Characterization of diverse bacteriohopanepolyols in a permanently stratified, hyper-euxinic lake

• DOI: 10.1016/j.orggeochem.2022.104431
• Publication Date: 2022-04-30T14:57:37Z
• Authors: Molly D. O'Beirne; Robert Sparkes; Trinity L. Hamilton; Bart E. van Dongen; William P. Gilhooly; Josef P. Werne
• Keywords: Chemocline

Bacteriohopanepolyols (BHPs) are a diverse class of bacterial lipids that hold promise as biomarkers specific microbes, microbial processes, and environmental conditions. BHPs have been characterized in variety terrestrial aquatic environments, but less is known about their distribution abundance extreme systems. In the present study, samples taken from water column upper sediments hyper-euxinic, meromictic Mahoney Lake (Canada) were analyzed for BHPs. Analyses show distinct BHP distributions within oxic mixolimnion, chemocline, euxinic monimolimnion. Bacteriohopanetetrol (BHT) unsaturated BHT dominant found mixolimnion at whereas novel (tentatively identified diunsaturated aminotriol) dominates Along with structure, composite (i.e., BHT-cyclitol ether BHT-glucosamine) observed monimolimnion sediments, indicating production by anaerobic bacteria. Complementary metagenomic analysis genes involved biosynthesis shc, hpnH, hpnO, hpnP, hpnR) further revealed most likely produced bacteria belonging to Deltaproteobacteria, Chloroflexi, Planctomycetia, Verrucomicrobia. The combined observations analyses additionally indicate 2- 3-methyl BHTs response low oxygen high osmotic concentrations, opposed being diagnostic cyanobacteria aerobic metabolisms.