Little is known about the vertical distribution of microplastics (MPs) in deep stratified lakes. This study investigates the MPs in the large and deep Lake Trichonis during the thermal stratification period, using two nets of different porosity (50 μm and 200 μm) in three depth strata. Fibers dominated over fragments with an average abundance of 10.63 ± 1.00 items m−3 and 3.10 ± 0.52 items m−3 respectively in the samples of the 50 μm net in the entire water column, while the respective values for the 200 μm net were 1.4 and 7.4 times greater. Fibers had the highest abundance within the thermocline, and most of them were blue with a length 1–2 mm. There were only abundance differences between the two nets and no qualitative disparities concerning color, size, shape and polymer types. There was a strong positive correlation between the abundance of fibers and the adults of the dominant copepod Eudiaptomus drieschi, which also accumulated within the thermocline. Considering that the adults of E. drieschi are among the preferred prey of Atherina boyeri, the most important commercial fish, certain issues arise concerning possible fiber bioaccumulation on the food web. The study highlights the importance of investigating MPs in connection with biotic elements.
Kehayias et al. (Sun,) studied this question.