碱溶性干酪根的成分结构及其对菲的吸附的影响

选取一个含II型干酪根的页岩样品,使用一系列化学分级提取方法对其进行分级,得到原始干酪根(BK)、溶剂处理干酪根(SEK)级分、分别在20°C、40°C和60°C温度条件下连续提取碱溶性干酪根(EKs)级分和碱难溶性干酪根(RK)级分。应用一系列表征手段包括元素分析、稳定碳同位素组成分析、X射线光电子光谱、表面积和孔径分析以及先进的固态核磁共振技术对这些不同干酪根级分进行了系统地表征,着重探讨不同干酪根级分的化学结构组成的差异,以及其结构组成与它们对菲的吸附行为的关系。研究表明20、40和60°C下连续43次提取的EKs级分占原始干酪根的比例(总产量)分别为10.47%、20.60%和27.9%,表明有相当比例的干酪根是碱性可溶解的,且温度是影响干酪根溶解的一个重要因素。本研究发现了干酪根在碱性条件下是可以逐步溶解的新现象。EKs中干酪根芳香基团含量(芳香C-C、C-H和C-O)占主导地位,其占总碳的60%以上。EKs的结构组成明显与原始干酪根(BK)、碱难溶性干酪根(RK60)和溶剂处理干酪根(SEK)不同,后者以脂肪碳占主导。EKs中的芳香基团较脂肪基团更容易溶解在碱性溶液中,因而芳香碳含量高的EKs级分易于被提取,脂肪碳含量相对较难溶解在碱性溶液中难于被提取。相对于BK,碱性提取后的RK60中芳香碳含量降低,溶剂提取后的SEK中非极性脂肪碳含量稍微降低。本研究提供新的证据证明了干酪根的超分子结构的观点,表明它主要是依靠弱相互作用(包括范德华力、π-π、δ-π键和氢键)稳定地存在。二氧化碳气体吸附数据表明EKs的比表面积和微孔体积明显大于其BK和RK60。后被提取出来的EKs比先被提取的EKs对菲的吸附非线性更强,且具有更强的吸附能力,说明BK中相对极性、吸附能力相对较弱的EKs级分先被提取。EKs对菲的吸附行为明显与BK、RK60和SEK不同。相对于BK而言,碱提取后的RK60的吸附能力降低;而溶剂提取后,SEK的吸附能力增强。EKs的吸附能力与其H/C比值以及与非极性脂肪碳含量呈正比,但是与总芳香碳含量和O/C比值呈反比;吸附非线性因子(n)与非极性脂肪碳含量呈反比,而与非质子芳香碳含量呈正比。这表明非极性脂肪碳含量越高,非质子芳香碳含量越低,吸附能力越强,吸附非线性也越强。EKs对菲的吸附能力与比表面积以及微孔体积呈正相关关系,说明微孔吸附的潜在重要性。     

DOM不同分子质量组分对石英砂吸附卡马西平的影响研究

为探究溶解性有机质(DOM)不同相对分子质量组分对药物和个人护理品(PPCPs)类污染物吸附过程的影响,以卡马西平(CBZ)为目标污染物,以石英砂代表无机矿物,用商用腐殖酸(HA)制备DOM并进行超滤分级,然后开展吸附实验,并采用荧光光谱和红外光谱表征等手段,研究了DOM不同分子质量组分对石英砂吸附CBZ的影响及机制。结果表明,以3 000和10 000的超滤膜进行分级后的不同相对分子质量HA结构有明显差别,大分子质量HA中苯环等疏水性结构以及羟基的含量较多,芳香构造化程度高,多为分子量较高、稳定性较好的疏水性有机物,但中、小分子质量HA结构差异不大,含有更多羰基、羧基等含氧官能团,主要是一些分子质量较小的亲水物质; DOM不同分子质量组分对CBZ在石英砂上的吸附有明显影响,其中大分子质量组分促进吸附,而中、小分子质量组分抑制吸附,原因在于大分子质量组分可疏水结合于矿物表面,增加介质表面的活性吸附位点,同时其芳香性或脂肪性结构可与CBZ的疏水基团发生疏水作用共吸附或累积吸附于介质表面,从而促进CBZ的吸附;而中、小分子质量DOM的极性官能团可与CBZ酰胺部分通过极性作用结合,对CBZ分子有增溶作用,从而抑制吸附。     

