Protection of phototrophic iron(II)-oxidizing bacteria from UV irradiation by biogenic iron(III) minerals: Implications for early Archean banded iron formation

Abstract

Research Article| December 01, 2015 Protection of phototrophic iron(II)-oxidizing bacteria from UV irradiation by biogenic iron(III) minerals: Implications for early Archean banded iron formation Tina Gauger; Tina Gauger 1Geomicrobiology, Center for Applied Geosciences, University of Tübingen, 72074 Tübingen, Germany Search for other works by this author on: GSW Google Scholar Kurt Konhauser; Kurt Konhauser 2Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2E3, Canada Search for other works by this author on: GSW Google Scholar Andreas Kappler Andreas Kappler * 1Geomicrobiology, Center for Applied Geosciences, University of Tübingen, 72074 Tübingen, Germany *E-mail: andreas.kappler@uni-tuebingen.de Search for other works by this author on: GSW Google Scholar Author and Article Information Tina Gauger 1Geomicrobiology, Center for Applied Geosciences, University of Tübingen, 72074 Tübingen, Germany Kurt Konhauser 2Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2E3, Canada Andreas Kappler * 1Geomicrobiology, Center for Applied Geosciences, University of Tübingen, 72074 Tübingen, Germany *E-mail: andreas.kappler@uni-tuebingen.de Publisher: Geological Society of America Received: 23 Jun 2015 Revision Received: 04 Oct 2015 Accepted: 05 Oct 2015 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2015 Geological Society of America Geology (2015) 43 (12): 1067–1070. https://doi.org/10.1130/G37095.1 Article history Received: 23 Jun 2015 Revision Received: 04 Oct 2015 Accepted: 05 Oct 2015 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Tina Gauger, Kurt Konhauser, Andreas Kappler; Protection of phototrophic iron(II)-oxidizing bacteria from UV irradiation by biogenic iron(III) minerals: Implications for early Archean banded iron formation. Geology 2015;; 43 (12): 1067–1070. doi: https://doi.org/10.1130/G37095.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract On the Archean Earth (4.0–2.5 Ga) the lack of a protective ozone layer meant that harmful ultraviolet radiation (UVR) reached the surface almost unattenuated. For survival, primitive photosynthetic bacteria would have required strategies preventing UV-induced damage to their DNA. At that time, a fraction of the planktonic cells were likely anoxygenic photosynthesizers that oxidized dissolved Fe(II) to Fe(III) during their metabolism. The result of their metabolism was most likely the ferric mineral precursors for the deposition of banded iron formations. Although Fe(III) (oxyhydr)oxide minerals absorb UV radiation while still transmitting higher wavelengths, it is unknown whether minerals produced by Fe(II) oxidizers could have acted as an in situ UVR sunscreen. Here we demonstrate that the anoxygenic phototrophic Fe(II) oxidizers Rhodopseudomonas palustris strain TIE-1 and Rhodobacter ferrooxidans strain SW2 form nanometer-sized grains of ferrihydrite that are loosely attached to the cell surfaces. These biogenic Fe(III) minerals were shown to protect the bacteria from UV-C irradiation, while cells grown in the absence of Fe(II) displayed diminished cell viability as a consequence of damage to their DNA. Importantly, this study implies that primitive Fe(II)-oxidizing bacteria would have been able to produce their own UV screen, enabling them to live in the shallow photic zone of ancient oceans. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.