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1.
Patrick Louchouarn Rainer M.W. Amon Shuiwang Duan Christina Pondell Shaya M. Seward Noah White 《Marine Chemistry》2010,118(1-2):85-97
A series of reference materials are proposed for intercomparison and quality control purposes during the quantification of lignin oxidation products (LOP) from diverse environmental matrices. These materials are all easily accessible and certified for diverse organic constituents (NIST and IHSS). They represent a suite of natural environmental matrices (from solids to aqueous) and are characterized by a wide range of organic carbon and lignin concentrations with abundant proportions of all major LOP. The variability of LOP concentrations and signatures for all these materials averages 3–5% and does not exceed 10%. Using these standards, a new quantification method was developed and validated for the determination of low-level CuO oxidation products using capillary gas chromatography–tandem mass spectrometry (GC/MS–MS). Tandem mass spectrometry provides both the high sensitivity and selectivity required for the identification and quantification of trace levels of dissolved lignin. The method is particularly useful for removing interference from co-eluting isotopes generated from the DOM matrix and during glucose amendment procedures of low-carbon samples. Such glucose amendment is not necessary, however, when the CuO to organic carbon weight-to-weight ratio can be kept at a value < 200–300. 相似文献
2.
海洋石油光化学降解的研究 总被引：1，自引：0，他引：1
石油进入海水会发生各种物理、化学变化,以往的研究已证明光化学氧化在石油及其精炼产品风化过程中具有重要意义.光化学氧化机理主要在于接受日光照射的能量,以不同的方式与溶解氧结合,从而最终降解石油烃.生成的光氧化产物一般为羧酸、醇、醚、羰基化合物等几类,还有一些产物尚不能确定其结构.光氧化产物仍然存在毒性,对海洋生物等十分有害.在动力学方面,针对其某一组分已证实为一级反应动力学行为,并定量地得出了速率常数.光降解速率会受到光照条件、溶解氧、金属离子等因素的影响.目前的研究表明,对石油光化学进行深入探讨具有较高的研究价值和现实意义. 相似文献
3.
Factors influencing the distribution of coastal lichens Hydropunctaria maura and Wahlenbergiella mucosa 
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下载免费PDF全文 Responses to abiotic and biotic stresses that potentially drive the vertical zonation of the intertidal lichens Hydropunctaria maura, an upper littoral lichen, and Wahlenbergiella mucosa, a lower littoral lichen, were investigated in field and laboratory experiments. When transplanted, both lichens exhibited an inability to survive outside their normal vertical distribution range. W. mucosa appeared to be unable to tolerate prolonged periods of desiccation following translocation from lower to upper littoral regions, whereas H. maura was unable to survive in lower littoral zones possibly owing to increased grazing pressure. The effect of desiccation in both lichens was compared using pulse amplitude modulated chlorophyll fluorescence and infra‐red gas analysis; results indicated a more hydration‐dependent nature of W. mucosa. Photosynthetic (algal) pigments and phenolic compounds were determined in both lichen thalli, and a range of additional coastal lichens occupying a natural gradient from upper to lower shore levels. Pigment composition and concentration in both lichen thalli were similar whereas levels of phenolic compounds were up to three times higher in W. mucosa than H. maura. Pigment and phenolic concentration and composition exhibited some seasonality across 13 different lichens originating from different shore levels. Phenolic concentration increased towards the lower shore, suggesting a potential anti‐herbivory function. This marks the first study of pigments and phenolics in coastal lichen communities, and prompts further investigations on the particular physiological features of marine and maritime lichens that enable them to thrive in this extreme environment. 相似文献
4.
