Exceptional Preservation of Fungi as H2-Bearing Fluid Inclusions in an Early Quaternary Paleo-Hydrothermal System at Cape Vani, Milos, Greece
by
Magnus Ivarsson 1,2,*, Stephanos P. Kilias 3, Curt Broman 4, Anna Neubeck 5, Henrik Drake 6, Ernest Chi Fru 7, Stefan Bengtson 2, Jonathan Naden 8, Kleopatra Detsi 3 and Martin J. Whitehouse 9
Magnus Ivarsson 1,2,*, Stephanos P. Kilias 3, Curt Broman 4, Anna Neubeck 5, Henrik Drake 6, Ernest Chi Fru 7, Stefan Bengtson 2, Jonathan Naden 8, Kleopatra Detsi 3 and Martin J. Whitehouse 9
1
Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
2
Department of Paleobiology, Swedish Museum of Natural History, Box 50007, 10405 Stockholm, Sweden
3
Department of Economic Geology and Geochemistry, Faculty of Geology and Geoenvironment, National and Kapodistrian University of Athens, Panepistimiopolis, Zographou, 15784 Athens, Greece
4
Department of Geological Sciences, Stockholm University, SE-10691 Stockholm, Sweden
5
Department of Earth Sciences, Uppsala University, SE-75236 Uppsala, Sweden
6
Department of Biology and Environmental Science, Linnæus University, 392 31 Kalmar, Sweden
7
School of Earth and Ocean Sciences, Institute for Geobiology and Geochemistry, Cardiff University, Park Place, Cardiff CF10 3AT, UK
8
British Geological Survey, Keyworth, Nottingham NG12 5GG, UK
9
Department of Geosciences, Swedish Museum of Natural History, Box 50007, SE10405 Stockholm, Sweden
*
Author to whom correspondence should be addressed.
Minerals 2019, 9(12), 749; https://doi.org/10.3390/min9120749
Received: 5 November 2019 / Revised: 26 November 2019 / Accepted: 2 December 2019 / Published: 3 December 2019
(This article belongs to the Special Issue Biomineralization in Ore Forming Processes)
The production of H2 in hydrothermal systems and subsurface settings is almost exclusively assumed a result of abiotic processes, particularly serpentinization of ultramafic rocks. The origin of H2 in environments not hosted in ultramafic rocks is, as a rule, unjustifiably linked to abiotic processes. Additionally, multiple microbiological processes among both prokaryotes and eukaryotes are known to involve H2-production, of which anaerobic fungi have been put forward as a potential source of H2 in subsurface environments, which is still unconfirmed. Here, we report fungal remains exceptionally preserved as fluid inclusions in hydrothermal quartz from feeder quartz-barite veins from the Cape Vani Fe-Ba-Mn ore on the Greek island of Milos. The inclusions possess filamentous or near-spheroidal morphologies interpreted as remains of fungal hyphae and spores, respectively. They were characterized by microthermometry, Raman spectroscopy, and staining of exposed inclusions with WGA-FITC under fluorescence microscopy. The spheroidal aqueous inclusions interpreted as fungal spores are unique by their coating of Mn-oxide birnessite, and gas phase H2. A biological origin of the H2 resulting from anaerobic fungal respiration is suggested. We propose that biologically produced H2 by micro-eukaryotes is an unrecognized source of H2 in hydrothermal systems that may support communities of H2-dependent prokaryotes.
Keywords:
fungi; hydrothermal system; molecular hydrogen
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
MDPI and ACS Style
Ivarsson, M.; Kilias, S.P.; Broman, C.; Neubeck, A.; Drake, H.; Fru, E.C.; Bengtson, S.; Naden, J.; Detsi, K.; Whitehouse, M.J. Exceptional Preservation of Fungi as H2-Bearing Fluid Inclusions in an Early Quaternary Paleo-Hydrothermal System at Cape Vani, Milos, Greece. Minerals 2019, 9, 749.
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