Production process of refractory marine dissolved organic matter by marine bacteria ; Experimental analyses using bacteria-specific D-amino acids.

海洋细菌生产难降解海洋溶解有机物的工艺；

• 批准号: 15510013
• 负责人: YANAGI Katsumi
• 金额: $ 2.3万
• 依托单位: Kyushu Sangyo University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15510013/
• 关键词: D-amino acid; Refractory dissolved organic matter; Bacteria; ^<13>C-labeled organic matter; ^<13>C-tracer method; GC; MS method; ^<13>C-標識有機物

Subjects in this study were to clear the biogeochemical process of production of marine dissolved organic matter(DOM), particularly that of refractory fraction(R-DOM), and to discuss the significance of DOM and /or R-DOM as an organic carbon reservoir on earth and its possible relation to global carbon change and recycle. An incubation experiment was carried out for the analyses of contribution of marine bacteria to DOM production, especially to R-DOM production, by tracing concentrations and composition of dissolved organic constituents, particularly those of bacteria-specific D-amino acids in culture samples, using combined methods of ^<13>C-tracer, GC, and GC/MS.Glucose(20mgC) labeled with ^<13>C and seawater(2l) of Tokyo Bay containing natural bacterial populations were added as a substrate and bacterial seeds to artificial seawater(18l) in polycarbonate bottle(20l). And then the solution was incubated for over 90days in the dark at 27℃. Aliquots of sample were recovered at interva … More ls 1-30days and filtered through a glass-fiber filter (Whatman, GF/F) so as to apply the filtrate to chemical analysis of DOM.Rapid increasing in concentration of dissolved amino acids, especially of alanine, and high values in ratio of D-alanine to L-alanine were found in early stage(1-4days) of incubation while the concentration of DOC and its initial ^<13>C/^<12>C ratio(^<13>C-atom%) strictly decreased, indicating most probable conversion (and/or consumption) of ^<13>C-glucose to other organic molecules and CO_2 by bacteria. It was obvious that DO^<13>C, ^<13>C-amino acids and D-amino acids, particularly ^<13>C-alanine and D-,L-alanine, were specifically produced by bacteria from ^<13>C-glucose during incubation. It was also revealed that no less than 1% of ^<13>C-DOC and D-alanine produced in early stage of incubation(up to 4days) remained stable even after 90days incubation, respectively.In previous study of Hama et al. 2004, about 5% of organic carbon produced initially by phytoplankton photosynthesis was observed to remain stable after 60days incubation in the dark, which was consisted of DOC and accounted for more over 60% of all organic carbon remained, having a relatively low molecular weight and more biorefractory natures.Form these results, it is obviously shown that major parts of marine R-DOM are produced by marine bacteria through their specific conversion from photosynthetic products of phytoplankton. It should be also enable to estimate a magnitude of contribution of bacteria to R-DOM production as a function of carbon isolation in concerning with the environmental importance of global carbon change and recycle. Less

本研究旨在明确海洋溶解有机物（DOM），特别是难熔组分（R-DOM）产生的生物地球化学过程，并探讨DOM和/或R-DOM作为有机碳储库的意义。进行了一项孵化实验，通过追踪溶解有机成分（特别是那些有机成分）的浓度和组成，分析海洋细菌对 DOM 生产（尤其是 R-DOM 生产）的贡献。的使用^<13>C-示踪剂、GC 和 GC/MS 的组合方法，检测培养物样品中细菌特异性的 D-氨基酸。^<13>C 标记的葡萄糖 (20mgC) 和东京湾的海水 (2l) 含有将天然细菌群体作为底物和细菌种子添加到聚碳酸酯瓶(20l)中的人造海水(18l)中，然后将溶液在27℃下避光培养90天以上。每隔1-30天回收等份样品，并通过玻璃纤维过滤器（Whatman，GF/F）过滤，以便将滤液用于DOM的化学分析。溶解氨基酸的浓度快速增加，尤其是丙氨酸含量高，D-丙氨酸与L-丙氨酸的比例在孵化初期（1-4天）呈高值，而DOC浓度及其初始值^<13>C/^<12>C比率(^<13>C-atom%)严格下降，表明^<13>C-葡萄糖最有可能通过以下方式转化(和/或消耗)为其他有机分子和CO_2很明显，DO^ 13 C、^ 13 C-氨基酸和D-氨基酸，特别是^ 13 C-丙氨酸和D-，L-丙氨酸是特异性产生的。还表明，在培养的早期阶段(最多4天)产生的13 C-DOC和D-丙氨酸不少于1％，即使在培养后仍保持稳定。分别培养 90 天。在 Hama 等人 2004 年的先前研究中，观察到浮游植物光合作用最初产生的约 5% 的有机碳保持稳定。在黑暗中培养60天后，开始DOC，占所有有机碳剩余量的60%以上，具有相对较低的分子量和更耐生物降解的性质。从这些结果中，可以明显看出海洋R的主要部分-DOM 由海洋细菌通过浮游植物光合产物的特定转化产生。它还应该能够估计细菌对 R-DOM 生产的贡献程度，作为碳隔离的函数。随着全球碳变化和回收的环境重要性。

项目成果

Hama, T., Yanagi, K., Hama, I.: "Decrease in molecular weight of photosynthetic products of marine phytoplankton during early diagenesis"Limnology and Oceanography. 49. 471-481 (2004)

Hama, T.、Yanagi, K.、Hama, I.：“早期成岩过程中海洋浮游植物光合产物分子量的降低”湖沼学和海洋学。

Effect of nutrient conditions on the composition of photosynthetic products in the East China Sea and surrounding waters.

东海及周边海域营养条件对光合产物组成的影响.

• 发表时间: 2003
• 期刊: Deep Sea Research II 50
• 作者: Shin;K.H.;T.Hama;N.Handa
• 通讯作者: N.Handa