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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Decomposition of dissolved organic matter released by an isolate of Microcystis aeruginosa and morphological profile of the associated bacterial community

Texto completo
Autor(es):
Moreira, I. C. [1] ; Bianchini Jr, I [2] ; Vieira, A. A. H. [1]
Número total de Autores: 3
Afiliação do(s) autor(es):
[1] Univ Fed Sao Carlos, Dept Bot, Lab Ficol, BR-13565905 Sao Carlos, SP - Brazil
[2] Bianchini Jr, Jr., I, Univ Fed Sao Carlos, Dept Hidrobiol, Lab Limnol, BR-13565905 Sao Carlos, SP - Brazil
Número total de Afiliações: 2
Tipo de documento: Artigo Científico
Fonte: Brazilian Journal of Biology; v. 71, n. 1, p. 57-63, FEB 2011.
Citações Web of Science: 5
Resumo

This study concerns the kinetics of bacterial degradation of two fractions (molecular mass) of dissolved organic matter (DOM) released by Microcystis aeruginosa. Barra Bonita Reservoir (SP, Brazil) conditions were simulated in the laboratory using the associated local bacterial community. The extent of degradation was quantified as the amount of organic carbon transferred from each DOM fraction (< 3 kDa and 3-30 kDa) to bacteria. The variation of bacteria morphotypes associated with the decomposition of each fraction was observed. To find the degradation rate constants (k(T)), the time profiles of the total, dissolved and particulate organic carbon concentrations were fitted to a first-order kinetic model. These rate constants were higher for the 3-30 kDa fraction than for the lighter fraction. Only in the latter fraction the formation of refractory dissolved organic carbon (DOC(R)) compounds could be detected and its rate of mass loss was low. The higher bacterial density was reached at 24 and 48 hours for small and higher fractions, respectively. In the first 48 hours of decomposition of both fractions, there was an early predominance of bacillus, succeeded by coccobacillus, vibrios and coccus, and from day 5 to 27, the bacterial density declined and there was greater evenness among the morphotypes. Both fractions of DOM were consumed rapidly, corroborating the hypothesis that DOM is readily available in the environment. This also suggests that the bacterial community in the inocula readily uses the labile part of the DOM, until this community is able to metabolise efficiently the remaining of DOM not degraded in the first moment. Given that M. aeruginosa blooms recur throughout the year in some eutrophic reservoirs, there is a constant supply of the same DOM which could maintain a consortium of bacterial morphotypes adapted to consuming this substrate. (AU)

Processo FAPESP: 05/51263-5 - Destino da matéria orgânica dissolvida liberada por Cyanobacteria em um reservatório eutrofizado do Rio Tietê: estudo de processos
Beneficiário:Armando Augusto Henriques Vieira
Linha de fomento: Auxílio à Pesquisa - Temático