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121.
I. P. F. M. Montenegro A. P. Mucha I. Reis P. Rodrigues C. M. R. Almeida 《International Journal of Environmental Science and Technology》2017,14(5):943-955
The bioremediation potential of microorganisms from a saltmarsh plant rhizosphere and application of bioaugmentation in estuarine sediment co-contaminated were investigated. Rhizosediment (sediment in contact with plant roots) of Juncus maritimus was contaminated with copper and/or petroleum, inoculated with different autochthonous microbial consortia (resistant to copper and/or with petroleum degraders) and put in vessels to which plants were transplanted. Vessels were irrigated through a system that simulated estuarine tides. After 5 months, vessels were dismantled and copper and petroleum content in rhizosediments were determined. Copper’s presence reduced the potential of the microorganisms associated to J. maritimus rhizosphere for bioremediation of petroleum hydrocarbons in co-contaminated sediment. Indeed, hydrocarbons removal decreased from 39 to 25% when copper was present. In addition, bioaugmentation was not effective to overcome metal negative effects on petroleum hydrocarbons degradation, and the same removal rate was being observed (ca. 25%). Different methodologies for the formulation of consortia must be tested in this situation of co-contamination. Obtained results should be taken in consideration when planning the recovery of moderately impacted estuaries, aiming an effective protection and management of these areas, in the case of co-contamination. 相似文献
122.
Modeling soil erosion using RUSLE and GIS in a watershed occupied by rural settlement in the Brazilian Cerrado 总被引:1,自引:0,他引:1
The installation of a rural settlement complex in the watershed stream Indaiá has promoted changes in land-use and vegetation cover dynamics; however, the effects of intensive agriculture and cattle farming in rural settlements on soil loss rates are not well known. Predictive models implemented in geographic information systems have proven to be effective tools for estimating erosive processes. The erosion predictive model Revised Universal Soil Loss Equation (RUSLE) is a useful tool for analyzing, establishing and managing soil erosion. RUSLE has been widely used to estimate annual averages of soil loss, by both interrill and rill erosion, worldwide. Therefore, the aim of this work was to estimate the soil loss in the watershed stream Indaiá, using the RUSLE model and geoprocessing techniques. To estimate soil loss, the following factors were spatialized: erosivity (R), erodibility (K), topography (LS), land-use and management (C) and conservation practices (P); the annual soil loss values were calculated using the RUSLE model equation. The estimated value of soil loss in the hydrographic basin ranged from 0 to 4082.16 Mg ha?1 year?1 and had an average value of 47.81 Mg ha?1 year?1. These results have demonstrated that 68.16 % of the study area showed little or no soil loss based on the Food and Agriculture Organization’s (FAO 1980) classification. When comparing the average value of soil loss obtained using the RUSLE model with the Natural Potential for Erosion, a 16-fold reduction in soil was found, which highlighted the fact that vegetation cover (C factor) has a greater influence than other factors (R, K and LS) on soil loss prediction attenuation. These results lead to the conclusion that soil loss occurs by different methods in each settlement in the basin and that erosive processes modeled by geoprocessing have the potential to contribute to an orderly land management process. 相似文献
123.
The aim of this paper was to analyse water dynamics in the soil from tensiometer data in two different plots, one with bare
soil and another with geotextiles and grass, correlating the information generated in the study concerning biotextile efficiency
in soil moisture maintenance, which is essential to vegetation development and to the recovery from and control of erosion.
Tensiometers were installed on the bare soil and grass plots at different depths (15, 30, 80 and 120 cm), and the respective
readings were taken with a digital tensimeter. Water dynamics inside the soil can be demonstrated by matric potential data
from pressure differences. A large difference between the bare soil and grass plots was demonstrated by matric potential medium
values at depths of 15, 30, 80 and 120 cm during monitoring. 相似文献
124.
We tested the effectiveness of stable isotopes as recorders of physiological changes that occur during coral bleaching and recovery. Montipora capitata and Porites compressa fragments were bleached in outdoor tanks with seawater temperature raised to 30 °C (treatment corals) for one month. Additional fragments were maintained at 27 °C in separate tanks (control corals). After one month, (0 months recovery), buoyant weight was measured and a subset of fragments was frozen. Remaining fragments were returned to the reef for recovery. After 1.5, 4, and 8 months, fragments were collected, measured for buoyant weight, and frozen. Fragments were analyzed for stable carbon and oxygen isotopic compositions of the skeleton (δ13Cs; δ18Os) and nitrogen and carbon isotopic compositions of the host tissue (δ15Nh; δ13Ch) and zooxanthellae (δ15Nz; δ13Cz). δ13Cs decreased immediately after bleaching in M. capitata, but not in P. compressa. δ18Os of both species failed to record the warming event. During the remaining months of recovery, δ13Cs and δ18Os were more enriched in treatment than control corals due to decreases in calcification and metabolic fractionation during that time. Increased δ15Nh of treatment P. compressa may be due to expelled zooxanthellae during bleaching and recovery. Increased δ15Nz at 1.5 months in treatment fragments of both species reflects the increased incorporation of dissolved inorganic nitrogen to facilitate mitotic cell division and/or chl a/cell recovery. Changes in δ13Ch and δ13Cz at 1.5 months in treatment M. capitata indicated a large increase in heterotrophically acquired carbon relative to photosynthetically fixed carbon. We experimentally show that isotopes in coral skeleton, host tissue and zooxanthellae can be used to verify physiological changes during bleaching and recovery, but their use as a proxy for past bleaching events in the skeletal record is limited. 相似文献
125.
