Characteristics and implications of isoprenoid and hydroxy tetraether lipids in hadal sediments of Mariana and Yap Trenches

Abstract As one of the least-explored regions on Earth, the hadal zone remains poorly understood in terms of sedimentary organic geochemistry. This study examined the composition of isoprenoid glycerol dialkyl glycerol tetraethers (Iso-GDGTs) and hydroxy GDGTs (OH-GDGTs) in sediment cores with water depths ranging from 5058 to 10,911 m from the Mariana and Yap Trenches. The results showed a higher proportion of GDGT-0 (25–73%, mean = 49%) in the trench Iso-GDGTs pool than those from shallower ocean counterparts ( 5000 m) revealed a significant negative linear correlation with water depth (TEX86H: R2 = 0.89, p