| 摘要: |
| 于1992年9月–1994年5月先后对崂山湾海域作了7个航次调查。由实验室培养试验和现场采样分析两种方法得出食物链一个营养级的13C富集度分别为(1.6±0.2)×10-3和1.7×10-3，两者几乎一致。由7个季度月的现场采集样品的同位素分析结果表明，从处在食物网底部的浮游植物到最高级的肉食性鱼类之间δ13C差值平均为6.9×10-3，相当于5个营养级；并由各类生物的碳同位素数据分别确定了它们在该食物网中的营养位置，其结果与食性分析方法所得结果基本吻合。同位素示踪方法研究的结果还表明，崂山湾水体生物食物网中碳的来源主要是浮游植物碳。 |
| 关键词: 碳同位素 食物网 水体生物 营养层次 |
| DOI： |
| 分类号: |
| 基金项目:国家自然科学基金资助项目，39170172号 |
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| STUDIES ON 13C/12C RATIOS AS A TRACER FOR FOOD WEB IN A MARINE ECOSYSTEM—THE TROPHIC RELATIONS IN PELAGIC FOOD WEBS IN LAOSHAN BAY |
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CAI De-ling, MENG Fan, HAN Yi-bing, GAO Su-lan
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First Institute of Oceanography, State Oceanic Adminislration, Qingdao, 266003
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| Abstract: |
| Seven cruise investigations were conducted in Laoshan Bay from September 1992 to May 1994 to study the trophic relations in pelagic food webs in Laoshan Bay ecosystem using a stable isotopic tracer. The 13C enrichment factors per trophic level in the food chain are (1.6±0.2)×10-3 and 1.7×10-3 with two methods for laboratorial culture tests and in situ sampling analyses, respectively, showing both are almost identical. The results of isotopic analyses of in situ samples in seven cruises indicate that the mean of δ13C value difference between phytoplankton at the bottom of the food webs and carnivorous fisher at the top level is 6.9×10-3, corresponding to 5 trophic levels, and their trophic locations in the food webs are determined for every species based on their δ13C values. This result is basically coincident with that by the feeding habit analyses. Compared with the results of isotopic research in other marine ecosystems in the world, the commonness is that the δ13C value distributions of various species of organisms reflect the carbon isotopic enrichment existing in food webs and there is some similarity in different ecosystems. The difference is that based on the measurements of seven months seasonally the samples collected from Laoshan Bay also reflect the seasonal variations in δ13C value distributions. The results in most references, however, have only data of one cruise; it is difficult to reflect the seasonal variations. Moreover, the differences of geographic positions, especially latitude, also have a large effect on δ13C values. The results of the isotopic tracer research show that the predominant source of carbon of pelagic food webs in Laoshan Bay is phytoplankton-derived carbon, while other carbon sources, such as the organic matter derived from terrestrial clastic and the organic matter in the bottom sediments, are secondary sources. |
| Key words: Carbon isotopes, Food web, Pelagic livings, Trophic level |
