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Hello everyone, SCIEN-SPOT is a podcast that shines a spotlight on the latest scientific technology from Japan.
Your host is REN from SCIEN-TALK.
Ocean Cleanupの取り組み
Today on SCIEN-SPOT, we are diving into the work of the Ocean Cleanup, a non-profit environmental engineering organization
tackling the global challenge of ocean plastic pollution with innovative technology.
We will explore how their latest Ocean Cleanup System, System 03, efficiently removes plastic from vast stretches of the ocean
and, crucially, how they do it while safeguarding marine life.
First, let's understand why this issue is so critical.
Our oceans are facing an unprecedented plastic pollution crisis,
with an estimated 8 million metric tons of plastic entering the ocean from land each year,
forming vast concentrations known as garbage patches.
The most famous of these is the Great Pacific Garbage Patch.
This pollution has devastating effects on the marine ecosystem.
An estimated 100 million marine animals die annually due to plastic,
and approximately 900 marine species are affected with over 100 of them designated as endangered.
Plastic not only causes endangerment and ingestion,
but also carries toxic pollutants through the food chain, potentially impacting human health.
Furthermore, plastic pollution is closely linked to climate change.
Microplastics, in particular, are suggested to hinder the ocean's carbon absorption capacity, often called the biological pump,
オーシャン・クリーニアップの戦略
with modeling studies suggesting a potential 30% to 65% reduction in carbon emissions in the GBGP.
The GBGP means the Great Pacific Garbage Patch.
This is equivalent to 7 to 13 million metric tons of carbon annually,
highlighting that it's not just an environmental issue,
but a crucial component of global climate change mitigation strategies.
However, once microplastics are non-plastics formed in the ocean,
they are considered extremely difficult, if not possible, to remove,
and this is why the Ocean Cleanup strategically focuses on micro- and megaplastics,
which constitute 92% of the mass in the GBGP.
This approach has the strategic significance of preventing plastic from breaking down further into even smaller, unmanageable particles.
Think of it like sweeping up the bigger crimes before they break into tiny, impossible-to-collect specks.
It makes the overall cleanup much more feasible.
The Ocean Cleanup employs two branched strategies,
first, removing legacy plastic already accumulated in the ocean,
and second, intercepting plastic flowing from rivers before it reaches the ocean.
Research indicates that these strategies alone would be sufficient to start reducing ocean plastic,
making this dual approach essential for achieving the ambitious goal of reducing floating ocean plastic by 90% by 2040.
Now, let's look at the specific mechanism of their Ocean Cleanup system.
System 03.
System 03 is a massive U-shaped floating barrier measuring 2,250 meters in length and towed by two vessels.
システム03の革新技術
Imagine the scale, it's like a giant funnel slowly moving across the ocean.
The key to its efficient plastic collection is creating a relative speed difference between the system and the plastic.
Floating plastic primarily resides just below the surface,
and by having the system move slightly faster than the plastic,
it effectively guides the debris into its U-shaped collection zone.
A system design explored using a sea anchor to slow the system down for allowing plastic to drift into it.
However, System 03 shifted this approach.
It now actively utilizes wind and wave drift forces to propel the system,
while ocean currents affect both the plastic and the system almost equally and thus cancel out.
This difference in forces allows the system to move faster than the plastic, enabling efficient collection.
This is truly sophisticated engineering that cleverly harnesses nature's natural forces.
Furthermore, beneath System 03's U-shaped barrier hangs a skirt that is 4 meters deep.
This skirt is tapered, being deeper in the center of shallower towards the end.
This tapering creates differential resistance to the water flow,
allowing the system to automatically maintain its U-shape and keep its opening pointed in the direction of travel,
even when the wind shifts.
This self-stabilizing mechanism ensures stable and continuous plastic collection without constant minor intervention.
The Ocean Cleanup also employs a smart strategy called hotspot hunting.
プラスチック除去の効率化
This involves using advanced computational modeling to predict where plastic accumulates in high concentration and deploying the system there.
This approach has improved cleaning efficiency by 1.5 times and also contributes to reducing removal costs.
It's like having a smart radar that pinpoints exactly where the plastic is sent.
Once plastic is concentrated by the ocean system and is collected by a support vessel approximately every 4 days,
the collected plastic is transported ashore and then recycled into durable products, aiming for zero-waste operation.
In fact, the first product, Ocean Cleanup Sunglasses, was made from the plastic collected by System001 in 2019.
A rigorous, certifiable chain of custody process is also implemented to ensure the authenticity of the collected ocean plastic.
And finally, let's address one of the most critical concerns, marine life protection.
The Ocean Cleanup operates under a preventative principle. If it proves harmful, we won't do it.
System001 incorporates multiple design safety features to ensure the safety of marine life.
First, the mesh size is relatively large, 15 mm, designed to allow smaller marine organisms like plankton to pass through the system.
The collection zone is equipped with multiple escape aids to allow trapped animals to swim out safely,
and it also features an innovative marine animal safety hatch.
In case of an emergency, there is an emergency release system that can flush out the entire collection zone, releasing any trapped animals.
Ocean Cleanupの取り組み
These measures are not just an afterthought. Dedicated marine biologists onboard vessels to record all instances of incidental bycatch and use this data to improve the system.
The Ocean Cleanup conducts a net environmental benefit assessment,
which has scientifically confirmed that the environmental benefits of plastic removal outweigh the potential negative impacts that might occur during the cleanup process.
Today's science podcast is about how the Ocean Cleanup addresses the complex issue of ocean plastic pollution
with innovative technology, a scientific approach, and a strong commitment to ecosystem protection.
Their work not only cleans our oceans but also contributes to climate change mitigation and aims to establish a sustainable circular economy model.
That's all for today's SciencePod. This podcast is broadcasted every on weekday morning and in both Japanese and English.
I'd love for you to listen to the podcast and post your notes and thoughts with the hashtag SciencePod.
If you have any questions, you can use this hashtag SciencePod. I'll pick up these questions and answer it.
Thank you for listening. See you next time.