来源于生物质和煤燃烧产生的soot和charcoal的Py-GC/MS研究

根据形成机制,黑碳可以分为烟炱(soot)和木炭(charcoal)。以稻秆、玉米秆、马尾松和煤为原料分别制备了soot和charcoal两类黑碳,并利用元素分析和热解-气相色谱/质谱联用技术(Py-GC/MS)研究了不同类型黑碳(soot和charcoal)的元素组成和热解特征。结果表明,不同类型黑碳的元素组成具有类似性,均表现为C含量最高,其次为O、H和N。但不同类型黑碳也具有一定的差异,soot黑碳的H/C、O/C、N/C和(O+N)/C原子比均高于charcoal黑碳,表明soot颗粒中含有较多的极性组分。Py-GC/MS分析结果显示,不同类型黑碳裂解产物组成具有一定的类似性,均以芳香化合物为主,还包括含氮化合物、呋喃类化合物、酚类化合物和含硫化合物等,表明黑碳都是以高度芳香性的结构为核心,连接有含氧、氮等杂原子基团等组成。研究还表明,不同类型的黑碳具有各自不同的特征,3种生物质soot样品包含更多的来自燃料本身如蛋白质类、木质素类和多糖类结构信息,而charcoal样品则具有更强的芳香性结构。本研究结果对于理解不同类型黑碳的分子结构和组成具有重要的意义。     

烃源岩热模拟分子标志物演化特征及分子解析

为了研究地质体中分子标志物随热成熟度的演化规律,开展了烃源岩热模拟实验,并对产物进行了分子标志物定量及分子解析.结果表明,随着模拟温度的增高,三环萜烷和藿烷含量均逐渐降低,但降低幅度有差异,藿烷和高相对分子质量的三环萜烷降低幅度大于低相对分子质量的三环萜烷,导致在热模拟温度升至370℃的情况下,低相对分子质量三环萜烷的峰高高于藿烷;高相对分子质量甾烷含量降低幅度大于低相对分子质量甾烷,相同相对分子质量不同构型化合物甾烷热解速率不一致,同碳数 ααα 甾烷热解速率大于αββ 甾烷,低相对分子质量的甾烷定量结果随热模拟温度升高先降低后升高再降低;低碳数的芳烃含量随热模拟温度升高先降低后升高,高碳数芳烃含量则一直处于降低状态.分子解析认为,C19和C20三环萜烷主要来自于高碳数三环萜烷的裂解,藿烷的贡献极低;17α(H)C27三降藿烷(Tm)来自高碳数藿烷的贡献,18α(H)C27三降藿烷(Ts)没有其他化合物加入;相同质量前提下,C29甾烷裂解速率为:C29ααS>C29ααR>C29ββS>C29ββR;孕甾烷和升孕甾烷含量升高来自高碳数甾烷的裂解;低碳数的芳烃含量随温度升高来源广泛,高碳数芳烃主要起裂解作用.     

氧化作用对气态烃组成和碳同位素组成的影响

通过加水模拟实验,揭示了气态烃在被矿物氧化过程中分子组成和碳同位素组成的变化.实验结果表明,随着反应时间的延长,气态烃、非烃 (H2、 CO2、 H2S)组成及碳同位素组成发生了明显且很有规律的变化.气态烃碳数越高,氧化速率越快,碳同位素变化 (增重 )越大.当氧化剂为赤铁矿或赤铁矿 硫酸镁时, CH4含量没有明显降低,δ 13C值增重 1‰～ 2‰; C2H6含量最后 (288h)降低了约 20%,δ 13C值增重约 3‰; C3H8含量最后降低了约 50%,δ 13C值增重约 5‰; Ic4h10含量在 72 h时即降低了约 80%,氧化速率远高于 Nc4h10.非烃 CO2的含量增加了 1.26～ 1.71倍.当氧化剂为硫酸镁时, CH4含量明显增高,最多时增加了 34.7%,δ 13C值增重约 8‰; C2H6含量在 72 h时降低了约 14%,在 144 h时降低了约 85%,δ 13C值增重约 24‰; C3H8含量在 72 h时降低了约 65%,在 144 h时降低了 98%以上; Ic4h10和 Nc4h10在 72 h时即降低了 90%以上.非烃 CO2含量最多增加了 1.86倍, H2S最多增加了 9.62倍.这些实验结果对认识天然气藏在矿物氧化过程中分子组成和碳同位素组成的变化具有重要意义.     

