ABSTRACT
Abstract:Sulfate-reducing bacteria (SRB) and methanogenic archaea (MA) share common niches in coastal sediments during the terminal phases of the anaerobic mineralization of organic matter. The purpose of this study was to analyze the spatial - temporal variation of SRB and MA in the sediments of a tropical coastal lagoon with ephemeral inlet (La Mancha, Veracruz, Gulf of Mexico) and its relationship with environmental changes. A total of 24 sediment samples were collected during the dry (April, May), rainy (July, September) and Northern (November, February) seasons in the period 2013-2014. Microbiological analyses included the quantification of the viable SRB and MA with different substrates, as well as mineralization experiments to determine the effect of sulfate on acetate oxidation. The analyzed environmental variables in the sediments included: temperature, pH, Eh, salinity, sulfates, H2S, volatile solids, carbohydrates, and granulometric characteristics. Major changes occurred between the dry and rainy seasons. During the dry season, sulfate-reducing abundance was significantly greater with lactate (8.3x105 - 1.2x107 cells / g) and propionate (1.8x105 - 6.6x106 cells / g) as substrates, while the MA that use methanol were dominant (4.2x105 - 9.1x106 cells / g). In contrast, during the rainy season, hydrogenophylic (2.6x105 - 8.3x106 cells/g) and acetoclastic (5.4x105-6.4x106 cells / g) MA increased significantly and SRB decreased in the analyzed substrates. An apparent competition for acetate was observed, with a greater oxidation in the media with sulfates in the dry season (0.06 mM acetate / g sediment / day), and a greater oxidation in the media without sulfates in the rainy season (0.02 mM acetate / g sediment / day). SRB and MA were present throughout the sediment column, however SRB dominated in the first centimeters of the sediment while MA were abundant in deeper layers. In conclusion, SRB and MA together played a role in the mineralization of organic matter in the sediments of La Mancha lagoon, with sulfate-reduction dominating in the dry season (closed inlet) and methanogenesis during the rainy season (open inlet). Changes in rainfall and river input in this lagoon significantly affect salinity and sulfate content, the main factors that regulate the dynamics of SRB and MA in the sediments. Rev. Biol. Trop. 64 (4): 1759-1770. Epub 2016 December 01.
Resumen:Las bacterias sulfatorreductoras (BSR) y las arqueas metanogénicas (AM) comparten nichos comunes en los sedimentos costeros durante las fases terminales de la mineralización anaerobia de la materia orgánica. El objetivo del presente estudio fue analizar la variación espacio-temporal de las BSR y AM en los sedimentos de una laguna costera tropical con una boca efímera (La Mancha, Veracruz, Golfo de México) y su relación con los cambios ambientales. Un total de 24 muestras de sedimentos fueron recolectadas en las temporadas de secas (abril, mayo), lluvias (julio, septiembre) y nortes (noviembre, febrero) en el periodo 2013 - 2014. Los análisis microbiológicos incluyeron la cuantificación de las BSR y AM viables con diferentes sustratos, así como experimentos de mineralización para determinar el efecto de los sulfatos en la oxidación del acetato. Las variables ambientales analizadas en los sedimentos incluyeron la temperatura, pH, Eh, salinidad, sulfatos, H2S, sólidos volátiles, carbohidratos y las características granulométricas. Los principales cambios se presentaron entre las estaciones de secas y lluvias. En la temporada de secas la abundancia sulfatorreductora fue significativamente superior con lactato (8.3x105 - 1.2x107 células / g) y propionato (1.8x105 - 6.6x106 células / g) como sustratos, mientras que las AM que emplean metanol dominaron (4.2x105 - 9.1x106 células / g). Por el contrario, en la época de lluvias aumentaron significativamente las AM hidrogenofílicas (2.6x105-8.3x106 células / g) y acetoclásticas (5.4x105-6.4x106 células / g), disminuyendo las BSR con los sustratos analizados. Se determinó una competencia aparente por el acetato. Su oxidación fue mayor en los medios con presencia de sulfatos en las temporadas de secas (0.06 mM acetato / g sedimento / día), mientras que aumentó en los medios sin sulfatos en la época de lluvias (0.02 mM acetato / g sedimento / día). Las BSR y las AM estuvieron presentes a lo largo de la columna sedimentaria; sin embargo, las BSR dominaron en los primeros centímetros del sedimento y las AM abundaron a mayor profundidad. En conclusión las BSR y AM participaron de manera conjunta en la mineralización de la materia orgánica en los sedimentos de la laguna de La Mancha, dominando la sulfatorreducción en la temporada de secas (boca cerrada) y la metanogénesis en la época de lluvias (boca abierta). Los cambios en el aporte fluvial y la precipitación en esta laguna afectaron significativamente la salinidad y el contenido de sulfatos, siendo los principales factores que regularon la dinámica de las BSR y AM en los sedimentos.
