IOCAS-IR
海水中信息有机物的鉴别及在典型海域表层水中的环境地球化学特征
Alternative TitleIdentification of informational organic matters and their environmental geochemical characteristics in the surface seawater of typical sea areas
张倩
Subtype博士
Thesis Advisor宋金明
2019-06
Degree Grantor中国科学院大学
Place of Conferral中国科学院海洋研究所
Degree Name理学博士
Keyword信息有机物 检测方法 胶州湾 西太平洋 环境地球化学
Abstract

信息有机物系指存在于自然环境中,对生物物种或生物类群生存和生长有促进或抑制作用,并能通过调控生物丰度与群落结构来影响生态系统和生态环境的微痕量有机物。将这些信息有机物的化学结构、含量的检测和其分布特征、生态学功能研究有机结合,对理解生态系统结构、阐明生态现象机理有重要意义。尽管目前海洋环境中关于信息有机物的研究已获得一些成果,但限于分析方法的不足,其研究零散而不系统。本论文以构建海水中信息有机物的提取检测方法为主,结合海水非定向筛查与文献调研结果,选择邻苯二甲酸酯、正构烷烃和植物激素这3类信息有机物作为研究目标,获得了如下的系列结果和认识:

1. 构建了两套海水中微痕量信息有机物的提取检测方法,基于固相萃取和Q-TOF质谱的非定向有机物筛查方法可用于非定向筛查和检测未知成分的海水样品中的潜在信息有机物,基于液相萃取和气质联用的非极性有机物检测方法可用于检测天然海水样品中的邻苯二甲酸酯(PAEs)等非极性有机物。

对现有邻苯二甲酸酯和正构烷烃的提取检测方法进行优化,建立了一种可同时检测海水中15种邻苯二甲酸酯和32种正构烷烃(C8-C40)的方法,该方法基于二氯甲烷液相萃取和气相色谱-质谱联用(GC-MS)分析,标准曲线相关系数高于0.996,加标回收率高于70%,已成功应用于胶州湾和西太平洋海山区表层海水中两种信息有机物的检测。首次建立了海水中13种植物激素的提取检测方法,该方法以C18HLB固相萃取小柱联用进行提取,使用液相色谱-质谱联用(LC-MS进样检测,标准曲线相关系数高于0.994,在加标浓度为100 ng·mL-11000 ng·mL-1时的回收率分别为58.6-117.3%96.2-100.7%,该方法对于研究藻华等生态现象中植物激素的角色和作用有潜在应用价值。

基于高分辨的四极杆飞行时间质谱(Q-TOF-MS/MS)所得一级、二级质谱数据,结合质谱数据库检索,可以在未知目标有机物的情况下,较为准确地定性分析海水中的微痕量有机物。探索不同pH条件对检测效果的影响,发现强酸性pH条件提取出的有机物分子异质性高, 对酸、酮等活性小分子和木质素、蛋白质、糖类等生物分子的提取效果好。强酸性pH条件更有利于提取带有含氧不饱和基团(如:羧基、羰基)和环氧结构的分子,较低pH条件对于极性较大的分子有更好的提取效果,更适合从天然海水中提取活性分子。pH=2时提取物有效峰数目最多,指认出的分子式种类最多,对定性分析海水溶解有机物的分子组成最为有利。定性筛查海月水母在饥饿状态下释放出的潜在活性物质,发现饥饿状态下的海月水母会释放出大量溶解态有机物,释放出的溶解有机氮(DON)占溶解态总氮(DTN)的30%,溶解有机磷(DOP)占溶解态总磷(DTP)的16%,为水母在环境压力下会释放信息有机物这一猜想提供了事实支持。Q-TOF质谱分析发现,具有显著统计学差异的特征离子m/z值主要分布在200-800之间,与之对应,解析出以脂类衍生物为主的13种潜在信息有机物,结合文献检索推测水母在极端环境条件下可能会释放出氧脂素类潜在信息有机物。用这种方法定性筛查胶州湾表层海水中的活性有机物,发现包括己二酸、十六环内酯、甘油酯、黄酮等在内的17 种潜在信息有机物。

2. 研究了胶州湾表层海水中邻苯二甲酸酯、正构烷烃和植物激素这三类信息有机物的环境地球化学特征。相对于其他研究海域,胶州湾表层海水中的信息有机物有相对较高的含量。邻苯二甲酸酯以DiBPDBP为主,浓度范围为6.00-56.93 μg·L-1,对海洋生物具有中到高等生态风险;正构烷烃由连续的分布的C11-C37同系物组成,总量为1.76-39.09 μg·L-1;植物激素仅检出生长素,含量为2.62-17.56 ng·L-1。信息有机物的组成与分布情况受人类活动影响强烈。

