Lake Batata Research Articles

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

AbstractThe aim of this study was to evaluate the influence of Campusurus notatus Eaton 1868 (Ephemeroptera: Polimitarciydae) and the impact of bauxite tailings on ammonium (NH4+) 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 NH4+, DOC, O2 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 (NH4+) 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.

Variation of biometric parameters and C, N, and P concentrations of Oryza glumaepatula at different depths of an Amazonian lake impacted by bauxite tailings (Lake Batata, Pará, Brazil).

Lake Batata is a typical Amazonian clear water lake which has undergone anthropogenic impacts. Thirty percent of its total area has been covered with bauxite tailings. Thus, it is possible to distinguish two areas in this ecosystem: the impacted and the natural. The goal of this research was to study C, N, and P content variation and the values of biomass, length, density, and culm diameter of Oryza glumaepatula at different depths in the natural and impacted areas of Lake Batata. The results obtained in this research suggest that the availability of P and N, in both water and sediment, is lower at the shallow site when compared to the deeper sites. On the other hand, C concentrations decreased as P and N concentrations increased. This may be explained by the structural function of C in aquatic macrophytes. At shallower sites, due to the reduced water column, individuals invest in supporting structures that display high C concentrations. The higher density and biomass of O. glumaepatula at the intermediate site indicate that this area presents the best conditions for germination and establishment of individuals of this species. The chemical composition and biometric parameters of O. glumaepatula have shown that this population has higher spatial variation in the natural area. In the impacted area, the absence of significant variations in N and P concentrations in O. glumaepatula among the three sampled sites promotes higher homogeneity in the stands. The high C:P and N:P ratios indicate that, in the impacted area, P is more limiting to the development of O. glumaepatula than it is in the natural area. The reduced values of biomass and density of O. glumaepatula in the impacted area suggest that the bauxite tailings limit the development of this population.

Nutrient limitation of bacterial production in clear water Amazonian ecosystems

The aim of this research was to determine the main limiting nutrient (carbon, nitrogen or phosphorus) to bacterial production in different clear water Amazonian ecosystems during the high water period, when there is influence of the flooded land, mainly as sources of organic matter. Five stations were sampled in three clear water ecosystems: Trombetas River, Lake Batata and Carana Stream. We estimated in each station the nutrient concentration, bacterial production and bacterial abundance. The experiment was set up with GF/F filtered water from all stations together with additions of glucose (400 μM C), KNO3 (15 μM N) and KH2PO4 (5 μM P) in accordance with each treatment (C, N, P ,CN, CP, NP, CNP and no amends). Bacterial production was estimated after 24 h of incubation. We observed that the values of bacterial production after additions of phosphate alone (P treatment) were 2- to 6-fold greater than the values measured in control flasks. Additions of nitrate (N treatment) and glucose alone (C treatment) had no effect on the bacterial production in four out of five ecosystems studied. However, additions of glucose with phosphate (CP treatment) strongly stimulated bacterial production in all ecosystems studied, including treatments with phosphate addition only. We conclude that phosphorus is the main limiting nutrient to bacterioplankton production in these clear water Amazonian ecosystems during the high water period. In addition, we conclude that, together with phosphorus, additions of glucose stimulated the bacterial production mainly due to the low quality of the carbon pool present in these ecosystems.

Potential denitrification in submerged natural and impacted sediments of Lake Batata, an Amazonian lake

Lake Batata is one of many clear water lakes located on the floodplain of the Trombetas River in the northern Brazilian Amazon. Lake Batata is distinctly different from other lakes of this region because, for a period of 10 years, its waters received tremendous amounts of aluminum ore tailings from a bauxite mining operation. Approximately 30% of the sediments of the upper basin of the 2100 hectare lake were covered by tailings before dumping was curtailed. The goal of this research was to identify factors controlling denitrification in the natural and impacted sediments of Lake Batata. Rates of denitrification in sediments were estimated in the laboratory by the acetylene blockage method. Denitrification was measured under four conditions: without amendment; amended with glucose; amended with nitrate; and amended with glucose and nitrate. Denitrification was observed only in assays amended with nitrate suggesting that availability of nitrate is a principle factor for controlling denitrification in the sediments of Lake Batata. Effects of nitrate amendments are most pronounced when the water level is low, i.e. during the hydroperiods of draw-down and low-water.

