Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2018-08-21T13:55:57Z No. of bitstreams: 1 2010 - Joaquim Neto de Sousa Santos.pdf: 1864983 bytes, checksum: e70ed9f5ee68c8f365819e496dbb0176 (MD5) / Made available in DSpace on 2018-08-21T13:55:57Z (GMT). No. of bitstreams: 1 2010 - Joaquim Neto de Sousa Santos.pdf: 1864983 bytes, checksum: e70ed9f5ee68c8f365819e496dbb0176 (MD5) Previous issue date: 2010-05-21 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico, CNPq, Brasil. / Morphodynamism, extratification and seasonality are among the main factor to influence the composition and abundance of the macroinfauna in sandy beaches. The macroinfauna of two sandy beaches were sampled between winter-2005 and summer-2006 during low tide; one beach was protected (Flamengo beach) located in Guanabara bay, and the other was exposed to waves in the oceanic zone (Grumari beach). The hypothesis that the physical characteristics of the beaches determine the difference in composition and relative abundance of the macroinfauna was tested. Flamengo beach was characterized as dissipative and had comparatively higher t?xon richenes and lower biomass, when compared with Grumari beach that was classsified as reflective. In Flamengo beaches, higher abundance was recordded for Enoploides sp, and Emerita brasiliensis, whereas in Grumari beach Sacocirrus sp and E. brasiliensis were the most abundant taxons. The beaches showed highe dissimilarity in composition and relative abundance of the taxons (91.75%). Sacocirrus sp, Enoploides sp, Dispio uncinata, Scolelepis goodbobyi and E. brasiliensis explained 63.70% of the dissimilarity between the two beaches. In both beaches, we observed extratification in occurence and abundance of the macroinfauna in two seasons. Emerita brasiliensis occurred mainly in Grumary beach in the extrate 1 and Sacocirrus sp in extrate 2, while in Flamengo beach E. brasiliensis and Enoploides sp had the highest abundance in extrate 1 and S. goodbody and D. uncinata in extrate 3. The hypothesis that the macrofauna differs among extrate and beaches was accepted and the differences in composition and relative abundance of the macroinfauna were attributed to morphodynamism, althought other environmental factores can be influencing such differences. / O morfodinamismo, estratifica??o e a sazonalidade s?o os fatores mais importantes na determina??o da composi??o e abund?ncia da macroinfauna em praias arenosas. A macroinfauna de duas praias foi amostrada no inverno/2005 e ver?o/2006 durante a mar? baixa, sendo uma praia protegida (Flamengo) localizada na ba?a de Guanabara, e outra praia exposta localizada na zona oce?nica (Grumari). Foi testada a hip?tese que as caracter?sticas f?sicas das praias determinam diferen?as na composi??o e abund?ncia da macroinfauna. A praia do Flamengo foi caracterizada como dissipativa e apresentou maior riqueza de t?xons, e menor biomassa, quando comparada com a praia de Grumari classificada como refletiva. Na praia do Flamengo as maiores abund?ncias foram registradas para Enoploides sp, e Emerita brasiliensis, enquanto em Grumari foram Sacocirrus sp e E. brasiliensis. As praias apresentaram elevada dissimilaridade na composi??o e abund?ncia relativa dos t?xons (91.75%), Sacocirrus sp, Enoploides sp, Dispio uncinata, Scolelepis goodbobyi e E. brasiliensis explicaram 63.70% das diferen?as entre as praias. Em ambas as praias foram observadas estratifica??es na ocorr?ncia e abund?ncia da macroinfauna nas duas esta??es analisadas. Na praia de Grumari, E. brasiliensis ocorreu principalmente no estrato 1 e Sacocirrus sp no estrato 2, enquanto na praia do Flamengo E. brasiliensis e Enoploides sp apresentaram as maiores abund?ncias no estrato 1 e S. goodbodyi e D. uncinata no estrato 3. A hip?tese da varia??o na composi??o da macroinfauna entre os extratos foi aceita, e as diferen?as observadas na composi??o e abund?ncia da macroinfauna foram atribu?das ao morfodinamismo; no entanto, outros fatores ambientais podem estar relacionados com tais diferen?as.