胶州湾表层海水中共检出12种邻苯二甲酸酯类有机物,浓度范围为6.00-56.93 μg·L-1,有明显的东北高于西南、青岛沿岸高于黄岛沿岸的分布特征。DiBP51.94%)和DBP21.59%)是含量最高的邻苯二甲酸酯,主要来自于人类工业生产或日常生活过程,通过废物丢弃或排污等方式直接进入环境。DiBP对鱼类的风险熵(RQ)值为12.49DEHP对藻类为5.09,均已远远超过了产生高等生态风险的水平。DBPDEHP对其他海洋生物的RQ值也超过了0.01,表示它们对海洋生物有中等生态风险。

胶州湾表层海水中的正构烷烃由连续的分布的C11-C37正构烷烃同系物组成,各站位正构烷烃总量为1.76-39.09 μg·L-1,高值区以湾口为主,其分布与胶州湾东北部和西部河流带来的工业废水、生活污水和湾口码头附近的船舶航运带来的正构烷烃输入有关。湾中部和湾外等受人类活动影响相对较小的海域正构烷烃有明显的C24主碳峰,前峰群有微弱的奇碳优势,后峰群有微弱的偶碳优势,表明这些正构烷烃以藻类和海洋细菌等海洋自生输入为主。人类活动输入的正构烷烃主要是石油类污染物经过高度风化后的产物,由C21-C33正构烷烃同系物组成,呈现出有微弱偶碳优势的后峰群单峰形分布特征。胶州湾表层海水对正构烷烃的去除机制以蒸发、稀释等物理风化过程为主,从湾内向湾外对正构烷烃的风化强度增大。

植物激素仅检出生长素,其含量为2.62-17.56 ng·L-1,在胶州湾表层海水中的分布情况与邻苯二甲酸酯恰恰相反。随着未来研究程度的深入,植物激素有望成为一类指示浮游植物分布和生存生长情况的生物标志物。

3. 首次报道了西太平洋海山区表层海水中邻苯二甲酸酯的环境地球化学特征,并研究了正构烷烃的环境地球化学特征。西太平洋海山区表层海水中的信息有机物浓度相对较低,邻苯二甲酸酯以DBPDEHPDiBP为主,浓度范围为12.13-60.69 ng·L-1;正构烷烃由碳数连续分布的C8-C20同系物组成,总量为0.73-0.74 μg·L-1。信息有机物在西太平洋表层海水中的分布相对均匀,正构烷烃来源以海洋自生为主,邻苯二甲酸酯虽然总体浓度很低,但某些种类已达到产生潜在生态风险的水平。

西太平洋海山区表层海水中共检出14种邻苯二甲酸酯,总浓度范围为12.13-60.69 ng·L-1,含量分布与海水深度有关,海底地形隆起导致的海山-海流相互作用是影响其分布的主要因素。DBP20.66%)、DEHP19.75%)和DiBP18.72%是含量最高的三种邻苯二甲酸酯。DiBP对藻类的RQ值为0.06,指示中等生态风险,DEHP对甲壳类和鱼类的RQ值也很接近0.01,暗示它们对西太平洋海山区的其他海洋生物也有潜在生态风险。西太平洋表层海水中的邻苯二甲酸酯主要来自于塑料残骸和大气沉降,经过洋流或大气长程传输到达此处。

西太平洋海山区表层海水中的正构烷烃由碳数连续分布的C8-C20正构烷烃同系物组成,总量为0.73-0.74 μg·L-1,不同站位之间总正构烷烃的含量差异很小。西太平洋海山区表层海水中的正构烷烃碳链长度全部小于C20,均位于前峰群中,指示该海域的正构烷烃完全由海洋自生输入。西太平洋表层海水中的正构烷烃以C9为主碳峰,碳优势指数CPI和奇偶优势指数OEP均接近于1,仅有非常微弱的偶碳优势,说明此处的正构烷烃并非新鲜产生的,可能是更深层或其他海域由生物代谢产生的正构烷烃经过微生物或其他的风化途径降解,并随海水运动而混合扩散,最终形成这种相对稳定又混合均匀的组成分布情况。

