What are microplastics, and why do they matter?

Microplastics are plastic fragments smaller than 5mm. They come from two main sources: primary microplastics, manufactured at that size (like microbeads in cosmetics), and secondary microplastics, created when larger plastic items break down in the environment.

Microplastics enter the ocean in two main ways: they wash in directly from coastlines, rivers and storm drains, or they're carried out by larger ocean currents after breaking down from bigger plastic debris — fishing gear, packaging, textiles, paint and more. Once in the water, currents like the North Pacific Current — the one my own voyage will sample — act as conveyor belts, sweeping plastic from coastal cities, fishing fleets and container ships across huge distances before it settles, or breaks down further, somewhere else entirely.

eXXpedition's research measures more than just how much plastic is there. Crew members use a portable FT-IR spectrometer to identify the exact polymer type of each fragment sampled — because every polymer has a unique chemical fingerprint, scientists can match fragments back to likely source materials. Combined with land-based investigations into litter, consumer goods and local waste infrastructure, this builds a picture not just of how much plastic is in the ocean, but where it came from — which is what actually makes prevention and policy possible.

This matters because microplastics don't stay contained. They're ingested by marine life at every level of the food chain, and increasingly, they're turning up in human blood, lungs and placentas. The scale is enormous: an estimated 171 trillion plastic particles are now floating in the world's ocean, up from around 5 trillion in 2014. Understanding where that plastic originates is the first step to actually stopping it.

More posts like this will go up as the voyage gets closer.