Tesis doctoral de Stefania Mattana
The soil microbial community is probably the most important functional component of the soil biota because the soil microorganisms perform a wide range of ecologically significant functions, which are essential for a normal and healthy soil. Therefore, the microbial parameters of the soils should be included in environmental monitoring, ecological risk assessment and soil quality evaluation. the current policy of the european commission is to encourage the beneficial use of sewage sludge on land, as it represents an apparent long-term sustainable solution to sludge disposal, provided that the quality of sludge is compatible with public health and environmental protection requirements. Land application of sewage sludge is in fact becoming a recognized method of recycling both the nutrients and the organic matter contained in the sludge and, at the same time, the most economic disposal way. Nevertheless, the presence of metallic and organic pollutants or pathogens can involve an environmental risk. This thesis evaluates the effect of sewage sludge on microbial community activity and diversity. Towards these ends seven types of wastes are studied: two dewatered sewage sludges, two composted sewage sludges, two thermally-dried sewage sludges, and one thermally-dried pig slurry. Changes in soil microbial functionality (sir, soil respiration, atp content, hydrolase activity and arginine ammonification) and soil microbial genetic diversity (eubacteria, actinobacteria and íY- proteobacteria) were studied in laboratory incubation within 28 days. in this study, the degree of stability of the organic matter of the sludge was a good indicator of the overall effects observed on soil microbial biomass functionality. In fact microbial activities were inversely correlated with the degree of stability of organic matter. Bacterial genetic diversity increased in sludge treated soils, but the type of sewage sludge also had influence on the composition of bacterial communities of the soil. However an increase in genetic diversity and activity was not accompanied with an increase in the size of the microbial community. we concluded that sewage sludge application to soil stimulated the resilience of the soil microbial community, which increases its own diversity to keep its functions. this thesis stresses the necessity to integrate molecular and classical techniques to gain a deeper understanding of the complex relationship between functional and genetic diversity of soil microbial communities in response to anthropogenic stress.
Datos académicos de la tesis doctoral «Effects of different types of sewage sludge on soil microbial functionality and diversity«
- Título de la tesis: Effects of different types of sewage sludge on soil microbial functionality and diversity
- Autor: Stefania Mattana
- Universidad: Autónoma de barcelona
- Fecha de lectura de la tesis: 21/01/2011
Dirección y tribunal
- Director de la tesis
- Josep Oriol Ortiz Perpiñá
- Tribunal
- Presidente del tribunal: rosa María Poch claret
- franklin gerardo Ojeda castro (vocal)
- (vocal)
- (vocal)