本研究建立了AMS(Accelerator mass spectrum,加速器质谱)测定海水中129 I的气载分离制样方法:对加入载体的海水样品进行氧化还原处理,在加热的条件下将生成的单质碘吹出,并使用吸收装置吸收,后经阴离子交换树脂富集纯化,最后生成用于AMS分析的AgI沉淀,本方法全程回收率50%~70%,在相对密闭的体系中进行,减少了碘的损失,相对于萃取-反萃取的制样方法具有可操作性强,避免有机试剂使用等优点,可用于固态、液态和气态样品中129 I的AMS分析制样。 相似文献
5.
DMS and its oxidation products in the remote marine atmosphere: implications for climate and atmospheric chemistry 总被引：1，自引：0，他引：1
DMS emitted into the atmosphere over the global oceans has a range of effects upon atmospheric composition (mediated through various oxidation products) that may be significant with regard to issues as important as climate regulation, and the trace gas oxidation capacity of the marine atmospheric boundary layer. The roles played by DMS oxidation products within these contexts are diverse and complex, and in many instances are not well understood. Here we summarize what is known, and suspected, about the couplings between the marine atmospheric sulfur cycle, other atmospheric chemical cycles, and the dynamics and microphysics of the marine atmospheric boundary layer. This overview focuses heavily on measurements carried out in clean Southern Ocean air masses in association with the Australian Baseline Air Pollution Station located at Cape Grim (40° 40′ 56″S, 144° 41′ 18″ E), Tasmania. The data confirm that in the remote marine atmosphere, DMS is a central player in a variety of important atmospheric processes, reinforcing the need to understand quantitatively the factors that regulate DMS emissions from the ocean to the atmosphere. 相似文献
6.
Patrick Raimbault Wilfried Pouvesle Frdric Diaz Nicole Garcia Richard Sempr 《Marine Chemistry》1999,66(3-4)
We developed a simple and reliable method which allows simultaneous determination of organic forms of carbon (DOC), nitrogen (DON) and phosphorus (DOP) dissolved in seawater. Conversion of dissolved organic matter (DOM) to inorganic products (carbon dioxide, nitrate+nitrite and soluble reactive phosphate) is performed by a persulfate wet-oxidation in low alkaline condition. After oxidation, the concentration of the inorganic products dissolved in the sample was measured automatically by colorimetry using a 3-channel Technicon AutoAnalyzer system. A number of pure organic compounds were tested in the concentration range encountered in coastal and open ocean, indicating a high efficiency of the digestion procedure. The recovery range is similar to that obtained by other wet-oxidation procedures and by high-temperature catalytic oxidation techniques. Direct comparisons with usual methods used for separate determination of DOC, DON and DOP indicated a high efficiency of the procedure. Reproducibility tests demonstrated a very good precision (around 5%) for lagoonal and coastal waters, while precision was sometimes around 10–25% in oligotrophic oceanic waters, especially for DOP where values approached limits of detection for measuring phosphate. This method is highly suitable for routine analysis and especially appropriate for shipboard work. 相似文献
7.
Algae(and their extracts)are increasingly important for pharmaceutical applications due to the diversity of useful compounds they contain.The genus Fucus contains one of the most studied species,Fucus vesiculosus.The species F.ceranoides differs from the others of the genus by presenting longitudinal air-vesicles and a capacity to survive at low salinities.It is an alga that inhabits the Mondego River estuary(Portugal),at the southern limit of its distribution,and can serve as a role model to understand the effect of a salt gradient on the production of bioactive compounds.We assessed the phenolic content and antioxidant activity of different F.ceranoides extracts(e.g.methanolic,aqueous and polysaccharide)prepared from samples harvested from two different zones to evaluate if the adaptation of F.ceranoides to different salinity levels influenced its chemical composition.The antioxidant activity of the extracts was determined using 1,2-diphenyl-picrylhydrazyl(DPPH)and 2.2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS)radicals.These assays demonstrated that the methanolic extract of lyophilized F.ceranoides that grew at low salinities was the most bioactive,i.e.DPPH(IC 50=50.39μg/mL)and ABTS(TEAC=2.42).The total phenolic content(Folin-Ciocalteu method)and the methanolic extract of the lyophilized F.ceranoides collected from a low salinity habitat exhibited the highest phenolic content(PGE=49.48μg/mg of lyophilized extract)amongst those sampled.Thin layer chromatography(TLC)and Fourier transform infrared spectroscopy(FTIR)were used for the identification of compounds in the extracts.This characterization allowed confirmation that the various extracts contained almost the same compounds but with notable quantitative differences.Based on these results,we conclude that there were differences in the quantity of the compounds due to the effect of salinity.The drying methods used were also found to have influenced the quality of the extracted compounds. 相似文献
8.
