On the sedimentary carbonate accumulation and dissolution in Western Pacific marginal basins

The critical role of marginal seas in the global carbon cycle and their response to climate and circulation changes are not well understood. In this study, we used long-term archives of sedimentary CaCO3 data and a conceptual model to systematically determine the spatial and vertical features of the sediment carbonate system in the marginal seas along the Western Pacific Ocean. Our results show that the northward-flowing Antarctic Bottom Water and Lower Circumpolar Deep Water produced shallower calcium carbonate preservation depths as they moved north and became more carbonate-undersaturated. This suggests that the carbonate chemistry in the deep Western Pacific marginal sea basins is mostly governed by the global ocean thermohaline circulation. In contrast, the carbonate system in the deep Japan/East Sea is unique, with limited sedimentary carbonate accumulation due to weak calcification and its internal overturning circulation. Despite differences in the hydrological and ecological settings, the sedimentary calcium carbonate profiles in the Tasman Sea and South Fiji Basin are comparable to those in the Atlantic and Pacific Oceans, reflecting the remarkable influence of open-ocean carbonate chemistry.

Automated summary

The study reveals that the carbonate system in the deep Western Pacific marginal sea basins is mostly governed by the global ocean thermohaline circulation, while the Japan/East Sea has unique carbonate characteristics with limited accumulation. The sedimentary calcium carbonate profiles in the Tasman Sea and South Fiji Basin are comparable to those in the Atlantic and Pacific Oceans, reflecting the influence of open-ocean carbonate chemistry.