DistribuiÃÃo espacial e sazonal da composiÃÃo e biomassa fitoplanctÃnica correlacionadas com a hidrologia do estuÃrio do rio Timbà (Paulista, Pernambuco)

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

This study was carried out at the Timbà River estuary of which the hydrographic basin includes the municipalities of Paulista, Abreu e Lima and Igarassu (7Â30â and 8Â05âS Lat. - 34Â45â and 35Â10âW Long.), at the north littoral of Pernambuco State. In this area, intensive fisheries activities are under strong anthropogenic pressure, mainly due to spilling of domestic sewage and industrial effluents, and also by the tourism. This research main objective was to assess the environmental condition based on the phytoplanktonic community and hydrology, comparing them with past data. Samples collections were made in three fixed stations, during the dry (October, November, December/2002) and rainy (May, June, July/2003) seasons. Among the hydrological parameters, were collected with a Nansen bottle, it was analyzed the local depth, transparency, water temperature, salinity, pH, dissolved oxygen, suspended material and nutrients, and for the biological the algae biomass and the net phytoplankton, this collected through 3 minutes superficial horizontal hauls with a plankton net 64μm mesh size. The water transparency was higher during the dry season, varying from 0.30 to 2.60 m; the dissolved oxygen data indicated that the estuary varied from semi-polluted to oversaturated (26.26 to 152.68%); the pH was alcaline; the salinity regime varied from mesohaline to euhaline and together with the temperature showed a well-mixed estuary. Nutrient concentrations were higher during the rainy season and low-tide, outranking the phosphate which varied from 0.23 to 10.99 μmol.l-1. The suspended material didnât present a seasonal pattern. The algae biomass characterized the area as euthrophic with a maximum value of 160.39 mg.m-3. It was identified 146 generic and infra-generic taxa, outranking the diatoms with 68,71%. The most frequent and abundant species were Coscinodiscus centralis, Gyrosigma balticum, Chaetoceros teres, Surirella febigerii and Thalassiosira sp2. The algae blue-greens, euglenoficeans and cloroficeans contributed to the species richness. The species Pleurosigma exsul, Oscillatoria sancta, Euglena deses, Protoperidinium divaricatum, Gymnodinium caudatum and Hyalotheca mucosa are first registered to Pernambuco State. The species diversity varied from low to high, according to the abundance of Thalassiosira sp2 and Protoperidinium divaricatum. Comparing the present results with past data it was observed a strong environmental change with a decrease in the dissolved oxygen concentration and an increase in nutrients, besides the occurrence of pollution bioindicators. It was evident the anthropogenic influence degrading the area

ASSUNTO(S)

fitoplÃncton estuarinoârio timbà (pe)âtaxonomia biomassa-fitoplÃncton estuarinoâ rio timbà (pe) microalgasârio timbà (pe)âtaxonomia ecologiaâmicroalgasârio timbà (pe) oceanografia

ACESSO AO ARTIGO

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