Geological Society of America

T24 New Advances in Geobiology

Monday, 26 October 2020
1:30 PM - 5:30 PM
Meeting Rooms

A COMPREHENSIVE APPROACH TO EXPLORING THE INTERPLAY OF MICROBES AND MINERALS IN LAVA TUBES

Paper number: T24-6
Program: Technical Sessions
Time: 2:45 PM – 3:00 PM

Authors

Dina Bower Presenting Author
University of Maryland College Park, College Park, MD
Jacob E. Bleacher
Greenbelt, MD
Kelsey E. Young
NASA Goddard Space Flight Center, Greenbelt, MD
Amy McAdam
NASA Goddard Space Flight Center, Greenbelt, MD
Cherie N. Achilles
USRA, Greenbelt, MD
Chloe Fishman
Georgetown University, Washington, DC
Christine A. Knudson
University of Maryland College Park, College Park, MD
Ricardo Arevalo
University of Maryland College Park, College Park, MD
Maeva Millan
Georgetown University, Washington, DC
Maggie Weng
Georgetown University, Washington, DC
Sarah S. Johnson
Georgetown University, Washington, DC

Abstract

The interplay between microbes and minerals has been key in shaping terrestrial landscapes throughout geologic time. Lava tubes are fertile grounds for microbial communities, providing nutrient-rich substrates, moisture, and shelter. As the microbial communities grow and thrive, they induce chemical changes in their immediate environment resulting in mineralogical variations. Many alteration minerals involve microbial interactions and others are the direct result of chemical weathering of the host basalts, yet the distinction between abiotic and biotic alteration is not always evident. In order to establish distinctive signatures of biotic activity, our interdisciplinary team conducted field work and collected solid and liquid samples from a basaltic lava tube on the Mauna Loa volcano in Hawaii. We characterized the host basalts, secondary mineral coatings/veneers, powdery precipitates, and seeping groundwater in sections of the tube exposed to sunlight and sections that remain dark using a suite of in situ and laboratory analytical techniques: Raman spectroscopy, X-ray fluorescence (XRF), laser induced breakdown spectroscopy (LIBS), X-ray diffraction (XRD), inductively coupled plasma mass spectrometry (ICP-MS), pyrolysis gas chromatography mass spectrometry (pyro-GCMS), and metagenomic analysis. The powdery precipitates throughout the lava tube are composed of predominantly metastable sulfate minerals, many of which are associated with microbial communities. In addition, significant abundances, and diversities, of organic compounds present in many of the tube’s secondary mineral deposits may be related to the tube-hosted microbial communities. We will discuss the implications of these and other associations for understanding geobiological systems on Earth and applications for life detection in similar subterranean systems on other planetary bodies in the solar system.

Geological Society of America Abstracts with Programs. Vol. 52, No. 6

doi: 10.1130/abs/2020AM-358435

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