Quantifying Vertical Nutrient Supply Influenced by Cold Eddies in the Western North Pacific Using Rare Earth Elements

抄録

The Western North Pacific Ocean, a dynamic marine region, is crucial to the global oceanic system due to its unique geological and oceanographic features. This area, connected to the East China Sea, is notable for its significant underwater structures, including a prominent seamount. The seamounts, along with interactions such as eddies and turbulence, enhance vertical mixing of water masses, redistributing nutrients and rare earth elements (REEs) from the deeper water to the euphotic zone. High chlorophyll concentrations (approximately 25-100 m) were observed at stations along 140°E-142°E, where the Izu Ridge is located. To identify the phenomena occurring in this layer, we quantified water mass contributions using optimum multiparameter analysis (OMPA) with potential temperature, salinity, and REEs. The results revealed that STMW contributed 14-18% around 100 m depth, likely due to the influence of cold eddies and turbulence bringing STMW from deeper layers to higher chlorophyll layers.