Subject(s)
Sulfur-Reducing Bacteria/isolation & purification , Archaea/isolation & purification , Geologic Sediments/microbiology , Spatio-Temporal Analysis , Microbiota , Fresh Water/microbiology , Rain , Reference Values , Temperature , Time Factors , Tropical Climate , Analysis of Variance , Archaea/metabolism , Gulf of Mexico , Acetates/metabolismABSTRACT
Introducción: La verificación y seguimiento de la presencia de microrganismos indicadores de la calidaddel agua es imprescindible debido al riesgo que representan para la población que la utiliza para consumo, recreación o deporte. Los reservorios acuíferos de Corrales de San Luis Beltrán, Atlántico, Colombia, son fuente de sustento de las comunidades campesinas aledañas, animales y plantas de la reserva; sin embargo, su calidad microbiológica no ha sido estudiada. Objetivo: Evaluar la calidad sanitaria del agua de reservorios acuíferos de Corrales de San Luis Beltrán. Materiales y métodos: Se realizaron muestreos de aguas superficiales y sedimento de reservorios acuíferos de Corrales de San Luis Beltrán, y se midieron in situ algunos parámetros fisicoquímicos (temperatura, pH, y oxígeno disuelto), y la calidad microbiológica (coliformes totales, coliformes fecales y bacterias reductoras de sulfato). Resultados: Se presentaron concentraciones bajas de oxígeno disuelto (2,71 mg/L), temperatura promedio de 26 °C y pH ligeramente básico (8,1). Los coliformes totales oscilaron entre 1,0x104 y 1,3x107 UFC/100 mL y los fecales entre 0 y 1,3x105 UFC/100 mL. Se encontró una correlación negativa entre el pH y los coliformes totales, y entre el oxígeno disuelto y los coliformes fecales; y una correlación positiva entre los coliformes fecales y la temperatura. Los recuentos de bacterias reductoras de sulfato fueron superiores a 103 UFC/100 g...
Introduction: The verification and monitoring of indicator microorganisms of water quality is essential.A low water quality may represent a risk for human health, because human populations frequently use it for consumption, recreation, or sport. Water reservoirs situated in Corrales de San Luis Beltran, Atlantico, Colombia, are source of sustenance to local peasant communities, animals, and plants around the village. However, the microbiological quality has not been established. Objective: To assess the sanitary water quality from Corrales de San Luis Beltran. Materials and methods: Surface water and sediment were sampled and some physicochemical parameters (temperature, pH, and dissolved oxygen), and the microbiological quality (total coliforms, fecal coliforms, and sulfate-reducing bacteria) were measured in situ. Results: The analysis showed low dissolved oxygen levels (2,71 mg/L), an average temperature of 26 °C and a slightly basic pH (8,1). Total coliform counts ranged from 1,0x104 and 1,3 x 107 CFU/100 mL and fecal coliform between 0 and 1,3 x 105 CFU/100 g. A negative correlation occurred between pH and total coliform as well as between dissolved oxygen and fecal coliforms. In addition, a positive correlation occurred between fecal coliform and temperature. The number of sulfate-reducing bacteria was more than 103 CFU/100 mL...
Subject(s)
Humans , Coliforms , Sulfur-Reducing Bacteria , Water QualityABSTRACT
Aims: The objectives were to evaluate the phosphate solubilization efficiency of different Thiobacilli strains and to find out the best combination of sulfur and Thiobacilli for enhancing bio-available P in soil. Study Design: An experimental study. Place and Duration of Study: Microbiology and Soil Fertility Labs, Department of Soil Science and Soil and Water Conservation, Pir Mehr Ali Shah Arid Agriculture University, Rawalpindi, Pakistan and Microbiology and Soil Chemistry Labs, Auriga Research Center, Lahore, Pakistan, between May 2011 and November 2012. Methodology: Fifty Thiobacilli strains were isolated from ten different ecologies. Then an incubation study of soil was performed wherein the most efficient four Thiobacilli strains were inoculated in combination with three different levels of elemental sulfur to determine pH, water soluble sulfur, sequential P fractions and bio-available phosphorous contents in the incubated soil. Results: All the four Thiobacillus strains (IW16, SW2, IW1 and IW14) dropped pH of the incubated soil along with three doses of S° (50, 75 and 100 kg ha-1). However, Thiobacillus strains IW16 and SW2 reduced soil pH quite sharply from 7.90 to 7.12 (net reduction of 0.78 points) and 7.28 (net reduction of 0.62 points) respectively where inoculated with S° @ 100 kg ha-1. The best P solubilizer was Thiobacillus strain IW16 and the best dose of S° was @ 100 kg ha-1 and their combination enhanced maximum quantity of P (22.26 mg kg-1) in the soil by solubilizing already present insoluble calcium bounded P fractions like octacalcium phosphate (Ca8-P) and apatite (Ca10-P). Conclusion: The present study suggests the use of Thiobacilli along with elemental sulfur for the dissolution and enhancement of bio-available P in alkaline and calcareous soils.
