| 自组装膜进样质谱系统及其在砂质沉积物异化硝酸盐还原研究中的应用 |
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| 引用本文： | 谢成军,宋国栋,刘素美,唐继尧,张桂玲.自组装膜进样质谱系统及其在砂质沉积物异化硝酸盐还原研究中的应用[J].海洋学报,2020,42(2):22-29. |
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| 作者姓名： | 谢成军 宋国栋 刘素美 唐继尧 张桂玲 |
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| 作者单位： | 1.中国海洋大学 海洋化学理论与工程技术教育部重点实验室/海洋高等研究院，山东 青岛 266100 |
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| 基金项目： | 国家自然科学基金（41606093，U1806211）；国家重点研发计划（2016YFA0600902，2016YFA0601302）；青岛海洋科学与技术试点国家海洋生态与环境科学功能实验室青年人才培育项目（LMEES-YTSP-2018-02-04）；泰山学者工程专项经费资助。 |
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| 摘 要： | 沉积物中的异化硝酸盐还原过程对于海洋氮循环起着至关重要的作用。基于15N标记的培养技术是目前测定沉积物异化硝酸盐还原的主要手段。准确快速测定15N标记的产物(29N2、 30N2)是量化异化硝酸盐还原各个过程速率的关键。本研究自行组装膜进样质谱系统用于29N2和30N2的测定,对其测量条件进行了优化。结果表明,进样蠕动泵进样流速0.80 mL/min,进样时间3~3.5 min,恒温槽温度20~25℃,同时铜还原炉温度在300~600℃的条件下,^29N2/^28N2和^30N2/^28N2的测试精密度分别可以控制在0.1%和1%以内,比较适合29N2和30N2的测定。利用自组装的膜进样质谱系统结合15N标记的培养技术研究了青岛石老人沙滩沉积物中的异化硝酸盐还原过程。石老人沙滩沉积物不存在将硝酸盐完全还原为氮气好氧的反硝化。厌氧铵氧化、厌氧反硝化和异化硝酸盐还原为铵(Dissimilatory Nitrate Reduction to Ammonium,DNRA)的潜在速率(以湿沉积物N计)分别为(0.05±0.01) nmol/(cm^3·h),(2.32±0.21) nmol/(cm^3·h)和(1.02±0.15) nmol/(cm^3·h)。厌氧反硝化是硝酸盐异化还原主要的贡献者,其比例接近70%,其次是DNRA,比例可达30%,而厌氧铵氧化的贡献最低,仅为1%。在N2产生过程中,主要贡献者是反硝化,厌氧铵氧化的贡献仅为2%。
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| 关 键 词： | 膜进样质谱 砂质沉积物 反硝化 厌氧铵氧化 异化硝酸盐还原为铵 |
| 收稿时间： | 2019/4/5 0:00:00 |
| 修稿时间： | 2019/5/30 0:00:00 |
Self-assembled membrane injection mass spectrometry system and its application on the study of dissimilatory nitrate reduction in sandy sediments |
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| Xie Chengjun,Song Guodong,Liu Sumei,Tang Jiyao and Zhang Guiling.Self-assembled membrane injection mass spectrometry system and its application on the study of dissimilatory nitrate reduction in sandy sediments[J].Acta Oceanologica Sinica (in Chinese),2020,42(2):22-29. |
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| Authors: | Xie Chengjun Song Guodong Liu Sumei Tang Jiyao and Zhang Guiling |
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| Institution: | 1.Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education/Institute for Advanced Ocean Study, Ocean University of China, Qingdao 266100, China2.Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, China3.College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China |
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| Abstract: | Dissimilatory nitrate reduction processes in sediments play a crucial role in marine nitrogen cycle. The most popular method to determine the rates of different dissimilatory nitrate reduction processes is the 15N labeled technique. Therefore, accurate and rapid determination the concentration of 15N-labeled products, such as 29N2 and 30N2, is the key to quantify the rate of each dissimilatory nitrate reduction process. In this study, we set up a membrane injection mass spectrometry (MIMS) and optimize the operating condition of the MIMS for the determination of 29N2 and 30N2. The optimization experiment results indicated that, when the peristaltic pump for sampling flow rate is 0.80 mL/min, the sampling time is 3～3.5 min, the thermostat water bath temperature is 20～25℃, and the copper reduction furnace temperature is 300～600℃, the precision (expressed in coefficient of variation) of the measured 29N2/28N2 and 30N2/28N2 can be controlled less than 0.1% and 1%, respectively. We used the self-assembled MIMS and combined the 15N labeling technique to study the dissimilatory nitrate reduction processes in the sandy sediment of the Shilaoren beach in Qingdao. There is no significant aerobic denitrification in the Shilaoren sand that can completely reduce nitrate to N2. The potential rates of anammox, anaerobic denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are (0.05±0.01) nmol/(cm3·h), (2.32±0.21) nmol/(cm3·h) and (1.02±0.15) nmol/(cm3·h) (N, wet sed.), respectively. Anaerobic denitrification is the major contributor to nitrate dissimilatory reduction, with a ratio of nearly 70%, followed by DNRA, with a ratio of up to 30%, while anammox has the lowest contribution of only 1%. In the N2 production, the main contributor is anaerobic denitrification, and the contribution of anammox is only 2%. |
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| Keywords: | membrane injection mass spectrometry (MIMS) sandy sediment denitrification anammox dissimilatory nitrate reduction to ammonium |
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