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

示踪剂试验分别于1994年8月和1996年10月在东中国海和北太平洋(1995年11月)在日本海洋科学技术中心的“凯约”号和东京大学海洋研究所的“白尾丸”号的R/V号上进行。培养实验持续24小时，用玻璃纤维过滤器(Whatman GF/F)将溶解有机物从颗粒有机成分中分离出来。过滤压力控制在150 mm Hg以下，初级生产力从副热带气旋的200mgCm^-1到长江口的1500mgCm~(-1)。颗粒脂肪酸产生率采用C/GC/MA法测定。14：0、16：0和16：1等脂肪酸是构成颗粒物的主要酸，其中16：1的贡献具有空间差异性。在测定溶解有机碳的~(13)C原子%时，溶解有机碳首先通过湿式氧化法转化为二氧化碳。各站溶解有机碳中的~(13)C原子百分数均略有增加，表明在培养过程中有溶解有机碳的产生。估算了溶解脂肪酸的~(13)C原子%，并在高产站的某些脂肪酸中发现原子%的增加。另一方面，在低生产力站点，没有脂肪酸表现出~(13)&C原子百分比的增加，表明浮游植物光合作用产生的溶解脂肪酸很少。

^<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.