H.P. Hansen 《Marine Chemistry》1975,3(3):183-195
Surface films of a crude-oil fraction were exposed to irradiation from different light sources. The physical behaviour is described. Degradation products were isolated and identified. Primarily they are aliphatic and aromatic acids and to a lesser extent alcohols and phenols. Acids were converted into their methylesters and identified by combined gas chromatography and mass spectrometry. The amount of oxidation products in the surface film was estimated by measurement of the CO-infrared absorption in the 1700 cm?1 region with “Attenuated Total Reflection” (ATR) infrared spectroscopy1. Comparison between the original crude-oil fraction and degradation products lead to an estimation of the decomposition rate under natural environmental conditions. 相似文献
9.
A detailed examination of a high-temperature catalytic oxidation method for liquid samples in the analysis of total nitrogen dissolved in seawater is reported. The nitrogenous compounds in liquid samples are oxidized on a platinum catalyzer at 680°C under oxygen atmosphere and the generated NO2 is absorbed into a chromogenic reagent, followed by a spectrophotometric determination. The results of this method are much higher than those of wet oxidation methods. Molecular size dependency of the results clearly indicates that the above discrepancy is caused by the low oxidation capacity of the wet oxidation method against high-polymer organic matter dissolved in seawater. The results revealed that the concentration of total nitrogen in seawater is nearly constant from surface to bottom, ranging from 30 to 40 μM 1?1, which organic nitrogen concentration higher in the surface layer, and a rapid decrease with depth. An examination of molecular size distribution indicates that the concentration of high-polymer organic nitrogen decreases rapidly from surface to deeper layers, with molecular sizes ranging from 5 × 103 to 3 × 104. Because of the well-defined principle of the oxidation process, its reliability, ease of sample handling and of analytical procedure on board or in the land laboratory, the present method is much more suitable for the marine analytical chemistry of total and organic nitrogen than the other previous methods. 相似文献
10.
Analyses by fluorescence spectrophotometry and computerized gas chromatography/mass spectrometry of the hydrocarbons present in surficial bottom sediments from Buchan Gulf, Baffin Island established that natural seepage of petroleum is occurring from the seabed. In addition, compounds of recent biosynthetic origin and from atmospheric fall-out of combustion products were identified. 相似文献
11.
本文通过线性连续梯度非变性电泳结合邻苯二酚发色法分离纯化了光棘球海胆(Strongylocentrotus nudus)体腔液上清中的酚氧化酶(PO),然后通过生长曲线测定法进行了光棘球海胆PO氧化产物的抗菌特性分析。结果显示:(1)光棘球海胆体腔液上清中存在3种PO(Sn PO1,Sn PO2,Sn PO3),在聚丙烯酰胺凝胶中与邻苯二酚反应分别呈现褐色、黄色和紫色;(2)以多巴胺为底物时,Sn PO1的氧化产物对灿烂弧菌Vibrio splendidus、哈维氏弧菌Vibrio harveyi和金黄色葡萄球菌Staphylococcus aureus有抗菌作用,Sn PO2氧化产物对哈维氏弧菌、金黄色葡萄球菌和拟诺卡式菌Nocardiopsis sp.有抗菌作用,Sn PO3氧化产物仅对哈维氏弧菌和拟诺卡式菌有抗菌作用;(3)以左旋多巴为底物时,仅Sn PO2氧化产物对拟诺卡式菌有抗菌作用;(4)光棘球海胆PO氧化产物对假交替单胞菌Pseudoalteromonas nigrifaciens、希瓦氏菌Shewanella baltica和溶壁微球菌Micrococcus lysodeikticus的生长无明显影响。上述结果表明,在光棘球海胆中,PO氧化产物具有窄谱抗菌活性,多巴胺氧化产物的抗菌活力高于左旋多巴氧化产物,并且不同PO亚型的氧化产物具有不同的抗菌谱和抗菌特性。 相似文献
12.