Life cycle and production of Campsurus notatus (Ephemeroptera, Polymitarcyidae) in an Amazonian lake impacted by bauxite tailings (Pará, Brazil)

Between 1979 and 1989, Lake Batata was subjected to ±50 000 m3 d−1 of bauxite tailings effluent, which impacted about 30% of the lake's area. The present research had as its main goal to study the life cycle and secondary production of Campsurus notatus on the tailings-impacted region of Lake Batata. Campsurus notatus is the species most adapted to the conditions imposed by the bauxite tailings. A central site in the impacted region of Lake Batata was established and sampled at fortnightly intervals between July 1996 and June 1997. The nymphs of C. notatus in the impacted region had a 105-day lifespan, with individuals between 2 and 17 mm in length. Estimated secondary production for C. notatus was 2.5 g DW m−2 yr−1in the impacted region. This was high compared to production rates estimated for other species of ephemeropterans, indicating the degree of successful adaptation of C. notatus to the conditions imposed by the bauxite tailings.

Actual and potential heterotrophicneutrogen fixation and detrification rates of oryza glumaepatula Steud in an amazonian lake

Estimates of the rates of heterotrophic nitrogen fixation (HNF) and denitrification by acetylene reduction and acetylene inhibition, respectively, were determined for the roots and culms of wild rice, Oryza glumaepatula, in Lake Batata, a lake severely impacted by the dumping of bauxite tailings into the lake basin. Two stations were established in different parts of the lake: one in a natural area and other in an impacted area of the lake. Plant assays were performed during the principle hydroperiods of dry (December) and flood (July) to determine both: a) Actual rates of HNF and denitrification, and b) potential rates of HNF after amending with glucose potential rates of denitrification after amending with glucose, glucose + nitrate, or nitrate alone. HNF was found to naturally exceed denitrification in this system. HNF and denitrification were consistently found to be greater for roots than culms but no correlation was found between rates of HNF or denitrification and water depth. It was determined that for HNF and denitrification that glucose and nitrate were the limiting factors in controlling those processes in roots and culms of O. glumaepatula . HNF and denitrification of O. glumaepatula does not appear to show differences between impacted and non-impacted areas.

Influences of suspended inorganic matter on carbon ingestion and incorporation rates of two tropical cladocerans, Diaphanosoma birgei and Moina minuta

Bauxite processing in Porto Trombetas, Brazil, generated a fine particulate effluent that was dumped into Lake Batata over a ten-year period, leading to high suspended solids, reduced water transparency and increased turbidity in parts of the lake. The influence of bauxite tailings on cladoceran feeding was studied by measuring carbon ingestion and carbon incorporation rates in Diaphanosoma birgei and Moina minuta. Feeding responses of animals exposed to bauxite tailings concentrations of 10, 20, 50, 100 and 200 mg/l were tested in laboratory experiments at two food levels (0.2 and 2.0 mg C/l) of 14 C-radiolabelled Scenedesmus acutus, and compared to bauxite-free experimental controls. Ingestion rates of both species varied in relation to food level and tailings concentration. Carbon incorporation rates generally declined with increased bauxite tailings levels in both cladoceran species, but precise responses varied between species and for the different combinations of tailings and food. Both carbon ingestion and incorporation rates were less adversely affected by rising bauxite tailings concentrations in M. minuta than D. birgei, indicating a clear differential susceptibility to suspended sediment contamination in these species.

