Spatial and temporal variation in algal epiphyte distribution on Ulva sp. (Ulvales, Chlorophyta) from northern Patagonia in Argentina

In this stu, dy of northern Patagonia in Argentina, we examined the annual cycle of the epiphyte composition and abundance on Ulva sp. with respect to intertidal elevation, season and position on host. We found spatial segregation in most environmental gradients. Local environmental conditions, intertidal levels, seasons and portion of host thalli had specific patterns of algal epiphytic community. The host population exhibited seasonality and differential morphological attributes according to the intertidal elevation. Thalli of Ulva sp. had the highest maximum diameters and were heavier in spring and summer at the upper elevation. Epiphytes were more abundant growing on host thalli at middle elevations. Epiphytic Dinophyceae, Chlorophyceae and Cyanophyceae presented clear seasonality. Epiphyte abundances were related to periods with high seawater temperature, long days and high radiation. Lyngbya sp., Cocconeis sp., Navicula spp., Rhabdonema arcuatum, Stylonema alsidii and Myrionema strangulans had the highest frequency. The highest epiphyte abundance was observed in holdfasts, with M. strangulans having the highest frequency and cover. These results are relevant to commercial aquaculture ventures for food and feed sources and application in bioremediation.Fil: Gauna, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Escobar, Juan Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; ArgentinaFil: Odorisio, Mariangeles. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Caceres, Eduardo Jorge. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Parodi, Elisa Rosalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentin