title: SENSITIVITY OF ANTARCTIC UROSPORA PENICILLIFORMIS (ULOTRICHALES, CHLOROPHYTA) TO ULTRAVIOLET RADIATION IS LIFE-STAGE DEPENDENT(1).
abstract: The sensitivity of different life stages of the eulittoral green alga Urospora penicilliformis (Roth) Aresch. to ultraviolet radiation (UVR) was examined in the laboratory. Gametophytic filaments and propagules (zoospores and gametes) released from filaments were separately exposed to different fluence of radiation treatments consisting of PAR (P = 400-700 nm), PAR + ultraviolet A (UVA) (PA, UVA = 320-400 nm), and PAR + UVA + ultraviolet B (UVB) (PAB, UVB = 280-320 nm). Photophysiological indices (ETRmax , Ek , and α) derived from rapid light curves were measured in controls, while photosynthetic efficiency and amount of DNA lesions in terms of cyclobutane pyrimidine dimers (CPDs) were measured after exposure to radiation treatments and after recovery in low PAR; pigments of propagules were quantified after exposure treatment only. The photosynthetic conversion efficiency (α) and photosynthetic capacity (rETRmax ) were higher in gametophytes compared with the propagules. The propagules were slightly more sensitive to UVB-induced DNA damage; however, both life stages of the eulittoral inhabiting turf alga were not severely affected by the negative impacts of UVR. Exposure to a maximum of 8 h UVR caused mild effects on the photochemical efficiency of PSII and induced minimal DNA lesions in both the gametophytes and propagules. Pigment concentrations were not significantly different between PAR-exposed and PAR + UVR-exposed propagules. Our data showed that U. penicilliformis from the Antarctic is rather insensitive to the applied UVR. This amphi-equatorial species possesses different protective mechanisms that can cope with high UVR in cold-temperate waters of both hemispheres and in polar regions under conditions of increasing UVR as a consequence of further reduction of stratospheric ozone.
authors.affiliation: Institute for Polar Ecology, Wischhofstraße 1-3, Bldg. 12, D-24148 Kiel, GermanyCONICET, Instituto Antártico Argentino, Cerrito 1248 (C1010AAZ), CA de Buenos Aires, ArgentinaSection Functional Ecology, Department Seaweed Biology, Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, D-27570 Bremerhaven, GermanyBiozentrum Klein Flottbek, University of Hamburg, Ohnhorst-Str. 18, D-22609 Hamburg, GermanyInstituto Antártico Argentino, Cerrito 1248 (C1010AAZ), CA de Buenos Aires, ArgentinaDepartment of Marine Ecology, Marine Botany, Gothenburg University, Box 461, SE 40530 Gothenburg, Sweden.
authors.forename: Michael Y
authors.initials: MY
authors.lastname: Roleda
authors.affiliation: Institute for Polar Ecology, Wischhofstraße 1-3, Bldg. 12, D-24148 Kiel, GermanyCONICET, Instituto Antártico Argentino, Cerrito 1248 (C1010AAZ), CA de Buenos Aires, ArgentinaSection Functional Ecology, Department Seaweed Biology, Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, D-27570 Bremerhaven, GermanyBiozentrum Klein Flottbek, University of Hamburg, Ohnhorst-Str. 18, D-22609 Hamburg, GermanyInstituto Antártico Argentino, Cerrito 1248 (C1010AAZ), CA de Buenos Aires, ArgentinaDepartment of Marine Ecology, Marine Botany, Gothenburg University, Box 461, SE 40530 Gothenburg, Sweden.
authors.forename: Gabriela L
authors.initials: GL
authors.lastname: Campana
authors.affiliation: Institute for Polar Ecology, Wischhofstraße 1-3, Bldg. 12, D-24148 Kiel, GermanyCONICET, Instituto Antártico Argentino, Cerrito 1248 (C1010AAZ), CA de Buenos Aires, ArgentinaSection Functional Ecology, Department Seaweed Biology, Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, D-27570 Bremerhaven, GermanyBiozentrum Klein Flottbek, University of Hamburg, Ohnhorst-Str. 18, D-22609 Hamburg, GermanyInstituto Antártico Argentino, Cerrito 1248 (C1010AAZ), CA de Buenos Aires, ArgentinaDepartment of Marine Ecology, Marine Botany, Gothenburg University, Box 461, SE 40530 Gothenburg, Sweden.
authors.forename: Christian
authors.initials: C
authors.lastname: Wiencke
authors.affiliation: Institute for Polar Ecology, Wischhofstraße 1-3, Bldg. 12, D-24148 Kiel, GermanyCONICET, Instituto Antártico Argentino, Cerrito 1248 (C1010AAZ), CA de Buenos Aires, ArgentinaSection Functional Ecology, Department Seaweed Biology, Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, D-27570 Bremerhaven, GermanyBiozentrum Klein Flottbek, University of Hamburg, Ohnhorst-Str. 18, D-22609 Hamburg, GermanyInstituto Antártico Argentino, Cerrito 1248 (C1010AAZ), CA de Buenos Aires, ArgentinaDepartment of Marine Ecology, Marine Botany, Gothenburg University, Box 461, SE 40530 Gothenburg, Sweden.
authors.forename: Dieter
authors.initials: D
authors.lastname: Hanelt
authors.affiliation: Institute for Polar Ecology, Wischhofstraße 1-3, Bldg. 12, D-24148 Kiel, GermanyCONICET, Instituto Antártico Argentino, Cerrito 1248 (C1010AAZ), CA de Buenos Aires, ArgentinaSection Functional Ecology, Department Seaweed Biology, Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, D-27570 Bremerhaven, GermanyBiozentrum Klein Flottbek, University of Hamburg, Ohnhorst-Str. 18, D-22609 Hamburg, GermanyInstituto Antártico Argentino, Cerrito 1248 (C1010AAZ), CA de Buenos Aires, ArgentinaDepartment of Marine Ecology, Marine Botany, Gothenburg University, Box 461, SE 40530 Gothenburg, Sweden.
authors.forename: Maria Liliana
authors.initials: ML
authors.lastname: Quartino
authors.affiliation: Institute for Polar Ecology, Wischhofstraße 1-3, Bldg. 12, D-24148 Kiel, GermanyCONICET, Instituto Antártico Argentino, Cerrito 1248 (C1010AAZ), CA de Buenos Aires, ArgentinaSection Functional Ecology, Department Seaweed Biology, Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, D-27570 Bremerhaven, GermanyBiozentrum Klein Flottbek, University of Hamburg, Ohnhorst-Str. 18, D-22609 Hamburg, GermanyInstituto Antártico Argentino, Cerrito 1248 (C1010AAZ), CA de Buenos Aires, ArgentinaDepartment of Marine Ecology, Marine Botany, Gothenburg University, Box 461, SE 40530 Gothenburg, Sweden.
authors.forename: Angela
authors.initials: A
authors.lastname: Wulff
keywords: DNA damage; P-E curves; UVR; Urospora penicilliformis; carotenoids; cyclobutane pyrimidine dimers; gametophytes; photosynthetic efficiency; pigments; propagules; rapid light curves; xanthophyll