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Why 99% of Ocean Plastic Pollution is "Missing"

 

For those of you who don’t have enough time, here are the key takeaways.

Tl;dr

• Only a fraction of oceanic plastic ends up in gyres.
• Microplastics double in deep-sea sediments every 15 years.
• Much "missing" plastic is buried deep, affecting marine life.
• Intact plastics found 2,500 meters deep in the Arctic.
• Marine creatures pull floating plastics down to the seabed.
• Newer plastic primarily found on coastlines.
• 77% of ocean plastic stays near beaches within five years.
• The "missing" 99% is dispersed—on coasts, deep-sea, and in marine life.

 

Okay let's go.

 

The vast Pacific, sprawling between California and Hawaii, should be a place of wonder and tranquillity. But beneath its waves lurks a grim reality: The Great Pacific Garbage Patch, a colossal expanse of debris, twice as large as Texas. It's a disheartening sight, but the mystery deepens when we realise that these floating patches account for merely a fraction of our dumped plastics. So, where is the 99% missing plastic? Let's journey through this enigma.

 

Larvaceans are sea creatures that build sticky mucous houses, which trap microplastics. Photo: The Monterey Bay Aquarium Research Institute

 

The Mystifying Case of Our Missing Ocean Plastic

 

You might think that spotting plastic in the vastness of our oceans would be akin to finding a needle in a haystack. And in some respects, you'd be right. While we often hear about the ominous 'Great Pacific Garbage Patch' and other such gyres around the globe, they surprisingly hold just about 1% of the ocean's surface plastic. These expansive, swirling vortexes, governed by the rhythm of ocean currents, naturally attract and trap drifting plastics.

 

It was back in the '90s when scientists first stumbled upon these gyres. Initially, there was an assumption that these circulating patches would be the final resting places for all the plastic waste we've been dumping into the seas. The maths seemed simple: our ever-increasing plastic consumption would inevitably end up in these oceanic traps.

 

In our oceans today, we've got a staggering 5.25 trillion mix of macro and micro plastics. If you break it down, that's about 46,000 pieces for every square mile of ocean. 

 

But let’s take a closer look at those numbers. The Great Pacific Garbage Patch, as vast and sprawling as it is, holds approximately 79,000 tons of our plastic waste. When we tally up all these surface-trapped plastics across the globe, the figure comes up to about 269,000 tons. Here's where things get puzzling. Every year, a staggering 8 million tons of plastic find their way into our oceans. So, if these gyres are holding just a fraction, barely scratching the 1% mark of the annual contribution, it begs the question: where's the rest of it?

 

Cleaning the Great Pacific Garbage Patch. Photo: The Ocean Cleanup

 

The Hidden Truth: Decoding the Seafloor Sediment Secrets

 

Following the breadcrumb trail of the missing plastic, scientists found themselves plunging to ocean depths, more specifically, to the Santa Barbara Basin. The revelation awaiting them was both enlightening and alarming.

 

From the sediments of this basin, a tangible timeline was drawn, spanning from 1870 to 2009. As they sifted through these layers, a noticeable invader emerged by 1945 – microplastics. Often measuring less than a millimetre in size, these minute particles began to insidiously pepper the sediment. With the dawn of the plastic production era around the same time, this wasn't mere coincidence.

 

Microplastic fragments found in the seafloor have doubled every 15 years, shadowing the very growth pattern of global plastic production.

 

But where are these microplastics coming from? The primary culprits: clothing fibres shedding from our daily laundry, and the relentless breakdown of larger plastic items. These minuscule particles have spread their tentacles throughout our oceans. And, unsettlingly, they're making their way into the stomachs of even the tiniest marine dwellers, like plankton.

 

A significant portion of our 'missing' plastic isn't just floating aimlessly. Instead, it's clandestinely buried, entrenched deep within the ocean's very foundations.

 

X-radiograph of sediment box core, Santa Barbara Basin. Photo: Science Advances

 

But another clue suggests that there’s more to it.

 

Unearthing the Depths: The Ocean Plastic Below

 

Deep down in the frigid Arctic depths, a startling sight emerges – a plastic bag. Resting quietly at a staggering 2,500 metres below the surface, it remains untouched by time. This solitary plastic artefact isn't alone; it's part of a photo collection of over 2,100 similar sightings, captured by researcher Melanie Bergmann of the Alfred Wegener Institute.

