Abstract

The population dynamics of the carrageenophyte Sarcothalia crispata is described from subtidal beds at two localities in south-central Chile. Seasonal fluctuations in total density and biomass were not evident. Fronds were identified to phase by the presence of reproductive structures and the resorcinol reaction. The monthly changes in abundance of each kind of frond were determined. Permanent gametophytic or sporophytic dominance was not evident: the more exposed site showed a seasonal shift from sporophytic dominance in summer to gametophytic dominance in winter, whereas the more protected site showed an interannual shift from gametophytic to sporophytic dominance. The differences between localities and years suggest a very local population dynamics with large contribution of self-seeding to the maintenance of the S. crispata beds.