DISTRIBUTION,SEASONALITY AND REPRODUCTIVE PHENOLOGY OF BANGIA ATROPURPUREA (RHODOPHYTA) IN RHODE ISLAND,U.S.A.1

Forty-seven sites along the Rhode Island coastline were sampled on a seasonal basis for the presence of the red alga Bangia atropurpurea (Roth) C. Ag. This species was found to be widely distributed, occurring at 94% of the hard, stable substrates sampled. Bangia populations were most, widespread in the winter (71% of sites) and least frequent in the summer (29% of sites). At one location, three high intertidal populations (average height 101 cm) and three low intertidal populations (average height 14 cm) were sampled monthly for two years. The upper intertidal populations appeared in September and persisted until at least May, whereas the lower populations were ephemeral, appearing for only a few months in late winter. The high intertidal populations were present on 85% of the sampling dates white the lower ones were observed on 25% of the sampling dates. Upper intertidal filaments reproduced exclusively by asexual monospores unlike those of the lower populations which were largely sexual. The maximum diameter of asexual and carpogonial filaments was 120 and 250 nm, respectively. Monosporagenesis was strongly correlated to temperature whereas gametogenesis was strongly correlated to photopriod.