北海道における融雪期河川水質の地域特性

概要

論文の詳細を見る
The quality of stream water during the snow-melting season results in both beneficial 'spring bloom' and harmful eutrophication. In this study, regional features of total nitrogen and phosphorus, and dissolved-silicate concentraion in stream water during the snow-melting season was characterized by land use and soil conditions in Hokkaido. Total nitrogen and phosphorus concentrations of stream water were below environmental criteria, that is 1 mg L^<-1> and 0.1 mg L^<-1>, respectively, in most areas of Hokkaido. However, the concentrations above those criseria were observed in particular cases such as Funka Bay and the surrounding area in southern Hokkaido, followed by the Tokachi, Kitami and Abashiri areas with upland cropping and livestock husbandry. On the other hand, silicate concentration, which corresponded to soil conditions, was higher in the areas with weathered volcanic-ash soil followed by those less weathered, whereas it was lower in the areas with lowland soils including peat soils. The mol mol^<-1> ratios of silica to total nitrogen or phosphorus concentration (Si/T-N and Si/T-P) of stream water were thought to be useful indicators in judging the effect of eutrophication in the coastal sea during the snow-melting season. Funka Bay and the surrounding area, southern Hokkaido, where both Si/T-N and Si/T-P ratios expressed the condition stimulating flagellates (non-siliceous phytoplankton) and undesirab1e impact had actually been observed, was identified to be most harmful area. It is, therefore, also indicated that the effect of eutrophication in the aquasphere is different due to soil conditions even if there was the same nutrient load.
2001-02-05

北海道における融雪期河川水質の地域特性

スポンサーリンク

概要

著者

関連論文

スポンサーリンク