[A-CG42] Coastal Ecosystems - 1. Water Cycle and Land-Ocean Interactions

[ACG42-P03] Carbon, nitrogen, and phosphorous dynamics in the coastal lagoon and its agricultural watershed facing the Sea of Japan

*Ryo Sugimoto¹, Tsuyoshi Mori¹, Taichi Murakami¹ (1.Faculty of Marine Biosciences, Fukui Prefectural University)

Keywords:Coastal lagoon, Eutrophication

Coastal seas and lagoons along the Sea of Japan face severe issues regarding the seawater level rise of the Sea of Japan. In recent years, the seawater intrusion into the Lake Kitakata from the Sea of Japan has been managed automatically by the moveable gate operating depending on the water level difference between the lake and the sea. Environmental indices (COD, TN, and TP) have exceeded the standard values in the lake, and eutrophication is a serious issue. Thus, we conducted bi-monthly surveys to clarify the eutrophication mechanisms. Furthermore, we conducted the synoptic surveys within the agricultural watershed in the farming and the non-farming periods to evaluate the sources of carbon, nitrogen, and phosphorous into the lake. The presentation will show the seasonal cycle of organic carbon and its constitute, and the distributions of C, N, and P within the watershed.