不同煤级煤的沥青质H~1-NMR分析及其地球化学意义

本文采用核磁共振(H'—NMR)分析,对来自鄂尔多斯盆地不同煤级煤(?)0.43%—1.80%),的沥青质结构组成特征和演化机理进行了探讨。研究表明煤沥青质分子结构组成与腐殖型母质密切相关,其基本结构单元可能是核心由2~3以上的芳环组成,取代烷基较多而短,以2~3个碳原子为主,芳香缩台程度低,结构松散．沥青质在热演化过程中和平酪根一样也经历了形成、解聚、凝缩和聚合等演化阶段。依据实验得到的沥青质各类氢相对含量、取代基的平均碳数和芳香度等结构参数不仅丰富了煤系热演化程度的指标、揭示了煤成烃的机理,而且为油源对比提供了新参数．经过数据处理所建立的各参数间的相互关系,如f_a~H与H_A和B,为直接利用H'—NMR资料提供了方便。     

温度影响东北地区更新世植被变化的黄土记录

温度、降水(湿度)和大气CO2含量被认为是影响C3植物生长的主要因素.大量的现代植物和土壤有机质碳稳定同位素(δ13C)研究表明,温度升高可使C3植物的碳同位素变重(正),降水增多(湿度增大)和大气CO2含量升高可使C3植物的碳同位素偏轻(负);同时,C4植物可明显地影响土壤的有机碳同位素组成.基于这些认识,以前对黄土高原的黄土-古土壤序列有机质碳同位素和植被组成变化进行过不少研究.但是,相关的研究在我国东北地区的黄土中还未开展.本文对我国东北地区厚度36m的喀喇沁旗牛样子沟黄土-古土壤剖面进行了间隔10cm的采样和总有机碳含量(TOC)、有机质稳定碳同位素的测试分析.结果表明,在间冰期发育的古土壤有机质含量高、δ13C值偏正;反之,在冰期堆积的黄土有机质含量低、δ13C值偏负.通过分析表明,研究区的植被类型是以C3植物占主导地位,C4植物对土壤有机质δ13C变化的贡献有限,并且气候变化具有冰期-间冰期季风气候变化的特点,据此推断温度是决定东北地区植被碳同位素组成变化的主要因素,超过了降水(湿度)和大气CO2含量对植被(植物碳同位素组成)变化的反向影响.这一发现揭示了温度对我国东北地区长时间尺度植被变化的控制作用.这些认识对于在未来全球变暖背景下,东北地区的林木和小麦、大豆、水稻等C3作物的种植有借鉴意义.     

腐泥煤的煤化作用研究

腐泥煤的煤化作用特征目前了解甚少.对我国产出的不同时代、不同煤化程度腐泥煤,结合热模拟试验,并通过与腐殖煤的对比,较系统地研究了在煤化作用过程中,腐泥煤的宏观和微观岩石学特征、元素组成和化学结构的演变规律。在此基础上,探讨了腐泥煤的煤化作用机理,研究了其煤化程度指标,提出了其煤级划分方案。      

北山地区矽卡岩型铜矿元素表生活动性规律——以辉铜山铜矿为例

元素表生活动性规律研究是制定地球化学勘查方法技术、开展地球化学找矿工作的前提和基础。以北山地区辉铜山铜矿为例,系统研究了元素的表生活动特性。结果表明：在不同母岩形成的土壤中,Cu、Mo、Pb、Zn、Au、Ag、As、Bi、Ba、Sr等微量元素富集作用存在差异;与粗粒级相比较,细粒级中元素的富集作用更加明显;随着样点到矿体之间距离的增加,粗粒级土壤样品的Cu、Mo元素含量降低,而Ba、Sr元素含量略有升高。土壤中常量元素含量特征表明：粗粒级与细粒级的物质组成、化学成分存在明显差异,粗粒级更接近于母岩。微量元素的富集作用与黏土矿物含量呈正比,与主要造岩矿物含量呈反比。以上述试验结果为基础,采用－4～＋40目粗粒级为采样介质,有效圈出了辉铜山铜矿元素正异常和负异常,为该地区的找矿靶区优选提供了依据。     

