河床付着生物膜現存量の周年変化シミュレーション

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In the Hinuma River, changes of periphyton biomass were observed weekly from September 1987 to March 1990 and compared with a model simulation to evaluate the dynamics of periphyton biomass.A model was developed for simulating the periphyton biomass in a river system. The model consists of two sub-models : growth and scouring models. Parameters of the growth model were estimated based on the daily observation for a two-week period in each season. The change of the periphyton biomass was compared with that calculated through the model. Reasonably close agreement was found between the observed and calculated biomass ; however, a significant deviation was observed for the winter seasons when the biomass loss did not occur through scouring due to storm events. This deviation may be caused by significant detachment of the periphyton biomass and intensive grazing by benthic animals during the winter seasons.The annual growth of periphyton biomass and the annual periphyton biomass scoured were found to be 110 g·m-2 and 80 g·m-2 as carbon, respectively. The periphyton communities may absorb dissolved nitrogen and phosphorus from river water for their growth. If this is case, in the Hinuma River, at 10-km downstream, 0.6% and 6.7% of the dissolved nitrogen and phosphorus in terms of the annual runoff loading may be utilized by the periphyton, respectively.
社団法人　日本水環境学会の論文