Effect of Campsurus notatus on NH⁺₄, DOC Fluxes, O₂ Uptake and Bacterioplankton Production in Experimental Microcosms with Sediment‐Water Interface of an Amazonian Lake Impacted by Bauxite Tailings

Abstract

The aim of this study was to evaluate the influence of Campusurus notatus EATON 1868 (Ephemeroptera: Polimitarciydae) and the impact of bauxite tailings on ammonium (NH 4 + ) and dissolved organic carbon (DOC) fluxes, oxygen uptake and bacterioplankton production in the sediment-water interface of Lake Batata, a shallow Amazonian floodplain lake. Mesocosms were constructed from natural and impacted areas of Lake Batata, to reproduce the sediment-water interface. The cores were incubated with 0 to 2,388 ind m -2 of Campsurus notatus nymphs, and the changes in NH 4 + , DOC, O 2 concentration and bacterioplankton production in the overlying water column were measured. Ammonium efflux (F = 9.8, p < 0.05, multiple regression) and oxygen uptake (F = 11.8, p < 0.05) showed a significant correlation with the density of C. notatus in the cores with natural sediment. No differences on DOC release were observed in cores with natural or impacted sediment. In the cores incubated with natural sediment and nymphs of C. notatus, a significant increase (Two-way ANOVA, p < 0.05) in bacterial production (0.44 µg C l -1 h -1 ) was observed after 3 hours of incubation. In cores incubated with sediment impacted by bauxite tailings, there was no difference in bacterial production with and without C. notatus. We conclude that C. notatus is an important bioturbator in Lake Batata, increasing the turnover rate of nitrogen (NH 4 + ) at the sediment-water interface and bacterial production in cores incubated with natural sediment. It is also clear that bauxite tailings reduce the nutrients turnover rates in impacted regions of Lake Batata and influence bacterial production. Internat. Rev. Hydrobiol. 88 2003 2 167-178

Virus-Bacterium Coupling Driven by both Turbidity and Hydrodynamics in an Amazonian Floodplain Lake

“…2C). The decreasing water depth enhances the resuspension of inorganic nutrients through the action of wind and benthic macroinvertebrates, which in turn would promote the growth of the plankton communities (28 ton cells would dominate the lake, and this scenario is propitious for viral infection and multiplication inside these cells. Therefore, the input of autochthonous inorganic nutrients in the drawdown season could promote a cascade effect, resulting in greater viral abundances and greater VBR than those in other seasons of the flood pulse.…”

“…related to the hydrological cycle have been observed during the last 20 years, keeping high concentrations of suspended sediments in the water column of the impacted site (28). Actually, they are quite rare nowadays.…”

“…Lake Batata is distinct because it was impacted by bauxite tailings for 10 years (1979 to 1989), affecting 30% of the lake's area. The tailings caused a huge increase in turbidity; large amounts of tailings settled on the sediment surface and often are resuspended by physical mixing or biotic movements (28). The presence of tailings resulted in a clear spatial variation in the lake, forming impacted and natural sites.…”

Benthic macroinvertebrates of a tropical lake: Lake Caçó, MA, Brazil

“…Benthic organisms actively participate in the energy flow and nutrient cycles within aquatic ecosystems, having a major role in the exchange of phosphorus and nitrogen between the sediment and the water (Gardner et al, 1983;Fukuhara and Sakamoto, 1988;Leal et al, 2003, Pelegri and Blackburn, 1996, Real et al, 2000. By constantly turning the sediment, through their digging and tunnelling activity, and by breaking down the solid organic matter that settles there, these organisms reduce the size of particles and this contributes to the liberation of nutrients trapped in the sediment, into the water column (Marques et al, 1999;Callisto and Esteves, 1998).…”

“…By constantly turning the sediment, through their digging and tunnelling activity, and by breaking down the solid organic matter that settles there, these organisms reduce the size of particles and this contributes to the liberation of nutrients trapped in the sediment, into the water column (Marques et al, 1999;Callisto and Esteves, 1998). They also form part of the food chain of diverse important aquatic animals, notably fish (Margalef, 1983) and have a relevant role in the recovery of organic matter and nutrients for the water column by bioturbation activity (Real et al, 2000;Leal et al, 2003;Caliman et al, 2007;Callisto et al, 2009).…”