發(fā)布時(shí)間：2018-02-24 10:23

  本文關(guān)鍵詞： 古氣候 石筍 土壤 3-羥基脂肪酸 脂肪酸 單體碳同位素　出處：《中國(guó)地質(zhì)大學(xué)》2016年博士論文　論文類型：學(xué)位論文

【摘要】：全球變化日益受到人們的關(guān)注,人們亟需了解地質(zhì)歷史時(shí)期的氣候變化規(guī)律,從而預(yù)測(cè)未來氣候的變化。石筍由于其產(chǎn)生連續(xù)、高分辨率不受干擾的記錄,精確的年代學(xué)以及全球陸地廣泛分布等獨(dú)特的優(yōu)勢(shì),已成為21世紀(jì)以來全球氣候變化研究中一類重要的陸相地質(zhì)載體,近年來,在國(guó)內(nèi)外學(xué)者的共同努力下,石筍中越來越多的環(huán)境替代指標(biāo)被挖掘用于重建古氣候,包括：氧同位素,碳同位素,二元同位素,年層,微量元素,磁信息,包裹體和生物標(biāo)志物等。在這些氣候替代指標(biāo)中,氧同位素的應(yīng)用最為廣泛,逐漸成為石筍分析的主流或標(biāo)準(zhǔn)方法。然而,氧同位素記錄的是混合的氣候信號(hào),受到區(qū)域尺度上溫度的變化,源水的同位素組成,降水以及其它復(fù)雜的因素的影響,因此對(duì)石筍氧同位素記錄的解譯需要考慮特定的沉積環(huán)境,并對(duì)相互作用的復(fù)雜因素進(jìn)行相關(guān)解析。石筍中含有豐富的生物標(biāo)志化合物,盡管其類脂物的來源相對(duì)復(fù)雜,但特定的化合物來源較為單一,尤其是來源于微生物的類脂。如3-羥基脂肪酸(3-hydroxy fatty acids,縮寫為3-OH-FAs),對(duì)環(huán)境變化敏感,并能很好地保存在石筍中,具有重建古環(huán)境的巨大潛力。3-羥基脂肪酸主要來源于革蘭氏陰性細(xì)菌的細(xì)胞膜磷脂脂多糖(LPS)的脂質(zhì)A (Lipid A),通過酯鍵或酰胺鍵與大分子鍵和,因而不易降解,能夠較為完好的保存在沉積物中。前人對(duì)石筍類脂提取的方法研究中,由洞穴石筍中檢測(cè)出含量豐富的類脂,然而用于古氣候重建的研究則非常少。因此本論文主要研究目標(biāo)是,進(jìn)一步優(yōu)化提取方法,在最優(yōu)方法下提取土壤以及洞穴沉積物中的3-羥基脂肪酸,分析其與環(huán)境因子間的相互關(guān)系,嘗試建立基于3-羥基脂肪酸構(gòu)建的環(huán)境替代指標(biāo),并將其應(yīng)用到石筍古氣候重建中。本論文的獲得的主要認(rèn)識(shí)如下：1.基于土壤3-羥基脂肪酸構(gòu)建的溫度、pH替代指標(biāo)提出基于土壤3-羥基脂肪酸構(gòu)建的溫度和pH替代指標(biāo)。對(duì)神農(nóng)架不同海拔高度土壤樣品中3-羥基脂肪酸與環(huán)境參數(shù)之間的關(guān)系研究發(fā)現(xiàn),支鏈比指數(shù)(RIAN)、支鏈化指數(shù)(Branched Index)以及異構(gòu)化比(RIN)均與土壤pH高度相關(guān)。此外,RAN15和RAN17與年均大氣溫度(MAAT)和年均降雨量(MAP)表現(xiàn)出顯著的相關(guān)性。由于神農(nóng)架常年處于濕潤(rùn)環(huán)境,MAP不可能成為微生物生態(tài)限制因素,因此推測(cè)MAAT是控制RAN15和RAN17變化的主要因素。需要注意的是,3-羥基脂肪酸的溫度替代指標(biāo)RAN15和RAN17是獨(dú)立于pH的,因此在pH值變化較大或者可能存在多個(gè)混雜變量的環(huán)境中用于古溫度重建具有很大優(yōu)勢(shì)�；�于神農(nóng)架表層土壤中3-羥基脂肪酸的pH和MAAT替代新指標(biāo)對(duì)古氣候和環(huán)境研究具有深遠(yuǎn)意義。通過將3-羥基脂肪酸的pH和溫度替代指標(biāo)與GDGT的環(huán)境替代指標(biāo)相結(jié)合,可以進(jìn)行多指標(biāo)的陸相古溫度和pH重建。此外,本論文在甘肅天池湖泊沉積物,波羅的海海洋沉積物和湖北清江和尚洞石筍中均發(fā)現(xiàn)了含量豐富的3-羥基脂肪酸,說明3-羥基脂肪酸分布廣泛,進(jìn)一步表明3-羥基脂肪酸的環(huán)境替代指標(biāo)具有廣泛的應(yīng)用前景。在不同載體中,3-羥基脂肪酸變化的差異可能是不同的環(huán)境因子影響細(xì)菌細(xì)胞膜變化的結(jié)果。然而,本論文僅在天池湖泊沉積物中檢測(cè)到偶碳數(shù)(C12,C14,C16,C18)一元不飽和3-羥基脂肪酸,說明天池湖泊沉積物中的3-羥基脂肪酸的來源較為特殊,因此針對(duì)特定的沉積環(huán)境可能需要建立新的3-羥基脂肪酸環(huán)境替代指標(biāo)。2.3-羥基脂肪酸環(huán)境替代指標(biāo)重建古溫度和古水文本文系統(tǒng)地對(duì)比3-羥基脂肪酸在和尚洞洞頂上覆土壤,洞穴表層沉積物和HS4石筍中的分布特征。結(jié)果顯示,洞頂土壤、洞穴表層沉積物和HS4石筍中3-羥基脂肪酸的分布相似,但石筍樣品中n-C12和i-C173-羥基脂肪酸的含量較高,推斷可能來源于石筍生長(zhǎng)過程中被包裹在石筍晶格中的微生物。將基于神農(nóng)架土壤建立的3-羥基脂肪酸溫度指標(biāo)RAN15應(yīng)用到HS4石筍中,恢復(fù)長(zhǎng)江中游地區(qū)9 ka BP以來的溫度變化,其溫度變化范圍為17.8到20.2℃。其中早中全新世是一個(gè)相對(duì)暖的時(shí)期(8.6-5.2 ka BP),5.2 ka BP以后溫度逐漸降低。RAN15重建的溫度與洞穴外長(zhǎng)期監(jiān)測(cè)的18℃年均溫接近。建立洞穴系統(tǒng)中基于3-羥基脂肪酸的水文指標(biāo),并將其應(yīng)用到石筍中,重建了長(zhǎng)江中游9 ka BP以來的水文條件變化。由于洞穴沉積物的pH變化范圍很小,因此神農(nóng)架土壤建立的3-羥基脂肪酸的pH指標(biāo)在洞穴系統(tǒng)中并不適用,需要建立洞穴系統(tǒng)的pH公式。我們對(duì)洞頂上覆土壤和洞穴表層沉積物中的3-羥基脂肪酸分布的調(diào)查發(fā)現(xiàn),i-C15和a-C15的比值(C15水文指數(shù))與樣品的pH有很好的線性相關(guān)(R2為0.65,p0.001)。