Abstract

Abstract Gigartina skottsbergii is a red seaweed used as raw material for extracting carrageenans, constituting an important economic resource for Chile. In 2009, extraction in the Magellan region reached 15,064 t. The growing demand has adversely affected the sustainability of natural beds, creating an interest in the culture of this resource. In order to provide information relevant to the culture and regeneration of this seaweed, the present study addresses the effects of different light intensities on the growth of G. skottsbergii gametophytes and tetrasporophytes during the early stages of development. Mature reproductive fronds were induced to release spores in the laboratory by a drying process. Gametophytes cultured at different light intensities showed an increase in diameter, which reached 519.13±108.95 μm with 4 μmol photons m−2 s −1 , while tetrasporophytes showed a greater increase in diameter, reaching 714.11±116.45 μm with 8 μmol photons m−2 s −1 . Results indicate that both stages of the reproductive cycle are influenced by different light intensities within a limited range. Therefore, both phases require different and specific ranges of light intensity