Disentangling the complexity of chemical and physical stressors impacting river systems
- Autores: Laia Sabater Liesa
- Directores de la Tesis: Damià Barceló i Cullerés (dir. tes.), Antoni Ginebreda Martí (codir. tes.)
- Lectura: En la Universitat de Girona ( España ) en 2021
- Idioma: español
- Tribunal Calificador de la Tesis: Julián Blasco Moreno (presid.), Isabel Muñoz Gràcia (secret.), Yolanda Picó García (voc.)
- Programa de doctorado: Programa de Doctorado en Ciencia y Tecnología del Agua por la Universidad de Girona
- Materias:
- Enlaces
- Tesis en acceso abierto en: TDX
- Resumen
Humanity has always been closely linked to rivers, benefiting from their resources while producing impacts associated with their activity. Thus, river systems have been exposed to multiple stressors, which have affected the quality of water and their biological communities. These physical and chemical impacts, not only have local effects but can spread their effects in space and time to the fluvial network. The effects of these impacts can change the structure and functioning of the biological communities inhabiting there, such as those attached to substrata (biofilms) or those that are suspended in water (phytoplankton). On the other hand, biological communities also respond and contribute to the transformation and/or degradation of certain anthropogenic organic compounds, such as pharmaceuticals.
This thesis investigates the chemical state of the river systems and their impacts on the biological communities, using different approaches and scales. The different chapters of the thesis show that the chemicals present in river systems play an essential role in a multiplicity of processes, but that this may differ according to the considered scale. In the case of the Ebro river mainstream, being regulated by dams, the chemical state of a certain section of the river becomes influenced by the contiguous sections, highlighting that it is necessary to consider the physical frame of the system to establish the complex interactions between chemical and biological processes. When the interaction of thousands of chemicals (including nutrients, organic matter, and/or micropollutants) is analyzed against the biological communities (biofilm) in more detail in artificial streams, it arises that they may act as enhancers or stressors of biological activity depending on concentration. Further, the intrinsic dynamics of the community itself plays an important role in the response to the potential effects caused by chemical stress. A closer look at the multiplicity of chemicals and their degradation products suggests that their identification is crucial in assessing the overall impact of pollutants on river systems. It may be seen as a final implication of our findings that chemical and biological complexity has various temporal and spatial scales, which must be considered for the improvement of the diagnosis of the impact of chemical contamination in the aquatic environment and on its biological communities.
