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Responses of the lower tropic level marine ecosystems to environmental variability in the Arctic Ocean.

低热带海洋生态系统对北冰洋环境变化的响应。

基本信息

批准号：
15510018
负责人：
CHIBA Sanae
金额：
$ 2.43万
依托单位：
Independent Administrative Institution, Japan Agency for Marine-Earch Science and Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

I conducted this study based on the observational data taken during the research cruises by R/V Mirai for the Japan-Canada Joint Arctic Study (JWACS) in autumn of FY2002 and 2004. The purpose of this study is to understand influences of physical and chemical environmental variation on the structure of the lower trophic level ecosystems in the western Arctic Ocean. I particularly focus on the spatial variation of ecology of the two copepod species, Calanus hyperboreus and C.glacialis, which dominated secondary producers in this region. The major finding of the results of FY2002 cruise was region-specific lower-trophic level structure and production We defined the four regions with the respective physical-biological characteristics. Coastal Pacific water inflow and dynamics of seasonal sea ice retreat were considered as the possible causes of the observed regional variations of the lower trophic level. As for the results of the FY2004 cruises, I also found the spatial variation in developmental timing of copepods between the east and west of Chukuchi Plateau (160-l70゜W) : more advanced stage of the copepods with high diatom availability was observed in the west while slow copepod development and poor phytoplankton abundance were observed in the east. Timing of ice edge retreat did not explain this results, but east-west contrast of surface layer stratification, which was presented by the complex water mess structure of this region, was considered as the direct determinant of the spatial difference in the ecosystem structure. Reduction of the Arctic sea iice for these decades has been reported, and these results implicated the future sea ice reduction and associated changes in the surface layer structure could drastically alter the ecosystem structure and biological production in the western Arctic Ocean.

本研究是基于2002财年和2004财年日本-加拿大联合北极研究（JWACS）的R/V Mirai在秋季的研究巡航期间的观测数据进行的。本研究的目的是了解物理和化学环境变化对北冰洋西部低营养级生态系统结构的影响。重点研究了在该地区次生种中占主导地位的两种桡足类物种——大北角虾（Calanus hyperboreus）和冰川虾（c.a glacialis）的生态空间变异。2002年度巡航结果的主要发现是区域特异性的低营养级结构和产量，并根据各自的物理生物学特征定义了四个区域。沿海太平洋海水流入和季节性海冰退缩的动态变化被认为是观测到的低营养层区域变化的可能原因。对于FY2004的巡航结果，我还发现了楚科奇高原东西两侧桡足类发育时间的空间差异（160-l70 W）：西部桡足类发育较晚，硅藻可用性较高，而东部桡足类发育较慢，浮游植物丰度较低。冰缘退缩的时间不能解释这一结果，但该地区复杂的水杂结构所表现出的地表分层的东西对比被认为是生态系统结构空间差异的直接决定因素。据报道，近几十年来北极海冰的减少，这些结果表明，未来海冰的减少和表层结构的相关变化可能会极大地改变北冰洋西部的生态系统结构和生物生产。