Subject(s)
Oxidation-Reduction , Phosphorus , Soil/chemistry , Soil/microbiology , Soil Microbiology , Sulfates/metabolism , Sulfides/metabolism , Sulfur/metabolism , Sulfur-Reducing Bacteria/metabolism , Thiobacillus/chemistry , Thiobacillus/metabolism , Thiobacillus/physiologyABSTRACT
Mercury is emitted to the atmosphere from various natural and anthropogenic sources, and degrades with difficulty in the environment. Mercury exists as various species, mainly elemental (Hg0) and divalent (Hg2+) mercury depending on its oxidation states in air and water. Mercury emitted to the atmosphere can be deposited into aqueous environments by wet and dry depositions, and some can be re-emitted into the atmosphere. The deposited mercury species, mainly Hg2+, can react with various organic compounds in water and sediment by biotic reactions mediated by sulfur-reducing bacteria, and abiotic reactions mediated by sunlight photolysis, resulting in conversion into organic mercury such as methylmercury (MeHg). MeHg can be bioaccumulated through the food web in the ecosystem, finally exposing humans who consume fish. For a better understanding of how humans are exposed to mercury in the environment, this review paper summarizes the mechanisms of emission, fate and transport, speciation chemistry, bioaccumulation, levels of contamination in environmental media, and finally exposure assessment of humans.
Subject(s)
Humans , Air Pollutants/chemistry , Environmental Exposure , Environmental Restoration and Remediation , Food Chain , Mercury/chemistry , Methylmercury Compounds/chemistry , Photolysis , Sulfur-Reducing Bacteria/metabolism , Water Pollutants, Chemical/metabolismABSTRACT
En el mundo uno de los mayores contaminantes para el medio ambiente son los drenajes ácidos de mina (DAM), los cuales están caracterizados por presentar elevadas concentraciones de metales pesados, sulfatos que contribuyen a la acidez del efluente.
Subject(s)
Bacteria , Metals , Metals, Heavy/chemistry , Sulfur-Reducing BacteriaABSTRACT
Biofilm reactors with turbulent agitation are often the best choice for sulfate reduction using hydrogen as electron donor for treatment of metal sulfate wastewater. In this paper, a simple activity set-up with self aspiration of gas into liquid is described for determining the sulphidogenic activity of biofilms on polystyrene beads. Sulfate reducing bacteria attached to the beads of size 1-2 mm and 2 mm were found helpful for 0.058 g SO4(2-) reduction per g of dry beads per day and 0.33 g SO4(2-) reduction per g of dry beads respectively. Also it is observed that zinc has no impact on this activity at the concentration of 680 mg/L.
Subject(s)
Bioreactors , Polystyrenes , Sulfates/metabolism , Sulfur-Reducing Bacteria/metabolism , Waste Disposal, Fluid , Water Pollutants, Chemical/metabolismABSTRACT
Industrial development in Egypt, like in many other developing countries in the world, is causing serious environmental problems due to the increasing influence of the disposal of heavy metals and organic wastes in the natural water bodies and on the land. Such pollutants in water, soil and air environments are causing damaging impact on the health of all the living beings. This study was carried out to develop new processes for the treatment of heavy metals and organic wastes, which can be considered as environment friendly, and will cause minimum damage to the environment and human health. The proposed method for the removal of heavy metals and organic matter from the waste stream is based on the use of sulfate reducing bacteria which convert sulfate to sulfide which in turn remove metals as metal sulfide. The sulfate reducing bacteria, SRB, have been used widely for the removal of heavy metals from industrial wastewaters. In this research, it was decided to determine the optimum controlling factors affecting the growth of the SRB utilizing acetate as an organic carbon source in an up flow anaerobic fixed film reactor, UAFFR. A series of continuous flow experiments were carried out to measure the optimum values for these parameters. Substrate, containing acetate as the organic carbon source along with other nutrients such as sulfate, ammonia and phosphates was fed to the experimental units. It was found experimentally that the optimum SRB growth activity occurred with an organic loading rate, OLR, of 6 kg/d/m[3], and the theoretical oxygen demand to sulfate ratio, Th.O.D./SO[4], ranged from 1.5 to 2.0. The optimum hydraulic retention time HRT was found to be equal to or higher than 11 hours. The effect of the reactor's packing material on SRB growth was also studied. Different packing materials with different surface areas were used. It was shown that the SRB growth does not depend on the nature of the packing material of the reactor