Program

Studies of the fate of carbon in marginal seas are vitally important to understanding of the ocean carbon cycle. As a part of the CHOICE-C project, an integrated study of carbon dynamics in the marginal sea, we collected sediment cores from the shelf of the northern South China Sea (SCS) and derived sediment accumulation rate from radionuclides including ²¹⁰Pb and ¹³⁷Cs. In the shelf region of NSCS, sedimentary rates by ²¹⁰Pb_ex range from 0.1 to 1.6 g cm^-2yr^-1 and generally show a decreasing trend from coast to the outer-shelf. By combining the TOC data with the results for sediment accumulation rates at the same interpolation gridding density, OC flux to surface sediments in the northern SCS shelf can be estimated. There are two patches of high OC accumulation :to the northeast of Pearl River estuary and in the southwest of the NSCS. A preliminary carbon budget for the northern SCS Shelf has been established. Carbon burial in the form of OC adds up to 2.5*10¹² g C/yr, accounting for 15–20% of the carbon inventory in the northern SCS.