Fossilized bioelectric wire - the trace fossilTrichichnus.
The trace fossilTrichichnusis proposed as an indicator of fossil bioelectric bacterial activity at the oxic-anoxic interface zone of marine sediments. This fulfils the idea that such processes, commonly found in the modern realm, should be also present in the geological past.Trichichnusis an exceptional trace fossil due to its very thin diameter (mostly less than 1 mm) and common pyritic filling. It is ubiquitous in some fine-grained sediments, where it has been interpreted as a burrow formed deeper than any other trace fossils, below the redox boundary.Trichichnus, formerly referred to as deeply burrowed invertebrates, has been found as remnant of a fossilized intrasediment bacterial mat that is pyritized. As visualized in 3-D by means of X-ray computed microtomography scanner,Trichichnusforms dense filamentous fabric, which reflects that it is produced by modern large, mat-forming, sulfide-oxidizing bacteria, belonging mostly toThioploca-related taxa, which are able to house a complex bacterial consortium. Several stages ofTrichichnusformation, including filamentous, bacterial mat and its pyritization, are proposed to explain an electron exchange between oxic and suboxic/anoxic layers in the sediment. Therefore,Trichichnuscan be considered a fossilized "electric wire".
Institute of Geological Sciences, Jagiellonian University, Oleandry 2a, 30-063 Kraków, Poland.
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Kędzierski
Institute of Geological Sciences, Jagiellonian University, Oleandry 2a, 30-063 Kraków, Poland.
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Uchman
Institute of Geological Sciences, Jagiellonian University, Oleandry 2a, 30-063 Kraków, Poland.
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Sawlowicz
Institut für Paläontologie, Universität Wien, Geozentrum, Althanstrasse 14, 1090 Vienna, Austria ; Faculty of Science, Department of Petroleum Geoscience, Universiti Brunei Darussalam, Jalan Tungku Link, Gadong BE1410, Brunei.
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Briguglio