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Role of biomineralization as an ultraviolet shield; implications for Archean life

V. R. Phoenix, K. O. Konhauser, D. G. Adams and S. H. Bottrell
Role of biomineralization as an ultraviolet shield; implications for Archean life
Geology (Boulder) (September 2001) 29 (9): 823-826

Abstract

Cyanobacteria, isolated from the Krisuvik hot spring, Iceland, were mineralized in an iron-silica solution and irradiated with high levels of ultraviolet light. Analysis of the rates of photosynthesis, chlorophyll-a content, and phycocyanin autofluorescence revealed that these mineralized bacteria have a marked resistance to UV compared to nonmineralized bacteria. Naturally occurring sinters composed of iron-silica biominerals collected from the Lysuholl hot spring, and made into wafers of 150-250 mu m thickness, also provided cyanobacteria with an effective UV screen. Analysis of the UV-absorbing capacity of these wafers showed that they absorbed an order of magnitude more UV than photosynthetically active light (required for photosynthesis). From these results, it is evident that both natural and experimental biomineralization provide bacteria with an effective UV screen through the passive precipitation of iron-enriched silica crusts. The UV-shielding capacity of iron-bearing silicate biominerals may have been important for early life forms. We propose that the biomineralization of Archean bacteria similarly provided protection from the high-intensity UV present at that time, and hence allowed colonization and bacterial diversification of shallow-water environments.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 29
Serial Issue: 9
Title: Role of biomineralization as an ultraviolet shield; implications for Archean life
Affiliation: University of Leeds, School of Earth Sciences, Leeds, United Kingdom
Pages: 823-826
Published: 200109
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 24
Accession Number: 2001-065818
Categories: Stratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus.
N63°40'00" - N66°30'00", W24°45'00" - W13°30'00"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 200120
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