Why secondary production of boreal brackish water is high?-Clarification over the maintenance mechanism of excellence and over benthic system-

我们进行了实地调查，比较了基于蛤种群二次生产的蛤的食物需求与蛤在野外的数量和潜在食物来源的稳定同位素对蛤的饮食贡献。我们讨论了在泻湖潮滩生态系统中如何维持蛤种群的密集斑块和高次生生产力。只使用同位素符号的贡献似乎有在某种程度上误导贡献的风险。仅根据稳定同位素数据，底栖硅藻的贡献范围相对较大。根据浮游植物生物量和蛤的食物需求，估计底栖硅藻的合理贡献可达68%，底栖硅藻似乎是蛤最重要的食物来源。在本研究中，潮下区大量的底栖硅藻似乎对蛤蜊的食物来源起着关键的作用

We carried out field surveys to compare the food demand of the clam based on the secondary production of the clam population to both the amount of the clam in the field and stable isotopic contribution to the diet of the clam of the potential food sources. We discuss how the dense patches and high secondary productively of the clam population are sustained in the ecosystem on tidal flats in the lagoon. The contribution by using only the isotope sign seems to have the risk of somewhat misleading of the contribution. Contribution of the benthic diatom showed relatively wider range based on only stable isotopic data. Subsequently, reasonable contribution of the benthic diatom was estimated up to 68 % based on the phytoplankton biomass and food demand of the clam, and the benthic diatom seemed to be the most important food sources of the clam. In this study, the large amount of the benthic diatom in subtidal area seemed to play a key role of the stock for the food sources of the clam