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| Fig. 1: Image of the convergence zone that makes the GPGP. [2] (Courtesy of NOAA) |
"Today's launch is an important milestone, but the real celebration will come once the first plastic returns to shore. For 60 years, mankind has been putting plastic into the oceans; from that day onwards, were taking it back out again." Boyan Slat, the CEO of The Ocean Cleanup, released this statement on September 8th, 2018, the launch day of System 001, the world's first major ocean cleanup machine. The system was designed and built by engineers at the Ocean Cleanup to collect and remove all trash and plastic from our oceans, specifically at what has now been labeled as the GPGP or the Great Pacific Garbage Patch.
Sixty percent of the plastic made today is less dense than water. This causes it to have a huge impact on ocean pollution. The plastic finds its way into the ocean and floats on the surface of the water, moving with the currents until it reaches the GPGP. The patch itself is caused by a convergence zone north of the equator involving two opposing Pacific currents diagramed in Fig. 1, resulting in a gyre. It has collected over 1.8 trillion pieces of floating plastic and other trash. [1,2] Our world today consumes over 320 million tonnes of plastic per year. In the last sixty years, at least 79 thousand of those tonnes have made their way from around the world into the GPGP. [1] The patch was discovered in 1997 and now has grown to cover an estimated 1.6 million square kilometers or three times larger than the size of France. [1] In addition to being dangerous and even lethal to ocean wildlife, the trash is also occasionally jetted out from the gyres into the 19 islands of the Hawaiian archipelago. The trash often covers beaches with sometimes five to ten feet of trash and invasive plastic sand: microplastics that are impossible to clean and horrible for marine life to ingest. [2]
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| Fig. 2: This is a Diagram of System 001 and its usage to fight the GPGP. [3] (Source: D. Woodhead) |
The problem of the Great Pacific Garbage Patch has led us to The Ocean Cleanup organization, and specifically to System 001. Engineers at The Ocean Cleanup designed the system to resemble an artificial, floating coastline that will corrall the plastic and then remove it with additional Garbage-Boats and nets. The system consists of a 600 meter long floater that resembles a lane line in a pool. [3] The floater provides the system with the buoyancy to float on the surface of the water while also acting as a sail, capturing the force of the wind which pushes the system along at a slightly faster rate than the current below. The system is equipped with a skirt that sits below the water and prevents floating trash from passing through, as shown in Fig. 2. The skirt is longest at the center of the floater, causing the edges of the floater to move faster than the center (due to drag forces) and creating a U shape that collects trash as the system flows. Because the system is driven by the current, it naturally moves with the trash and to the areas with the highest trash density. System 001 is fitted with anti-collision systems, sensors, satellites, cameras, and solar power helping it communicate and send data to scientists on a nearby observation boat and back on land. [3]
System 001 launched on September 8th, 2018 in San Francisco, CA. The system preceded to successfully perform two weeks of trials off the coast of San Francisco where scientists tested the hydrodynamic movement and reorientation abilities of System 001. The 600-meter floating coastline arrived at the GPGP in October and is showing early signs of success. [3] The Ocean Project predicts the first trash will be collected six months after System 001's deployment and plans to soon after produce and deploy another 59 systems that will remove an estimated fifty percent of the Garbage Patch in two years. All of these projects by The Ocean Cleanup are aimed at their ultimate goal: to remove 90% of all trash in the worlds oceans by 2040, a necessary goal that will compliment hopefully many others in an effort to protect our world from human impact.
© Dylan Woodhead. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] L. Lebreton et al., "Evidence that the Great Pacific Garbage Patch Is Rapidly Accumulating Plastic," Sci. Rep.-UK 8, 4666 (2018).
[2] M.-H. Chen et al., "Stratigraphic Distribution of the Radiolarian Spongodiscus Biconcavus haeckel at IODP Site U1340 in the Bering Sea and Its Paleoceanographic Significance," Palaeoworld 23, 90 (2014).
[3] H. Summers, "Scientists Get Ready to Begin Great Pacific Garbage Patch Cleanup," The Guardian, 8 Sep 18.