对测量海水中总溶解氮(TDN)的两种常用方法——高温燃烧法和过硫酸钾氧化法进行了比较。结果表明,两种方法在空白、精密度和准确度实验中不存在显著差异。对不同化合物的回收率均在92%～107%之间,加标回收实验回归曲线的斜率分别为0.93和0.92。对于现场海水样品的测定结果,两个断面拟合的斜率分别为0.92和0.97。HTC法比PO法对实际海水样品的氧化效率略高,在操作上也更方便、快捷。因此,高温燃烧法更适合海水中总溶解氮(TDN)的测定。 相似文献
13.
P.S. Loh A.D. Reeves S.M. Harvey J. Overnell A.E.J. Miller 《Estuarine, Coastal and Shelf Science》2008
Sea lochs are zones of rapid organic matter (OM) turnover. Most of this OM is of allochthonous origin, being introduced into the lochs via freshwater input. In this study the behaviour of terrestrially derived OM was elucidated using a combination of parameters which indicate OM diagenesis in the near surface sediments from two Scottish sea lochs, Loch Creran and Loch Etive. Alkaline CuO oxidation was used to determine lignin phenols which serve as biomarkers for terrestrial OM in sediments. Stable carbon isotope, total carbon and nitrogen and total OM (including the labile and refractory fractions) compositions were also determined. 相似文献
14.
《Marine and Petroleum Geology》2012,32(1):27-42
The gas generative potential of organic matter is one key parameter for the calculation of total gas in place (GIP) when evaluating thermogenic shale gas plays. Having first demonstrated that late gas-forming structures are present in coals of anthracite rank (>2% R0) we go on to examine other rocks at the immature stage of maturity and report on how to recognise which might generate significant amounts of late dry gas at geologic temperatures well in excess of 200 °C in the zone of metagenesis (R0 > 2.0%), i.e. subsequent to primary and secondary gas generation by thermal cracking of kerogen or retained oil. Such a distinction could clearly be of major value when assessing risks and pinning down “sweet spots”. A large selection (51 samples) of source rocks, i.e. shales and coals, stemming from different depositional environments and containing various types of organic matter which contribute to the formation of petroleum in putative gas shales were investigated using open- and closed-system pyrolysis methods for the characterisation of kerogen type, molecular structure, and late gas generative behaviour. A novel, rapid closed-system pyrolysis method, which consists of heating crushed whole rock samples in MSSV-tubes from 200 °C to 2 different end temperatures (560 °C; 700 °C) at 2 °C/min, provides the basis for a newly proposed approach to discriminate between source rocks with low, high, or intermediate late gas potential. It is noteworthy that late gas potential goes largely unnoticed when only open-system pyrolysis screening-methods are used. High late gas potentials seem to be mainly associated with heterogeneous admixtures or structures in terrestrially influenced, in some cases marine, Type III and Type II/III coals and shales. Aromatic and/or phenolic signatures are therefore indicative of the possible presence of elevated late gas potential at high maturities. High temperature methane was calculated to potentially contribute an additional 10–40 mg/g TOC, which would equal up to 30% of the total initial primary petroleum potential in many cases. Low late gas potentials are associated with homogeneous, paraffinic organic matter of aquatic lacustrine and marine origin. Source rocks exhibiting intermediate late gas potentials might generate up to 20 mg/g TOC late dry gas and seem to be associated with heterogeneous marine source rocks containing algal or bacterial derived precursor structures of high aromaticity, or with aquatic organic matter containing only minor amounts of aromatic/phenolic higher land plant material. 相似文献
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M.D. MacKinnon 《Marine Chemistry》1978,7(1):17-37
A high-temperature oxidation method is described for the accurate and precise determination of the total organic carbon (TOC) in seawater. Problems of contamination in sample storage, preparation, and oxidation which are evident in previous dry oxidation methods have been controlled. The TOC results from different areas are determined and compared directly with the results obtained on duplicate samples with the persulfate oxidation method. Significantly higher TOC values (15–20%) are obtained with the dry oxidation procedure, but the relative difference in the methods is relatively constant over depth and geographic areas. A high correlation between the methods was obtained. For accurate results, the dry method is recommended but conclusions based on profiles of TOC determined by either method should be similar if the proper precautions in analysis are followed. 相似文献
17.
