Bacteriohopanepolyols across environmental gradients in Lake Vanda, Antarctica

• Published in: Geobiology
• Main Authors: Matys, Emily D., Mackey, Tyler, Grettenberger, Christen, Mueller, Elliott, Sumner, Dawn Y., Hawes, Ian, Summons, Roger E.
• Other Authors: NASA Astrobiology Institute, National Aeronautics and Space Administration, Foundation for Research, Science and Technology
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2019
• Subjects: McMurdo Dry Valleys; Vanda; Lake Vanda; Antarc*; Antarctica
• Online Access: http://dx.doi.org/10.1111/gbi.12335; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fgbi.12335; https://onlinelibrary.wiley.com/doi/pdf/10.1111/gbi.12335; https://onlinelibrary.wiley.com/doi/full-xml/10.1111/gbi.12335

Abstract Bacteriohopanepolyols ( BHP s) are bacterial membrane lipids that may be used as biological or environmental biomarkers. Previous studies have described the diversity, distribution, and abundance of BHP s in a variety of modern environments. However, the regulation of BHP production in polar settings is not well understood. Benthic microbial mats from ice‐covered lakes of the McMurdo Dry Valleys, Antarctica provide an opportunity to investigate the sources, physiological roles, and preservation of BHP s in high‐latitude environments. Lake Vanda is one of the most stable lakes on Earth, with microbial communities occupying specific niches along environmental gradients. We describe the influence of mat morphology and local environmental conditions on the diversity and distribution of BHP s and their biological sources in benthic microbial mats from Lake Vanda. The abundance and diversity of C‐2 methylated hopanoids (2‐Me BHP ) are of particular interest, given that their stable degradation products, 2‐methylhopanes, are among the oldest and most prevalent taxonomically informative biomarkers preserved in sedimentary rocks. Furthermore, the interpretation of sedimentary 2‐methylhopanes is of great interest to the geobiology community. We identify cyanobacteria as the sole source of 2‐Me BHP in benthic microbial mats from Lake Vanda and assess the hypothesis that 2‐Me BHP are regulated in response to a particular environmental variable, namely solar irradiance.