基于磷脂脂肪酸的热带西太平洋沉积物生源要素矿化过程探析     

杨梓阳  任登龙  贺志鹏  李学刚  宋金明  袁华茂  段丽琴  李宁  张倩 《地学前缘》2022,29(4):93-102

甄别生源要素参与的海洋沉积物矿化过程对探析生源要素的生物地球化学循环有重要的作用,矿化作用包括有氧呼吸、硝酸盐还原、铁锰异化还原及硫酸盐还原等多个过程,但如何区分这些过程一直是海洋沉积物矿化研究的难点。本研究采用气相色谱-质谱(GC-MS)联用对热带西太平洋沉积物中的磷脂脂肪酸(phospholipid fatty acid, PLFA)的组成进行了解析,并分析不同矿化过程中的主要PLFA种类及其影响因素,探究PLFA对沉积物矿化的指示作用。结果表明,PLFA总量在有氧呼吸过程中最高,而在硝酸盐还原过程中最低;且14:0、i14:0、i15:0和i19:0是有氧呼吸过程中微生物PLFA的主要组成,当其含量明显降低时可以指示沉积物矿化从有氧呼吸转变为硝酸盐还原;而10:0、17:0、20:0和22:0含量之和显著增加时则指示了硫酸盐还原过程的发生。在热带西太平洋沉积物中,总有机碳(TOC)和总有机氮(TON)含量以及间隙水NO₃-N含量是PLFA含量的重要影响因素,PLFA总量随着TOC和TON含量的减少而减少,并且TOC和TON的降解能够促进PLFA降解的发生,对PLFA组成有更直接的影响。  相似文献   

有机磷农药污染地块异味污染调查与健康风险评估     

孟洁  王静  肖咸德  张妍  翟增秀  李伟芳 《岩矿测试》2021,(6):907-918

农药污染地块修复过程中频繁出现异味污染问题,严重影响周边居民日常生活和身体健康。以往报道多集中在场地内有毒有害物质分析,较少关注场地异味污染问题。为预测某有机磷农药场地修复过程异味污染情况,本文以该地块7个潜在异味污染控制区为研究对象,分析了近土壤空气异味污染程度和影响范围,并应用气相色谱-四极杆/静电场轨道阱高分辨质谱技术测定近土壤空气、土壤中挥发性有机物（VOCs）和半挥发性有机物（SVOCs）,阐明地块控制区内异味污染排放特征,评估近土壤空气地块污染的人体健康风险。结果表明,7个区域监测点位散发不同程度刺激性气味,臭气浓度值范围为309~72443;生产区异味影响范围最大,达到3.2km;共识别出近土壤环境空气中209种VOCs、土壤样品中246种VOCs和SVOCs,主要包括芳香化合物、卤代物、烷烯烃和含氧有机物;主要异味贡献物质种类包括有机硫化物、芳香化合物和含氧有机物;7个区域近土壤空气均存在致癌风险（>1.0×10^-4）,5个区域存在非致癌风险,主要致癌物质为1,4-二氯苯、苯、四氯化碳。本文开展的农药场地异味物质组分与致病致癌风险持续研究结果,可为研究区生态环境修复和居民健康保护等提供重要依据。  相似文献   

南黄海和中国东海中挥发性卤代烃的分布与海气通量   总被引：1，自引：0，他引：1  

杨桂朋  李莉  陆小兰  张亮 《海洋学报(英文版)》2015,34(2):9-20

Distributions and sea-to-air fluxes of five kinds of volatile halocarbons(VHCs) were studied in the southern Yellow Sea(SYS) and the East China Sea(ECS) in November 2007. The results showed that the concentrations of 1,1,1-trichloroethane(C2H3Cl3), 1,1-dichloroethene(C2H2Cl2), 1,1,2-trichloroethene(C2HCl3), trichloromethane(CHCl3) and tetrachloromethane(CCl4) in the surface water were 0.31–4.81, 2.75–21.3, 1.21–17.1, 5.02–233 and 0.045–4.47 pmol/L, respectively, with the average values of 1.89, 12.20, 6.93, 60.90 and 0.33 pmol/L. On the whole, the horizontal distributions of C2H3Cl3, C2H2Cl2 and CCl4 were affected mainly by anthropogenic activities, while C2HCl3 and CHCl3 were influenced by biological factors as well as anthropogenic activities. In the study area, the concentrations of VHCs(except C2HCl3) exhibited a decreasing trend from inshore to offshore sites, with the higher values occurring in the coastal waters. The sea-to-air fluxes of C2H3Cl3, C2HCl3, CHCl3 and CCl4 were calculated to be-56.00–(-5.68),-7.31–123.42, 148.00–1 309.31 and-83.32–(-1.53) nmol/(m2·d), respectively, with the average values of-6.77, 17.14, 183.38 and-21.27 nmol/(m2·d). Our data showed that the SYS and ECS in autumn was a sink for C2H3Cl3 and CCl4, while it was a source for C2HCl3 and CHCl3 in the atmosphere.  相似文献   

