01

What is a microplastic?

A microplastic is any piece of plastic smaller than 5 mm, about the size of a grain of rice or smaller. Some are made that small on purpose, like the microbeads that used to be in face scrubs. Most are pieces broken off bigger things: bottles, bags, rope, fishing gear, and the clothes we wear.

Every confirmed piece I caught came from bigger plastic breaking down, except one: a single manufactured bead in sample 28.

Each step is 10 times closer. My filter holes were half a millimetre wide.

02

One bottle cap

"When a single bottle cap breaks down at sea, it can turn into hundreds of thousands of tiny pieces of microplastic."

On the left is one plastic bottle cap. On the right is the same kind of cap, broken down into tiny pieces. Out in the ocean, sun, waves and salt do that work over time, and every one of those pieces is small enough for a krill or a fish to swallow.

That's why stopping plastic before it reaches the ocean matters so much: once it's in pieces, there's no getting it back.

03

Why it matters

Once plastic breaks into tiny pieces it is almost impossible to clean up. Clear, blue and black fragments look a lot like the tiny animals that krill, fish and seabirds eat, so they get swallowed, and they move up the food chain from there.

Antarctic krill and penguins have already been found with the same kinds of plastic I collected. And the Southern Ocean isn't just a remote corner: it drives ocean currents and helps regulate the climate for the whole planet.

If plastic is here, thousands of kilometres from any city, it's everywhere.

04

How I collected them, solo

A pump in the hull of Climate Action Now drew in seawater from about 30 cm below the surface. It passed through a coarse grid, then a stainless-steel filter with holes half a millimetre wide.

Each filter ran for 22 hours, about 1,400 L of seawater (that's over 50 tinny fuel tanks) across at least 200 km of ocean. Then I stopped the pump, swapped the filter, sealed the used one in a labelled foil bag and logged the GPS position. I did that every single day, through blizzards, gales and knockdowns, alongside a second, finer filter that ran for 2 hours a day.

One sample, one day: the pump runs 22 hours, then the filter is swapped.

05

Keeping the results honest

The boat is full of plastic too: ropes, sails, clothes. So every time I changed a filter, a clean "blank" filter sat open next to the sampler to catch anything floating around in the cabin air. Any particle that matched the boat or the lab was thrown out of the results.

At the end of the voyage, all the sealed filters were packed in a case and sent to AIMS in Townsville, where the real detective work began.