓝细菌异形细胞的分化机制和HGs结构性质,总结HGs在指示环境温度、异形胞蓝细菌群落演变、陆源有机质输入以及固氮活动中的应用情况,并对其在重建古海洋固氮活动以及古气候的重建等方面提出研究展望。 相似文献
5.
甘南沼泽沉积脂类生物标志化合物的组成特征 总被引：10，自引：2，他引：10
较为系统地分析了寒冷潮湿高原气候条件下形成的沼泽泥炭中脂类化合物，研究了它们的组成，来源和成岩过程，结果表明，正构烷烃，正构烯烃，正构脂肪酸，直链烷基酮和直链烷基醇都由长链组分所构成，这些长链组分来自草本植物，并且得到它们单体碳同位素证据的支持，丰富的奥利烯醇和羽扇烷醇均起源于陆源高等植物，存在很少报道过的一系列藿醇化合物，它们起源于细菌，甾酮和甾醇都以C29组分为主，C28和C29组分主要来自高等植物，而27组分则具有一个细菌源。无奇偶优势的短链正构烷烃，细菌起源的脂肪酸（C14，C15，异构和不饱和脂肪酸），直链烷基－2－酮，藿类和一些甾酮的存在，都说明在这种沉积环境中沉积有机质已经历了强烈改造作用。甾烯酮和甾烯醇分别向它们烷烃的化学和生物化学转化也十分明显。 相似文献
6.
微生物四醚膜脂化合物在湖泊环境中的研究进展 总被引：2，自引：0，他引：2
近十几年来,甘油二烷基甘油四醚类化合物(GDGTs)已成为生物地球化学研究的热点,此类化合物广泛分布在海洋、湖泊、土壤、泥炭以及热泉等不同类型的环境载体中,并且携带丰富的环境信息,基于此类化合物分布构建的参数已成为重建古环境变迁的重要指标。本文首先从GDGTs化合物的结构以及生物来源出发,重点阐述了基于此类化合物构建的几个指标TEX86、BIT、MBT/CBT以及ACE在湖泊环境研究中的应用及存在的不足,随后概述了特殊类型湖泊即富营养、高盐度湖泊中GDGTs化合物的分布特征,最后对GDGTs化合物在湖泊环境的研究提出总结以及展望。 相似文献
7.
海洋和湖泊具有重要的气候环境和生态调节功能。研究地质历史时期海洋和湖泊生态系统的生物群落的组成、结构和演变,将为解决当前面临的环境问题,评估可持续发展提供科学依据。生物标志物具有生物专属性,提供了使我们能够从分子水平上研究地质历史中各种生物演变的工具。本文初步总结了海洋和湖泊生态系统中的生物标志物(烷烃、酸类、醇类、酮类、酯类、甾类、藿类、萜类和甘油四醚类等)的特征和来源。陆生高等植物来源的生物标志物,以长链的烷烃、脂肪酸、脂肪醇和木质素、萜类等较为常见;水生微藻来源的生物标志物有长链烯酮、烷基二醇和高度支链类异戊二烯类化合物(HBIs)等;微生物来源的生物标志物有细菌藿烷多元醇(BHPs)、异形胞糖脂和支链烷烃类等。今后结合生物标志物单体同位素分析和基因、蛋白质组学等现代分子生物学研究,加强不同生物标志物对应的生物种属的生态学研究,古今生态研究相结合,可以为某些生物标志物的分子来源研究提供新的可行途径。本文还综述了生物标志物指标在重建海洋和湖泊生态系统的组成、结构、生产力和营养状况方面的应用。未来的研究将偏向于从定性向定量化重建转变,在海洋研究中应用较成熟的指标将越来越多的被用于湖泊环境中。此外,多指标结合使用将提高重建古生态系统的可靠度。 相似文献
8.
示踪全球环境变化的微生物代用指标 总被引：3，自引：0，他引：3
文章详细总结了示踪全球环境变化的一系列微生物替代指标。重建古温度的定量指标包括藻类长链烯酮的U、古菌甘油二烷基甘油四醚化合物(GDGTs)的TEX_(86)指标、细菌GDGTs的甲基化指数(MBT)与环化指数(CBT)的组合。古温度的定性指标有脂类单体的氢同位素组成、不饱和脂肪酸的相对含量、有孔虫和硅藻的组合及其生物体的同位素组成和微量元素比值。重建古水文的指标包括有壳变形虫组合、细菌GDGTs的环化指数CBT、细菌和古菌GDGTs的陆源输入指数BIT、古菌和细菌GDGTs的相对丰度R、直链脂肪族化合物的碳优势指数CPI、好氧与厌氧微生物的丰度。古大气CO_2分压的估算可采用藻类长链烯酮的碳同位素组成、有孔虫的硼同位素组成。认为这些微生物指标在古环境重建中潜力巨大,并对一些重要微生物指标的应用原理和限定条件进行了分析。有些指标因受多种环境因子和成岩作用的影响,在应用中需特别的注意,不能无限夸大其应用领域。 相似文献
9.
