This study concerns the kinetics of bacterial degradation of two fractions (molecular mass) of dissolved organic matter ( @entity13304 ) released by @entity16589 . 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 @entity505 transferred from each @entity13304 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 (kT), the time profiles of the total, dissolved and particulate organic @entity505 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 @entity505 (DOCR) 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 @entity13304 were consumed rapidly, corroborating the hypothesis that @entity13304 is readily available in the environment. This also suggests that the bacterial community in the inocula readily uses the labile part of the @entity13304 , until this community is able to metabolise efficiently the remaining of @entity13304 not degraded in the first moment. Given that @entity16589 blooms recur throughout the year in some eutrophic reservoirs, there is a constant supply of the same @entity13304 which could maintain a consortium of bacterial morphotypes adapted to consuming this substrate.

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

@entity505 :: ('MESH:D002244', 'Chemical') :: ['carbon'] @entity16589 :: ('1126', 'Species') :: ['Microcystis aeruginosa', 'M. aeruginosa'] @entity13304 :: ('MESH:D004290', 'Chemical') :: ['DOM']
@entity16589 :: (1126,Species) :: ['Microcystis aeruginosa']
