Authors: Andrés Mansilla C Werlinger M Palacios N P Navarro P Cuadra
Publish Date: 2006/09/27
Volume: 18, Issue: 3-5, Pages: 451-459
Abstract
The effects of UVB radiation on the growth of macroalgal thalli were evaluated using tetrasporophytic fronds of the Rhodophytes Gigartina skottsbergii Sarcothalia crispata and Mazzaella laminarioides The tetrasporophytic fronds were collected from nature and the tetrasporophyte sporelings grown in a temperature regulated chamber at 8 ± 2 ∘C with a 12L12D Light Dark photoperiod Photosynthetically Active Radiation PAR of 55 μmol photons m−2 s−1 and seawater enriched with 20 mL L−1 of Provasoli medium We exposed the thalli of these macroalgae to PAR 55 μmol photons m−2 s−1 and three treatments using a combination of PAR with three different levels of UVB radiation 010 015 and 023 W m−2 for G skottsbergii and S crispata and 002 005 and 010 W m−2 for M laminarioides during a period of 71 days Growth of thalli was quantified by measuring their length using digitized photographs of samplesImportant differences were detected in the growth of individuals cultured under the effects of UVB radiation when compared to the control ie plants exposed to PAR only In the case of G skottsbergii and S crispata higher levels of UVB radiation resulted in slower growth of thalli In nearly all measurements for the first two species UVB radiation levels of 01 W m−2 induced differences in thallus growth while for M laminarioides levels of UVB radiation of 01 W m−2 were effective only after a prolonged period of exposureDifferential effects of UVB radiation on G skottsbergii S crispata and M laminarioides could interfere with the natural populations of these economically important macroalgal species in southern Chile where they occur under the annual influence of the Antarctic Ozone Hole and the general thinning of the ozone layer
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