东海内陆架沉积物中有机硫形态的K边XANES谱分析

有机硫是海洋沉积物重要的硫形态,与有机质保存及多种元素的地球化学循环密切相关。利用硫的K边XANES谱从分子水平研究了东海内陆架沉积物中腐殖酸硫(HA-S)、富里酸硫(FA-S)以及铬不可还原有机硫(non-CROS)的形态及相对含量。结果表明,HA-S和FA-S总体上均以氧化态有机硫为主,其相对平均含量分别为56%和69%,而non-CROS则以还原态有机硫为主(86%)。HA-S和FA-S的强还原态硫为还原态有机硫的主要组成,磺酸盐和硫酸酯为HA-S中氧化态有机硫的主要组分,硫酸酯为FA-S中氧化态有机硫的主要组分。FA-S的强还原态有机硫为硫化成因,HA-S的强还原态硫可能与硫化和生物成因有关,而non-CROS的强还原态有机硫则主要为生物成因。如non-CROS能近似代表海洋沉积物中的有机硫总量,则表明该沉积物中总有机硫以还原态硫为主;而腐殖质硫(HA-S+FA-S)较高比例的氧化态硫则表明腐殖质硫不能全面反映沉积物中有机硫的组成和来源。     

Elucidation of different forms of organic carbon in marine sediments from the Atlantic coast of Spain using thermal analysis coupled to isotope ratio and quadrupole mass spectrometry

Analysis of river, estuary and marine sediments from the Atlantic coast of Spain using thermogravimetry–differential scanning calorimetry–quadrupole mass spectrometry–isotope ratio mass spectrometry (TG–DSC–QMS–IRMS) was used to (a) distinguish bulk chemical hosts for C within a sediment and humic acid fraction, (b) track C pools with differing natural C isotope ratios and (c) observe variation with distance from the coast. This is the first application of such a novel method to the characterisation of organic matter from marine sediments and their corresponding humic acid fractions. Using thermal analysis, a labile, a recalcitrant and a refractory carbon pool can be distinguished. Extracted humic fractions are mainly of recalcitrant nature. The proportion of refractory carbon is greatest in marine sediments and humic acid fractions. Quadrupole mass spectrometry confirmed that the greatest proportion of m/z 44 (CO₂) and m/z 18 (H₂O) were detected at temperatures associated with recalcitrant carbon (510–540 °C). Isotope analysis detected progressive enrichment in δ¹³C for the sediment samples with an increase in marine influence. Isotopic heterogeneity in the refractory organic matter in marine sediments could be due to products of anthropogenic origin or natural combustion products. Isotope homogeneity of humic acids confirms the presence of terrigenous C in marine sediments, allowing the terrestrial input to be characterised.     

Spectroscopic characterization of fulvic acids extracted from the rock exudate Shilajit

The present work describes the extraction of fulvic acids (FA) from Shilajit and its spectroscopic and mass spectrometric characterization. The spectral features obtained from FT-IR and ¹HNMR were similar to those reported for humic substances from other sources. The molecular elemental composition analysis by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) in electrospray negative ion mode resulted in extraordinary high average O/C ratios (0.55) which might be caused by a significant contribution of carbohydrates in Shilajit. A very high average H/C ratio of 1.27 also points to dominant aliphatic or alicyclic structures and relatively low aromaticity. The average molecular formula of the nitrogen free elemental compositions measured by FT-ICR mass spectrometry is C_18.2H_23.0O_10.0.     

Molecular formulae of marine and terrigenous dissolved organic matter detected by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry

The chemical structure of refractory marine dissolved organic matter (DOM) is still largely unknown. Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR-MS) was used to resolve the complex mixtures of DOM and provide valuable information on elemental compositions on a molecular scale. We characterized and compared DOM from two sharply contrasting aquatic environments, algal-derived DOM from the Weddell Sea (Antarctica) and terrigenous DOM from pore water of a tropical mangrove area in northern Brazil. Several thousand molecular formulas in the mass range of 300-600 Da were identified and reproduced in element ratio plots. On the basis of molecular elemental composition and double-bond equivalents (DBE) we calculated an average composition for marine DOM. O/C ratios in the marine samples were lower (0.36 ± 0.01) than in the mangrove pore-water sample (0.42). A small proportion of chemical formulas with higher molecular mass in the marine samples were characterized by very low O/C and H/C ratios probably reflecting amphiphilic properties. The average number of unsaturations in the marine samples was surprisingly high (DBE = 9.9; mangrove pore water: DBE = 9.4) most likely due to a significant contribution of carbonyl carbon. There was no significant difference in elemental composition between surface and deep-water DOM in the Weddell Sea. Although there were some molecules with unique marine elemental composition, there was a conspicuous degree of similarity between the terrigenous and algal-derived end members. Approximately one third of the molecular formulas were present in all marine as well as in the mangrove samples. We infer that different forms of microbial degradation ultimately lead to similar structural features that are intrinsically refractory, independent of the source of the organic matter and the environmental conditions where degradation took place.     