Andr Weissheimer de Borba Ana Maria Pimentel Mizusaki Diogo Rodrigues Andrade da Silva Edinei Koester Fabio de Lima Noronha Júnia Casagrande 《Gondwana Research》2006,9(4):464-474
This paper reports the integrated application of petrographic and Sm–Nd isotopic analyses for studying the provenance of the Neoproterozoic Maricá Formation, southern Brazil. This unit encompasses sedimentary rocks of fluvial and marine affiliations. In the lower fluvial succession, sandstones plot in the “craton interior” and “transitional continental” fields of the QFL diagram. Chemical weathering probably caused the decrease of the 147Sm/144Nd ratios to 0.0826 and 0.0960, consequently lowering originally > 2.0 Ga TDM ages to 1.76 and 1.81 Ga. 143Nd/144Nd ratios are also low (0.511521 to 0.511633), corresponding to negative εNd present-day values (− 21.8 and − 19.6). In the intermediate marine succession, sandstones plot in the “dissected arc” field, reflecting the input of andesitic clasts. Siltstones and shales reveal low 143Nd/144Nd ratios (0.511429 to 0.511710), εNd values of − 18.1 and − 23.6, and TDM ages of 2.16 and 2.37 Ga. Sandstones of the upper fluvial succession have “dissected arc” and “recycled orogen” provenance. 143Nd/144Nd isotopic ratios are also relatively low, from 0.511487 to 0.511560, corresponding to εNd values of − 22.4 and − 21.0 and TDM of 2.07 Ga. A uniform granite–gneissic basement block of Paleoproterozoic age, with subordinate volcanic rocks, is suggested as the main sediment source of the Maricá Formation. 相似文献
126.
The role of SST on the South American atmospheric circulation during January, February and March 2001 总被引:1,自引:0,他引:1
Precipitation deficits were observed over southeastern, northeastern and Central Brazil during the 2001 Austral Summer. They
contributed to the worsening of the energy crisis that was occurring in the country. A low-level anomalous anticyclonic circulation
observed over eastern Brazil enhanced the deviation of moisture transport that usually occurs from the Amazon Basin to southeastern
Brazil and inhibited the occurrence of South Atlantic Convergence Zone events in that period. However, an anomalous low-level
northerly moisture flux was observed over the La Plata Basin, and positive precipitation anomalies occurred over Bolivia,
Paraguay, northeastern Argentina and southern Brazil. Using the ensemble technique, a numerical study was carried out to investigate
the role of different sea surface temperature (SST) forcings observed over this anomalous South American atmospheric circulation.
Reynolds SST monthly means were used as boundary conditions to study the influence of South Atlantic, South Indian, South
Pacific and Equatorial Pacific oceans. The simulations were run from September 2000 to April 2001 using the Community Climate
Model version 3.6 General Circulation Model. Ten integrations using different initial conditions were done to each experiment.
Numerical experiments suggested that the combined influence of South Pacific and Equatorial Pacific oceans could be responsible
for the drought observed over Central Brazil. These experiments simulated the low-level anticyclonic anomaly observed over
eastern Brazil. However, both experiments have poorly reproduced the intensity of the anomalous low-level northerly moisture
flux observed over the La Plata Basin. Therefore, the intensity of the simulated precipitation anomalies over the subtropical
regions was much weaker than observed. 相似文献
127.
Conventional and non-conventional flotation for mineral processing and for water (and wastewaters) treatment and reuse (or recycling) is rapidly broadening their applications in the mining field. Conventional flotation assisted with microbubbles (30–100 μm) finds application in the recovery of fine mineral particles (< 13 μm) and flotation with these fine bubbles is being used as a solid/liquid separation to remove pollutants. The injection of small bubbles to conventional coarse bubbles flotation cells usually leads to general improvements of the separation parameters, especially for the ultrafines (< 5 μm) ore particles. Results obtained are believed to occur by enhancing the capture of particles by bubbles, one of the main drawbacks in fine ore flotation. It is believed that by decreasing the bubble size distribution (through the injection of small bubbles), increases the bubble surface flux and the fines capture. DAF or dissolved air flotation with microbubbles, treating water, wastewater and domestic sewage is known for a number of years and is now gradually entering in the mining environmental area. This technology offers, in most cases, advantages over settling, filtration, precipitation, or adsorption onto natural and synthetic adsorbents. The targets are the removal of oils (emulsified or not), ions (heavy metals and anions) and the reuse or recirculation of the process waters. Advantages include better treated water quality, rapid start up, high rate operation, and a thicker sludge. New applications are found in the mining vehicles washing water treatment and reuse, AMD (acid mining drainage) neutralization and high rate solids/water separation by flotation with microbubbles. This work reviews some recent applications of the use of microbubbles to assist the recovery of very small mineral particles and for the removal of pollutants from mining wastewaters. Emphasis is given to the design features of innovative devices showing the potential of conventional and unconventional DAF flotation. 相似文献
128.
