Scientists have created a shocking animation showing how tiny bits of plastic are moving around Earth’s oceans.
The researchers used NASA satellite data to track the movement of microplastics – tiny plastic fragments less than five millimeters long in diameter.
Plastic that falls into our rivers or is engulfed by tides at beaches gets transported by currents before ending up in the open ocean.
These plastics are broken down by waves and sunlight into small microplastics, which can be mistaken for food by marine life with fatal consequences.
Plastic that falls into our rivers or is engulfed by tides at beaches gets transported by currents before ending up in the open ocean (stock image)
Eventually plastic becomes trapped in the centres of ocean basins or subtropical ‘gyres’ – large systems of rotating currents in each of the five major oceans.
Unfortunately, the world’s five subtropical gyres can go on to host ‘garbage patches’, comprised of plastic waste, fishing gear and other debris.
WHAT ARE GARBAGE PATCHES?
Garbage patches are regions with high concentrations of marine debris, according to the NOAA.
They form from rotating ocean currents called gyres, and are not actually ‘islands of trash,’ as commonly believed.
These patches are mostly composed of microplastics, most of which are the remnants of larger pieces of plastic garbage that have been broken up by the sun, salt, wind, and waves.
The Great Pacific Garbage Patch, between California and Hawaii, is the most well-known because a lot of ship traffic passes through it.
About 8 million tons of plastic flow from rivers and beaches into the ocean every year, according to NASA.
The animation was created by scientists at the University of Michigan and detailed in a new paper published on IEEE Xplore.
‘Ocean microplastic concentrations are known to vary significantly by location, with especially high levels in the North Atlantic and North Pacific gyres,’ they say.
‘A new method is presented for detecting and imaging the global distribution of ocean microplastics from space.’
The animation shows the location and concentration of floating plastics between April 2017 to September 2018.
It shows some seasonal variations in microplastic concentrations – in the Great Pacific Garbage Patch, for example, microplastic concentrations appear greater in the summer and lower in winter.
This is likely due to more ‘vertical mixing’ of the ocean when the temperatures are cooler.
Vertical mixing is the upward and downward movement of air or water that occurs as a result of temperature differences between layers of the fluid.
The animation and images on this page show the location and concentration of floating plastics between April 2017 to September 2018. Data were collected between approximately 38 degrees north and 38 degrees south latitude, the observation range for the CYGNSS mission
Scientists typically estimate the amount plastic in marine garbage patches by dragging nets behind boats.
However, this sampling method is ‘geographically sparse’, according to NASA’s Earth Observatory, and does not give a sense of how much plastic concentrations change over time.
So the University of Michigan researchers developed a new method to map the concentration of ocean microplastics around the world.
They used data from eight microsatellites that are part of the Cyclone Global Navigation Satellite System (CYGNSS) mission.
The $157 million CYGNSS project, launched in 2016, is primarily meant to improve hurricane forecasting.
Radio signals from GPS satellites reflect off the ocean surface, and CYGNSS satellites detect those reflections.
Scientists can then analyse the signals to measure the roughness of the ocean surface.
These measurements already provide scientists with a means to derive ocean wind speeds, useful for studying phenomena like hurricanes, but the signals also reveal the presence of plastic.
When there is plastic or other debris near the ocean surface, waves are dampened and the sea surface is less rough than it would be otherwise.
‘In cleaner waters, there’s a high degree of agreement between ocean roughness and wind speed,’ said Chris Ruf, principal investigator of the CYGNSS mission and one of the two authors of the paper.
‘But as you head into the Great Pacific Garbage Patch, you see a bigger discrepancy between wind speed measurements and the roughness of the surface.’
The new method will provide better monitoring of ocean microplastics and ‘support future model development and validation’, according to the team.
An analysis earlier this year by researchers at Kyushu University found there are 24.4 trillion pieces of microplastics in the ocean and counting.
WHAT ARE MICROPLASTICS AND HOW DO THEY GET INTO OUR WATERWAYS?
Microplastics are plastic particles measuring less than five millimetres (0.2 inches).
They have hit the headlines over recent years, as improper disposal has resulted in tonnes of waste making its way into the ocean.
Each year, tonnes of plastic waste fails to get recycled and dealt with correctly, which can mean they end up in marine ecosystems.
Although it’s unclear exactly how they end up in the water, microplastics may enter through simple everyday wear and tear of clothing and carpets.
Tumble dryers may also be a source, particularly if they have a vent to the open air.
Plastics don’t break down for thousands of years and it is estimated that there are already millions of items of plastic waste in the oceans. This number is expected to rise.
Studies have also revealed 700,000 plastic fibres could be released into the atmosphere with every washing machine cycle.
Current water systems are unable to effectively filter out all microplastic contamination, due to the varying size of particles.
The amount of plastic rubbish in the world’s oceans will outweigh fish by 2050 unless the world takes drastic action to further recycle, a report released in 2016 revealed.
More than 80 per cent of the world’s tap water is contaminated with plastic, research published in September 2017 revealed.
The US has the highest contamination rate at 93 per cent, followed by Lebanon and India, experts from the University of Minnesota found.
France, Germany and the UK have the lowest levels, however, they still come in at 72 per cent.
Overall, 83 per cent of water samples from dozens of nations around the world contain microplastics.
Scientists warn microplastics are so small they could penetrate organs.
Bottled water may not be a safer alternative, as scientists have found contaminated samples.
Creatures of all shapes and sizes have been found to have consumed the plastics, whether directly or indirectly.
Previous research has also revealed microplastics absorb toxic chemicals, which are then released in the gut of animals.