*Sayaka Yasunaka1
(1.Tohoku University)
Keywords:subsurface Chlorophyll-a cooncentration, photosynthetically active layer, nutricline, oxygen oversaturation
BGC Argo float is equipped with biogeochemical sensors to measure oxygen concentration, nitrate concentration, pH, chlorophyll-a (Chl-a) concentration, suspended particles, and downwelling irradiance. Recently, we integrated Chl-a concentration data from biogeochemical floats as well as from historical ship-based and other observations, and clarified the spatio-temporal variability of subsurface Chl-a concentration. Subsurface Chl-a maximum was stably observed in the world ocean, and closely related with the depths of the mixed layer, the photosynthetically active layer, the nutricline, and the oxygen oversaturation layer. The seasonal cycle and the interannual variation of subsurface Chl-a concentration were also described. I would like to share the idea of the possible future study in the day when data from BGC Argo are accumulated.