Lake Water Depth Controlling Archaeal Tetraether Distributions in Midlatitude Asia: Implications for Paleo Lake-Level Reconstruction

Lake-level reconstructions, related to terrestrial hydrological changes, are important for our understanding of past and future climates. Currently, however, reliable lake-level proxies are still limited. Here we report distributions of archaeal tetraether lipids in 70 surface sediment samples collected from 55 lakes in midlatitude Asia. We have found that among various lake physico-chemical characteristics, the relative abundances of crenarchaeol and Hydroxylated isoprenoid glycerol dialkyl glycerol tetraethers (%cren and %OH-GDGTs) are best correlated with lake water depth, due to a preference of Thaumarchaeota, the producer of these biomarkers, for a niche in subsurface lake water. This supports the recent hypothesis based on single-lake investigations that %cren and %OH-GDGTs are potentially novel lake-level proxies. Our results also suggest that %OH-GDGTs is less affected by soil input than %cren. Nevertheless, other confounding factors should be well constrained and local/site-specific calibrations are needed before the two molecular proxies are used quantitatively in down-core applications.

Plain Language Summary Lake-level reconstructions can provide useful information about past changes in hydroclimate, which impact both ecosystems and socio-economic sustainable development in fundamental ways, but reliable lake-level proxies are still limited to date. Here we show that the %cren and %OH-GDGTs indices, calculated based on the distributions of archaeal membrane lipids, are controlled by lake water depth in lake surface sediments across a variety of lake conditions. This suggests that past lake level changes can be inferred by analyzing the ubiquitous archaeal lipids preserved in downcore lake sediments.