Distribuição vertical e flutuação sazonal da macrofauna vágil associada a Sargassum cymosum C. Agardh, na praia do Lázaro, Ubatuba, São Paulo, Brasil

Abstract

ABSTRACT. Depth distribution and seasonal fluctuations of vagile macrofauna associated with Sargassum cymosum C. Agardh at Lázaro beach, Ubatuba, São Paulo, Brazil. Seasonal tluctuations and depth distribution of the vagile macrofauna associated with Sargassum cymosum at Lazaro beach, Ubatuba, São Paulo State, were evaluated through density comparison of higher taxonomic groups among three depth intervals in four periods of the year. Ten groups were identified and among them gammarid and caprellid amphipods were numerically dominant in ali sampling periods and did not show any consistent zonation trend. Gastropods, polychaetes and ophiuroids ocurred in lower densities and tended to dominate as depth increased. Wet weight a1gae variation did not explain the observed spatial and temporal patterns. Biotic interactions, recruitment and environmental parameters are probably involved in seasonal density variation of the faunal groups studied but it was evident lhat the depth gradient play an important role in vagile macrofauna vertical distribulion. KEY WORDS. Depth distribution, seasonal tluctuations, macrofauna, Sargassum, phytal, Brazil A comunidade fitaI associada a macrófitas marinhas é altamente diversa no que se refere à composição faun ística e à caracterização das espécies que a constituem. A estruturação dessas comunidades fitais é influenciada por uma série de fatores ambientais, cuja contribuição relativa pode variar espacial e temporalmente, sendo muitas vezes difícil determinar seus efeitos individuais nas macrófitas e na fauna associada, devido à interação existente entre esses fatores (EDGAR 1983a).O movimento da água tem sido considerado um dos fatores mais importantes na estruturação da fauna associada a macrófitas (EDGAR & MOORE 1986), embora os resultados obtidos muitas vezes tenham sido conflitantes. DOMMASNES (1968), estudando o efeito da exposição às ondas na comunidade associada a Corallina officinalis Linnaeus, verificou que a abundância da fauna se modificava tanto devido à variação no crescimento da alga quanto ao hidrodinamismo propriamente dito. Por sua vez, MOORE (1973) concluiu que a quantidade de sedimento depositado entre as frondes de Laminaria hyperborea (Gunn). Fosl. constituía o principal fato r de variação da fauna, sendo o efeito direto do movimento da água pouco importante. Diferenças na densidade de vários organismos associados a Amphiroa beauvoisii

Seasonal variation of epiphytic hydroids (Cnidaria: Hydrozoa) associated to a subtropical Sargassum cymosum (Phaeophyta: Fucales) bed

“…Gammarid amphipods are important meso-herbivores on macroalgal communities, grazing on Sargassum and associated epiphytes (JACOBUCCI & LEITE 2008). JACOBUCCI & LEITE (2002) observed that the abundance of gammarid amphipods associated with S. cymosum from Lázaro beach was higher during winter (minimum hydroid cover) and lower during summer, which coincides with the period of maximum hydroid algal cover recorded in this study. Their grazing activity on S. cymosum during the period of their maximum abundance (winter) may have contributed to the lower levels of hydroid algal cover recorded in this season.…”

“…This area presents large and continuous macroalgal beds that extend from the infralittoral fringe to approximately 4 m deep, and is moderately sheltered from wave action (JACOBUCCI & LEITE 2002). Sargassum cymosum is dominant in the area but other species of algae such as Dictyopteris delicatula Lamouroux may be found in lower abundances (SZÉCHY & PAULA 1997).…”

Small-scale experimental contamination with diesel oil does not affect the recolonization of Sargassum (Fucales) fronds by vagile macrofauna

“…Marine macrophyte faunas are often dominated by gammarideans, crustaceans that may select areas with more availability of food and refuges against predators and unfavorable conditions (BUSCHMANN 1990). On the other hand, similar, relatively low numbers of turbellarians, pycnogonids and ophiuroids in the treatments and natural conditions, were also detected in other Sargassum studies in this region (JACOBUCCI & LEITE 2002), and these groups occurred in low abundance on the Sargassum fronds before the treatment.…”

“…The phytal community associated with marine macrophytes is highly diverse in composition, and in the characteristics of the species that constitute it (JACOBUCCI & LEITE 2002). The phytal supports large faunal densities and species richness (SCHNEIDER & MANN 1991), because of the large number of microhabitats offered (WALTHERS & WETHEY 1996) and the interactions among macrophytes, epiphytic algae and invertebrates, functioning on many different spatial and temporal scales (JERKANOFF et al 1996, DUFFY & HAY 2000.…”

Temporal variation of epi- and endofaunal assemblages associated with the red sponge Tedania ignis on a rocky shore (São Sebastião Channel), SE Brazil

“…The organisms that form these substrates are considered ecosystem engineers, increasing local habitat complexity and therefore infl uencing biodiversity patterns (Voultsiadou et al, 2007). Biogenic substrates such as sponges (Duarte & Nalesso, 1996;Ribeiro et al, 2003;Marin, 2007;Garcia et al, 2009), sabellariid polychaetes (Nalesso et al, 1995;Bosa & Masunari, 2002a,b), bryozoans (Conradi et al, 2000;Morgado & Tanaka, 2001), mussels (Jacobi, 1987;O'Connor & Crowe, 2007), barnacles (Crain & Bertness, 2006), ascidians (Castilla et al, 2004) and macroalgae (Tararam & Wakabara, 1981;Masunari, 1982;Jacobucci & Leite, 2002;Tanaka & Leite, 2003) shelter a rich and diverse fauna in varied types of association, including commensalism, mutualism and parasitism.…”