5:15 PM - 7:15 PM
[U02-P06] Reconstructing Ocean Carbonate System in the Tropical South China Sea: A multi-proxy approach using foraminiferal shell chemistry
Keywords:Ocean carbonate system, Boron isotopes, Multi-proxy, Foraminiferal shell chemistry, South China Sea
The carbon cycle in the upper ocean plays a crucial role in regulating atmospheric CO2 concentrations, thereby influencing global climate change. In recent years, the role of marginal seas in the global carbon cycle has garnered increasing research attention. These seas can act as either a net source or sink of atmospheric CO2, depending on physical and biological processes, highlighting the importance of understanding their ocean carbonate chemistry of these seas. The South China Sea (SCS), the largest sea in Southeast Asian, however, remains poorly understood in term of the contribution of the carbonate pump.
This study aims to elucidate the relationship between foraminiferal shell chemistry and the carbonate system, as well as to reconstruct glacial-interglacial variations in seawater pH using sediment cores from ODP Site 1145 and MD97-2142, located in the northern and eastern SCS, respectively. A significant increase in oceanic pCO2 (or a decline in seawater pH) has been observed in the northern SCS since the Last Glacial Maximum. However, the complexity of factors influencing ocean carbonate proxies, along with the multiple assumptions required for pCO2 estimation, may introduce substantial uncertainties. To enhance the reliability of these proxy records, a higher temporal resolution δ11B record spanning multiple glacial-interglacial cycles, combined with an extended dataset for comparison with the ice core CO2 records, is necessary. Furthermore, since the surface hydrology of the SCS is primarily influenced by the East Asian Monsoon (EAM), longer records will facilitate a better understanding of the interplay between the ocean carbonate system and monsoon dynamics. This approach will provide valuable insights into the relationship between the marine carbon cycle and the EAM.
This study aims to elucidate the relationship between foraminiferal shell chemistry and the carbonate system, as well as to reconstruct glacial-interglacial variations in seawater pH using sediment cores from ODP Site 1145 and MD97-2142, located in the northern and eastern SCS, respectively. A significant increase in oceanic pCO2 (or a decline in seawater pH) has been observed in the northern SCS since the Last Glacial Maximum. However, the complexity of factors influencing ocean carbonate proxies, along with the multiple assumptions required for pCO2 estimation, may introduce substantial uncertainties. To enhance the reliability of these proxy records, a higher temporal resolution δ11B record spanning multiple glacial-interglacial cycles, combined with an extended dataset for comparison with the ice core CO2 records, is necessary. Furthermore, since the surface hydrology of the SCS is primarily influenced by the East Asian Monsoon (EAM), longer records will facilitate a better understanding of the interplay between the ocean carbonate system and monsoon dynamics. This approach will provide valuable insights into the relationship between the marine carbon cycle and the EAM.