根據(jù)C1s水文指數(shù)與降雨量間的半定量關(guān)系,將C15水文指數(shù)應(yīng)用到石筍中,重建了過去9 kaBP以來的古水文變化。從C15水文指數(shù)反演出的古水文記錄觀察到兩個(gè)持續(xù)較長(zhǎng)時(shí)間的相對(duì)濕潤(rùn)階段(8.1-6.0 ka BP和3.5-0 ka BP)和一個(gè)相對(duì)干旱階段(6.0-3.5 ka BP)。同時(shí)還有幾次顯著的干旱事件,分別發(fā)生在8.2 ka BP,3.8 ka BP和0.5 ka BP。3.石筍中脂肪酸的單體碳同位素重建古植被信息對(duì)石筍中的脂肪酸進(jìn)行單體同位素分析,并重建長(zhǎng)江中游9 ka BP以來的植被變化。洞頂土壤、洞內(nèi)表層沉積物以及HS4石筍樣品中脂肪酸的分布類似。碳數(shù)分布為C12-C32,表現(xiàn)出明顯的偶奇優(yōu)勢(shì),主峰碳均為C16。石筍中低碳數(shù)脂肪酸的來源復(fù)雜,既有高等植物的貢獻(xiàn),也有土壤微生物以及洞穴微生物的貢獻(xiàn),而高碳數(shù)脂肪酸則主要來源于高等植物。C16脂肪酸的碳同位素(δ13C16 FA)變化范圍為-27.5‰到-25.2‰,C18脂肪酸的碳同位素(613C18 FA)的變化范圍為-27.0‰到-23.4‰。δ13C16 FAδ13C18 FA的變化趨勢(shì)一致,說明兩者的來源基本相同。HS4石筍中高碳數(shù)脂肪酸C22和C24的碳同位素(分別用δ13C22FA和813C24FA表示)變化范圍比低碳數(shù)脂肪酸更大,δ13C22FA從-32.9‰到-25.7‰,δ13C24 FA從-33.5%o到-25.29‰。根據(jù)HS4石筍中δ13C24 FA的值以及C3和C4植物中C24脂肪酸碳同位素的平均值重建了長(zhǎng)江中游地區(qū)9 ka BP以來的古植被變化。植被的變化特征主要分為三個(gè)階段：第一階段8.6-6.8 ka BP,C3植物比例逐漸增加,C4植物比例逐漸減��；第二階段6.8-3.3 ka BP,C3植物比例逐漸減小,C4植物比例逐漸增加；第三階段3.3-0 ka BP,C3和C4植物比例波動(dòng)頻繁,呈現(xiàn)周期性變化。長(zhǎng)江中游地區(qū)植被的變化主要受溫度控制,水文條件對(duì)植被的變化也有一定的影響�？傊�,本論文初步建立基于3-羥基脂肪酸的溫度、pH替代指標(biāo),并在石筍中得到較好的應(yīng)用,揭示長(zhǎng)江中游地區(qū)全新世9 ka BP以來的古溫度和古水文變化。此外,本論文首次對(duì)石筍中脂肪酸進(jìn)行單體碳同位素分析,并重建長(zhǎng)江中游地區(qū)9ka BP以來的古植被變化。希望通過本研究能夠開辟3-羥基脂肪酸和石筍類脂單體同位素的研究新方向。
[Abstract]:Global change has been concerned, people need to understand the climate changes in the geological history, so as to predict future climate change. Because of the stalagmite to produce continuous, high-resolution undisturbed record, the precise chronology of the global land and the advantages of widely distributed and unique, has become since twenty-first Century a study of global climate change an important continental geological carrier, in recent years, with the joint efforts of the scholars at home and abroad, more and more environmental indexes in stalagmite mining was used to reconstruct the paleoclimate, including: oxygen isotope, carbon isotope, two yuan annual layer, isotope, trace elements, magnetic information, inclusions and biomarkers in these. The climatic indexes, the most widely used oxygen isotope, has gradually become the mainstream of stalagmites or standard methods. However, the oxygen isotope record is mixed climate signal, by To change the temperature on a regional scale, water isotopic composition, precipitation and other complex factors, so the translation needs to consider the specific depositional environment solution of stalagmite oxygen isotope records, and complex factors on the interaction of biomarkers related to parsing. Contains rich in stalagmite, although the source of the lipids is relatively complex, but specific compound source is relatively single, especially from microbial lipids such as 3- hydroxy fatty acids (3-hydroxy fatty acids, abbreviated as 3-OH-FAs), sensitive