Adaptación de microalgas a contaminantes antropogénicos emergentesaplicaciones

Résumé

Anthropogenic global change with its impact on global warming and pollution is causing an extraordinary loss of biodiversity (called The Sixth Great Extinction). Very little is known about the effects of global change on important organisms such as phytoplankton, although they are responsible for half of the primary production of the Earth, controlling the biogeochemical cycles of C, P and N. Among the biggest anthropogenic polluters are the crude oil and its derivatives, which have a great effect on phytoplankton organisms. This paper studies the adaptation of phytoplankton species to crude oil and diesel. Due to the diversity of phytoplanktonic species we work with diverse species representing different functional - taxonomic groups. The first part of our work demonstrates (through fluctuation analysis) that phytoplankton can adapt to low doses of oil or diesel only by mean of physiological acclimation mechanisms. However as contaminant doses are increased, only the appearance of new mutants conferring resistance ensures adaptation. These mutants appear randomly before the exposure to hydrocarbons. In any case, neither oil nor oil favor the emergence of resistant . We also perform a study to determine the maximun capability of these organisms to adapt to crude oil and diesel (by a process of Ratchet). There are huge differences in the adaptability of different species, but some of them were able to adapt and growth under large doses of pollutants. In this section we make a conceptual contribution by determining the response to selection and the heritability (defined as the ability to respond to selection). Finally we study the possibility of using this adaptability in the practice. Analytical results demonstrates that the selected organisms with high oil resistance are able to effectively degrade these hydrocarbons in a quick time. This fact opens interesting possibilities for practical applications.