Diurnal variation of rates of denitrification and nitrogen fixation of periphyton associated with Oryza glumaepatula Steud in an Amazonian Lake

The rates of denitrification and biological nitrogen fixation of the periphyton communities associated with the culms and adventitious root of Oryza glumaepatula in Lake Batata, State of Para, Brazilian Amazonia, were investigated over the course of 24 h. N2O was not detected during the period, demonstrating that denitrification was not occurring. The low concentration of nitrate in the water column was indicated as the main factor limiting the denitrification process. The rates of biological nitrogen fixation (BNF) in culms were lowest at night and early morning, while the highest values were measured at 1200 h. BNF rates in periphyton associated with adventitious roots were lowest during the morning, while highest values were measured at 1600 h. The difference in the daily patterns of BNF rates in the periphyton of culms and roots of O. glumaepatula in the euphotic zone was attributed to defferences in the availability of organic carbon which supports this process. In the periphyton of the culms, the BNF process was carried out by heterocystous cyanobacteria, which was photoautotrophs. In the periphyton of the adventitious roots, BNF was carried out by periphytic bacteria, and is heterotrophically mediated.

Effects of bauxite tailing on PAR attenuation in an Amazonian crystalline water lake

The PAR attenuation in Batata Lake, an Amazonian crystalline system subject to the effect of bauxite mining, was increased through dumping of tailing by 35% during low periods in impacted areas. Subsequently, the euphotic zone was reduced by 1 meter and phytoplankton production decreased by 60%. The tailing, which are frequently resuspended and transported into non-impacted areas by currents, and remain in suspension as small particles (>50% of frequency distribution), thereby increasing inorganic turbidity (>25 NTU) and PAR scattering. However, during the high water hydrological phase, there was no distinct difference in PAR attenuation between the impacted and non-impacted areas.

Chemical, physico-chemical and physical conditions of the soil and water in natural and impactedigapóareas of Batata Lake (PA), Brazil

(1997). Chemical, physico-chemical and physical conditions of the soil and water in natural and impacted igapo areas of Batata Lake (PA), Brazil. SIL Proceedings, 1922-2010: Vol. 26, No. 2, pp. 297-299.

Influence of the Hydrological Cycle on the Bacterioplankton of an Impacted Clear Water Amazonian Lake

Free-living and attached bacterial population sizes were determined fortnightly from December 1991 to December 1992 in natural and disturbed areas of an Amazonian clear water lake (Batata Lake, Para, Brazil) impacted by bauxite tailings. The bacterioplankton showed distinct patterns during different phases of the hydrological cycle. Total bacterial population size and rates of thymidine incorporation (measured during high and low water phases) were high during low water, with values ranging from 3.3 × 105 to 1.1 × 106 cells ml−1, and from 0.28 to 4.01 μg C l−1 h−1, respectively. The population size of free-living bacteria was larger at the natural station, while no differences were observed between attached bacterial populations at both stations. However, production and turnover rate of attached bacteria were high at the disturbed area. During low water, bacterial growth appeared to be driven mainly by the input of dissolved organic carbon (DOC) from phytoplankton origin. During high water, bacterial abundance was reduced, probably as the result of dilution and the input of less labile DOC from floodplains. The presence of bauxite tailings seems to influence bacterial dynamics in an indirect way, probably due to shading of phytoplankton cells and, hence, reducing the DOC supply for bacterial growth. This study, the first on the microbial ecology of an Amazonian clear water lake, demonstrated that water level variations exert a strong influence on the bacterioplankton dynamics.

The Influence of Bauxite Tailings on the Cladoceran Populations of Lake Batata, Amazonia, Brazil

AbstractLake Batata receive tailings from bauxite mining for ten years (1979‐1989). This material, with 7‐9% of solid particles, changed some ecological conditions of part of the lake. In order to study the influence of this material on the cladoceran populations, seasonal and intensive studies were made of abundance and brood size of the animals and of some environmental parameters such as transparency, suspended material, POC (<30pm), total bacteria and chlorophyll a.Reduced transparency and high suspended matter attested to the greater quantity of tailings in the water column, in the area impacted by tailings. Greater oscillations of density and brood size at stations in the impacted area appear to indicate less stable conditions in this part of the lake.

Dynamics of phosphorus, carbon and nitrogen in an Amazonian lake impacted by bauxite tailings (Batata Lake, Pará, Brazil)

Dynamics of phosphorus, carbon and nitrogen in an Amazonian lake impacted by bauxite tailings (Batata Lake, Pará, Brazil)