[M-IS19] [JJ] 生物地球化学

[MIS19-05] 丘陵地における渓流水の高リン酸濃度と底層藻類の一次生産

*笹 孝明¹、武井 六華、楊 宗興² (1.東京大学、2.東京農工大学)

キーワード：リン、丘陵地、一次生産、河川、還元

Phosphate is an essential mineral nutrient for all life forms. However, little phosphate is present in river waters, because it is strongly adsorbed on particulates such as oxides and hydroxides of iron and aluminum. Wakamatsu et al. (2006) reported low concentrations of phosphate in many headwater streams in Japan, which was presumed to vary depending on geological features. Here, we report high concentrations of phosphate in streams of hilly areas, which are created through a topographical feature of hilly areas. The reduction of Fe under humid soils resulted in the release of phosphate, which could act as a prime source of phosphate in a watershed. Moreover, we report an occurrence of significant primary production by benthic algae on sediments of a shallow pond, which may be stimulated by phosphate released from sediments.