Mikroplastikoen inpaktua, hedapena eta mikroorganismoen bidezko biodegradazioa ozeanoetan

Abstract

Synthetic microplastics (≤ 5 mm) are environmental pollutants found in ever-increasing quantities, accumulating in estuaries and marine systems worldwide, because they cannot be easily degraded. Their abundance, small size, and low density help in their dispersal and transport by ocean currents. These contaminants can reach aquatic systems by pouring widely used products or can be produced from larger plastic debris that is decomposed due to exposure to environmental conditions (freeze thaw, ultraviolet radiation, water currents, etc.). Worldwide annual manufacturing of these plastics has increased greatly over the past decade, and if a solution is not offered soon, the accumulation and expansion of marine microplastics will continue to increase, with the ecological and toxicological effects that it entails. On the one hand, microplastic surface is suitable for colonization of microorganisms that provoke changes in the activity and composition of natural communities, causing changes in biogeochemical cycles. On the other hand, marine animals have a high potential for ingestion of microplastics and chemical contaminants or heavy metals that are adsorbed, which accumulate in their tissues and organs, and that are captured, transferred and bioincremented through trophic networks. In addition, microplastics participate in the dispersion of pathogens, biotoxins and antibiotic resistant genes, and can have a direct effect on public health. In nature, there are microorganisms capable of degrading all or part of the microplastics by enzymes and using them as an energy source. Therefore, identifying microorganisms that can degrade microplastics is a promising strategy to facilitate natural biodegradation and assist in the cleaning of natural ecosystems without causing adverse environmental impacts.