The Times Australia
The Times World News

.
Men's Weekly

.

Most plastics are made from fossil fuels and end up in the ocean, but marine microbes can’t degrade them – new research

  • Written by Victor Gambarini, PhD Student in Marine Science, University of Auckland, Waipapa Taumata Rau
Most plastics are made from fossil fuels and end up in the ocean, but marine microbes can’t degrade them – new research

Marine plastic pollution is a massive environmental issue, with a plastic smog[1] of an estimated 170 trillion particles afloat in the world’s oceans. This highlights how urgently we need to develop strategies to mitigate this environmental crisis.

We know some microbes can break down certain plastics[2], but our new study[3] finds no clear correlation between plastic pollution levels and the production of plastic-degrading enzymes by marine microorganisms.

To address this issue, we need to understand the varying properties and environmental impacts of different types of plastic.

Most plastics are not degradable

There are four main types of plastics: biodegradable, bio-based, fossil-based and non-biodegradable. The terms can be confusing and lead to misunderstandings about their environmental impact.

Biodegradable plastics can break down naturally through the action of living organisms such as bacteria. They are made from renewable sources such as corn starch or sugar cane and don’t linger in the environment for long periods. Examples of biodegradable plastics are polycaprolactone (PCL), polylactic acid (PLA) and polyhydroxybutyrate (PHB).

Bio-based plastics are also derived from natural materials such as plants. These plastics include polyethylene terephthalate (PET), which is widely used for clothing and containers for liquids and food. However, while PET can be made from renewable sources, most of its production is derived from fossil fuels.

Fossil-based plastics are made from oil and gas. They include common types like polyethylene (PE), which is used for single-use food packaging, and polyvinyl chloride (PVC), commonly used for water pipes and wire insulation.

These plastics are generally not biodegradable. They do not decompose naturally and can persist in the environment for centuries, contributing significantly to pollution and global warming.

This Venn diagram shows plastic classifications and how different types of plastics overlap
Truly sustainable and degradable plastics are made from biological materials. Victor Gambarini, CC BY-SA[4]

PE is the most manufactured[5] plastic type in the world. It accounts for 103.9 million metric tonnes (mmt) per year, followed by PET (65.4 mmt) and PVC (50.5 mmt). However, globally only 9% of all plastic waste is recycled.

According to Plastics NZ[6], terms such as “bioplastic”, “biopolymer”, “bio-based” and “biodegradable” are being used interchangeably, even though they signify entirely different things.

Ocean microbes cannot break down plastics

Our study analysed genetic information from microorganisms in the ocean, using data from hundreds of water samples collected during expeditions[7].

This provided us with insights about the genes marine bacteria use to make enzymes, including the one they use to degrade some plastics. We can then track which enzymes these microbes use at any given time.

The idea is that if marine microorganisms are breaking down plastics, they have to produce the enzymes capable of doing it. Therefore, if microbes are biodegrading plastics in our oceans, locations with more plastic pollution should have higher levels of enzymes for plastic degradation.

This map shows the distribution of plastic pollution across the ocean.
This map shows the distribution of plastic pollution across the ocean, with higher concentrations in the main oceanic gyres. Victor Gambarini, CC BY-SA[8]

Our study found no clear global connection between plastic pollution levels in the ocean and the enzymes produced by marine microbes to degrade plastics. This suggests the ocean microbiome hasn’t evolved efficient mechanisms to break down various types of plastic.

There are several reasons for this. Plastics are very different and complex. Each type of plastic has its own structure and properties, and microbes might not have had enough time or pressure to evolve special enzymes for each type.

Environmental conditions such as temperature, currents and nutrient availability could also play a role in influencing microbial plastic degradation.

This graph shows that locations with more plastic pollution do not necessarily have higher amounts of enzymes for plastic degradation.
This graph shows that locations with more plastic pollution do not necessarily have higher amounts of enzymes for plastic degradation. Victor Gambarini, CC BY-SA[9]

Overall, our findings suggest the global ocean microbiome has not yet evolved to efficiently degrade the many types of plastic pollution plaguing marine ecosystems. This highlights the ongoing danger plastic pollution poses for marine environments.

