The role of microbial mats in the bioremediation of coastal areas subject to contamination by oil spills

Nowadays, accidental oil spills constitute one of most worrying environmental problems. More than two decades ago, first in situ actions on the places affected by this type of catastrophes were started to be taken. Among the treatments that can be applied for the decontamination of polluted areas, biological degradation processes, based on the action of the microorganisms on polluting petroleum hydrocarbon components, deserve a special attention. Microbial mats are ecosystems, widely distributed along the shorelines, which have been considered as promising agents for bioremediation, because they group in a space of few millimetres complex populations of aerobic and anaerobic microorganisms able to colonize zones highly contaminated. A very useful approach for evaluating the impact of such a contamination event on the microbial diversity, and the biodegradation processes that take place in this type of communities, is to reproduce them in a laboratory scale. The true value of these model systems, called microcosm, is that they provide an instrument for understanding the function of the ecosystem and the factors that control the flow of energy and matter, allowing, therefore, the development of a predictive capacity, essential for developing useful strategies of bioremediation.