to the change of the environment, and can be well preserved in the stalagmite, with great potential of.3- hydroxy fatty acid the main source of paleoenvironment reconstruction in gram negative bacterial cell membrane phospholipid lipopolysaccharide (LPS) lipid A (Lipid, A) by ester or amide bonds with large molecular bonds and, therefore not easy to degrade, can be preserved in the sink Deposit. Previous research methods for the extraction of lipids from Stalagmite in the stalagmite was detected in the rich content of lipids, but for the study of paleoclimate reconstruction is very small. So the main goal of this thesis is to further optimize the extraction method, extraction method, the optimal 3- hydroxy fatty soil and cave sediments acid, analysis of its relationship with the environmental factors, try to establish 3- hydroxy fatty acid construction environment substitute index based, and its application to the stalagmite paleoclimate reconstruction obtained. The main conclusions of this paper are as follows: 1. based on soil 3- hydroxy fatty acid construction temperature, pH index of soil 3- hydroxy fatty replacement the acid temperature and pH index. Based on the study of alternative relationship between different altitudes in Shennongjia soil samples 3- hydroxy fatty acids and environmental parameters, branch ratio index (RIAN), branched Index (Branched Index) and the ratio of isomerization (RIN) were highly correlated with soil pH. In addition, RAN15 and RAN17 (MAAT) and the average air temperature and annual precipitation (MAP) showed a significant correlation. Because Shennongjia is in the moist environment can not become a perennial, MAP micro biological and ecological factors, suggesting that MAAT is the main factors that control the RAN15 and RAN17 changes. Note that the temperature of 3- hydroxy fatty acid substitution indexes of RAN15 and RAN17 are independent of pH, so the pH value changes greatly or there may be a number of confounding variables in the environment of palaeoreconstructions has great advantages. 3- hydroxy fatty acids in the surface soil of Shennongjia pH and MAAT instead of the new index is of far-reaching significance for the study of paleoclimate and environment. Based on the environmental indexes of 3- hydroxy fatty acid pH and temperature alternative indicators combined with GDGT, can be a The Lu Xianggu temperature and pH reconstruction. In addition, the sediments of Gansu Tianchi Lake, the Baltic Sea sediment and Hubei Qingjiang monk Cave Stalagmite was found in 3- hydroxy fatty acid, 3- hydroxy fatty acids are widely distributed, further showed that 3- hydroxy fatty acid environment substitute index has a wide application prospect. In different carriers, different changes of 3- hydroxy fatty acids may be the bacterial cell