Spatial and temporal dynamics of phytoplankton functional group in a blocked valley (Brazil)
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Data
2007
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Resumo
Lake Tigres is a blocked-valley lake, formed by tributary obstruction from sediment
deposition during flooding in the main course of the river. Few studies have treated
phytoplankton dynamics in blocked-valley lakes. The aim of this study was to investigate
the temporal and spatial patterns of phytoplankton biovolume, to detect and describe the
dominant phytoplankton functional groups in Lake Tigres during the dry season and the
beginning of the rainy season in 2004. The mean phytoplankton biovolume was
<0.4mm3.L-1, characterizing Lake Tigres as oligotrophic. During the entire study period, 18
functional groups were found, with a predominance of phytoflagellate functional groups
(Y, W1, W2, Lo) and some diatoms (N, P, D). Because of limnological differences in each
sampling period, the functional groups were different in each month and principally between
the dry and rainy seasons, which was shown by canonical correspondence analysis (CCA).
The CCA indicated that in the dry season, the predominant functional groups Y, W1, W2,
and Lo were favored by higher nutrient concentrations and high oxygen content. At the
beginning of the rainy season, the predominant functional groups P, S1, S, T and N were
favored by surface drainage and high water temperature. The dry-season biovolume samples
were characterized by nanoplankton species (C-strategists), suggesting that small size is
an optimal strategy for nutrient absorption. However, during the early rainy season, biovolume
was dominated by microplankton species (SR-strategists).
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Lake Tigres, Dry and rainy seasons, Tropical environment, Ambiente tropical, Lago dos Tigres, Estações chuvosa e seca
Citação
NABOUT, J. C.; NOGUEIRA, I. S. Spatial and temporal dynamics of phytoplankton functional groups in a blocked valley (Brazil). Acta Limnologica Brasiliensia, Rio Claro, SP, v. 19, n. 3, p. 305-314, 2007.