Microplastics in surface waters surrounding a touristic beach at the Gulf of California, Mexico

Plastic waste, fragmented into microplastics (MPs), is an undeniable threat to marine ecosystems. This study analyzed the abundance of MPs in surface seawater samples collected in four locations surrounding a tourism destination in the Gulf of California before and after spring vacation. The mean concentration of MPs increased significantly between the two periods (up to a 2.02-fold increase), and the average number of natural/artificial microfibers was significantly more abundant after the vacation period (up to a 3.4-fold change). The most common colors of microfibers were black and blue, with red microfibers being the least abundant. Furthermore, in this study, the total abundance of microfibers slightly outnumbered microplastic particles (50.8 and 49.2%, respectively), with natural/artificial microfibers being more abundant than synthetic sources. Fluorescent microplastic particles (FMPs) were found in all seawater samples collected at different sites in both periods. Interestingly, the concentration of FMPs in some sampling sites increased after the intense incursion of tourists for the spring vacation. The low abundance of white microfibers before spring vacation could be due to the preference of some marine animal species to consume transparent or white MPs. This study highlights the importance of addressing the issue of microplastics on tourist beaches.