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

Abstract:

In this study 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.

Key Words::

• Dynamic and zonation gradients
• Epiphytic assemblage
• Myrionema strangulans
• North Patagonian Atlantic coast
• Ulva sp. seasonality

ACKNOWLEDGEMENTS

M.C.G. and E.R.P. are researchers of CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas). E.J.C. is a researcher of CIC (Comisión de Investigaciones Científicas de la Provincia de Buenos Aires, Argentina). Support was provided by grants from the Secretaría de Ciencia y Tecnología de la Universidad Nacional del Sur (PGICSU-24/B186) and CONICET (PIP-11220130100070CO). We thank two anonymous reviewers for commenting on various drafts of the manuscript and Rosemary Scoffield, MSc, for reading the manuscript.