membrane environment factors affecting the change of different results. However, this thesis only in the Tianchi lake sediments detected even carbon number (C12, C14, C16, C18) 3- hydroxy mono unsaturated fatty acids, explain the sources of 3- hydroxy fatty acids in the sediments of Tianchi Lake is very special, so the specific depositional environment may need to establish a new environment 3- hydroxy fatty acid substitution index.2.3- hydroxy fatty acid environment substitute index paleotemperature reconstruction And the ancient water text paper comparing 3- hydroxy fatty acids in the monk hole top cover soil, the distribution characteristics of cave sediments and HS4 in stalagmite. The results showed that the soil, similar to the distribution of 3- hydroxy fatty acid and HS4 in surface sediments of cave stalagmites, but n-C12 and i-C173- hydroxy fatty acids in stalagmite samples higher content of inference may be derived from the stalagmite growth process is wrapped in Stalagmite in the lattice will be based on Shennongjia soil microorganisms. The establishment of the 3- hydroxy fatty acid temperature index RAN15 to HS4 in the stalagmite, restoration of the middle reaches of the Yangtze River 9 Ka BP since the temperature changes, the temperature changes in the range of 17.8 to 20.2 degrees. The early in the the Holocene is a relatively warm period (8.6-5.2 Ka BP), 5.2 Ka BP after the temperature is gradually reduced temperature and cave.RAN15 reconstruction outside the long-term monitoring of the annual temperature close to 18 degrees. The establishment of the cave system in the base In the 3- hydrological index hydroxy fatty acid, and its application to the reconstruction of the Stalagmite in the middle reaches of the Yangtze River hydrological conditions. Since 9 Ka BP due to pH changes in the scope of the cave sediments is very small, so the pH index of 3- hydroxy fatty acid soil of Shennongjia established does not apply in the cave system, the pH formula to establish the cave system. We found that the investigation of roof overlying soil and cave in the surface sediments of 3- hydroxy fatty acid distribution, the ratio of i-C15 and a-C15 (C15 hydrology index) have good linear correlation with the sample of pH (R2 = 0.65, p0.001). According to the semi quantitative relationship between C1s hydrology index and rainfall. The C15 index is applied to the hydrology in the stalagmite, the reconstruction of the ancient hydrological changes over the past 9 kaBP. Since the ancient hydrological records from C15 hydrology index inversion observed relatively humid stage two of longer duration (8.1-6.0 Ka BP and 3.5-0 Ka BP) And a relatively arid stage (6.0-3.5 Ka BP). At the same time, there are several significant drought events occurred in 8.2, Ka BP respectively, 3.8 Ka BP