WATER BLOOM AND NUTRIENT LOADING IN SEASIDE PARK POND CONSISTED OF BRAKISH WATER

Water bloom and nutrient loading in Hasunuma seaside park pond which is consisted of brackish water and located in Hasunuma Watetr Garden in Kujyukurihama coastal line in Chiba Prefecture was investigated. In this pond, the massive water bloom (Aoko) has been observed in summer in recent years, but there are no rivers into this pond. As results of this study, the followings were made clear. (1) The main nutrient loading source was considered as pollen of Pinus thunbergii as sandbreak wood, excrement of Anas platyrhynchos as immigration bird and rainfall including NO3-N, (2) The dominant species of water bloom were Anabaena spiroides and Microcystis aeruginosa in summer and Cryptomonas spp. in winter. (3) The peculiar loading source of nutrient against seaside park pond should be paid attention to preservation the water environment in seaside area.