Evaluating the application of branched tetraether proxies in surface soils along the altitudinal transect at Mount Dabie, China

The branched glycerol dialkyl glycerol tetraethers (brGDGTs) are a series of bacterial membrane lipids commonly proposed as a proxy for estimating mean annual air temperature (MAAT) and pH. The biochemical response to moisture was also assumed to need to maintain the bacterial membrane integrity in arid and humid terrestrial environments. Here, we test the impact of soil chemical parameters, including pH, temperature, and moisture, on brGDGT distributions along altitudinal transect at Mount (Mt.) Dabie. The proxies (CBT, CBT′, IBT, and IR 6ME ) are significant correlated with measured soil pH values ( R 2 = 0.62, 0.60, 0.79, 0.64, respectively), implying the application of these proxies for pH reconstructions. Although the certain degree of scatter between brGDGT-derived temperature and altitude ( R 2 = 0.62) may be attributed to the soil water content, the MBT′ 5ME -derived temperature lapse rate (− 6.4 °C/1000 m) resembles the measured mean annual air temperature (MAAT) lapse rate (− 5.7 °C/1000 m), which suggest the MBT′ 5ME index is mainly controlled by the MAAT values. The MBT′ 5ME index is mainly controlled by the MAAT values in the north subtropical humid climate. The physiological alteration rather than community change may be the main mechanism underlying the variation in the MBT′ 5ME paleothermometer along Mt. Dabie.