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- 1. Ariake Bay, which is located in western Japan, has a large tidal range (>6 m) and a vast tidal flat (200 km2). In the early 1990s, the government‐managed Isahaya Reclamation Project began in the western part of Ariake Bay. A 16‐km2 area of tidal flat in the inner part of Isahaya Bay was destroyed through reclamation and separated from the sea by a dyke, which created land and a freshwater reservoir.
- 2. Since the initiation of the project, fishery yields around Isahaya Bay have dramatically decreased. The objective of this study was to clarify the relationship between the work associated with the Isahaya Reclamation Project and the recent environmental deterioration in Ariake Bay, with references to present sediment thickness and organic matter content, and hypoxic water distributions in Isahaya Bay.
- 3. The organic matter load from the reservoir has increased since the initiation of the reclamation project and has been associated with a thick layer of fine sediment at the bottom of Isahaya Bay. The thickness of fine sediment and the total organic carbon content were higher in Isahaya Bay than in the freshwater reservoir.
- 4. Based on measurements in August 2001, hypoxic water spread widely in and around Isahaya Bay; the lowest dissolved oxygen (DO) concentration (0.53 mg L?1) was observed just outside the dyke. An analysis based on a two‐layered box model using data obtained in August 2001 showed that the DO consumption rate in the bottom layer was high (0.61 mg O2 L?1 day?1), and that 22–41% of the total organic carbon load needed to induce the hypoxic water was derived from the reclamation area.
- 5. Our findings strongly suggest that enclosed seas may suffer from eutrophic and hypoxic conditions because of their low seawater‐exchange rate. A comprehensive conservation programme and environmental assessment including physical and material transport processes in the system is needed to manage the environment of the enclosed sea.
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入世以来中国水产品贸易的格局特征及发展前景 总被引:2,自引:0,他引:2
水产品是中国传统的出口优势产品。加入WTO以来,中国水产品贸易在进出口双向快速增长的局面下,保持了净出口态势。文章在总结中国水产品入世几年来进出口的发展趋势、产品结构以及国别特征的基础上,着重分析了其发展前景。结果表明,增强质量竞争力是优势水产品出口实现持续增长的关键,未来几年对国外捕捞类水产品进口将继续大规模增长,中国水产品进出口的产品结构特征短期内不会有显著变化。最后,基于提高出口水产品竞争力、优化中国水产品贸易格局的目的提出了一些对策建议。 相似文献
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基层农机工作要适应时代的需要,其管理职能也要随之做出相应调整,由过去的管理型向管理服务型转变。既要管理好农机安全生产及农机有序合理流动,又要搞好服务,当好农机教练员,做好农机推广工作,成为一名合格农机服务员,主动为机手和经销商及厂家搭起桥梁和纽带,促进农机的发展。 相似文献
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