[M-IS21_28PM2] 生物地球化学

[MIS21-24] 森林生態系における大気降下物由来硝酸イオンの利用率に関する研究

*尾坂 兼一¹、小牧 直人¹、川村 湧也¹、村田 哲也¹、久郷 達朗¹、中村 高志²、西田 継²、永淵 修¹ (1.滋賀県立大学環境科学部、2.山梨大学国際流域環境研究センター)

キーワード：森林流域, 安定同位体比, 硝酸イオン, 大気降下物

Nitrogen is an important element for forest ecosystems; shortage of nitrogen limits plant growth [Vitousek andHowarth, 1991], however, nitrogen discharged from forested ecosystems link to various environmental problems, such as eutrophication of aquatic ecosystems and deterioration of drinking water quality. Recently, atmospheric nitrogen deposition into terrestrial ecosystems is increasing [Galloway et al., 2008]. However, influence of the increase of atmospheric nitrogen deposition on forested ecosystem is not clear because the interaction between nitrogen input/output and inner nitrogen cycle is not sufficiently understood. In this study, to clarify the interaction between nitrogen input/output and inner nitrogen cycle, we investigate the atmospheric nitrate discharge rate from forested watershed and discuss the availability of atmospheric nitrate deposited into forested watersheds.