Phenological studies in populations of Hypnea musciformis (Rhodophyta: Gigartinales) in a tropical region of Brazil

Abstract

(Phenological studies in populations of Hypnea musciformis (Rhodophyta: Gigartinales) in a tropical region of Brazil). The species H. musciformis is one of the main natural sources of k-carrageenan, a polysaccharide widely used in the cosmetics, textiles and food industries. There are few phenological studies with natural populations of this species, especially in the northeast of Brazil. This study aims to contribute to the knowledge of the biology and ecology of H. musciformis in a tropical region of Brazil by analyzing its reproductive and phenological aspects. Two epiphytic populations of this species were analyzed on the beaches of Stella Maris (Salvador) and Itacimirim (Camacari), located in Bahia, Brazil. A total of eight sampling were made during the dry and rainy seasons from 2007 to 2009. The samples were obtained using transects (20 m) and square (0.04 m2) in three regions based on different reef hydrodynamics: tidal pool, protected reef region and front reef region. For statistical analysis, Fisher’s exact test was used with confidence level of significance for all tests set at 95 % (P = 0.05). No male specimens were observed and carposporophytes were rare during the study. The occurrence of infertile specimens was low, especially at Stella Maris. The tetrasporophytic phase was dominant in all sampled sites. The seasonality analysis showed higher percentage of samples in tetrasporophytic phase in Stella Maris, during the dry season, while in Itacimirim there were no differences between dry and rainy seasons. The phenology of algae could have been influenced by the interaction of abiotic and biotic factors, modifying their reproductive behavior according to environmental changes.