Flux of organic matter from phytoplankton to bacteria

1.用气相色谱-质谱法(GC-MS)测定脂肪酸的~(13)C同位素比值：用富含~(13)T；C的棕榈酸测定脂肪酸~(13)C同位素比值的准确性。结果表明，C-GC-MS方法可用于估算浮游植物向细菌的碳流量。2.北太平洋亚北极和亚热带地区脂肪酸的产生：在北太平洋亚北极和亚热带地区开展了13&gt；C示踪实验。采用C-GC-MS法测定了浮游植物光合作用产物的脂肪酸组成。亚北极地区以多不饱和脂肪酸为主，亚热带地区以饱和脂肪酸为主。这种差异主要是由于这些地区水温的差异造成的。亚北极地区多不饱和脂肪酸的高贡献率可以保持浮游植物细胞膜的流体状态。3.细菌特定脂肪酸的碳通量：用GC-MS测定细菌特定脂肪酸的~(13)C原子比，以阐明浮游植物向细菌的碳流。对来自亚北极和亚热带地区的样品进行了分析。细菌专性脂肪酸的~(13)&C原子百分比远低于浮游植物脂肪酸，表明浮游植物向细菌的碳流不高。然而，在估算碳通量时，必须同时考虑孵化时间和浮游植物碳的~(13)C原子百分比等因素的影响。

1.Estimation of ^<13>C isotopic ratio of fatty acid by gas chromatography-mass spectrometry(GC-MS): The accuracy of the estimation of ^<13>C isotopic ratio of fatty acid was ascertained by using ^<13>C enriched palmitic acid. The results indicated the applicability of ^<13>C-GC-MS method to estimate the carbon flow from phytoplankton to bacteria.2.Production of fatty acid at subarctic and subtropical area of Northern Pacific: ^<13>C tracer experiments were carried out at subarctic and subtropical area of Northern Pacific. Fatty acid composition of photosynthetic products of phytoplankton was determined by ^<13>C-GC-MS method. Polyunsaturated fatty acids constituted major part of products at subarctic area, whereas saturated fatty acids were main product at subtropical region. This defference was mainly due to the difference in the water temperature of these region. High contribution of polyunsaturated fatty acids at subarctic region can keep the fluid condition of membrane of phytoplankton.3.Carbon flux to the bacterial specific fatty acids: The ^<13>C atomic ratio of bacterial specific fatty acids were estimated by GC-MS to elucidate carbon flow from phytoplankton to bacteria. Samples obtained from subarctic and subtropical region were analyzed. The ^<13>C atom % of bacterial specific fatty acids were much lower than phytoplankton fatty acids, indication that carbon flow form phytoplankton to bacteria was not high which has been suggested by ^<14>C tracer studies. However, the effects of same factors such as incubation length and ^<13>C atom% of phytoplankton carbon must be considered to estimate carbon flux.