Observation based study of stable isotope effect in the food chain for different oceanic regions

2014 Fiscal Year Final Research Report

• Project/Area Number: 23310020
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Environmental dynamic analysis
• Research Institution: Japan Agency for Marine-Earth Science and Technology
• Principal Investigator: AITA Maki 独立行政法人海洋研究開発機構, 地球環境観測研究開発センター, 技術主任 (90463091)
• Co-Investigator(Kenkyū-buntansha): KITAMURA Minoru 独立行政法人海洋研究開発機構, 地球環境観測研究開発センター, 技術研究員 (00392952) ; KOBARI Toru 鹿児島大学, 水産学部, 准教授 (60336328)
• Co-Investigator(Renkei-kenkyūsha): YOSHIKAWA Chisato 独立行政法人海洋研究開発機構, 生物地球化学研究分野, 技術研究員 (40435839)
• Research Collaborator: WADA Eitaro 独立行政法人海洋研究開発機構, JAMSTECフェロー (40013578)
• Project Period (FY): 2011-04-01 – 2015-03-31
• Keywords: 海洋生態系 / 安定同位体比 / 食物連鎖 / 環境動態モデル / 物質循環

Outline of Final Research Achievements

Carbon and nitrogen isotope ratios of biota are controlled by two factors, a metabolic system and a life style of predator and a regional variability of environmental parameters on food-web system. To evaluate the environmental factors on the basic food-web in marine ecosystem, we studied the seasonal variation of nitrogen and carbon isotope ratios of zooplankton and ambient water in the subarctic site of K2 and the subtropical one of S1 in the western North Pacific. The δ15N values of zooplankton and nitrate ions in the water at the S1 site tended to be lower than those at the K2 site, indicating that the basic food-web is affected by nitrogen fixation. We further compared the trophic fractionation of carbon and nitrogen isotopes (Δδ13C, Δδ15N). It is observed that a simple relationship exists in the Δδ15N/Δδ13C regardless of species and ecosystems. This contention suggests an unified regularity is maintained in the lower to higher trophic level in the marine ecosystem.

Free Research Field

同位体海洋生態学