INVESTIGADORES
PARODI Elisa Rosalia
congresos y reuniones científicas
Título:
EPIPHYTISM IN DICTYOTA DICHOTOMA POPULATION FROM ARGENTINA
Autor/es:
GAUNA, M.C.; PARODI, E.R.; CÁCERES, E.J.
Lugar:
Rhodos
Reunión:
Congreso; Fifth European Phycological Congress; 2011
Institución organizadora:
Federation of European Phycological Societies (FEPS) Council
Resumen:
Dictyota is one of the largest genera of the order Dictyotales (Phaeophyceae) that habit template and tropical coasts. Dictyota dichotoma is characterized by parenchymatous and flabelled thalli, which grow from single apical cells transversally oriented. In Argentina as in other sites of the world, the epiphytic relationships on this host are scarce known. The main aim of this work is study the presence, abundance and seasonal variations of the epiphytic load on D. dichotoma. Samples were collected from subtidal zone by scuba driving during April 2008 to March 2009 in “Las Grutas” beach from Rio Negro Province, Argentina. Samples were fixed in formaldehyde 5% solution to posterior observation under OM. D. dichotoma thalli were divided in apical, medial and basal regions, where it was analyzed the epiphytism’s degree. Each of these sections was subdivided in other 5 consecutive subsections to determined possible epiphytic gradients of distribution. D. dichotoma were colonized by 37 epiphytic organisms. The diatoms had higher representation in number of genera. The more abundant species were: Microchaete auriginea, Calothrix fusca, Grammatophora marina, Cocconeis sp., Stylonema alsidii, Audouinella secundata, Polysiphonia sp. and Acrochaete marchantiae. During January a higher amount of represented phylla was observed. During August the higher epiphytic abundance was registered, mainly represented by G. marina, M. auriginea and Cocconeis sp. During spring was observed the higher epiphytic load, accounted for M. auriginea. Medial host’s regions presented the higher number of represented phylla and epiphytic load in winter, mainly represented by G. marina, Cocconeis sp. and M. auriginea. In the other two regions, apical and basal, it was during spring. Moreover, it was observed a gradual increase of epiphytic load from subsections 1 to 5 in all three regions of host’s thalli.