and 0.5 Ka BP.3. in stalagmite monomer carbon isotope fatty acid reconstruction of paleovegetation information on fatty acid analysis of the monomer in the stalagmite isotope, and vegetation reconstruction changes in the middle reaches of the Yangtze River since 9 Ka BP. The soil, the surface sediments and the distribution of the fatty acids in the sample. HS4 from similar carbon number distribution of C12-C32, showed the even odd predominance, the peak carbon was C16. from low carbon number fatty acid complex sources, both higher plants have contribution. Soil microbe and microbial cave contribution and high carbon number fatty acids were mainly originated from the carbon isotope of higher plant.C16 fatty acids (delta 13C16 FA) ranged from -27.5% to -25.2%, the carbon isotope of fatty acid C18 (613C18 FA) in the range -27.0% to -23.4% in the same trend. 8 13C16 FA Delta 13C18 FA, shows that the carbon isotope of high carbon number fatty acids C22 and C24 both sources are basically the same.HS4 in stalagmite (represented as delta 13C22FA and 813C24FA) range greater than low carbon number fatty acids, Delta 13C22FA from -32.9 1000 -25.7 13C24 FA 8%, from -33.5%o to -25.29 per thousand. According to HS4 in stalagmite Delta 13C24 values of FA and C3 and C4 C24 in plant fatty acid carbon isotope average value of the reconstruction of the middle reaches of the Yangtze River 9 Ka BP since the paleovegetation changes. The variation of vegetation is mainly divided into three stages: the first stage 8.6-6.8 Ka BP, C3 plant proportion gradually increased, the proportion of C4 plants decreased gradually; the second stage of 6.8-3.3 Ka BP, C3 plant ratio decreased, the proportion of C4 plants increased gradually; the third stage 3.3-0 Ka BP C3, and the proportion of C4 plants fluctuated frequently presents periodic variation in the Yangtze river. Change of tourism in the area of vegetation is mainly controlled by temperature, changes in hydrological conditions of vegetation have a certain effect. In short, this paper established 3- hydroxy fatty acid based on the temperature of pH alternative indicators, and get better application in stalagmite, paleo temperature and paleo hydrologic changes since Holocene in the middle reaches of the Yangtze River region revealed 9 Ka BP. In addition, this is the first time that specific carbon isotope analysis of fatty acid in the stalagmite, and reconstruction of the middle reaches of the Yangtze River 9ka BP since the paleovegetational changes. Hope that through this study can open up the lipid hydroxy fatty acid monomer and stalagmite 3- isotopes of the new research direction.

【學(xué)位授予單位】：中國(guó)地質(zhì)大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類號(hào)】：P532;P593

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本文編號(hào)：1529882