Navegando por Assunto "Plankton"

Agora exibindo 1 - 3 de 3

Acesso aberto (Open Access)
Caracterização quali-quantitativa do fitoplâncton da zona de arrebentação de uma praia amazônica
(Sociedade Botânica do Brasil, 2012-12) QUEIROZ, Jislene Brito Matos; SILVA, Nayra Iris Sozinho da; PEREIRA, Luci Cajueiro Carneiro; COSTA, Rauquírio André Albuquerque Marinho da
The structure of the phytoplankton community of Princesa beach (Maiandeua island) was investigated during a nyctemeral cycle in the months of November/08, March/09, June/09 and September/09 to verify the effects of certain environmental variables on this community. The microphytoplankton of Princesa beach was represented by 98 taxa with the dominance of the diatoms, which were followed by the dinoflagellates and cyanophytes. The qualitative study revealed that Coscinodiscus perforatus Ehrenberg was abundant in March (45.6%) and June (45.1%), whereas in the quantitative analysis Dimeregramma minor (Gregory) Ralfs was dominant, mainly in November/08 (82.0%) and September/09 (83.0%). Biomass (chlorophyll-a content) was significantly higher in March/08 (U= 0.0; p <0.05). The average total phytoplankton density was significantly higher during the rainy period (F= 6.2; p< 0.05), mainly in June (1,223 ±110 x 103 cell L-1). K-dominance curves showed a gradual decrease in diversity along the dry period. Non-Metric Mul
Acesso aberto (Open Access)
Chemical composition of phytoplankton from the estuaries of Eastern Amazonia
(Instituto Nacional de Pesquisas da Amazônia, 2014-12) VILHENA, Maria do Perpétuo Socorro Progene; COSTA, Marcondes Lima da; BERRÊDO, José Francisco; PAIVA, Rosildo Santos; ALMEIDA, Pryscila Denise
Phytoplankton is important bioindicator of chemical and biological modifications of natural ecosystems. The objective of this study was to determine the total chemical composition of the phytoplankton of the Pará and Mocajuba estuaries on the eastern coast of the Amazon region in the Brazilian state of Pará. The chemical composition of the surface water, bottom sediments (total sample and bioavailable fraction), and the phytoplankton were determined by inductively coupled plasma optical emission spectrometry. Phytoplankton contained high concentrations of Ca, P, Mn, Fe, Zn, Al, Ba, and Pb. The phytoplankton of the Mocajuba estuary is rich in Fe (2,967-84,750 µg g-1), while those from the Pará is rich in Al (1,216-15,389 µgg-1), probably reflecting divergent anthropogenic inputs. Both samples indicated a high bioconcentration factor derived from both the water and the bioavailable fraction, reflecting the efficiency of these organisms in the concentration of metals.
Acesso aberto (Open Access)
Variação temporal do fitoplâncton e dos parâmetros hidrológicos da zona de arrebentação da Ilha Canela (Bragança, Pará, Brasil)
(Sociedade Botânica do Brasil, 2009-12) SOUSA, Eliane Brabo de; COSTA, Vanessa Bandeira da; PEREIRA, Luci Cajueiro Carneiro; COSTA, Rauquírio André Albuquerque Marinho da
Seasonal and nyctemeral variations of the phytoplankton and hydrological parameters were studied at a fixed station (00º46'37.2"S-046º43'24.5"W) situated in Canela Island (Bragança-Pará) in September and December, 2004 and in March and June, 2005. Subsurface water samples were taken for qualitative and quantitative phytoplankton studies and to determine chlorophyll a concentrations. Simultaneously physical and chemical parameters were measured: salinity, temperature, pH, dissolved oxygen and percent of oxygen saturation. A total of 64 taxa belonging to Cyanophyta (one taxon), Bacillariophyta (54 taxa) and Dinophyta (nine taxa) were identified. Chlorophyll a concentrations ranged from 4.67 mg m-3 (dry season), to 5.44 mg m-3 (rainy season) and follow phytoplankton densities, which were higher during the rainy period (mean values of 1,870 x 103 cell L-1). Phytoflagellates quantitatively dominated the local phytoplanktonic community followed by diatoms. Dimeregramma minor and Skeletonema sp. were abundant and ve