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.

Microbial ether lipids are versatile tools for paleoclimatic studies. These biomarkers have been successfully used to reconstruct past changes in temperature, salinity, pH, etc.

Recently, a joint study led by Prof. LIU Weiguo from Institute of Earth Environment of Chinese Academy of Sciences, with the University of Hong Kong, Zhejiang University, Lanzhou University, and Institute of Geology and Mineralogy SB RAS systematically investigated the relationships between archaeal tetraethers and environmental parameters in a set of 55 lakes in arid/semi-arid mid-latitude Asia.

This study published on Geophysical Research Letters, showed that archaeal tetraethers could be widely used to reconstruct past lake-level variations, further expanding the significance of these novel lipids in paleoclimatic studies.

They found that among various lake physico-chemical characteristics, the relative abundances of crenarchaeol and OH-GDGTs (%cren and %OH-GDGTs) were 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 supported their recent hypothesis based on single-lake investigations that %cren and %OH-GDGTs were potentially novel lake-level proxies.

The researchers also pointed out that other confounding factors should be well constrained and local/site-specific calibrations were needed before the two molecular proxies were used quantitatively in down-core applications.

This work was financially supported by CAS, HKRGC, NSFC, SKLBEG, RSF and RFBR.

Fig. 1 Redundancy analysis (RDA) showing relationships between environmental variables and fractional abundances of archaeal tetraethers. (Imaged by WANG, Huanye, et al.)

Fig. 2 Plots of archaeal tetraether distributions vs. lake water depth for lakes in mid-latitude Asia. (Imaged by WANG, Huanye, et al.)

Contact: Bai Jie, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China. Email: baijie@ieecas.cn