Re-evaluating modern and Palaeogene GDGT distributions: Implications for SST reconstructions

Unusually low TEX86 values in the transitional zone between Pearl River estuary and coastal South China Sea: Impact of changing archaeal community composition

“…6d), suggesting that the GDGT-2 and GDGT-3 are key components causing the bias of TEX 86 in the transitional zone. Similar observations were made by Taylor et al (2013) and Hernandez-Sanchez et al (2014) for other marine environments. On the other hand, the variation of GDGT-1 and crenarchaeol regioisomer exhibited no correlation with TEX 86 in this region (data not shown), suggesting that these two compounds may have little impact on the variation of TEX 86 in the transitional zone.…”

The Paleocene–Eocene Thermal Maximum at DSDP Site 277, Campbell Plateau, southern Pacific Ocean

“…There is considerable debate about the veracity of such high-temperature estimates in high-latitude regions, with concerns raised about calibrations, seasonal bias and archaeol physiology processes Hollis et al, 2012;Taylor et al 2013;Inglis et al, 2015). However, the consistency between SSTs derived from Mg / Ca and TEX 86 Hollis et al, 2012) suggests that the high temperatures are due to factors that the proxies may have in common, such as a warm-season bias, rather than problems with respective calibrations or physiological factors.…”

Archaeal and bacterial assemblages in the Oxygen Minimum Zone of the upwelling ecosystem off Central Chile as determined by organic biomarkers

“…The GDGT-2/GDGT-3 ratio was calculated according to Taylor et al (2013) in order to evaluate the contribution from archaeal community inhabiting deeper water column during both upwelling and non-upwelling contrasting conditions.…”

“…2) has previously been reported in subsurface, sub-oxic water in the Arabian Sea , and the eastern tropical North Pacifi c (Xie 2013), and South Pacifi c (Sepúlveda et al 2013). A recent revision of global data sets of suspended organic matter indicates that GDGT-2/GDGT-3 increases with water depth, particularly in water columns affected by O 2 -defi ciency (Taylor et al 2013), suggesting that GDGT-derived temperature must therefore consider export dynamics and water depth, whereas a growing body of information suggests that O 2 concentrations should also be taken into account. However, the exact mechanism behind the increased proportion of GDGT-2 in subsurface waters, especially in sub-oxic areas, remains poorly understood.…”