柴达木盆地西部原油主要形成于高盐强还原环境和有机质低成熟演化阶段。这种特殊成油环境，为研究原油中极性生物标志物示踪作用提供了有利条件。对6个原油胶质馏分硅醚衍生物进行了GC—MS分析，从中检出丰富的脂肪酸、烷基醇、脂肪酸甘油—酯、酰胺和甾烯醇化合物，并且脂肪酸甘油—酯为首次从原油中检出。研究认为，这些生物标志化合物主要来自母源。它们的分布特征为链状化合物以短链组分为主，甾醇主要为C27甾烯醇，指示成油母质主要为菌藻类；高丰度脂肪酸甘油—酯的存在，提出生物油脂是这些原油的重要成油母质。原油中存在不饱和链状化合物及其高的CPI值和甾烯醇都说明原油具有低的成熟度。通过原油极性和烷烃化合物的对比研究，认为成油物质及其低演化产物的可溶有机质胶质组分，对原油的形成可能起了重要的作用。 相似文献
10.
《地球科学进展》2020,(5)
甘油二烷基甘油四醚广泛存在于黄土、泥炭、湖泊、海洋等各类沉积载体中,并有效地记录了地质历史时期的古环境信息。简要概述了甘油二烷基甘油四醚的结构、生物源以及常见的甘油二烷基甘油四醚陆地环境代用指标,重点阐述了甘油二烷基甘油四醚在黄土古环境重建中的研究进展,并提出了展望。主要研究进展包括:①甘油二烷基甘油四醚古环境指标在黄土古气候研究中得到了较广泛的应用,并重建了黄土高原地区过去80万年的古温度变化;②黄土高原地区温度变化主要受当地夏季太阳辐射驱动,并受植被下垫面调控;③黄土高原地区末次冰消期降水的增加明显滞后于温度的升高。甘油二烷基甘油四醚在黄土古环境研究中仍存在重建温度偏高、环境指标与气候因子关系复杂等问题。未来对新指标的开发以及区域性转换函数的建立和应用将有望进一步提高甘油二烷基甘油四醚在黄土古环境重建中的准确性,并为解决不同气候区空间上的水—热配置模式和气候变化机制提供依据。 相似文献
11.
Long-chain alkyl diols contain an alkyl chain with alcohol groups at C1 and at the middle position of carbon chain, which exist widely in seas, rivers and lakes. It has been proven that these compounds are relatively resistant to degradation and have an extended occurrence in the geological record. In addition, they are relatively easy to identify. Therefore, long-chain alkyl diols can be used as potential biomarkers to trace the past change in paleoenvironment and paleoclimate. Although the sources of long-chain alkyl diols are still uncertain, the studies indicate that 1, 13 and 1, 15-diols are mainly produced by eustigmatophytes, while 14-diols are mainly from diatom Proboscia. So far, some proxies based on long-chain alkyl diols have been established to indicate the change in diatom productivity, upwelling intensity, salinity, sea surface temperature, riverine organic matter input and surface seawater nutrient concentration, which are significant for paleoenvironmental reconstruction. Current research and application of long-chain alkyl diols proxies were summarized, which would be helpful for further studying the source of long-chain alkyl diols and the application of relevant proxies in China’s marginal sea. 相似文献
12.
Jaap S. Sinninghe Damsté Sebastiaan Rampen C. Rijpstra Gerard Muyzer Stefan Schouten 《Geochimica et cosmochimica acta》2003,67(7):1339-1348
For the first time a biological source for the long-chain alkyl 1,14-diols and 12-hydroxy methyl alkanoates, lipids widely occurring in the marine water column and sediments, has been identified. Cultures of Proboscia indica and Proboscia alata, rhizosolenoid diatoms belonging to the widespread diatom genus Proboscia, contain C28, C28:1, C30, and C30:1 alkyl 1,14-diols, and C27 and C29 12-hydroxy methyl alkanoates as major neutral lipids. These components form a substantial fraction of lipid fractions from sediment traps or sediments, especially in areas with an elevated primary production such as upwelling regions. Examination of literature data reveals that as much as 20 to 35% of the total lipid flux in the Arabian Sea is derived from Proboscia diatoms during the start of the upwelling season. Their rapid transfer to the water-sediment interface may explain why corresponding 1,14-keto-ols, inferred oxidation products of diols, are hardly formed. These interpretations are supported by compound-specific carbon isotopic analysis of long-chain keto-ols and diols in surface sediments of the Arabian Sea. The data indicate that long-chain alkyl 1,14-diols and 12-hydroxy methyl alkanoates can be applied as indicators for high-nutrient conditions in the photic zone. 相似文献
13.
