Abstract

he coastal marine ecosystems of the sub-Antarctic ecoregion of Magallanes in southern Chile are strongly char- acterized by environmental heterogeneity with a unique and high biodiversity of benthic macroalgae. The kelp Durvillaea antarctica (Phaeophyceae) is abundant in the intertidal in this region. Two morphotypes, one with elongated-cylindrical (Bmorphotype EC^) and one with laminar (Bmorphotype L^) blades, have been collected from a wave-protected site at the Strait of Magellan and the wave-exposed shores of the isolated Otway Sound. Morphometric and physiological (by chloro- phyll fluorescence) analyses showed significant differences between the two morphotypes regarding the morphology, the maximum electron transport rates (ETRmax), and the chloro- phyll c concentration. These morphological and physiological differences can be linked to their hydrodynamic environment. The presence of two different species in the region of Magallanes based on the measured parameters is discussed. This study may be useful for future genetic and biotechnolog- ical investigations and draws attention to D. antarctica as a species of commercial value among the marine resources of Chile.