Effects of nitrogen and phosphorus on the abundance and cell size of planktonic nanoflagellate communities
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Data
2012-12
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Associação Brasileira de Limnologia
Resumo
Aim: We experimentally investigated the effects of nutrients (Nitrogen and Phosphorus) enrichment on the density, biomass, and cell size of pigmented and heterotrophic plankton nanoflagellates communities. Methods: The experiment was done in mesocosms in a tropical reservoir during a 19-day period. Four different treatments were carried out: Control (non-nutrient addition - C), phosphorus additions (P), nitrogen addition (N) and phosphorus + nitrogen addition (N + P). Each treatment was performed in triplicate, sorted randomly, thus giving a total of 12 experimental carboys, which were
placed transversely in the middle of the reservoir. Results: In general, pigmented and heterotrophic nanoflagellates fractions responded to nutrient addition, increasing densities and biomass values at the fertilized treatments. Opposed to expected, enriched treatments resulted in a slight decrease in mean cell size of the pigmented fraction. Moreover, in nutrient-rich treatments, pigmented nanoflagellates had higher relative abundance than in the control. Conclusions: Our results indicate that: i) the density and biomass of nanoflagellates responded to the nutrient enrichment, mainly when N and P were added
together; ii) the pigmented and heterotrophic fractions showed distinct time responses to fertilization; iii) the growth of nanoflagellate community seems to be co-limited by N and P; iv) the nutrient enrichment led to a greater pigmented than heterotrophic fraction contribution; and v) among the analyzed variables, nanoflagellate densities seem to be more sensitive to changes in nutrient availability than biomass or mean cell size.
Descrição
Palavras-chave
Plankton, Protozoa, Fertilization, Mesocoms, Plâncton, Protozoários, Fertilização, Mesocosmos
Citação
PEREIRA, Danielle Goeldner; TÔHA, Fábio Amodêo Lansac; PAULETO, Gustavo Mayer; BINI, Luis Mauricio; VELHO, Luiz Felipe Machado. Effects of nitrogen and phosphorus on the abundance and cell size of planktonic nanoflagellate communities. Acta Limnologica Brasiliensia, Rio Claro, v. 24, n. 4, p. 427-437, Oct./Dec. 2012.