Presentation Information
[AOS26-P05]Comparison of dissolved organic matter and nutrient characteristics in three rivers with different land use conditions
*Aki Ito1, Ryo Sugimoto1, Satoshi Nakada2 (1.Faculty of Marine Biosciences,Fukui Prefectural University, 2.National Institute for Environmental Studies)
Keywords:
DOM,Nurient
Riverine dissolved substances have a significant impact on the material cycle and ecosystem structure of coastal waters. Understanding the relationship between watershed characteristics and river water quality is important for understanding the material cycle from the watersheds to coastal seas, as well as for carrying out appropriate environmental management. This study focused on three first-class rivers (Shonai River, Suzuka River, and Miya River) that flow into Ise Bay and have different basin characteristics. The aim was to clarify changes in the concentrations and qualitative characteristics of dissolved organic matter (DOM) and nutrients from upstream to the river mouth. Surface river waters were collected from multiple locations along the rivers at four times in 2025: February, May, July, and November. The results showed that dissolved organic carbon(DOC) and PO43-concentrations in the Shonai River were significantly higher than those in the other two rivers. The increase in NO3-+NO2- concentrations in the Suzuka River exceeded that of the Shonai River. Principal component analysis (PCA) revealed that the water quality characteristics of the three rivers were distinctly different, reflecting the differences in the watershed characteristics of each river. These results suggest that the quality of river water is strongly influenced by the intensity and type of human activities within the basin. This provides valuable insights for watershed management and assessing the supply of riverine materials to coastal areas. The presentation will also introduce results based on the qualitative characteristics of DOM using its three-dimensional fluorescence properties.