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Late Ediacaran life on land: desiccated microbial mats and large biofilm streamers

The Ediacaran period witnessed transformational change across the Earth–life system, but life on land during this interval is poorly understood. Non-marine/transitional Ediacaran sediments preserve a variety of probable microbially induced sedimentary structures and fossil matgrounds, and the ecolog...

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Autores principales: McMahon, S., Matthews, J. J., Brasier, A., Still, J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Royal Society 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8564610/
https://www.ncbi.nlm.nih.gov/pubmed/34727717
http://dx.doi.org/10.1098/rspb.2021.1875
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author McMahon, S.
Matthews, J. J.
Brasier, A.
Still, J.
author_facet McMahon, S.
Matthews, J. J.
Brasier, A.
Still, J.
author_sort McMahon, S.
collection PubMed
description The Ediacaran period witnessed transformational change across the Earth–life system, but life on land during this interval is poorly understood. Non-marine/transitional Ediacaran sediments preserve a variety of probable microbially induced sedimentary structures and fossil matgrounds, and the ecology, biogeochemistry and sedimentological impacts of the organisms responsible are now ripe for investigation. Here, we report well-preserved fossils from emergent siliciclastic depositional environments in the Ediacaran of Newfoundland, Canada. These include exquisite, mouldically preserved microbial mats with desiccation cracks and flip-overs, abundant Arumberia-type fossils and, most notably, assemblages of centimetre-to-metre-scale, subparallel, branching, overlapping, gently curving ribbon-like features preserved by aluminosilicate and phosphate minerals, with associated filamentous microfossils. We present morphological, petrographic and taphonomic evidence that the ribbons are best interpreted as fossilized current-induced biofilm streamers, the earliest record of an important mode of life (macroscopic streamer formation) for terrestrial microbial ecosystems today. Their presence shows that late Ediacaran terrestrial environments could produce substantial biomass, and supports recent interpretations of Arumberia as a current-influenced microbial mat fossil, which we here suggest existed on a ‘streamer–arumberiamorph spectrum’. Finally, the absence of classic Ediacaran macrobiota from these rocks despite evidently favourable conditions for soft tissue preservation upholds the consensus that those organisms were exclusively marine.
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spelling pubmed-85646102021-11-20 Late Ediacaran life on land: desiccated microbial mats and large biofilm streamers McMahon, S. Matthews, J. J. Brasier, A. Still, J. Proc Biol Sci Palaeobiology The Ediacaran period witnessed transformational change across the Earth–life system, but life on land during this interval is poorly understood. Non-marine/transitional Ediacaran sediments preserve a variety of probable microbially induced sedimentary structures and fossil matgrounds, and the ecology, biogeochemistry and sedimentological impacts of the organisms responsible are now ripe for investigation. Here, we report well-preserved fossils from emergent siliciclastic depositional environments in the Ediacaran of Newfoundland, Canada. These include exquisite, mouldically preserved microbial mats with desiccation cracks and flip-overs, abundant Arumberia-type fossils and, most notably, assemblages of centimetre-to-metre-scale, subparallel, branching, overlapping, gently curving ribbon-like features preserved by aluminosilicate and phosphate minerals, with associated filamentous microfossils. We present morphological, petrographic and taphonomic evidence that the ribbons are best interpreted as fossilized current-induced biofilm streamers, the earliest record of an important mode of life (macroscopic streamer formation) for terrestrial microbial ecosystems today. Their presence shows that late Ediacaran terrestrial environments could produce substantial biomass, and supports recent interpretations of Arumberia as a current-influenced microbial mat fossil, which we here suggest existed on a ‘streamer–arumberiamorph spectrum’. Finally, the absence of classic Ediacaran macrobiota from these rocks despite evidently favourable conditions for soft tissue preservation upholds the consensus that those organisms were exclusively marine. The Royal Society 2021-11-10 2021-11-03 /pmc/articles/PMC8564610/ /pubmed/34727717 http://dx.doi.org/10.1098/rspb.2021.1875 Text en © 2021 The Authors. https://creativecommons.org/licenses/by/4.0/Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, provided the original author and source are credited.
spellingShingle Palaeobiology
McMahon, S.
Matthews, J. J.
Brasier, A.
Still, J.
Late Ediacaran life on land: desiccated microbial mats and large biofilm streamers
title Late Ediacaran life on land: desiccated microbial mats and large biofilm streamers
title_full Late Ediacaran life on land: desiccated microbial mats and large biofilm streamers
title_fullStr Late Ediacaran life on land: desiccated microbial mats and large biofilm streamers
title_full_unstemmed Late Ediacaran life on land: desiccated microbial mats and large biofilm streamers
title_short Late Ediacaran life on land: desiccated microbial mats and large biofilm streamers
title_sort late ediacaran life on land: desiccated microbial mats and large biofilm streamers
topic Palaeobiology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8564610/
https://www.ncbi.nlm.nih.gov/pubmed/34727717
http://dx.doi.org/10.1098/rspb.2021.1875
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