应用平衡分配模型评价渤海湾和莱州湾沉积物重金属潜在生物毒性     

李力  王小静  白亚之  孙翌  刘季花 《海洋学报》2015,37(2):75-84

为探讨渤海沉积物中重金属的生物毒性,采集了渤海湾和莱州湾共72个站点的表层沉积物,测定了酸可挥发性硫化物(AVS)、同步萃取金属(SEM)、有机碳(TOC)等参数,应用平衡分配模型(EqP Model)评价了沉积物中重金属的潜在生物毒性。研究显示,有8个站点超过了EqP Model的毒性阈值,显示潜在生物毒性,而61%的站点应无生物毒性。本研究同时测定了沉积物的总含量,应用几种常用的沉积物质量基准进行了评价虽然有部分站点的Cu、Ni、Cr超过了基准值,但与渤海的背景值比较,这些基准值可能并不适用于评价渤海沉积物。研究显示,EqP Model可以更有效的评价沉积物中重金属的活性和生物毒性,尤其针对我国近岸海域的沉积物,TOC和AVS含量偏低而重金属生物毒性偏高的情况可能普遍存在,更应积极考虑应用EqP Model进行重金属生物毒性的评价。  相似文献   

The role of organic matter in the sorption capacity of marine sediments   总被引：1，自引：0，他引：1  

Zhanfei Liu  Cindy Lee 《Marine Chemistry》2007,105(3-4):240-257

Past studies have suggested that desiccation enhances hydrophobicity of salt marsh sediment, and that drying and rewetting sediment can be used to investigate sorption mechanisms of amino acids and other organic compounds [Liu, Z., Lee, C., 2006. Drying effects on sorption capacity of coastal sediment: The importance of architecture and polarity of organic matter. Geochim. Cosmochim. Acta 70, 3313–3324]. Here we further develop this technique to study sorption of hydrophobic and hydrophilic organic compounds in a wide range of marine sediments. Our results show that hydrophilic compounds sorb strongly to wet coastal sediments; in dried sediments, sorption of hydrophilic compounds decreases, while sorption of hydrophobic compounds is greatly enhanced. Small compounds with aromatic rings sorb more in dried than wet coastal sediments, suggesting that aromatic groups have a stronger effect on sorption than polar groups like amino and carboxyl moieties. Sorption of lysine, glutamic acid and putrescine decreases greatly when sediment is pretreated with KCl, indicating the importance of cation ion exchange. However, α-amino acids sorb much more than corresponding β- or γ-amino acids, and l-alanine sorbs more than d-alanine, suggesting that amino group location and chiral selectivity play an important role in sorption. Comparison of lysine and tyrosine sorption in different sediments indicates that source and diagenetic state of organic matter are important factors determining sorption capacity. Lysine sorbs much more to organic detritus from salt marsh sediment than to fresh Spartina root materials, marine particles, lignin or humic acids, indicating the importance of structural integrity in sorption. Desorption hysteresis of glutamic acid, putrescine and lysine (in dried sediment) suggests the presence of enzyme-type sorption sites of high sorption energy or multiple binding mechanisms. Taken together, these findings suggest that organic matter plays the major role in amino acid sorption in organic-rich sediments.  相似文献   

Emission of fine organic aerosol from traditional charcoal broiling in China     

Ximei Hou  Guoshun Zhuang  Yanfen Lin  Juan Li  Yilun Jiang  Joshua S. Fu 《Journal of Atmospheric Chemistry》2008,61(2):119-131

The indoor PM_2.5 aerosol samples for charcoal broiling source under Chinese traditional charbroiling and the ambient fine aerosols samples (PM_2.5) were collected in Beijing to investigate the characteristics of the charcoal broiling source and its impact on the fine organic aerosols in the atmosphere. The concentrations of 20 species of the trace organic compounds, including polycyclic aromatic hydrocarbons (PAHs), fatty acids, levoglucosan, and cholesterol in PM_2.5 were identified and quantified by GC/MS. The total PAHs and fatty acids emitted from charcoal broiling to PM_2.5 were 8.97 and 87,000 ng mg⁻¹ respectively. The concentrations of the light molecular weight (LMW) 3- and 4-ring PAHs were much higher than those of the high molecular weight (HMW) 5- and 6-ring PAHs. Fatty acids were the most abundant species in source profile, accounting for over 90% of all identified organic compounds. More polyunsaturated fatty acid (linoleic acids) than the saturated fatty acid (stearic acids) emitted in the cooking. Charcoal broiling is a minor source of PAHs compared to the source of biomass burning. Comparing the ratios of levoglucosan/fatty acid and levoglucosan/cholesterol in the charcoal broiling samples to the ambient samples, it is evident that meat cooking is an important source of fatty acids, but a less important source of cholesterol. Cooking, as one of the source of fine organic particles, plus other anthropogenic sources would be related to the formation of the severe haze occurred and spread over the urban atmosphere in most of the cities of China in the past several years.  相似文献   