过硫酸盐氧化法测定海水中溶解总磷 总被引：6，自引：0，他引：6
实验研究在碱性和酸性条件下过二硫酸钾高温氧化四种不同类型含磷标准化合物在海水中的回收率和影响回收率的因素。结果表明 :在碱性条件下过二硫酸钾高温氧化可使海水中非聚磷类化合物完全回收 ,而聚磷类化合物回收率不高 ,延长消化时间聚磷类化合物的回收率有一定提高。除个别化合物外 ,各类含磷化合物在酸性条件下可被定量回收。依此 ,建立酸性过硫酸盐氧化法分解测定海水中溶解态总磷的方法。 相似文献
18.
南海神狐天然气水合物系统沉积物中自生黄铁矿的特征研究 总被引：1，自引：0，他引：1
南海神狐海域是中国最重要的天然气水合物调查研究区之一,为了解水合物存在对沉积物地球化学环境的影响,对采自神狐海域W19B井位的沉积物样品进行了矿物学和地球化学研究。X射线衍射分析和主量元素结果显示部分层位有异常高含量的硫化物（主要为黄铁矿）。扫描电镜结果表明随着样品深度的增加,黄铁矿的晶面、晶棱更加明显,且集合体形态呈现聚莓→单莓→细粒的变化趋势,扫描电镜还观察到草莓状黄铁矿向细粒自形黄铁矿转化的中间产物。在53.0 mbsf（meters below seafloor）和140.4 mbsf层位均发现异常高含量的黄铁矿。其中140.4 mbsf层位黄铁矿充填有孔虫壳体的现象普遍,并伴有大量柱状黄铁矿产出,可能与有机质和甲烷厌氧氧化相关,但主导作用应为甲烷厌氧氧化,该层位可能位于古硫酸根-甲烷界面（sulfate-methane interface,SMI）附近。根据所得结果,推测地质历史时期中甲烷异常渗漏事件的发生,致使向上的甲烷通量增加,推动SMI上移,导致53.0 mbsf和140.4 mbsf界面处因甲烷厌氧氧化而形成大量黄铁矿。多个黄铁矿富集层的存在可能表示沉积史中曾发生多期次的深部流体渗漏或者天然气水合物的分解活动。 相似文献
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《Marine Chemistry》1987,22(1):85-94
A number of aromatic alcohols, aldehydes and ketones were found in organic concentrates obtained by liquid-solid adsorption from the waters of Hamilton Harbour, Bermuda. The compounds were characterized and identified using authentic reference materials by their mass spectra and relative retention indices. The origins of the aromatic alcohols, aldehydes and ketones, theoretically deduced from the results of earlier model experiments involving the sensitized photo-oxidation of alkylbenzenes, were demonstrated to be gasoline components. Sensitized photooxidation of a seawater solution of gasoline yielded oxidation products identical to those found in the water of Hamilton Harbour. 相似文献