Earth & climate
Ocean plastic
From bag to micro particle: how plastic reaches the sea and why it stays there so long.
A plastic bag lying on the beach looks like a small problem. But every year millions of tonnes of plastic end up in the sea. Unlike an apple core, plastic does not rot away in a few weeks. It stays for decades or even centuries. In that time it travels halfway around the world with the currents and harms animals and people. Time to take a closer look.
How the plastic gets into the sea
Most plastic in the sea does not come from ships but from the land. Litter that is carelessly thrown away blows away in the wind, ends up in a drain and finally in streams and rivers. The rivers carry it to the sea, just as they carry the water there. A single large river can deliver thousands of tonnes of plastic to the sea year after year. Where waste is not collected well, the problem is greatest.
The sun warms the sea, water turns into invisible vapor.
Microplastics
In the sea plastic does not simply disappear, it breaks into ever smaller pieces. Sun and waves grind a bottle into countless tiny crumbs. Every plastic particle smaller than 5 millimetres is called microplastic, and the smallest of them are finer than a grain of sand. Once they are in the water these particles can hardly be collected again. Some microplastic is also created directly, for example as wear from car tyres or as tiny fibres that come loose from synthetic clothing during washing.
Harm to the animals
Sea creatures easily mistake plastic for food. A turtle takes a drifting bag for a jellyfish, a bird feeds its chicks colourful plastic crumbs. The stomach fills up, but there is no nourishment in it, and the animals starve despite a full belly. Tiny microplastic in turn is eaten by small sea creatures and so moves step by step up the , right onto our plate.
What helps
The best plastic is the one that is never made in the first place. A refillable drinking bottle, a cloth bag instead of the plastic one, less unnecessary packaging: that saves waste from the start. Whatever does arise belongs sorted and recycled properly, not in nature. And along coasts and rivers many people team up to collect litter before it reaches the open sea.
Exercises
0 of 6 solvedTime to try it yourself. You can't break anything, every attempt counts.
Where does most plastic in the sea come from?
What is microplastic?
At a litter collection, volunteers fill 7 bags, each weighing 4 kg. How many kilograms is that in total?
Put the path of plastic from the land to microplastic into the correct order.
- 1Microplastic forms that can hardly be collected again
- 2The rivers carry the litter all the way to the sea
- 3Sun and waves grind the plastic into tiny pieces
- 4Wind and drain carry it into streams and rivers
- 5Litter is carelessly thrown away on land
A reusable bottle replaces 3 single use bottles on a school day. How many single use bottles does it save in 5 school days?
Unlike an apple core, plastic does not … in a few weeks, it stays for decades or centuries.