Response of two Antarctic bryophytes to stratospheric ozone depletion

• Published in: Global Change Biology
• Main Authors: Newsham, K. K., Hodgson, D. A., Murray, A. W. A., Peat, H. J., Smith, R. I. Lewis
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2002
• Subjects: Antarc*; Antarctic; Antarctic Peninsula
• Online Access: http://dx.doi.org/10.1046/j.1365-2486.2002.00509.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1046%2Fj.1365-2486.2002.00509.x; https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-2486.2002.00509.x

Abstract We report a study which measured changes to the radiative environment arising from stratospheric O 3 depletion at Rothera Point on the western Antarctic Peninsula (67°S, 68°W) and subsequent associations between these changes and the pigmentation and maximum quantum yield of photochemistry ( F v / F m ) of two Antarctic bryophytes, the liverwort Cephaloziella varians and the moss Sanionia uncinata . We found a strong relationship between O 3 column depth and the ratio of UV‐B to PAR irradiance ( F UV‐B / F PAR ) recorded at ground level. Weaker, but significant, associations were also found between O 3 column depth and noon irradiances and daily doses of unweighted and biologically effective UV‐B radiation received at ground level. Regression analyses indicated that F UV‐B / F PAR and daily dose of unweighted UV‐B were best predictors for concentrations of total carotenoids and UV‐B screening pigments extracted from bryophyte tissues. Concentrations of these pigments were loosely but significantly positively associated with O 3 ‐dependent irradiance parameters. HPLC analyses of carotenoids also suggested that both species increased the synthesis of neoxanthin during periods of O 3 depletion. Violaxanthin, lutein, zeaxanthin and b,bββ‐carotene concentrations were also apparently influenced by O 3 reduction, but not consistently across both bryophyte species. Concentrations of chlorophylls a and b were apparently unaffected by O 3 depletion. No direct associations between F v / F m and O 3 ‐dependent irradiance parameters were found. However stepwise multiple regression analyses suggested that the production of UV‐B screening pigments conferred protection from elevated F UV‐B / F PAR on F v / F m in both species and that carotenoids conferred protection on F v / F m in Sanionia . Our data suggest that changes to the radiative environment associated with stratospheric O 3 depletion influence the pigmentation of two Antarctic bryophytes, but that F v / F m is unaffected, at least in part because of rapid ...