Developing solutions will likely require dramatically reducing new plastic waste, recovering existing ocean plastic and shifting to biodegradable plastic types.

While disappointing from an environmental remediation perspective, the lack of widespread microbial plastic degradation confirms the durability of synthetic polymers and highlights the vast challenge we face to clean up the oceans.

References

  1. ^ plastic smog (doi.org)
  2. ^ plastics (doi.org)
  3. ^ new study (doi.org)
  4. ^ CC BY-SA (creativecommons.org)
  5. ^ most manufactured (doi.org)
  6. ^ Plastics NZ (www.plastics.org.nz)
  7. ^ collected during expeditions (fondationtaraocean.org)
  8. ^ CC BY-SA (creativecommons.org)
  9. ^ CC BY-SA (creativecommons.org)

Read more https://theconversation.com/most-plastics-are-made-from-fossil-fuels-and-end-up-in-the-ocean-but-marine-microbes-cant-degrade-them-new-research-230530

Times Magazine

From Beach Bops to Alpine Anthems: Your Sonos Survival Guide for a Long Weekend Escape

Alright, fellow adventurers and relaxation enthusiasts! So, you've packed your bags, charged your devices, and mentally prepared for that glorious King's Birthday long weekend. But hold on, are you really ready? Because a true long weekend warrior kn...

Effective Commercial Pest Control Solutions for a Safer Workplace

Keeping a workplace clean, safe, and free from pests is essential for maintaining productivity, protecting employee health, and upholding a company's reputation. Pests pose health risks, can cause structural damage, and can lead to serious legal an...

The Science Behind Reverse Osmosis and Why It Matters

What is reverse osmosis? Reverse osmosis (RO) is a water purification process that removes contaminants by forcing water through a semi-permeable membrane. This membrane allows only water molecules to pass through while blocking impurities such as...

Foodbank Queensland celebrates local hero for National Volunteer Week

Stephen Carey is a bit bananas.   He splits his time between his insurance broker business, caring for his young family, and volunteering for Foodbank Queensland one day a week. He’s even run the Bridge to Brisbane in a banana suit to raise mon...

Senior of the Year Nominations Open

The Allan Labor Government is encouraging all Victorians to recognise the valuable contributions of older members of our community by nominating them for the 2025 Victorian Senior of the Year Awards.  Minister for Ageing Ingrid Stitt today annou...

CNC Machining Meets Stage Design - Black Swan State Theatre Company & Tommotek

When artistry meets precision engineering, incredible things happen. That’s exactly what unfolded when Tommotek worked alongside the Black Swan State Theatre Company on several of their innovative stage productions. With tight deadlines and intrica...

The Times Features

Running Across Australia: What Really Holds the Body Together?

How William Goodge’s 3,800km run reveals the connection between movement, mindset, and mental resilience As a business owner, I’ve come to realise that the biggest wins rarely com...

Telehealth is Transforming Healthcare Services in Australia

It has traditionally not been easy to access timely healthcare in Australia, particularly for people who live in remote areas. Many of them spend hours on the road just to see a...

Launchd Acquires Huume, Strengthening Creative Firepower Across Talent-Led Marketing

Launchd, a leader in talent, technology and brand partnerships, has announced its acquisition of influencer talent management agency Huume from IZEA. The move comes as the medi...

Vietnam's "Gold Coast" Emerges as Extraordinary Investment Frontier and Australian Inspired Way of Life

$2 Billion super-city in Vung Tau set to replicate Australia's Gold Coast success story A culturally metamorphic development aptly named "Gold Coast" is set to reshape Vietna...

Choosing the Wrong Agent Is the #1 Regret Among Aussie Property Sellers

Selling your home is often one of the largest financial transactions you’ll make, and for many Australians, it’s also one of the most emotional. A new survey of Australian home se...

Travel Insurance for Families: What Does it Cover and Why it’s Essential

Planning a family trip is exciting, but unexpected mishaps can turn your dream vacation into a stressful ordeal. That’s where travel insurance comes in—it’s your safety net when ...