Microplastics of surface waters of Colombian Caribbean

In some regions of the world, such as Colombian Caribbean microplastic pollution remains understudied. Therefore microplastics (MP) of surface waters of two sectors influenced by te Magdalena and Sinú rivers were sampled, quantified and characterized as well as the microbe assemblage associated with these particles. Water samples collected during the 2022 dry and rainy season were wet sieved through two mesh sizes (0.3 mm and 1.4 mm) and manually extract the plastic particles. The microplastics extracted were classified by size (0.3 mm to <1.4 mm and 1.4 mm to 5 mm), shape (fibers, films, fragments, foams). The identification and quantification of the particles were carried out using a stereoscope. Concentration of MP are reported in number of particles per volume unit of filtered water (MP/m3). Each individual piece was extracted with stainless steel fine-tip tweezers and then stored in 1.5 mL microcentrifuge tubes for the metagenomic and FTIR spectrometry analysis. To compare the microbial assemblage of the microplastics with indigenous marine microbes, 3 L of surface seawater samples were collected at each station and stored until further processing. Seawater and microplastic samples were kept refrigerated on ice until further processing. The seawater samples of each locality (9 L) were integrated and 825 mL of them were filtered through 0.22 μm polycarbonate filters (SUPOR) and frozen at – 80 ◦C until DNA extraction along with microplastic samples which was performed by "Centro Nacional de Secuenciación Genómica" in Colombia.