Researchers from the University of Western Australia (UWA) have tracked ocean plastic waste in the Indian Ocean. The Indian Ocean is the world’s biggest dumping ground for plastic waste. However, where the plastic waste ends up has been a mystery.
Researchers have found that the floating plastic wastes are pushed from the southern Indian Ocean towards the western side of the ocean. From there it leaks past South Africa into the South Atlantic Ocean.
This is because of the Asian Monsoon system. The southeast trade winds in the southern Indian Ocean are stronger than the trade winds in the Pacific and Atlantic Oceans. These strong winds push floating plastic material further to the west in the southern Indian Ocean than they do in the other oceans.
Researchers have further said that there may be an accumulation of plastic waste in the Bay of Bengal. These plastic waste are most likely to end up on beaches, transported by the reversing monsoon winds and currents.
The researchers have highlighted that annually up to 15 million tonnes of plastic waste make its way into the ocean through coastlines and rivers. Some of these wastes sink into the oceans, some are washed on beaches and other remains floating.
Some floating plastics accumulate in the centre of subtropical gyres (large systems of circulating ocean currents) in ‘garbage patches’. Example: Great Pacific Garbage Patch– the largest accumulation of ocean plastic in the world which is located between Hawaii and California.
However, the atmospheric and oceanic attributes of the Indian Ocean which are different to other ocean basins may have not led to formation of concentrated garbage patches.