Original paper

Influence of Campsurus notatus bioturbation on oxygen profile and uptake in sediments of an Amazonian lake impacted by bauxite tailings

Leal, João JoséFonseca Enrich-Prast; Assis Esteves, Francisco; Bozelli, Reinaldo; Farjalla, Vinicius; Fortes,


Oxygen uptake rates and vertical profiles were determined in sediment taken from natural areas and areas impacted by bauxite tailings in Lake Batata, and in the U-shaped burrows constructed by the nymphs of the benthic ephemeropteran Campsurus notatus, under laboratory conditions.Sediment from impacted and natural areas containing different densities of nymphs of C. notatus (0 to 1,200 ind. m-2) were incubated in acrylic cores. In sediment from the natural area, O2 was present only in the upper 3.5 mm. In the impacted area, the aerobiclayer was deeper, with O2 detected down to 6.5 mm depth. O2 uptake was twice as high in sediment from the natural area (1.11 mmol O2 m-2 h-1) as from the impacted area (0.61 mmol O2 m-2 h-1).In cores containing nymphs of C. notatus, O2 uptake was significantly higher than in sediments without C. notatus. The increase in the rates of O2 uptake was positively correlated with the biomass of the nymphs (gDW m-2). The presence ofC. notatus resulted in alteration of the O2 profiles in the sediment of both areas, indicating the importance of these larvae in structuring O2 profiles in the sediments of Lake Batata.


bioturbationamazonian lakecampsurus notatusimpacted sedimentoxygen