Oceanic plastic, the ocean cleanup project and plastic eating bacteria
Updated: May 26, 2022
Changing the theme today from tracking carbon emissions to talking about oceans and plastic in the ocean. Hope you enjoy it! If you have any ideas on how to improve this newsletter then we would love to hear from you here!
What to expect today:
Also - quizzes are back! Check out this week’s quiz in the recommendations section.
Great pacific garbage patch
The Great Pacific Garbage Patch is a collection of marine debris in the North Pacific Ocean. Marine debris is litter (usually fishing equipment and plastic) that ends up in oceans, seas, and other large bodies of water. The patch is actually composed of the Western Garbage Patch, located near Japan, and the Eastern Garbage Patch, located between the U.S. states of Hawaii and California.
What is the garbage patch made of?
For many people, the idea of a “garbage patch” conjures up images of an island of trash floating on the ocean. In reality, these patches are almost entirely made up of tiny bits of plastic, called microplastics. The microplastics of the Great Pacific Garbage Patch can simply make the water look like a cloudy soup. This soup is intermixed with larger items, such as fishing gear and shoes. Some of the plastic in the patch is over 50 years old, and includes items (and fragments of items) such as "plastic lighters, toothbrushes, water bottles, pens, baby bottles, cell phones and plastic bags.
The seafloor beneath the Great Pacific Garbage Patch may also be an underwater trash heap. Oceanographers and ecologists recently discovered that about 70% of marine debris actually sinks to the bottom of the ocean.
How big is it?
Researchers from The Ocean Cleanup project claimed that the patch covers 1.6 million square kilometres (620 thousand square miles) or roughly half the size of India. If it was a country, it would be the 18th largest country by size in the world.
The Great Pacific Garbage Patch is not the only marine trash vortex—it’s just the biggest. The Atlantic and Indian Oceans both have trash vortexes. Even shipping routes in smaller bodies of water, such as the North Sea, are developing garbage patches.
Source: National Geographic, Wikipedia
Ocean cleanup project
The Ocean Cleanup is a nonprofit engineering environmental organization based in the Netherlands, that develops technology to extract plastic pollution from the oceans and intercept it in rivers before it can reach the ocean.
How does it work?
The ocean system consists of a floating barrier at the surface of the water that collects marine debris as the system is pushed by wind, waves and current, and slowed down by a sea anchor (as shown in the photo). The latest design uses a towed, floating structure which acts as a containment boom. A permeable screen underneath the float catches subsurface plastic and other pollutants. The barrier is 800 m (2,600 ft) long and has an active propulsion to allow the system to operate at higher speed. Crewed boats tow the U-shaped barrier through the water at 1.5 knots. The ship can also be steered to areas with higher waste densities.
Tackling waste at the source
1,000 rivers, or 1% of the world’s rivers, account for 80% of the plastic flowing into the oceans from land. The Ocean Cleanup project’s “Interceptor” vessel is the first scalable solution to prevent plastic from entering the world’s oceans from rivers. The vessel (100% solar powered) works on a similar principle but is deployed in rivers and runs autonomously.
Long term goals
The project aims to launch a total of 60 such systems, and they predict this capability could clean up 50% of the debris in the Great Pacific Garbage Patch in five years from full scale deployment. Their goal is to remove 90% of the oceanic plastic by 2040.
Source: Ocean Cleanup Project
Plastic eating bacteria
In March 2016, scientists in Japan published an extraordinary finding. After scooping up some sludge from outside a bottle recycling facility in Osaka, they discovered bacteria which had developed the ability to decompose, or “eat,” plastic. The bacteria, Ideonella sakaiensis, was only able to eat a particular kind of plastic called PET, from which bottles are commonly made, and it could not do so nearly fast enough to mitigate the tens of millions of tons of plastic waste that enter the environment every year.
An evolutionary barrier
The scientists working to find and develop plastic-eating organisms must contend with a basic reality: evolution. Microbes have had millions of years to learn how to biodegrade organic matter such as fruits and tree bark. They have had barely any time at all to learn to decompose plastics, which did not exist on Earth at any scale before roughly 1950. Yet scientists are hopeful and are working alongside nature to improve the process of decomposing plastic. In 2018 scientists in the U.K. and U.S. modified bacteria so that they could begin breaking down plastic in a matter of days.
Challenges in mass deployment
Even if these are one day deployed at scale, they would still face major limitations such as:
Limitation on type of plastic: the current microbes can only decompose one out of seven major plastics that we use today
Limited decomposition: Micro-organisms today are only able to break the polymers into monomers and not decompose all the way to basic elements
Release in uncontrolled environments: Scientists still don’t know how these would react in the open world and what repercussions it might have on our food chains etc.
While these challenges remain, scientists and companies are already testing this method. Carbios, a French start-up, is building a facility to break up PET bottles, the ones used by soft drink manufacturers, as a demonstration plant that will be able to enzymatically biodegrade PET plastic.
Recommendations from the team
Ocean Quiz - How much do you know about our Oceans? (I scored 9/9)
Youtube - Watch the Interceptor vessel in action (7 min video)
Netflix - Seaspiracy - documentary on impact of fishing (1hr 30min documentary)