Multi-method study of the characteristic chemical nature of aquatic humic substances isolated from the Han River,Korea

Natural organic matter (NOM) from the Han River, Korea was fractionated into humic and non-humic fractions by absorbing onto XAD-7HP, and these fractions were analyzed using UV-absorption, and for dissolved organic C (DOC). The humic fraction (i.e. humic substances; HS) was extracted and its characteristics were compared to commercial humic materials using various spectroscopic methods such as Fourier transform infrared (FT-IR), proton nuclear magnetic resonance (¹H-NMR) and fluorescence spectroscopy. The humic fraction as organic C was 47.0% on the average, however, a rainfall event brought a higher humic fraction into Han River water. The molar ratios of H/C and O/C in the HS from Han River water (HRHS) were 1.40 and 0.76, respectively, and the ratio of aliphatic to aromatic protons in the HS (P_Al/P_Ar ratio) was 5.8. Aromaticity and humification degree (i.e., degree of condensation) of HRHS were relatively lower than those from other humic materials, while the portion of oxygenated functional groups was relatively higher. FT-IR, ¹H-NMR and fluorescence spectroscopy showed distinct differences between HRHS and the commercial humic materials. Commercial humic materials are not representative of HS extracted from Han River water. The fluorescence spectra, relatively simple measurements, were found to be most useful as fingerprints for humic materials from particular sources.     

Cross polarization, magic-angle spinning C nuclear magnetic resonance spectroscopy of soil humic fractions

Cross polarization, magic-angle spinning ¹³C nuclear magnetic resonance spectroscopy was used to characterize humic fractions isolated from different soils. The acid fractions are more aromatic than the humin fractions, probably due to the higher polyssaccharide content of humins. However, fulvic acid fractions are more aromatic than the corresponding humic acid and humin fractions. These results can be interpreted in terms of the isolation procedure, because the high affinity of Polyclar AT for phenols results in higher aromaticities as compared with other isolation methods (e.g. charcoal).     

Molecular weight distribution,analytical and spectroscopic characterization of humic fractions sequentially isolated by organic solvents from a brown coal humic acid

A sequential fractionation procedure employing a series of selected mild organic solvents of different polarity has been applied for the isolation of chemically different organic fractions from a brown coal humic acid. Elemental composition, molecular weight distribution, i.r. and electron spin resonance analysis were carried out on the isolated humic fractions. They were characterized by: (a) a low polydispersity, (b) a decreasing aliphatic and increasing aromatic character along the series, (c) very different molecular weight which significantly correlated with E₄/E₆ ratios (particle aggregation and molecular association) and free radical concentrations (chemical and biochemical activity). Significant correlations were found between physico-chemical parameters of the isolated humic fractions, i.e. M_n, M_w, E₄/E₆ ratios, spins/g contents and the dielectric constants of the solvents used. This suggested the efficiency of the applied procedure in isolating chemically different organic fractions from the bulk, original humic acid.     

Molecular characterization of dissolved organic matter in pore water of continental shelf sediments

Dissolved organic matter (DOM) in sediment pore water is a complex molecular mixture reflecting various sources and biogeochemical processes. In order to constrain those sources and processes, molecular variations of pore water DOM in surface sediments from the NW Iberian shelf were analyzed by ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and compared to river and marine water column DOM. Weighted average molecular element ratios of oxygen to carbon ((O/C)_wa) and hydrogen to carbon ((H/C)_wa) provided general information about DOM sources. DOM in local rivers was more oxygenated ((O/C)_wa 0.52) and contained less hydrogen ((H/C)_wa 1.15) than marine pore water DOM (mean (O/C)_wa 0.50, mean (H/C)_wa 1.26). The relative abundance of specific compound groups, such as highly oxygenated aromatic compounds or nitrogen-bearing compounds with low H/C ratios, correspond to a high concentration of lignin phenols (160 μg/g sediment dry weight) and a high TOC/TN ratio (13.3) in the sedimentary organic matter and were therefore assigned to terrestrial sources. The lower degree of unsaturation and a higher relative abundance of nitrogen-bearing compounds in the pore water DOM reflected microbial activity within the sediment. One sampling site on the shelf with a high sediment accumulation, and a humic-rich river sample showed a wide range of sulfur compounds in the DOM, accompanied by a higher abundance of lipid biomarkers for sulfate-reducing bacteria, probably indicating early diagenetic sulfurization of organic matter.     

