MEPS 197:217-229 (2000)  -  doi:10.3354/meps197217

Impact of UV-radiation on viability, photosynthetic characteristics and DNA of brown algal zoospores: implications for depth zonation

Christian Wiencke1,*, Iván Gómez1,**, Hans Pakker2, Antonio Flores-Moya3, María Altamirano3, Dieter Hanelt1, Kai Bischof1, Félix L. Figueroa4

1Foundation Alfred Wegener Institute, Projectgroup: Solar UV-radiation, Columbusstrasse, 27515 Bremerhaven, Germany
2Department of Marine Biology, University of Groningen, PO Box 14, 9750 AA Haren, The Netherlands
3Department of Plant Biology, and
4Department of Ecology, University of Málaga, Campus de Teatinos s/n, 29071 Málaga, Spain
*E-mail: **Present address: Foundation Alfred Wegener Institute, Section Coastal Ecology, Hafenstrasse 43, 25992 List/Sylt, Germany

ABSTRACT: Measurements of photosynthesis, germination capacity and assessment of DNA damage were carried out in the laboratory to determine the effect of different conditions of ultraviolet (UV) and photosynthetically active radiation (PAR) on zoospores of various large brown algae collected on Spitsbergen (Svalbard, High Arctic) and Tarifa (Cádiz, southern Spain). Results were correlated to in situ light conditions and indicated that zoospores suffer photoinhibition of photosynthesis, loss of viability and DNA damage in relation to the growth depth of parental sporophytes. At both sites, germination capacity of zoospores in species collected in deep waters was more strongly impaired after exposure to the same UV doses than in species from shallower waters. In general, zoospores exposed to PAR+UVA+UVB showed higher mortality rates than after exposure to PAR+UVA or PAR alone. For Laminaria digitata from Spitsbergen, it was found that the loss of zoospore viability is the result of DNA damage and photodamage of the photosynthetic apparatus. UVB irradiances occurring in southern Spain at water depths shallower than 7 m prevented the germination of spores of deep water Laminariales from this region.

KEY WORDS: Macroalgae · Laminaria · Arctic · Zoospores · UV-radiation · DNA damage · Photosynthesis

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