Comparison of the U37K′, LDI, TEX86H, and RI-OH temperature proxies in sediments from the northern shelf of the South China Sea


Contact
Gesine Mollenhauer

Abstract

The temperature proxies UK′37, LDI, TEXH86, and RI-OH are derived from lipid biomarkers, namely long-chain alkenones from coccolithophorids and long-chain diols ascribed tentatively to eustigmatophytes, as well as glycerol dialkyl glycerol tetraethers (GDGTs) and OH-GDGTs produced by Archaea. The applicability of these proxies in the South China Sea (SCS) has been investigated previously. However, in each study only one or two of the proxies were compared, and the recently updated calibrations or new calibrating methods such as BAYSPAR and BAYSPLINE were not applied. Here, we investigate four proxies in parallel in a set of surface sediment samples from the northern SCS shelf and relate them to local sea surface temperature (SST), which allows for us to compare and assess similarities and differences between them and also help improve regional multiproxy seawater temperature reconstructions. Our results indicate that UK′37 reflects annual mean SST with a slight bias toward the warm season. Terrestrial inputs appear to have a significant impact on LDI, TEXH86, and RI-OH proxies near the coast, leading to colder LDI- and TEXH86-derived temperatures but a warmer RI-OH temperature estimate. After excluding samples influenced by terrestrial materials, we find that LDI-derived temperature agrees well with annual SST, while TEXH86- and RI-OH-derived temperature estimates are close to SSTs in seasons dominated by the East Asian winter monsoon and summer monsoon, respectively. The different seasonal biases of these temperature proxies provide valuable tools to reconstruct regional SSTs under different monsoonal conditions.



Item Type
Article
Authors
Divisions
Primary Division
Programs
Primary Topic
Publication Status
Published
Eprint ID
59529
DOI 10.5194/bg-17-4489-2020

Cite as
Wei, B. , Jia, G. , Hefter, J. , Kang, M. , Park, E. , Wang, S. and Mollenhauer, G. (2020): Comparison of the U37K′, LDI, TEX86H, and RI-OH temperature proxies in sediments from the northern shelf of the South China Sea , Biogeosciences, 17 (17), pp. 4489-4508 . doi: 10.5194/bg-17-4489-2020


Download
[thumbnail of Wei et al 2020 bg-17-4489-2020.pdf]
Preview
PDF
Wei et al 2020 bg-17-4489-2020.pdf - Other

Download (5MB) | Preview

Share
Add to AnyAdd to TwitterAdd to FacebookAdd to LinkedinAdd to PinterestAdd to Email


Citation


Actions
Edit Item Edit Item