%0 Journal Article
%T Decomposi  o e dinamica de libera  o de nitrog那nio e f車sforo de fra  es vegetais de Salvinia auriculata Aubl. em um reservat車rio da Amaz nia legal = Decomposition and release dynamics of nitrogen and phosphorous from vegetal fractions of Salvinia auriculata Aubl. in a Legal Amazon reservoir
%A Deivid Sousa Silva
%A Marcela Bianchessi da Cunha-Santino
%A Elineide Eugenio Marques
%J Acta Scientiarum : Biological Sciences
%D 2011
%I Eduem - Editora da Universidade Estadual de Maring芍
%X Este estudo teve como objetivo determinar os coeficientes de decomposi  o da parte submersa (PS) e a谷rea (PA) de Salvinia auriculata em duas profundidades da coluna de 芍gua (superf赤cie e sedimento). Tamb谷m visou avaliar o rendimento do processo de perda de massa assim como a evolu  o temporal dos teores de f車sforo e nitrog那nio. As macr車fitas foram separadas em partes; em seguida, foram secas at谷 peso constante. Os materiais vegetais foram depositados em sacos de decomposi  o e incubados no reservat車rio da UHE Lajeado, Tocantins. As an芍lises dos resultados de perda de massa revelaram que n o houve diferen as significativas entre os PA-sed e PA-sup (p > 0,05), entretanto, os PA-sed foram significativamente diferentes dos PS-sed (p < 0,05) e dos PS-sup (p < 0,01). Os PA-sed apresentaram k = 0,0102 dia-1 e as incubadas na superf赤cie (PA-sup) um k = 0,0067 dia-1, os PS-sed apresentaram um k = 0,0027 dia-1 e os PS-sup um k = 0,0040 dia-1. Durante os primeiros dias de decomposi  o foram liberadas grandes concentra  es de f車sforo e nitrog那nio pelo processo de lixivia  o; a partir do 14o dia foi observada uma tend那ncia de aumento nas concentra  es de nitrog那nio, fato provavelmente relacionado com o enriquecimento dos detritos pela biomassa microbiana. This study aimed to determine the decomposition coefficients of the submerged (SP) and aerial part (AP) of S. auriculata at two different depths within water column (surface and sediment). It also quantified the decomposition yield of S. auriculata and the temporal changes of nitrogen and phosphorous content of the remaining biomass. The macrophytes were fractionated in parts and were dried in sequence until attaining constant weight. The litterbags with plant material were incubated in the reservoir of UHE Lajeado. The results of mass loss showed that there were no significant differences among the AP-sed and AP-sur (p > 0.05). However, the AP-sed was significantly different from SP-sed (p < 0.05) and SP-sur (p < 0.01). The AP-sed presented a decay coefficient (k) of 0.0102 day-1 and AP-sur a k of 0.0067 day-1. The SP-sed presented a k of 0.0027 day-1 and the SP-sur 0.0040 day-1. It was also noticed that during the first days ofdecomposition great amounts of nitrogen and phosphorous were solubilized. This event was related to the leachate process; from the 14th day of decomposition, an increasing trend was observed in nitrogen concentrations. This fact was probably related to detritus enrichment by microbial colonization.
%K macr車fitas aqu芍ticas
%K sacos de decomposi  o
%K UHE Lajeado
%K Estado do Tocantins
%K aquatic macrophyte
%K litterbags
%K UHE Lajeado
%K Tocantins State
%U http://periodicos.uem.br/ojs/index.php/ActaSciBiolSci/article/view/5630/5630