 

Here's the revelation: plastic isn’t just skimming the ocean's surface or fracturing into micro-sized villains. A chunk of it descends into the abyss, unaltered.

 

How's that possible? Well, half of the plastic trash we discard is denser than seawater. It's naturally programmed to sink. The lighter half? Over time, marine creatures like barnacles and mussels latch onto them, acting as anchors, pulling these floating relics down to the seabed.

 

Exploring these deep-sea crypts hints at an unsettling reality: vast amounts of our discarded plastic might be lurking in the ocean's underbelly, wholly preserved.

 

Plastic bag at the HAUSGARTEN, the deep sea observatory of the Alfred Wegener Institute in the Fram Strait. This image was taken by the OFOS camera system in a depth of 2500 m. Photo: Alfred Wegener Institut / Melanie Bergmann OFOS

 

 

Plastic cooling box at the bottom of the ocean.

 

But that’s still not all the plastic accounted for.

 

Shoreline Findings: Ocean Plastic's Preference for the Coast

 

In the vast expanse of the Great Pacific Garbage Patch, researchers found an unexpected artefact: a 1971 crate from Taiwan. A significant portion of this oceanic garbage is old, which raises the question: where's all the new plastic? Interestingly, our coastlines have the answer.

 

The plastics on our beaches are newer compared to those floating out in the open sea.

 

Enter oceanographer Erik Van Sebille. Using advanced simulations, he’s tracing the paths plastics take. The results? Most discarded plastic stays close to coasts, moving between beaches and nearshore waters. This movement is explained by the Lagrangian model, similar to tracking leaves in a stream influenced by winds and currents.

 

Within five years of entering the ocean, about 77% of plastic is found near coastlines. Most of it remains within 100 miles of the shore, in a continual cycle between land and sea.

 

While ocean clean-ups are important, they only address part of the issue. To truly tackle the plastic problem, understanding its movement and accumulation patterns is crucial. Armed with this insight, we can take effective steps to reduce its impact.

 

Plastic migration Erik Van Sebille, Lagrangian model. Source: Erik Van Sebille

 

 

Virtual model showing plastic moving across the Pacific. Source: Erik Van Sebille

 

 

Cleaning Our Oceans: A Mission in Motion

Ocean cleanups are making waves. Thanks to research insights, the ocean plastic initiative we support can pinpoint plastic accumulations, paving the way for effective removal both offshore and on our beaches.

Here’s the plan:

1. Identify	2. Establish	3. Collect	4. Process
Plastic pollution hotspots along the Yangtze River and the East China Sea are identified.	A network of local collection stations is established. Training and equipment is supplied to increase efficiency and quality.	The plastic is collected.	The plastic is processed, safeguarded by  blockchain.

Interestingly, this initiative is also a beacon of hope for ex-fishermen from the Yangtze River, China. Environmental regulations put their livelihoods on pause, but now they, alongside enthusiastic volunteers, are diving into a purposeful venture: extracting discarded plastics.

From food wrappers to bottle caps, every piece we collect tells a story of past carelessness. But each cleanup effort is rewriting that story, turning it into one of responsibility and transformation.

 

Volunteers collecting plastic for Collect Paris for our first recycling run from plastic to fabric. Photo: Waste2Wear / Collect Paris

 

Wrapping It Up: A Cleaner Tomorrow

Aside from stopping plastic production at its source, stopping plastic from entering the ocean is our best shot. This calls for efficient recycling and, even better, reducing our plastic use from the get-go.

 

With almost 400,000 miles of coastline globally, we can't reach every inch. But understanding that much of our plastic clings to these shores before breaking down or drifting out gives us a clear target. Beach cleanups and ocean initiatives can create a sizable dent in this challenge.

And about that elusive "missing" plastic? Our journey through various research findings suggests it’s a mix of hiding in plain sight on our coastlines, sinking to the ocean floor, embedding in sediments, and being swallowed by marine life. The complex dance between plastic and nature is one that we're still learning about.

If you spot plastic on the beach, it's a call to action. Pick it up; every bit counts.