Phosphorus dynamics in water and sediments in urbanized and non-urbanized rivers in Southern Brazil 总被引:1,自引:0,他引:1
Pagliosa PR Fonseca A Bosquilha GE Braga ES Barbosa FA 《Marine pollution bulletin》2005,50(9):965-974
Phosphorus flux models show that the removal tends to be a common feature in polluted estuarine systems whereas the release of P to the adjacent coastal area occurs in pristine environments. This study analyzes the distribution of P in water and sediments along six rivers in the south coast of Brazil. Three rivers located inside protected areas were considered non-polluted and used as a control of urbanization. The other three, situated within urbanized areas, were considered as having highly elevated concentrations of P. Results showed a different behavior of P in water and sediments located in urbanized and non-urbanized areas. The concentrations of dissolved organic (P-org) and inorganic (P-inorg) phosphorus in water, and the total phosphorus (P-tot) and polyphosphate (P-poly) in sediments where higher in the urbanized rivers compared to the non-urbanized ones. Both P of punctual origin and of diffuse origin contributed to the maintenance of elevated concentrations and disturbed the natural fluxes along the polluted rivers. The minimum and maximum concentrations in urbanized areas varied from 0.39 to 12.45 (microM) for P-org and 0.00 to 5.92 (microM) for P-inorg in water, and in sediments from 89.90 to 808.16 (microM g(-1)) for P-tot and 0.00 to 76.51 (microM g(-1)) for P-poly. In non-urbanized areas concentrations in water varied from 0.22 to 1.20 (microM) for P-inorg and 4.43 to 5.56 (microM) for P-org, and in sediments from 45.91 to 652.26 (microM g(-1)) for P-tot and 0.00 to 8.61 (microM g(-1)) for P-poly. Using a hierarchical sampling design and a simple model of variation of P (K(d) model) it was possible to demonstrate that urbanized and non-urbanized estuaries may act as sinks or sources of P. The variation of P analysis in different points along each of the six rivers showed that release and removal areas may occur within a same river independently of its urbanization. 相似文献
129.
On climate variability in Northeast of Brazil 总被引:3,自引:0,他引:3
The time-series (annual period and dry- and wet-season) of eight climatic variables were analysed to ascertain the existence of climate variability in Northeast of Brazil. Results indicated generally increasing trends in most of these variables (statistically significant at p<0.01 or <0.05) by Mann–Kendall test. However, relative humidity and rainfall presented decreasing behavior. The study showed that most of the stations studied are going through a process of environmental dryness. The results also suggest that the historical trends may be related to climate variability in Northeast of Brazil, which affects both semi-arid and coastal part of the region. 相似文献
130.
Andr Weissheimer de Borba Ana Maria Pimentel Mizusaki Anderson Jos Maraschin Diogo Rodrigues Andrade da Silva 《Journal of South American Earth Sciences》2008,26(4):485-497
Integrated petrographic and Sm–Nd isotopic data were applied in order to constrain the provenance of the Early Paleozoic Santa Bárbara Formation, Sul-rio-grandense Shield, southern Brazil. This unit comprises continental sandstones, conglomerates and siltstones deposited under semi-arid climate in a rift or pull-apart basin. Samples were collected within a stratigraphic framework composed of three sequences, in which the two basal ones present northeastwards paleoflow, and the third one marks the inversion of basin filling. Samples from sequence I show, in the south, a strong influence of intermediate volcanic (Hilário Formation) sources, and a significant increase in quartz and metamorphic fragments upsection. In the northern deposits, there is a possible influence of juvenile units (Cambaí/Vacacaí), and a more significant input of Paleoproterozoic-sourced sedimentary rocks (e.g. Maricá Formation) upsection. Samples collected from the topmost deposits of sequence II present a clear increase in the amount of volcanic fragments (mostly acidic), reflecting denudation of the “Caçapava high”. Data obtained in sequence III (Pedra do Segredo) show a progressive decrease in quartz content and a significant increase in feldspathic, plutonic fragments. A more evolved phase of denudation of the “Caçapava high”, exposing leucogranitoids of the Caçapava do Sul complex, is proposed for this interval. 相似文献