Here is a pataphysical approach to the Great Pacific Garbage Patch.
SROPSU is a self replicating sea borne plastic dissembly/replication unit. The abundant scrap plastic floating in the world’s oceans is taken into its maw with a conveyor belt. The plastic is molecularly recombined to self replicate RepRap in the fabricator end of the unit. When there are enough RepRaps to tackle the patch, they switch production modes and start creating useful things like furniture, housewares and footwear that wash ashore in tidy bundles to be collected by school children.