Sebastiaan W. Rampen Stefan Schouten Enno Schefuß Jaap S. Sinninghe Damst 《Organic Geochemistry》2009,40(11):1124-1131
Long chain 1,14-diols and 12-hydroxy methyl alkanoates are biomarker lipids for Proboscia diatoms and occur widely in Quaternary sediments. To determine the effect of temperature on the lipid composition of these algae, a new Proboscia sp. culture grown at 8 °C and Proboscia indica cultures grown at 18, 21, 24 and 27 °C were examined. The results were combined with lipid data from a P. indica culture and a Proboscia alata culture, grown at 20 and 2 °C, respectively, from previous studies. The data showed a strong relationship between long chain diol and 12-hydroxy methyl alkanoate composition and growth temperature, i.e. the chain length increases and the degree of unsaturation of long chain 1,14-diols decreases with increasing growth temperature. To determine the effect of temperature on Proboscia lipid compositions in natural environments, we also analyzed fossil long chain 1,14-diols and 12-hydroxy methyl alkanoates in surface sediments derived from Proboscia diatoms living in the water column of the eastern South Atlantic. The results indicate a significant relationship between sea surface temperature and chain length distribution of saturated long chain diols, but also suggest that the relative abundances of unsaturated long chain diols and 12-hydroxy methyl alkanoates in sediments are predominantly determined by factors other than temperature. 相似文献
14.
Recently, a new organic geochemical paleothermometer based on the relative abundance of long chain alkyl 1,13- and 1,15-diols, the so-called long chain diol index (LDI), was proposed. Because of its novelty, the proxy has not been reported for sediments older than 43 ka. We therefore determined the LDI for 14 sediment samples from the early Pleistocene between 2.49 and 2.41 Ma, comprising Marine Isotope Stage (MIS) 98 to 95, and converted the values to sea surface temperature (SST) estimates to test whether the LDI could be applied or not to the early Quaternary. We show that the long chain diols can be preserved in marine sediments from the early Pleistocene, although at our study site this is limited to periods of increased biomarker accumulation (glacials). Although the results are based on a limited time interval and number of samples, the similarity between LDI-based SST and alkenone-based SST from the same samples suggests that the LDI proxy may have potential for studies covering the entire Quaternary. 相似文献
15.
Lipid biomarkers widely dotted in marine sediments, as their distribution characteristics accurately record huge information on the metabolism of the original organisms and migration and transformation of these organic components, are often used to reconstruct the paleoclimatic and paleoenvironmental conditions. This paper reviewed the progress in the study of paleoclimatic-environmental changes during the late Quaternary using abundant core lipids Glycerol Dialkyl Glyceryl Tetraethers (GDGTs) and long-chain alkyl diols in marginal sea sediments. It is pointed out that clarifying the “source-sink” process of lipid biomarkers buried in marine sediments is a prerequisite for paleoclimatic-environmental reconstruction. It is believed that the use of multiple indicators that are less affected by early diagenesis can increase the accuracy of reconstructing paleoclimatic changes. In the large-river dominated marginal seas, the mechanism of land-sea climate coupling evolution stimulated by the paleoclimatic-environmental changes can be elucidated based on paleoclimatic records reconstructed from core lipids GDGTs and long-chain alkyl diols in marine sediments. It is hoped that this paper can provide reliable technical means and a solid theoretical basis for predicting future temperature and rainfall changes. 相似文献
16.
