Long chain diol index (LDI) as a potential measure to estimate annual mean sea surface temperature in the northern South China Sea

Abstract

Long chain alkyl diols (LCDs) were studied to probe the ability of long chain diol index (LDI) as a sea surface temperature (SST) or temperature record at depth in the open northern South China Sea (SCS). The results showed that riverine LCDs, which may affect LDI-derived SSTs, was less significant due to the substantially low fractional abundance (generally < 20% and averaged 10%) of 1,15-C32 diol in core sediments. The LDI-derived SSTs demonstrated a generally similar trend as SST records calculated from other proxies in nearby cores, suggesting that the LDI proxy can be a potential index to estimate ancient annual mean SST in the open northern SCS. The integration of novel data from the open sea with already published data in the coastal area would provide comprehensive information on the paleo-temperature evolution of the northern SCS.