柴达木盆地察尔汗湖区古湖相沉积物中含氮类分子化石的检出   总被引：1，自引：1，他引：0  

蒲阳  张虎才  雷国良  常凤琴  杨明生 《地球学报》2010,31(2):155-162

利用气相色谱质谱联用仪(GC-MS)对青藏高原柴达木盆地察尔汗湖区贝壳堤剖面古湖相沉积物样品进行了系统地分析, 检测出系列脂肪酸酰胺与脂肪腈类含氮类脂物分子化石。并对其在古湖相沉积物中的分布特征作了详细描述。对它们综合研究认为, 早期成岩作用使来源于各种生物体的脂肪酸酰胺类分子化石部分地转化为脂肪腈类化合物。此外, 不饱和脂肪酸酰胺与饱和脂肪酸酰胺的含量比值在剖面上并没有呈现明显下降的趋势, 说明在降解过程中各种生物、物理及化学作用对它们不存在明显的选择性, 指示有机质在沉积过程中可能处于一个偏氧化的环境。本文首次报道这两类物质, 为更好地理解含氮类脂物分子化石在湖泊沉积物中的转化过程提供了一定的理论依据。  相似文献   

酸碱软硬度在成矿理论研究中的应用     

兰斌明  贾建业  谢娟  王建成 《地球科学与环境学报》1999,21(2):71

以Ｌｅｗｉｓ酸碱理论为基础发展起来的酸碱软硬度的理论广泛地应用于解释各类化学现象，包括类质同象置换，共生，应用于评价和预测化学反应极为简便和实用。然而，软硬酸碱度原理的理论基础尚在不断地充实之中。本文简要讨论了硫化物矿物的酸碱势标度，用酸碱软硬度理论解释了矿物的类质同象现象，是应用酸碱软硬度理论揭示和完善矿物成矿理论的一种偿试。  相似文献   

珠江口沉积物柱状样的脂肪酸垂向变化特征     

伏美燕  周怀阳  王虎  李季伟  尹希杰  杨伟芳 《海洋湖沼通报》2010,(1)

珠江口3个站位沉积柱的脂肪酸研究结果显示:沉积物中含量最高的脂肪酸是C16:0,其他脂肪酸包括不饱和脂肪酸、单甲基支链脂肪酸和长链脂肪酸。脂肪酸组成表明研究区有机质主要来源于藻类、细菌和陆源有机质。由于横琴岛附近的HQ1031站位靠近外海,初级生产力较高,因而含较多藻类脂肪酸。离淇澳岛较远的QA-B站位处于河口上缘,陆源物质丰富,初级生产力较低,因此该站位含较多陆源脂肪酸。横琴岛附近HQ1031站位的TOC值和总脂肪酸含量均大于QA-B站位,这两个站位的TOC值与总脂肪酸含量在垂向上的相关性差。横琴岛附近HQ1031站位和离淇澳岛较近的QA-A站位分别在20-22cm和16-18cm处藻类脂肪酸突然大量增加,可能与藻类输入突然增多有关。沉积物中所检测到的能指示厌氧微生物或革兰氏阳性菌的脂肪酸含量高于革兰氏阴性菌,表明珠江口沉积物微生物群落中以厌氧微生物为主。  相似文献   

越冬前后海马齿脂肪酸和挥发性有机物组成和变化特征          下载免费PDF全文

毕正浩  杨芳  潘渊博  杨玲  林忠州  罗冬莲  周成旭 《海洋科学》2023,47(12):40-54

海马齿是一种热带和亚热带盐生植物, 既是传统野生菜蔬, 也在海岸带生态修复中发挥重要作用。北移种植海马齿进行生态修复时, 越冬低温的影响是成功与否的首要关注问题, 其机制尚待解明。脂肪酸在生物耐受低温中发挥作用, 挥发性有机物与脂肪酸代谢关系密切。本研究利用海湾环境中生态修复浮床上的海马齿样品, 重点解析北移种植环境下, 海马齿植株不同部位受越冬影响前后的脂肪酸和挥发性有机物的组成、差异及变化特征。结果显示, 海马齿的花、叶、茎和根样本中, 共检出14种脂肪酸, 根中的脂肪酸种类数相对最多; 多不饱和脂肪酸在花和叶中的含量(平均分别为56.46%和60.23%)总体大于茎和根(平均分别为41.56%和44.45%)。茎、叶中共检出86种挥发性有机物, 蘑菇醇为优势种类。越冬后脂肪酸和挥发性有机物种类数量显著降低, 多不饱和脂肪酸比例在冻伤植株中显著升高; 就植株脂质营养指数而言, 耐受越冬低温的植株其脂质营养品质提高。越冬造成海马齿两类化合物发生显著变化, 其中C18脂肪酸代谢响应有重要贡献, C18: 3(n-3)和蘑菇醇分别是脂肪酸与挥发性物质中最为重要的两个代谢产物, 可能与抗冻应激有密切关系。本研究为推广海马齿种植以构建可持续近海生态修复体系提供了参考。  相似文献