The role of dissolved organic matter in marine carbon cycle elucidation by production and turnover rates

1994年8月和1996年10月，日本海洋科学技术中心的"海洋"号考察船和东京大学海洋研究所的"白凤丸"号考察船分别在东海和北太平洋进行了^C示踪实验。<13>继续孵育实验24小时，并通过使用玻璃纤维过滤器（Whatman GF/F）过滤将溶解的有机物与颗粒有机成分分离。初级生产力在亚热带环流的200mgC·m·d~（-1）和长江口的1,500mgC·m·d~（-1）之间。<-2><-1><-2><-1>颗粒脂肪酸产生速率通过13C/GC/MA方法测定。<13>14：0、16：0和16：1脂肪酸是构成颗粒产物的主要酸，且16：1脂肪酸的贡献存在空间变异性。<13>溶解有机碳中的~（13）C原子%在各站位均略有增加，表明在培养实验过程中溶解有机碳的产生。<13>^估算了溶解脂肪酸的C原子%，并注意到在高生产率站点的一些脂肪酸中原子%的增加。<13>另一方面，在低生产力站，没有脂肪酸显示出^C原子%的增加，这表明通过浮游植物的光合作用产生的溶解脂肪酸很少。<13>

^<13>C tracer experiments were carried out in the East China Sea (Aug.1994 and Oct.1996) and North pacific (Nov.1995) during the cruises of R/V "Kaiyo", Japan Marine Science and Technology Center and R/V "Hakuho-maru", Ocean Research Institute, University of Tokyo, respectively. Incubation experiments were continued for 24h and dissolved organic matter was separated from particulate organic constituents by filtration using glass fiber filter (Whatman GF/F). The pressure for the filtration was controlled less than 150mmHg.Primary productivity varied form 200mgC m^<-2>d^<-1> at subtropical gyre to 1,500mgC m^<-2>d^<-1> at the Changjian estuary. Particulate fatty acid production rate was determined by ^<13>C/GC/MA method. Fatty acids such as 14 : 0,16 : 0 and 16 : 1 were major acids constituting particulate products and the contribution of 16 : 1 showed a spatial variation.For the determination of ^<13>C atom % of dissolved organic carbon, dissolved organic carbon was firstly converted to carbon dioxide by wet oxidation method. A little increase in the ^<13>C atom % in dissolve organic carbon was found at every station, indicating the production of dissolved organic carbon during the incubation experiments. ^<13>C atom % of dissolved fatty acid estimated and increase in the atom % was noted in some fatty acids at the high productivity stations. At low productivity stations, on the other hand, no fatty acid showed the increase in the ^<13>C atom %, showing little dissolved fatty acid was produced through photosynthesis of phytoplankton.