Other Abstract

Informational organic matters refer to the trace organic matters in the natural environment, which can promote or inhibit the survival and growth of biological species or biota, and influence the ecosystem and ecological environment by regulating the abundance and community structure of organisms. It is of great significance to understand the structure of the ecological system and elucidate the mechanism of ecological phenomena by combining the detection of informational organic matters’ chemical structures and concentrations with the research of their distribution characteristics and ecological functions. Although some results had been achieved by the current research on informational organic matters in the marine environment, limited to the lack of analytical methods, the research is fragmented instead of systematic. This dissertation mainly focuses on the establishment of methods extracting and detecting informational organic matters in seawater. Based on literature investigation and non-targeted screening of potential informational organic matters in seawater, phthalates, n-alkanes and phytohormones were selected as objective informational organic matters. The following new results and understandings were obtained:

1. Two sets of methods were constructed to extract and detect trace informational organic matters in seawater. The method of non-polar organic compounds, such as phthalates (PAEs), is based on liquid-liquid extraction and gas chromatography-mass spectrometry. The other method is based on solid phase extraction and Q-TOF mass spectrometry and can be used for non-targeted screening and detecting potential informational organic compounds in components-unknown seawater samples.

A method for simultaneously extracting and detecting 15 phthalates and 32 n-alkanes (C8-C40) in seawater was established by optimizing the available extraction and detection methods. This method was based on dichloromethane extraction and gas chromatography-mass spectrometry (GC-MS) analysis. The correlation coefficients of the standard curves are higher than 0.996, and the spiked recoveries are higher than 70%. Now the method has been successfully applied to the extraction and detection of phthalates and n-alkanes in surface seawater of Jiaozhou Bay and seamounts area in the western Pacific Ocean. The extraction and detection method of 13 phytohormones from seawater was established for the first time. Phytohormones were extracted by C18 and HLB solid phase extraction cartridges and analyzed by liquid chromatography-mass spectrometry (LC-MS). The correlation coefficients of the standard curves were higher than 0.994, and the spiked recoveries of 100 ng mL-1 and 1000 ng mL-1 were 58.56-117.3% and 96.16-100.7%, respectively. This method has potential application value for the study of phytohormones’ roles and effects in ecological phenomena such as algal blooms.

Based on the data of the high-resolution quadrupole time-of-flight mass spectrometry (Q-TOF-MS) and various mass spectrum databases, it is practicable to qualitatively analyze trace organic matters in seawater accurately without objective targeted organic matter. Explore the effect of different pH on the extraction and detection of bioactive organic compounds from seawater. Extracts with strong acidic pH condition were found to be with higher molecular heterogeneity, and their extraction effects to bioactive molecules such as acid and ketone, and biomolecules such as lignin, protein and sugar was better than extracts with other pH conditions. Strong acidic pH benefits to the extraction of molecules with oxygen-containing unsaturated groups (such as carboxyl and carbonyl) and epoxy structures. Lower pH conditions have a better extraction effect for polar molecules, therefore more suitable for extracting bioactive molecules from natural seawater. When pH=2, extracts were extracted with most effective peaks and recognizable molecular formula, which is most favorable to the qualitative analysis of the molecular composition of seawater dissolved organic matter. Qualitatively screen the potential active compounds released by hungry Aurelia aurita. Dissolved organic nitrogen (DON) accounted for 30% of the dissolved total nitrogen (DTN), and dissolved Organic phosphorus (DOP) accounted for 16% of the dissolved total phosphorus (DTP), which provides evidence to the assumption "jellyfish release informational organic matters under environmental stress". Q-TOF mass spectrum showed that the m/z of featured ions with significant statistical differences was mainly distributed between 200-800. Thirteen potential informational organic compounds were identified correspondingly, most of which were lipid derivatives. It suggested that jellyfish might release oxylipins and their derivatives as potential informational organic matters under extreme environmental conditions. Qualitatively screen bioactive organic compounds in the surface seawater of Jiaozhou Bay with the method above, 17 potential informational organic matters were found, including adipic acid, 16-epoxy lactone, glycerol ester and flavonoids.

2. The environmental geochemical characteristics of 3 informational organic matters, phthalates, n-alkanes and phytohormones, in the surface seawater of Jiaozhou Bay, were studied. Compared to other sea areas, informational organic matters in the surface seawater of Jiaozhou Bay were with relatively higher concentrations. Phthalates are dominated with DiBP and DBP, with a concentration ranged from 6.00 μg L-1 to 56.93 μg L-1, and pose medium to high ecological risk to marine organisms. N-alkanes were composed of C11-C37 congeners with a concentration of 1.76-39.09 μg L-1. Among phytohormones, only auxin was detected in the surface seawater of Jiaozhou Bay with a concentration of 2.62-17.56 ng L-1. The composition and distribution of informational organic matters are strongly influenced by human activities.