Jaap S Sinninghe Damsté W.Irene C RijpstraGert-jan Reichart 《Geochimica et cosmochimica acta》2002,66(15):2737-2754
Biomarker accumulation rates in nine different time slices in three cores on and at the foot of a submarine high in the northern Arabian Sea (the Murray Ridge) were measured to investigate the influence of oxygen exposure time on the preservation of biomarker signals in the sedimentary record. All three sites experienced the same history of surface water productivity and sediment supply but had different bottom-water redox conditions due to their different positions (in, just below, well below) relative to the present location of the intense oxygen minimum zone (OMZ). Past variations in the intensity and position of the OMZ, known from a wide variety of proxies (TOC content, distribution and abundance of planktonic and benthic foraminifera and pteropods, trace metals, and δ15N), enabled specific biomarker (i.e., n-alkanes, steroids, alkenones, alkyldiols, C26 fatty acid, loliolide, biphytane diols, and archaeal tetraether lipids) accumulation rates at contrasting oxygen exposure times to be compared. The results indicate that these accumulation rates can vary by more than an order of magnitude for marine biomarkers. In addition, there are significant differences in the degree of oxic degradation of different types of biomarkers: Terrestrial n-alkanes are much more resistant than alkenones and n-alkyl diols, which are more refractory than steroids and biphytane diols. These differences in degree of oxic degradation indicate that biomarker distributions will change on increasing exposure to oxygen. These findings have a significant impact on the application of biomarkers to sedimentary settings in which oxygen exposure time is likely to change significantly. 相似文献
17.
Sarah Metcalfe Ann Breen Malcolm Murray Peter Furley Anthony Fallick Angus McKenzie 《第四纪科学杂志》2009,24(6):627-641
Cores from the New River Lagoon in Belize have been analysed using a range of palaeolimnological proxies to reconstruct change since the latest Pleistocene. The combination of diatom and stable isotope analyses (supported by mineralogical and major element data) indicate that the New River Lagoon has been a freshwater system throughout the period of record. For most of this time the lagoon has been hydrologically open, but there are indications that it may have become closed in the latest Pleistocene or very early Holocene. This may have been associated with a drier climate and lower sea level. Mid‐Holocene records are consistent with those from elsewhere in the region, indicating a stable and moist climate. The late Holocene was marked by greater variability, but there is no clear evidence of any drying in the late Classic coincident with the Maya ‘collapse’ ca. AD 900. Our results indicate that the continuity of occupation at the Maya site of Lamanai on the shores of the New River Lagoon is consistent with continued access to freshwater during periods of regional climatic variability. The importance of conditions at individual sites when considering both system response and human vulnerability to climate change is emphasised. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
18.
The changing of atmospheric carbon dioxide concentration is closely related with the changing of global ice sheet,temperature and sea level. Knowledge of the past atmospheric carbon dioxide concentration and its relationship with climate is an important method of predicting the future climate change. Coccolith derived long-chain alkenone carbon isotope is one of the important proxies to reconstruct past carbon dioxide, which is wildly applied in the reconstruction of the Cenozoic atmospheric carbon dioxide. In this paper, we focused on the method of alkenone-based atmospheric carbon dioxide concentration, including the geochemical properties of long-chain alkenone, carbon diffusive model and the carbon isotope fraction. Then, we introduced the development of alkenone-based carbon dioxide proxy and its uncertainty. Coccolith cell geometry and growth rate have great influence on carbon dioxide fraction. Besides, there are some uncertainties about carbon concentration mechanisms in coccolithes, which may have some influence on alkenone-based carbon dioxide method to reconstruct ancient carbon dioxide more accurately. At the end, we summarized the Cenozoic carbon dioxide record with various proxies including alkenone carbon dioxide, boron isotope, palaeosol carbonate nodules and stomatal indices of fossil leaves. 相似文献
19.
利用GC-MS技术对若尔盖高原一湖沼沉积剖面（深346 cm）沉积有机质的饱和烃馏分进行了分析,结合已有的AMS 14C年代、剖面岩性和TOC资料,探讨了该剖面分子化石分布特征及其相关参数对有机物来源、微生物活动和气候变化等环境信息的指示意义。分析表明,中高碳数占绝对优势的正构烷烃反映了有机物主要来源于高等植物,且草本高等植物输入丰富;岩相、TOC和Pr/Ph比值很好地指示了该剖面沉积物从早全新世（约11.4~7.3 cal ka BP,深度346~203 cm）强还原深湖条件到中全新世（约7.3~4.5 cal ka BP,>203 cm）弱还原沼泽条件的演化过程,正构烷烃参数奇偶优势（OEP1和OEP2）、C25/C31和轻烃/重烃比值（∑C21-/∑C22+）详细反映了这种水文演变过程中生物源的变化,尤其剖面120 cm以上很可能有泥炭藓(Sphagnum)的重要输入,而且敏感地指示了剖面120 cm以上有机物遭受了明显的微生物改造作用,从而引起正构烷烃组分的改变。另外,在约9.8~8.6 cal ka BP（深度286~240 cm）期间剖面岩性及其以上各项代用指标发生明显快速变化,说明早全新世若尔盖高原气候相对暖湿阶段具有不稳定性。 相似文献