Development of a regional glycerol dialkyl glycerol tetraether (GDGT)-temperature calibration for Antarctic and sub-Antarctic lakes

摘要: a b s t r c A regional network of quantitative reconstructions past climate variability is required to test models. In recent studies, temperature calibration models based on the relative abundances sedimentary glycerol dialkyl tetraethers (GDGTs) have enabled in both marine and terrestrial environments. Nevertheless, date these methods not been widely applied high latitude environments due poor performance GDGT-temperature calibrations at lower temperatures. To address this we studied 32 lakes from Antarctica, sub- Antarctic Islands Southern Chile to: 1) quantify their GDGT composition investigate environmental controls composition; 2) develop model for inferring temperatures sub-Antarctic lakes. GDGTs were found all 31 branched (brGDGTs) dominant compounds. Statistical analyses brGDGT relation temperature, pH, conductivity water depth showed that brGDGTs strongly correlated with mean summer air (MSAT). This development first brGDGT-temperature use using four compounds (GDGT-Ib, GDGT-II, GDGT-III GDGT-IIIb). key discovery was GDGT-IIIb particular importance cold lacustrine The addition compound significantly improved model's r2 = 0.67, RMSEP-LOO (leave-one-out) 2.23 ◦ C, RMSEP-H (h-block) 2.37 C when applying re-calibrated global GDGT-