Amino acid composition of organic matter associated with carbonate and non-carbonate sediments

Amino acids comprise from 15 to 36% by weight of humic substances from carbonate and non-carbonate sediments. Humic and fulvic acids extracted from carbonate sediments are characterized by an amino acid composition consisting primarily of the acidic amino acids, aspartic and glutamic acid. Humic substances from non-carbonate sediments have a distinctly different amino acid composition consisting primarily of glycine and alanine. Amino acid analyses of various molecular weight fractions of fulvic acids extracted from carbonates show that lower molecular weight fractions have appreciably higher relative abundances of the acidic amino acids compared to higher molecular weight fractions. Based on typical values for carboxyl group content in humic substances, acidic amino acids may be a significant contributor of these functional groups. Carbonate surfaces appear to selectively adsorb aspartic acid-enriched organic matter while non-carbonates do not have this property.     

Multi-method characterization of DOM from the Turia river (Spain)

Water concentrates from Turia river (1.5 mg L⁻¹ total organic C) obtained by nanofiltration (membrane mass cut-off 90 Da) were fractioned by non-ionic Amberlite resins (DAX8 and XAD4) to afford three samples termed as hydrophobic acid (50%), transphilic acid (24%) and hydrophobic neutral (12%). If a nanofiltration membrane 270 Da mass cut-off is used then about 50% of dissolved organic matter is not retained. These three fractions were characterized by analytical and spectroscopic techniques (¹H NMR, MALDI–TOF-MS, ESI–API-MS, ESI–MS/MS). Overall, these data are compatible with the presence of oligosaccharides, oligopeptides and fatty acids as the main components of dissolved organic matter. Particularly revealing was the information from MALDI–TOF-MS and ESI–MS/MS where series of compounds differing in the number of hexose units were identified. The three fractions have many spectroscopic similarities and, particularly the hydrophobic and transphilic ones, are really almost identical. This similarity in the fraction composition shows that the conventional fractionation procedure is inefficient as a standard general method for separation of different compound types. The composition of dissolved organic matter was confirmed, and some individual organic compounds identified, by GC–MS analysis of the silylated derivatives obtained by reacting the fractions with a mixture of N,O-bis(trimethylsilyl)trifluoroacetamide with trimethylchlorosilane (10%). Thus, rather surprisingly, the dissolved organic matter of this natural raw water is predominantly composed of a relatively simple mixture of a few types of compounds with molecular weights well below 1100 Da (about six hexose units). These results, particularly the absence of detectable amounts of high molecular weight humic acids and low molecular weight phenolic compounds indicates that trihalomethanes formed in the water disinfection process by Cl₂ really derive from oligosaccharides and oligopeptides. Also, the data suggests alternative strategies to effect a more efficient fractionation of the dissolved organic matter.     

The lignin component of humic substances: Distribution among soil and sedimentary humic,fulvic, and base-insoluble fractions

Vanillyl, syringyl and cinnamyl phenols occur as CuO oxidation products of humic, fulvic and base-insoluble residual fractions from soils, peat and nearshore marine sediments. However, none of these lignin-derived phenols were released by CuO oxidation of deepsea sediment or its base-extractable organic fractions. Lignin analysis indicated that peat and coastal marine sediments contained significantly higher levels of recognizable vascular plant carbon (20–50%) than soils and offshore marine sediments (0–10%).Although accounting for less than 20% of the total sedimentary (bulk) lignin, lignin components of humic acid fractions compositionally and quantitatively resembled the corresponding bulk samples and baseinsoluble residues. Recognizable lignin, presumably present as intact phenylpropanoid units, accounted for up to 5% of the carbon in peat and coastal humic acids but less than 1% in soil humic acids. Fulvic acid fractions uniformly yielded less lignin-derived phenols in mixtures that were depleted in syringyl and cinnamyl phenols relative to the corresponding humic acid fractions.Within the vanillyl and syringyl families the relative distribution of acidic and aldehydic phenols is a sensitive measure of the degree of oxidative alteration of the lignin component The high acid/aldehyde ratios and the low phenol yields of soils and their humic fractions compared to peat and coastal sediments indicate extensive degradation of the lignin source material. Likewise, the progressively higher acid/aldehyde ratios and lower phenol yields along the sequence: plant tissues (plant debris)-humic acids-fulvic acids suggest that this pattern represents the diagenetic sequence for the aerobic degradation of lignin biopolymers.