Forty years ago, people didn’t think about plastic pollution in the ocean. Fast forward to today, and it’s everywhere – in the bodies of dead whales and seabirds who wash up on the beach, and even in the deepest parts of the ocean – near the Mariana Trench at 36,000 feet below sea level.
A large concentration of ocean trash is caught in gyres (also referred to as vortices, or whirlpools), which are produced from ocean currents. There’s chemical sludge and other manmade debris in these gyres, and a very large proportion of the pollution is plastic.
One such gyre is in the Pacific Ocean between Hawaii and California. It’s known as the Pacific Gyre or the Great Pacific Garbage Patch, and it’s larger than the state of Texas.
This video from the National Oceanic and Atmospheric Administration (NOAA) explains what the Great Pacific Garbage Patch is:
According to National Geographic and a study published in Nature, in 2018, there were about 79,000 metric tons of plastic in the Pacific Garbage Patch. This was 4-16 times larger than what was previously estimated, and the Patch was continuing to expand.
Much of the plastic pollution in the Pacific Gyre is microplastics – pieces of plastic that are less than five millimeters in length. There are roughly 1.8 trillion pieces of microplastic in the Pacific Gyre.
Discarded fishing nets and gear comprise 46% of the 79,000 metric tons of plastic pollution in the Pacific Garbage Patch.
It’s estimated that the plastic pollution in the Pacific Gyre weighs about 79,000 metric tons (or 79,000,000 kgs) and microplastics make up about 8 percent of that weight. Scientists estimate that 20 percent of the debris is from the 2011 Japanese tsunami. And 46 percent is from commercial fishing nets and fishing industry gear, including ropes, oyster spacers, eel traps, crates, and baskets.
Laurent Lebreton, an oceanographer with The Ocean Cleanup, a nonprofit that’s developing advanced technologies to reduce ocean plastic, and the lead author of the study in Nature, said “I knew there would be a lot of fishing gear, but 46 percent was unexpectedly high. Initially, we thought fishing gear would be more in the 20 percent range. That is the accepted number [for marine debris] globally – 20 percent from fishing sources and 80 percent from land.”
Scientist Use Drones and GPS Trackers to Find the Ghost Nets
But thanks to scientists and activists from another nonprofit – Ocean Voyages Institute – as of June 18, 2019, about 40 fewer tons of fishing nets and other plastic pollution are in the Pacific Gyre.
During a 25-day ocean cleanup mission on the sailing cargo ship S/V KWAI, the Ocean Voyages (OV) team removed a whopping 40 tons of plastic pollution from the Pacific Gyre.
Here’s a video from GC Hustle Hawaii with some of the crew of the S/V KWAI before they set sail on the cleanup mission:
One of the team’s prime targets in the cleanup was discarded fishing nets, or ghost nets, which are made with nylon or polypropylene and can weigh in the tens of thousands of pounds. According to the United Nations, about 380,000 marine mammals are killed every year by either ingesting plastic pollution or by getting caught in these nets.
How did the OV team and KWAI crew successfully remove that much debris from the ocean? GPS tracking was a big part of the effort. During the year prior to the cleanup mission, OV recruited yachts and ships to attach GPS satellite trackers to any ghost nets they encountered in the ocean.
The size of bowling balls, the GPS trackers would signal the location of the drifting ghost nets in real-time. The OV team also enlisted the help of expert drone operators to conduct flying survey patterns off of both the KWAI and the OV Institute’s plastic survey vessel, AVEIA, to find more debris. Often, the areas where the team found the nets were concentrated with other heavy debris, so they were able to retrieve additional nets and even more trash.
“Satellite technology played a key role in our recovery effort, offering an innovative solution to finding areas of dense plastic pollution,” said Mary Crowley, the founder and executive director of the OV Institute. “The nets and other debris are signs of the proliferating plastic pollution that poses threats to marine life, coastal environments, shipping, fisheries, wildlife, and our health.”
Crowley is a lifelong sailor. In 2009, she launched her first 30-day research expedition and other cleanup missions occurred after that, each one increasing in scale.
“It is very disturbing to be sailing through what was only decades ago a pristine ocean wilderness and find it filled with our all-too-familiar garbage,” says Crowley. “Urgent action is needed at all levels: curtailing the manufacture of throwaway plastics, preventing plastic trash from entering the oceans, and enlisting the public, corporations, and the maritime industry in education, prevention, innovation, and massive cleanup efforts. The question is, are we ready to make it a priority to protect 72 percent of the planet?”
Crowley and the OV team are now planning an even larger ocean cleanup expedition. But they’ll need more reusable GPS trackers to do so, and each costs about $1,600.
“It’s our goal to have about 150 of them to hand out this year,” said Crowley. “Our plan is to duplicate this very successful mission next year for a three-month period.”
To learn more, visit Ocean Voyages Institute.