A total of 12 phthalates were detected in the surface seawater of Jiaozhou Bay, with a concentration of 6.00-56.93 μg L-1. They were concentrated in the northeast than the southwest and concentrated near Huangdao coast than Qingdao. DiBP (51.94%) and DBP (21.59%) are the dominated PAEs. They were accessed to the environment directly by waste disposal or sewage during industrial production or daily life. The risk quotient (RQ) of DiBP to fish is 12.49, and the RQ of DEHP to algae is 5.09, far above the level of high ecological risk. The RQ of DBP and DEHP to other marine organisms also exceeds 0.01, indicating moderate ecological risk to marine organisms.

N-alkanes in the surface seawater of Jiaozhou Bay were composed of C11-C37 congeners, with a concentration of 1.76-39.09 μg L-1. N-alkanes were concentrated in the mouth of Jiaozhou Bay. Their distribution corresponds to the input of industrial wastewater, domestic sewage from the northeastern and western rivers, and ship shipping in the port near the mouth of Jiaozhou Bay. In the middle and outside of the bay, with relatively less influence from human activities, n-alkanes are with obvious main carbon peaks of C24. The anterior peak group has a weak advantage of odd carbon, and the posterior peak group has a weak even advantage, indicating that these n-alkanes are mainly generated by marine algae and bacteria. N-alkanes from human activities were mainly weathered petroleum pollutants, which are composed of C21-C33 congeners, with weak even carbon advantage and single-peak shaped of posterior peaks. The removal mechanism of n-alkanes in surface seawater of Jiaozhou Bay is dominated with physical weathering such as evaporation and dilution. The weathering strength is increased from the inside to the outside of the bay.

Only auxin was detected with a concentration of 2.62-17.56 ng L-1. The distribution of auxin in the surface seawater of Jiaozhou Bay was opposite to phthalates, which indicated that the distribution of phytohormones was similar to marine phytoplankton. With further research, phytohormones are expected to be a biomarker indicating the distribution and growth of phytoplankton in the future.

3. The environmental geochemical characteristics of phthalates and n-alkanes in the surface seawater of seamounts area in the western Pacific Ocean were systematically studied. It was found that the concentration of informational organic matters in the surface seawater of the western Pacific Ocean lower than other sea areas. Phthalates are dominated by DBP, DEHP and DiBP, with concentrations ranged from 12.13 ng L-1 to 60.69 ng L-1. N-alkanes were composed of C8-C20 congeners with concentrations of 0.73-0.74 μg L-1. The distribution of informational organic matters in the surface seawater of the western Pacific Ocean is of little difference. N-alkanes were mainly self-generated from marine organisms. Although the concentration of phthalates is very low, they had reached the level of posing a potential ecological risk to marine organisms, indicating that marine plastic pollution could not be ignored anymore.

A total of 14 phthalates were detected in the surface seawater in the seamount area of western Pacific Ocean with concentrations of 12.13-60.69 ng L-1. Their distribution corresponded to the depth of seawater. Seamount-current interaction was the main factor affecting the distribution of PAEs. DBP (20.66%), DEHP (19.75%) and DiBP (18.72%) were PAEs with the highest concentrations. The RQ of DiBP to algae was 0.06, indicating moderate ecological risk. The RQ of DEHP to crustaceans and fish were also close to 0.01, suggesting potential ecological risks to other marine organisms in the seamounts area of western Pacific Ocean. PAEs in the surface seawater of the western Pacific is mainly derived from storage media such as plastic wreckage or atmospheric particles. They were carried to the western Pacific through long-range atmospheric transportation or currents and were released into the marine environment slowly as the carrier weathering.

N-alkanes in the surface seawater of seamount area in the western Pacific Ocean were composed of C8-C20 congeners with concentrations of 0.73-0.74 μg L-1, and distribution with little difference. The distribution of n-alkanes congeners was completely in the anterior peak group before C20, indicating they were generated by marine organisms. N-alkanes in the surface seawater of the western Pacific Ocean were dominated with C9, with an extremely weak even advantage and CPI and OEP close to 1, showing that the n-alkanes here are not freshly generated. Marine bacterial were involved in the process of their production and degradation, but their contribution is not dominant.

Subject Area海洋化学
MOST Discipline Catalogue理学::海洋科学
Language中文
Document Type学位论文
Identifierhttp://ir.qdio.ac.cn/handle/337002/156877
Collection中国科学院海洋研究所
Recommended Citation
GB/T 7714
张倩. 海水中信息有机物的鉴别及在典型海域表层水中的环境地球化学特征[D]. 中国科学院海洋研究所. 中国科学院大学,2019.
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