Plastic Gyres: Ocean Surface Coverage Explored

Plastic gyres are a major contributor to the global issue of marine plastic pollution. While the exact area of ocean surface covered by plastic gyres is difficult to determine, it is estimated that there are currently more than 170 trillion plastic particles, weighing 2 million tonnes, afloat in the world's oceans. With 1.15 to 2.41 million metric tonnes of plastic entering the ocean each year, the concentration of microplastics in these gyres will only continue to increase.

The Ocean Cleanup project

It is estimated that only three to five percent of all plastic trash floats on the ocean's surface. The rest is suspended just below the surface or sinks to the ocean floor. This is why satellites and airplanes are unable to detect the ocean gyres, let alone determine their true size.

While The Ocean Cleanup project is making strides in addressing the issue of plastic pollution in the ocean, it is important to note that the most advocated solution to decreasing the number of plastics in the ocean is to stop using and producing plastics in the first place.

The Coriolis effect

The Ekman spiral is a distinctive pattern of water flow within the gyre. While surface currents experience the greatest deflection due to the Coriolis effect, the deflection gradually diminishes with depth. This results in a spiral structure where the water flows in a circular motion, gradually descending towards the centre of the gyre.

While the Coriolis effect is a natural phenomenon, its interaction with human-made plastic pollution has significant implications for the marine environment. The complex water movements driven by the Coriolis effect can hinder the detection and cleanup of plastic waste, making it challenging to address the issue of plastic pollution in ocean gyres.

The Great Pacific Garbage Patch

In 2014, it was estimated that there were 5.25 trillion plastic particles, weighing 269,000 metric tons, on the ocean's surface. An updated estimate in 2023 revealed that there are now more than 170 trillion plastic particles, weighing 2 million tonnes, afloat in the world's oceans.

The Ocean Cleanup is a project that aims to clean up the larger parts of floating plastic debris in the Great Pacific Garbage Patch. However, the most advocated solution to decreasing the number of plastics in the ocean is to stop using and producing plastics altogether.

The concentration of microplastics

The majority of plastic debris in the ocean does not float on the surface. In fact, only three to five percent of all plastic trash is estimated to be visible on the surface. The rest is either suspended just below the surface or sinks to the ocean floor. This makes it challenging to detect and clean up the plastic pollution.

The plastic debris that does reach the surface is often transported by converging currents, eventually accumulating in patches known as "plastic soups". These patches can be resilient and persist at the sea surface as they are carried over long distances. Once they enter a gyre, they are unlikely to leave until they degrade into smaller microplastics under the effects of sun, waves, and marine life.

As more plastics are discarded into the environment, the concentration of microplastics in these patches will continue to increase. This is a pressing issue as microplastics can have detrimental effects on marine life and ecosystems. The most advocated solution to decreasing plastic pollution in the ocean is to stop using and producing single-use plastics.

The challenge of eliminating plastic from gyres

Gyres are often referred to as "plastic islands" or "plastic soups" in the media. However, the reality is that only three to five per cent of plastic trash floats on the surface. The rest is suspended just below the surface or sinks to the ocean floor. This is why satellites and aeroplanes cannot detect ocean gyres or determine their true size.

The middle of the gyres are thousands of miles away from the mainland, making them difficult to access. Most of the debris in the gyres is not large, easy-to-clean pieces of plastic. Instead, there are millions of tiny microplastic particles that are too small to be caught in nets.

An innovative project called The Ocean Cleanup is trying to clean up the larger parts of the floating plastic debris. However, the most advocated solution to decreasing the number of plastics in the ocean is to stop using and producing plastics in the first place.

The Ocean Cleanup has collected plastic debris from the Great Pacific Garbage Patch (GPGP), where 1.15 to 2.41 million metric tonnes of plastic are entering the ocean each year. Once plastics enter the gyre, they are unlikely to leave the area until they degrade into smaller microplastics under the effects of the sun, waves and marine life. As more plastics are discarded into the environment, microplastic concentration in the GPGP will only continue to increase.

Frequently asked questions