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Plant spore walls as a record of long-term changes in ultraviolet-B radiation

Lomax, Barry H.; Fraser, Wesley T.; Sephton, Mark A.; Callaghan, Terry V.; Self, Stephen; Harfoot, Michael; Pyle, John A.; Wellman, Charles H. and Beerling, David J. (2008). Plant spore walls as a record of long-term changes in ultraviolet-B radiation. Nature Geoscience, 1(9) pp. 592–596.

URL: http://www.nature.com/ngeo/journal/v1/n9/full/ngeo...
DOI (Digital Object Identifier) Link: http://dx.doi.org/10.1038/ngeo278
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Abstract

Stratospheric ozone screens the Earth’s surface from harmful
ultraviolet-B radiation. Concentrations of stratospheric ozone are governed by a variety of natural and anthropogenic factors, including solar cycles, volcanic aerosols, ozone-depleting substances and climate change. However, assessing this variability before instrumental records has proved difficult owing to the lack of a well-constrained proxy. Here, we use microspectroscopy to analyse the chemical composition of herbarium samples of clubmoss (Lycophyta) spores originating from high- and low-latitude localities, where they were exposed to different ultraviolet-B histories. We show that the concentration of two ultraviolet-B-absorbing compounds in the walls of high-northern- and southern-latitude spores is strongly regulated by historical variations in ultraviolet-B radiation. Conversely, we find little change in the concentration of these compounds in spores originating fromtropical Ecuador, where ultraviolet levels have remained relatively stable. Using spores from Greenland, we reconstruct past (1907–1993) changes in ozone concentration and ultraviolet-B flux; we reveal strong similarities between spore-wall reconstructions, and independent instrumental records and model results. Our findings suggest that ultraviolet-B-absorbing compounds in plant spore walls have the potential to act as a proxy for past changes in terrestrial ultraviolet-B radiation and stratospheric ozone. The chemical signature of plant spore walls in herbaria, and possibly also in sedimentary and ice-core archives, may therefore prove valuable for reconstructing past variations in stratospheric ozone and their connections with changes in solar radiation and climate.

Item Type: Journal Article
Copyright Holders: 2008 Macmillan Publishers Limited
ISSN: 1752-0908
Project Funding Details:
Funded Project NameProject IDFunding Body
Not SetNER/A/S/2002/00865NERC
Not SetECF/2006/0492Leverhulme Trust
Not SetNot SetThermo Fisher Scientific
Keywords: plant; spores; ultraviolet; proxy; biochemical; UV-B; Greenland
Academic Unit/Department: Science > Environment, Earth and Ecosystems
Item ID: 11584
Depositing User: W Fraser
Date Deposited: 02 Sep 2008 07:07
Last Modified: 20 Mar 2014 13:30
URI: http://oro.open.ac.uk/id/eprint/11584
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