Skip to Main Content
Skip Nav Destination
GEOREF RECORD

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

Tina Gauger, Kurt Konhauser and 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 (Boulder) (December 2015) 43 (12): 1067-1070

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.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 43
Serial Issue: 12
Title: Protection of phototrophic iron(II)-oxidizing bacteria from UV irradiation by biogenic iron(III) minerals; implications for early Archean banded iron formation
Affiliation: University of Tuebingen, Center for Applied Geosciences, Geomicrobiology, Tubingen, Germany
Pages: 1067-1070
Published: 20151222
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 42
Accession Number: 2016-002009
Categories: General geochemistryStratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Annotation: GSA Data Repository item 2015355
Illustration Description: illus.
Secondary Affiliation: University of Alberta, CAN, Canada
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 201601
Close Modal

or Create an Account

Close Modal
Close Modal