Marine microplastics on the rise in the Eastern Tropical Pacific: Abundance doubles in 11 years and a ten-fold increase is projected by 2100.

Plastic abundance in the ocean has increased systematically since the mid-20th century. Here we present a time-series dataset of microplastic abundance collected at several stations located in the Eastern Tropical Pacific Ocean off Ecuador from 2008 to 2018. The data reveals a significant and sustained increase in the abundance of microplastics over time across all sampling sites; this implies a homogeneous and sustained input, which likely also occurs at other coastal and marine ecosystems. Fiber strands were the most common microplastic observed, while polyethylene and polypropylene were the principal polymers identified by μFTIR analysis. A forecast model of the time-series data predicted that microplastics will be 3.2, 5.1 and 9.7 times more abundant in 2030, 2050 and 2100, respectively, relative to 2008 observations. These results provide insights into the decade-plus trend in microplastic abundance observed in coastal waters, which have important implications for future marine plastic pollution projections and associated ecosystem impacts.