Benthic communities of impacted coastal lagoons from Recife and Olinda, Pernambuco State - a likely biological bioindicator grouping of organic pollution

Abstract

The Araçá Lagoon (Recife) and Manguezal Chico Science (Olinda) are two estuarine-lagoons environments in Pernambuco State, that receive organic and inorganic wastes from urban origin. From the hypothesis that they show a low biological diversity this work aimed at making an inventory of the vegetation and epibenthic fauna from the intertidal zone, to assess how environmental changes affected the biological community composition. Four samplings were done in each lagoon in 2005, seeking to relate the species with its ecological preferences about substrate and tide height. Both lagoons showed a defi cient hydrodynamism on account of the nature and formatting of the artifi cial canals that conduct the tides, the considerable affl uence of domestic sewers waters and the low indices of dissolved oxygen. The fauna of these lagoons differed very little among itself, being constituted by mollusks (Littoraria angulifera, Melampus coffeus, Neritina virginea, Mytilopsis leucophaeta) and crustacean species (Ucides cordatus, Aratus pisonii, Goniopsis cruentata, Sesarma rectum and Amphibalanus amphitrite). In the Chico Science mangrove forest, in addition to the species Avicennia schaueriana, Rhizophora mangle and Laguncularia racemosa (predominant), there were also found Ligia exotica and Uca thayeri. In the Araçá Lagoon, with a monospecifi c forest of L. racemosa these animal species were replaced by Uca burgesi and U. rapax. Considering that the sampled benthic macrofauna was comprised of species with a pantropical distribution, eurihaline and suffi ciently resistant to the environmental and anthropic actions, it is suggested that the faunistic grouping common to both lagoons be a bioindicator of organic sewerage pollution, as long as only those species are found to in the estuarine environment.