Modeling submerged biofouled microplastics and their vertical trajectories ...

• Main Authors: Fischer, Reint, Lobelle, Delphine, Kooi, Merel, Koelmans, Albert, Onink, Victor, Laufkötter, Charlotte, Amaral-Zettler, Linda, Yool, Andrew, van Sebille, Erik
• Format: Text
• Language: unknown
• Published: Copernicus 2022
• Subjects: 530 Physics; Pacific; Southern Ocean
• Online Access: https://dx.doi.org/10.48350/168209; https://boris.unibe.ch/168209/

The fate of (micro)plastic particles in the open ocean is controlled by physical and biological processes. Here, we model the effects of biofouling on the subsurface vertical distribution of spherical, virtual plastic particles with radii of 0.01–1 mm. For the physics, four vertical velocity terms are included: advection, wind-driven mixing, tidally induced mixing, and the sinking velocity of the biofouled particle. For the biology, we simulate the attachment, growth and loss of algae on particles. We track 10,000 particles for one year in three different regions with distinct biological and physical properties: the low productivity region of the North Pacific Subtropical Gyre, the high productivity region of the Equatorial Pacific and the high mixing region of the Southern Ocean. The growth of biofilm mass in the euphotic zone and loss of mass below the euphotic zone result in the oscillatory behaviour of particles, where the larger (0.1–1.0 mm) particles have much shorter average oscillation lengths (< ...