Interference of glitter with the photosynthetic rates of a submerged macrophyte, Egeria densa

Abstract

ABSTRACT Thousands of glitter particles are potentially daily released into aquatic ecosystems, but their effects on the ecological processes of aquatic species remain unknown. The metallic coating of glitter could potentially reflect light and interfere with photosynthesis, so this study analysed the photosynthetic rates of the macrophyte Egeria densa in the presence and absence of 0.04 g/L glitter using the light and dark bottle method. We collected 400 individuals of E. densa and separated them into four equal-sized treatment groups (with and without glitter under iluminated and dark conditions). We found that the presence of glitter reduced the rates of net photosynthesis (P N) and gross photosynthesis (P G) of E. densa by 34.61%, and 29.65%, respectively, compared with the control treatment without glitter, and also decreased the light intensity inside the bottles. These results suggest that the metal coating of glitter particles attenuates light penetration and increases water reflectance, wich interferes with underwater radiation and light absorption for photosynthetic processes.