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Avaliação dos parâmetros abióticos e caracterização da comunidade planctônica em um viveiro de cultivo de Litopenaeus vannamei (Boone, 1931) no município de Curuçá - Pará
(Universidade Federal do Pará, 2009-11-09) SILVA, Rayette Souza da; MELO, Nuno Filipe Alves Correia de; http://lattes.cnpq.br/4989238044542736
This work aimed at to evaluate during a cycle of cultivation of Litopenaeus vannamei with biweekly periodicity from 20/09/08 to 05/12/08 the community planktonic and the abiotic parameters in two stations inside of a pond in the municipal district of Curuça, State of Pará. They were measured transparency, pH, dissolved oxygen, salinity and temperature, being the last four registered in the surface and close to the bottom and accomplished collections for the study of the microfitoplankton, zooplankton and chlorophyll “a”. The temperature varied from 31,5ºC to 35ºC. The dissolved oxygen varied from 4,2 mg/l to 15,5 mg/l. The pH stayed lightly alkaline, between 8,1 and 9,4. To smallest salinity it was 26,9 and the largest, 30 ppm. The transparency decreased of 55 cm to 17 cm. Chlorophyll a had a minimum of 2,33mg/m3 and a maximum of 471,34 mg/m3. They were identified 95 taxa and Bacillariophyta was the most important group, being Navicula, Pleurosigma and Nitzschia the main ones responsible for her dominance. The largest density registered for the microfitoplankton was of 104.400 org/l in the beginning of the cultivation (20/09) and to smallest it was 3.600 org/l in the last collection (05/12). The diversity average for the fitoplakcton in the Station 01 was 1,49 bits/ind and in the Station 02, 1,43 bits/ind. They were identified 34 taxa zooplanktonic, being Copepoda the most important group and Acartia lilljeborgi, Euterpina acutifrons, Oithona hebes, Oithona oswaldocruzzi and Parvocalanus crassirostris the main ones responsible for her dominance. The largest density registered for the zooplâncton was of 162.000 org/m3 in the beginning of the cultivation (20/09) and to smallest it was 375 org/m3 in day 05/11. The diversity was also low tends averages of 1,34 bits/ind and 1,10 bits/ind in the stations 01 and 02, respectively. Enter the main conclusions: the microfitoplanktonic community was dominated by the diatom, being the main ones responsible for her dominance: Pleurosigma, Nitzschia and Navicula and the division Bacillariophyta was the most important group so much in wealth terms as of density; the class dinophyceae revealed to be better adapted in clearer waters; the copepods were dominant, being Acartia lilljeborgi, Oithona hebes, Oithona oswaldocruzzi, Parvocalanus crassirostris and Euterpina acutifrons the species that more they contributed to this dominance; Chlorophyll “a” answered to the largest ration contributions during the cultivation, increasing with the time; the physio-chemical variables that suffered influence of the cultivation, varying significantly along the time was: pH, dissolved oxygen and transparency and the investigated pond was considered homogeneous evaluating her depth and area.