The plastic bottle and the ocean

De plastic fles en de oceaan

An albatross flies hundreds of kilometers over open sea, searching for food for its chick. It sees something colorful floating and picks it up. Back at the nest, it feeds it to its young. It is not a small fish, but a bottle cap.

A plastic bottle is empty in a few minutes. But if it ends up in the sea, it stays there for a very long time: first as a bottle, then as a cap and fragments, and eventually as microplastic. In this blog, you will read how many plastic bottles we buy worldwide, where they end up, what they do to marine animals, and how you can do your part.

One million bottles per minute

Worldwide, we buy almost one million plastic bottles per minute. That comes down to about 482 billion bottles per year, more than 50 percent more than in 2009 (Reuters analysis of Euromonitor data). And that is the most recent public figure: the actual number is probably higher now.

Most bottles are made of PET, a plastic that is easy to recycle. Yet very little of it is. Less than half of all purchased bottles are collected, and of what is collected, only 7 percent becomes a new bottle again (The Guardian, via Gulf News). The rest ends up in landfills, incinerators, or the environment.

You can see this reflected on the beach. At the worldwide International Coastal Cleanup of 2025, plastic bottles were the most frequently found waste item: volunteers picked up more than 1.3 million in a single day. Bottle caps came in third place, with almost 886,000 pieces (Ocean Conservancy).

Once in the sea, a bottle does not simply disappear. A frequently cited estimate is that it takes about 450 years for it to break down. In fact, no one knows exactly: plastic breaks down under the influence of the sun and waves into smaller and smaller pieces, but whether it ever completely disappears is uncertain (GRID-Arendal).

How a bottle becomes a danger

Ocean Conservancy counts plastic bottles and caps among the waste items that are deadliest to marine life (Ocean Conservancy). This is because a bottle causes damage in three forms at sea.

The cap. Caps are small, hard, and often brightly colored. They float and break down very slowly. Seabirds, fish, and marine mammals mistake them for food (The North Sea Foundation). A stomach full of caps feels full, but provides no nutrition: the animal slowly starves.

The bottle itself and the pieces. Under the influence of sunlight and waves, a bottle becomes brittle and breaks into sharp fragments. These can block the intestines or damage the intestinal wall. Plastic fragments are the most frequently found material in the stomachs of marine animals worldwide (University of Plymouth).

Microplastics. Eventually, the bottle breaks down into particles smaller than five millimeters. These are eaten by plankton, mussels, and small fish, the base of the marine food web. Plastic also attracts toxic substances from the water, which then end up in the bodies of animals.

Who are the victims?

By now, 914 marine species are known to have ingested plastic or become entangled in it. In 1997, there were only 267 (Wageningen Marine Research).

Seabirds. Albatrosses and storm petrels scoop food from the water surface, exactly where caps and bottle fragments float. They also feed it to their chicks. Researchers estimate that around 90 percent of all seabirds have ingested plastic at least once (TIME). The northern fulmar has also been used for years in the North Sea as an indicator of plastic in the sea.

Sea turtles. All seven species of sea turtles have been found with plastic in their stomachs or entangled in debris. An estimated more than half of all sea turtles worldwide have eaten plastic or other waste (University of Queensland).

Whales, dolphins, and seals. All whale species that have been studied were found to have come into contact with plastic. Of the 31 seal species, 22 were found with plastic (Hakai Magazine).

Fish. The biggest increase. The number of fish species with documented plastic ingestion rose from 166 to 430. Often, this involves microplastics, the final stage of a discarded bottle.

The bottle comes back to us

Microplastics move up the food chain: from plankton to small fish, to large fish, to our plates. But you do not need to eat fish to ingest plastic. It is also in the bottle itself.

Researchers from Columbia University and Rutgers University found an average of about 240,000 plastic particles per liter of bottled water in 2024. About 90 percent of these were nanoplastics, particles smaller than one thousandth of a millimeter (NPR, via GPB). That is ten to a hundred times more than previously assumed.

What this means for our health is still being investigated, and the bottled water industry points out that there is no scientific consensus. But it does make one thing clear: the plastic bottle is not just a problem for turtles and albatrosses.

How to do away with the plastic bottle

The good news: the disposable bottle is one of the easiest pieces of plastic to cut back on. A few habits make a difference.

  • Bring a reusable bottle with you. One good bottle replaces hundreds of disposable bottles per year. Choose one you really like taking with you, so it does not sit in the cupboard.
  • Drink tap water. Dutch tap water is of high quality and costs a fraction of bottled water. If you want to improve the taste, use a filter.
  • Refill on the go. More and more stations, gyms, and restaurants have water refill points or fill your bottle for free.
  • Return deposit bottles. In the Netherlands, small and large plastic bottles have a deposit. Returning them means the bottle is recycled instead of thrown away.
  • Throw a bottle you do buy in the right bin. Litter in the city often ends up in the sea via rivers and canals.
  • Help clean up. Participate in a beach or river cleanup and see for yourself how many bottles and caps are lying around.

Finally

You use a plastic bottle for a few minutes. In the sea, it lingers for centuries, as a bottle, as a cap, and as microplastic in the stomachs of birds, turtles, and fish. That is a bad trade.

Start today with one thing: take your own bottle with you and fill it with tap water. A small effort for you. For an albatross, it might be the difference between a small fish and a bottle cap.

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