Relationship between water quality and algal biomass in outdoor experimental ponds with continuous flow:system.

Research Project

Project/Area Number	61540480
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	生態学
Research Institution	The National Institute for Environmental Studies
Principal Investigator	AIZAKI Morihiro the National Institute for Environmental Studies,, 水質土壌環境部, 主任研究官 (20109911)
Co-Investigator(Kenkyū-buntansha)	HANAZATO Takayuki the National Institute for Environmental Studies., 生物環境部, 研究員 (60142105) KAWAI Takayoshi the National Institute for Environmental Studies., 計測技術部, 主任研究員 (50109906)
Project Period (FY)	1986 – 1987
Project Status	Completed (Fiscal Year 1987)
Budget Amount *help	¥1,400,000 (Direct Cost: ¥1,400,000) Fiscal Year 1987: ¥500,000 (Direct Cost: ¥500,000) Fiscal Year 1986: ¥900,000 (Direct Cost: ¥900,000)
Keywords	屋外実験池 / リンの蓄積率 / 動物プランクトンの影響 / 栄養塩回帰 / 微生物変動 / リンの挙動 / 動物プランクトン影響 / 藻類種変動 / 細菌数変動
Research Abstract	Relationship between nutrient loading and phytoplankton standing crop and the effect of zooplankton on phosphorus retention were studied using six outdoor experimental ponds with continuous flow system. Phytoplankton standing crops reached the maximum values on 1 to 2 weeks after beginning of experiments except in winter and abruptly decreased by grazing of zooplankton. In winter,since zooplankton do not grow until April,phytoplankton standing crop continuously increased from Janualry to April. Phytoplankton standing crop exhibited by POC and PON showed linear relationship with phosphorus loadings during the period of no zooplankton growth,but chloropgyll concentration did not correlate with phosphorus loadings. Ch1/PP ratio increased continuously during January to April and changed from 1.1 to 3.9. Regenration of dissolved phosphorus according to the decrease of phytoplankton due to the grazing of zooplankton was scarcely observed,while dissolved organicnitrogen concentration increased according to the decrease of phytoplankton standing crop. Apparent settling velocities of phosphorus were insreased by the existence of sooplankton.