Permalink : http://hdl.handle.net/2115/91807

JaLCDOI : 10.14943/lowtemsci.82.83

KEYWORDS : 溶存鉄;湿地;土地利用;魚附き林;dissolved iron;wetland;land use;fish-breeding foresten

海洋表層において植物プランクトンの光合成に利用される溶存鉄の供給源は多様であるが，その一部は河川から流入する．本研究は，北海道の河川を対象に，異なる土地被覆・土地利用状況にある流域において，時間・空間的に河川水中の溶存鉄濃度がどのように変化するかを多地点における季節を通じた採水・分析によって明らかにした．その結果，湿原を有する流域で溶存鉄濃度が高く，森林を主体とした流域では濃度が低いことが判明した．一方，農地を起源とする溶存鉄も存在する可能性があることがわかった．季節的には，夏期に溶存鉄濃度が上昇するという先行研究の成果を追認した．
The dissolved iron utilized in photosynthesis by phytoplankton in the surface layer of the ocean includes various sources, but a certain amount of the dissolved iron is supplied from rivers. In this study, focusing on rivers in Hokkaido, we elucidated how the dissolved iron concentration in river water changes over time and space in different land cover and land use conditions in the watershed. This was achieved through seasonal sampling and analysis at multiple locations. The results revealed that areas with wetlands in low-lying watersheds had higher dissolved iron concentrations, while watersheds dominated by mountain forests showed lower concentrations. On the other hand, it was found that dissolved iron of agricultural origin might also be present. Seasonally, the study confirmed previous research findings that dissolved iron concentrations increase during the summer.