Plastic pollution Flashcards
Turbulent transport
advection and diffusion: Movement with the currents in rivers and oceans
Settling
The sinking of particles, removal from the water column to the sediment
Resuspension
Movement of particles from the sediment into the water column
Aggregation
The collection of suspended particles into bigger clusters or aggregates
Biofouling
The accumulation of bacteria, algae, and other organisms on a surface
Burial
The movement of particles to deeper layers of sediment
Fragmentation
The breaking up of particles into smaller pieces
Polypropylene (PP)
Most common plastic. Application: Food packaging and wrapping
Low-density plyethylene (LDPE)
application: reusable bags, trays, containers, food packaging film, agricultural film
High-density polyethylene (HDPE)
application: toys, shampoo bottles, pipes, houseware
Polyvinylchloride (PVC)
application: Window frames, pipes, inflatable pools, garden hoses
Polyurethane (PUR)
application: building insulation, matrasses, insolation foam for fridges
Polyethylene terephthalate (PET)
application: bottles
(Expended) Polystyrene ((E)ps)
application: food packaging, building insolation, electronic equipment
Primary microplastics
Micrometre-sized particles deliberately manufactured for specific applications or products. E.g. those used in personal care products.
Secondary microplastics
particles formed from the fragmentation and breakdown of larger plastic debris.
Chemical uptake pathways for aquatic organisms
- Ingestion of both plastic
and chemicals - Dermal uptake of chemicals
- Chemical leaches out of plastic
- Plastic reabsorbs chemicals
- Excretion of plastic and chemicals
turnover time of the ocean
about 37000 years
residence time of water in the atmosphere
about 10 days
Ekman transport
The flow direction of the water is not the same as that of the wind. Instead, the water movement rotates away from the wind direction, and this rotation increases with depth. Ekmar transport creates regions of convergence and divergence.
Subtropical gyres
Basin-scale current systems defined by wind stress and coastal boundaries. These fyres rotate clockwise in the northern hemisphere and anticlockwise in the southern hemisphere.
Thermohaline circulation
deep-ocean currents are driven by differences in the water’s density, which is controlled by temperature (thermo) and salinity (haline)
buoyant plastic
floating plastic
Why do buoyant plastics tend to accumulate in the subropical convergence zones?
In the convergence zones, the surface water is pumped down, a phenomenon known as Ekman downwelling, to depths of several hundred meters. However, the downward velocity of the water is much smaller than the upward (or rising) velocity of buoyant plastics, so the plastics stay behind and thus accumulate.
