Living to Lithified: Construction and Preservation of Silicified Biomarkers.

Autor: Rasmussen KL; Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado, USA., Thieringer PH; Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado, USA., Nevadomski S; Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado, USA., Martinez AM; Department of Environmental Sciences, Rutgers University, New Brunswick, New Jersey, USA., Dawson KS; Department of Environmental Sciences, Rutgers University, New Brunswick, New Jersey, USA., Corsetti FA; Department of Earth Sciences, University of Southern California, Los Angeles, California, USA., Zheng XY; Department of Earth and Environmental Sciences, University of Minnesota, Minneapolis, Minnesota, USA., Lv Y; Department of Earth and Environmental Sciences, University of Minnesota, Minneapolis, Minnesota, USA., Chen X; Department of Earth and Environmental Sciences, University of Minnesota, Minneapolis, Minnesota, USA., Celestian AJ; Natural History Museum of Los Angeles County, Los Angeles, California, USA., Berelson WM; Department of Earth Sciences, University of Southern California, Los Angeles, California, USA., Rollins NE; Department of Earth Sciences, University of Southern California, Los Angeles, California, USA., Spear JR; Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado, USA.; Quantitative Biosciences and Engineering Programs, Colorado School of Mines, Golden, Colorado, USA.
Jazyk: angličtina
Zdroj: Geobiology [Geobiology] 2024 Sep-Oct; Vol. 22 (5), pp. 1-30.
DOI: 10.1111/gbi.12620
Abstrakt: Whole microorganisms are rarely preserved in the fossil record but actively silicifying environments like hot springs provide an opportunity for microbial preservation, making silicifying environments critical for the study of microbial life through time on Earth and possibly other planetary bodies. Yet, the changes that biosignatures may undergo through lithification and burial remain unconstrained. At Steep Cone Geyser in Yellowstone National Park, we collected microbial material from (1) the living system across the active outflows, (2) the silicified areas adjacent to flows, and (3) lithified and buried material to assess the preservation of biosignatures and their changes across the lithification transect. Five biofabrics, built predominantly by Cyanobacteria Geitlerinema, Pseudanabaenaceae, and Leptolyngbya with some filamentous anoxygenic phototrophs contributions, were identified and tracked from the living system through the process of silicification/lithification. In the living systems, δ 30 Si values decrease from +0.13‰ in surficial waters to -2‰ in biomat samples, indicating a kinetic isotope effect potentially induced by increased association with actively growing biofabrics. The fatty acids C 16:1 and iso-C 14:0 and the hydrocarbon C 17:0 were disentangled from confounding signals and determined to be reliable lipid biosignatures for living biofabric builders and tenant microorganisms. Builder and tenant microbial biosignatures were linked to specific Cyanobacteria, anoxygenic phototrophs, and heterotrophs, which are prominent members of the living communities. Upon lithification and burial, silicon isotopes of silicified biomass began to re-equilibrate, increasing from δ 30 Si -2‰ in living biomats to -0.55‰ in lithified samples. Active endolithic microbial communities were identified in lithified samples and were dominated by Cyanobacteria, heterotrophic bacteria, and fungi. Results indicate that distinct microbial communities build and inhabit silicified biofabrics through time and that microbial biosignatures shift over the course of lithification. These findings improve our understanding of how microbial communities silicify, the biomarkers they retain, and transitionary impacts that may occur through lithification and burial.
(© 2024 John Wiley & Sons Ltd.)
Databáze: MEDLINE
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