DistribuiÃÃo espaÃo-temporal da meiofauna e da nematofauna no ecossistema recifal de Porto de Galinhas, Ipojuca, Pernambuco, Brasil

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

From all the beaches on Pernambuco coast âPorto de Galinhasâ is the one which receives the largest tourist flow. The aims of this research were to evaluate the meiofauna and nematofauna spatial and temporal distributions in tidal ponds as well as in the inner part of the reef ecosystem. To evaluate the vertical distribution of meiofauna and Nematoda genera sediment samples were taken in tidal ponds and in the inner part of the reef ecosystem using a corer with 2.4cm2 inner area and cutting it in 0-2 and 2-10cm layers. To evaluate the spatial and the temporal distributions sediment samples were taken monthly from November 1997 to October 1998 removing a two centimeters layer in squares of 25x25cm. Plancton samples were also collected with a 65μm mesh to estimate the dispersion of the nematofauna. The salinity, temperature and chlorophyll-a concentration of sediment, as well as the granulometry, were correlated with the community structure. The meiofauna was composed by sixteen groups, dominated by Copepoda Harpacticoida and Nematoda in both environments in which there was a space partition vertically and horizontally. Statistic analyses did not detect significant differences related to diversity, evenness, genera richness and associations of meiofauna major taxa between the environments and vertical strata sampled. Also, significant differences were not detected between the sediment layers and environments considering the densities of meiofauna major taxa. Considering the spatiotemporal study, the nematofauna was composed by seventy three monotypic species, distributed into twenty-six families. Of these genera, a new species was present in Theristhus. Thirty new genera occurrences were found for Pernambuco and ten to Brazil. The community structure was defined according to the following criteria: high diversity, high richness and low frequency, reflecting a subtidal coarse on sediment association. The meiofauna major taxa composition was correlated with nine enviromental factors detecting weak positive correlations only with the assimetry and the gravel fraction in the tidal ponds and with the standard deviation and assimetry in the inner part of the reef. The nematofauna generic composition presented significant differences on the space and time and was correlated with the grain size and standard deviation in both environments. The trophic groups had a very well defined space partition in which the epistrate feeders dominated in the tidal ponds and the non-selective deposit feeders were dominant in the inner part of the reef. The genera dispersion in the water column, in more than fifty per cent of the samples during the dry season, added to the occurrence of one species, which was only noticeable in the plankton, suggested a sediment ressuspension related to a possible antropic effect

ASSUNTO(S)

horizontal distribution nematofauna distribuiÃÃo vertical temporal distribution oceanografia meiofauna recifes vertical distribution reefs distribuiÃÃo temporal meiofauna nematofauna distribuiÃÃo horizontal

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