Life and its traces in Antarctica's McMurdo Dry Valley paleolakes: a survey of preservation

TitleLife and its traces in Antarctica's McMurdo Dry Valley paleolakes: a survey of preservation
Publication TypeJournal Article
Year of Publication2020
AuthorsGreenfield, SR, Tighe, SW, Bai, Y, Goerlitz, DS, Von Turkovich, M, Taatjes, DJ, Dragon, JA, Johnson, SStewart
JournalMicron
Volume131
Pagination102818
Date PublishedJan-04-2020
ISSN09684328
KeywordsAntarctica, Biosignatures, Microbes, Paleolakes, SEM
Abstract

The extremely cold and arid conditions of Antarctica make it uniquely positioned to investigate fundamental questions regarding the persistence of life in extreme environments. Within the McMurdo Dry Valleys and surrounding mountain ranges are multiple ancient relict lakes, paleolakes, with lacustrine deposits spanning from thousands to millions of years in age. Here we present data from light microscopy, scanning electron microscopy, electron dispersive x-ray spectroscopy, and radiocarbon dating to catalog the remarkable range of life preserved within these deposits. This includes intact microbes and nanobacteria-sized cocci, CaCO3 precipitations consistent with biogenic calcium, previously undescribed net-like structures, possible dormant spores, and long-extinct yet exquisitely preserved non-vascular plants. These images provide an important reference for further microbiome investigations of Antarctic paleolake samples. In addition, these findings may provide a visual reference for the use of subsurface groundwater microbial communities as an analog for paleolake subsurface water on planets such as Mars.

URLhttps://linkinghub.elsevier.com/retrieve/pii/S0968432819304160
DOI10.1016/j.micron.2019.102818