Archaeal Hydroxylated Isoprenoid GDGTs in Asian Lake Sediments: A New Tool for Terrestrial Paleotemperature Reconstructions

Hydroxylated isoprenoid GDGTs (OH-GDGTs) have emerged as a novel tool for reconstructing sea surface temperatures. However, when using marine OH-GDGT calibration in lacustrine settings, it leads to a significant overestimation of temperatures, emphasizing the necessity for a thorough examination of OH-GDGTs in lakes. Here, we investigated OH-GDGT distributions in surface sediments from 65 lakes in West China and compiled published Asian lake and global marine OH-GDGT data sets. Among all GDGT-based indices, RI-OH showed the strongest correlation with temperature across Asian lakes. The RI-OH value was higher in lakes than in marine sediments, likely due to differences in the composition of Group 1.1a thaumarchaeotal species between the two settings. The first RI-OH temperature calibration for lakes was developed and it addressed the issue of temperature overestimation when applied to both water column and sediment core, highlighting the potential of OH-GDGTs as a new terrestrial paleothermometer.