Environmental Impacts of an Alien Kelp Species (Undaria pinnatifida, Laminariales) along the Patagonian Coasts

Undariapinnatifida(Harvey) Suringar was recorded in Argentina for the first time in December 1992. Since then, it shows an invasive and competitive behavior, spreading quickly from the initial focus and increasing its population density. The first individuals were found attached to the port of Puerto Madryn, suggesting that the vector of introduction was the ballast water of cargo ships arriving to Golfo Nuevo from overseas. Since U. pinnatifidawas recorded, it has been spreading along the Argentina coasts, extending its range within and outside Golfo Nuevo, along the coasts of Argentina from Puerto Deseado (Santa Cruz province) to Mar del Plata (Buenos Aires province) far as 1850 kilometers from each other. The invasive condition of this species creates an awareness of the effects inflicted upon the indigenous biodiversity of this region, as well as, on the commercially-important benthic community structure. Moreover, the detachment of subtidal algae, especially during the summer, and its deposition upon the beach, have altered the sedimentary balance along the overall transverse beach profile. This effect, in addition with algal extraction by trucks mainly during tourist seasons, may increase beach erosion processes along Patagonian coasts.Fil: Bunicontro, Maria Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Marcomini, Silvia Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Casas, Graciela Noemi. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; Argentin

Hydroids (Cnidaria, Hydrozoa): A Neglected Component of Animal Forests

Hydroids, one of the dominant components of the zoobenthic communities, share comparable growth patterns with higher plants because of their modular body organization, high potential of asexual reproduction, and phenotypic plasticity. These features, together with the ability to enter dormancy to overcome unfavorable conditions, make hydroids successful organisms adaptable to a wide range of environmental scenarios. Depending on their wide range of shapes and sizes, hydroids form three-dimensional forests at different dimensional scales, establishing both trophic and non-trophic relationships with several other organisms, from virus to vertebrates. Despite numerous researches conducted to study the hydroid ecology, the putative importance of hydroids in structuring zoobenthic communities is underestimated. Here, information available about hydroid ecology is summarized, in order to emphasize the role of hydroids as forest formers, as well as their function in the bentho-pelagic coupling