The Yellow Sea (YS) and East China Sea (ECS) are marginal seas in the Northwestern Pacific that receive large amounts of aged, terrestrial organic matter. In this study, we measured dissolved organic carbon (DOC) concentrations and radiocarbon contents (Δ 14 C) in these seas during summer and autumn, extending a previous winter study to provide a more comprehensive understanding of the DOC cycle, including its sources and remo...

We investigated the effects of eddies and typhoons on the biogeochemistry of the tropical northwest Pacific by examining the distribution of nutrients, dissolved oxygen (DO), chlorophyll- a (Chl- a ), gross primary production (GPP), dissolved organic carbon (DOC), and fluorescent dissolved organic matter (FDOM). Water samples were collected from anticyclonic and cyclonic eddies in September 2019 and 2020, and before and after...

We examined particulate organic carbon (POC) export using 238 U– 234 Th disequilibrium in the tropical northwest Pacific Ocean, where numerous eddies are present. We obtained data from an anticyclonic eddy in 2019 and from both anticyclonic and cyclonic eddies in 2020. In 2019, excess 234 Th and higher POC concentrations were observed in the upper 100 m layer inside the anticyclonic eddy compared with the outer area of the edd...

The East Sea (also known as the Japan Sea; hereafter, EJS) is a semi-enclosed marginal sea surrounded by the Korean Peninsula, Russia, and the Japanese Islands. The EJS is connected to the Pacific through shallow straits. Thus, the EJS has its own thermohaline circulation and the characteristic biogeochemistry. The deep overturning circulation plays a critical role in carbon cycling including absorption of atmospheric CO 2 and...

The East Sea (also known as the Japan Sea; hereafter, EJS) has its own deep overturning circulation, that operates over a centurial timescale compared with a millennial timescale in the ocean. This allows the EJS to be used as a natural laboratory for investigating potential future changes in the oceanic system. Dissolved inorganic carbon (DIC), total alkalinity (TA), and pH were measured in 2019 in a wide area of the EJS to i...

Experimental determinations of nitrogen cycling in deep‐sea sediments are strongly underrepresented in the databases. To investigate the total N 2 production rates and relative contribution of denitrification and anaerobic ammonium oxidation (anammox) to benthic fixed‐N removal processes, we conducted 15 N isotope‐labeling incubation experiments in whole cores and slurries at nine stations across the continental margin from th...