This story is part of a series on ocean plastics .

Imagine an area 34 times the size of Manhattan. Now imagine it covered ankle-deep in plastic waste piles of soda bottles and plastic bags, takeout containers by the mile, drinking straws as far as the eye can see.

Thats a total of about 19 billion pounds of garbage. And according to one of the best estimates available, thats how much plastic waste ends up in our oceans every year.

Were being overwhelmed by our waste, said Jenna Jambeck, an environmental engineer who led the 2015 study that determined this staggering number. According to Jambecks research, this figure is on track to double by 2025 unless something is done, swiftly and at a global scale, to stem the tide of garbage.

Plastic a versatile, durable and inexpensive material has in many ways been a boon to humanity, used in everything from medical equipment to parts of airplanes. But some of the very traits that have made plastics so popular (theyre cheap, and therefore easy to throw away) have also made them a growing problem in our landfills and oceans. Today, plastics are the No. 1 type of trash found in the sea. Ocean Conservancy, a nonprofit that organizes an annual coastal cleanup event in more than 150 countries worldwide, said plastic debris makes up around 85 percent of all the trash collected from beaches, waterways and oceans and thats just the stuff we can see.

There are also untold numbers of extremely small plastic fragments in marine waters. Plastics are non-biodegradable and merely break down into smaller and smaller pieces with exposure to sunlight. These fragments, known as microplastics, are less than 5 millimeters long, or about the size of a sesame seed. Some are microbeads , tiny pieces of plastic that are added as exfoliants to health and beauty products, while others come from larger plastic pieces that have degraded over time.

Recent studies have found that microplastics can also get washed out of synthetic clothing, like those made of polyester or acrylic. A 2016 paper concluded that a single cycle of a washing machine could release more than 700,000 microplastic fibers into the environment.

The United Nations Environment Programme says there could be as many as 51 trillion microplastic particles in our seas. Many of them have accumulated in five enormous swirling ocean convergences known as gyres. Marcus Eriksen, a co-founder of the 5 Gyres Institute , an organization dedicated to reducing plastic pollution, describes marine microplastics as a plastic smog throughout the worlds oceans.