Distribución y abundancia de microplástico en fondos marinos arenosos de tres islas pobladas de Galápagos

Abstract

The presence of microplastics in marine environments has become an important environmental concern. The Galapagos Islands waters, recognized for their high endemism and diversity of marine species, are exposed to these contaminants produced by local human population or transported by marine currents. Some of these particles sink to the sea bottom and mix with the sediment. Consequently, it is important to analyze the presence, distribution and morphological composition of microplastic particles in marine bottoms of the Galapagos. In the present study, sediment samples from coastal subtidal soft bottoms were collected using a Van Veen dredge to assess the existence of microplastics particles around three populated islands of the archipelago (Santa Cruz, San Cristobal and Isabela). Sampling was conducted at 27 stations, and microplastic particles were counted and classified according to size and shape. Total abundance and volume were estimated and compared using non-parametric statistical analysis among islands. A total of 669 microplastic particles were counted and analyzed estimating volume and abundance. Santa Cruz showed the higher volume of microplastic in comparison with other islands (308706 mm3/L), while San Cristobal showed the higher abundance of microplastic (34275 particles/L). PCA indicated that ‘fragment’ type microplastic was more common in places near docks, and ‘row’ type microplastic is characteristic of places with little influence of currents (i.e. enclosed bays). This is the first study that contributes to the understanding of microplastic presence and abundance in subtidal soft bottoms in the Galapagos Marine Reserve. It is intended to provide valuable information as a baseline for further studies, which assess the effects of microplastic pollution on marine benthic communities and their habitat.