Effect of the secondary natural condition to a nutrient cycle and habitat for shells in the coastal zone, Ise Bay, Japan

本研究旨在探讨伊势湾西部(密西州中部)河口区海底地下水排泄点贝壳分布与营养盐排放的关系。结果表明，贝壳分布不仅与坚果补给量有关，还与溶氧量有关。在海底地下水排泄量分布的潮汐带上，分布着多种贝壳。此外，在距河口1公里以上的河段，一些生活在微咸水条件下的贝类分布在较高的溶氧值和低盐度区域。贝类的栖息地与当地地下水流动系统的排泄区有关，补给区提供营养物质。

The purpose of this study is to evaluate relationship between the some kind of shells distribution and the nutrient discharge from the submarine groundwater discharge points at river mouth area of western part of Ise Bay (central part of Mie Prefecture area).Results as follows; the shells distributions depend on not only volume of nut rient supply but dissolved oxygen value. Some kind of shells is distributed at tidal zone where submarine groundwater discharge is distributed. Further, at upward 1km river section from river mouth, some shells living in the brackish condition are distributed at relatively high value dissolved oxygen and low saline area. The habitat for shells is related to the discharge area of local groundwater flow system which has nutrient supplied from recharged area.