Marine Fungus Discovered to Decompose Ocean Plastic

Researchers from the Royal Netherlands Institute for Sea Research (NIOZ) have identified a marine fungus, Parengyodontium album, capable of breaking down polyethylene (PE), the most prevalent plastic in the ocean. This discovery, made in the North Pacific Ocean, could be a significant step towards addressing the growing issue of plastic pollution in marine environments.

The fungus was found living in thin layers on plastic litter floating in the ocean. It can decompose PE particles at a rate of approximately 0.05% per day under laboratory conditions. The research team, led by Annika Vaksmaa, used 13C isotopes to track the carbon from the plastic and quantify the degradation process.

Why this matters: The discovery of a marine fungus that can decompose plastic in the ocean has significant implications for addressing the growing issue of plastic pollution in marine environments. This breakthrough could lead to the development of new biological solutions to mitigate the environmental impact of plastic waste.

One of the key findings is that the fungus requires ultraviolet (UV) light to initiate the breakdown of PE. This means the fungus can only degrade plastic that has been exposed to sunlight, typically near the ocean's surface. 'UV light was already known to break down plastic on its own mechanically, but our results show that it also facilitates the biological breakdown of plastic by marine fungi,' said Vaksmaa.

The process converts most of the PE into carbon dioxide, which the fungus then excretes. The amount of CO2 released is comparable to human respiration and does not pose an additional environmental threat. 'What makes this research scientifically outstanding is that we can quantify the degradation process,' Vaksmaa noted.

This discovery adds Parengyodontium album to the short list of only four known marine fungi that can degrade plastic. Given the massive scale of plastic pollution—over 400 billion kilograms of plastic are produced annually, with much of it ending up in the ocean—this finding is particularly significant.

The researchers believe that there are likely many more plastic-degrading fungi yet to be discovered, particularly in deeper parts of the ocean. As plastic waste sinks to greater depths, it becomes less exposed to sunlight, necessitating the identification of organisms capable of breaking down plastic in these darker environments.

The study was conducted in collaboration with Utrecht University, the Ocean Cleanup Foundation, and research institutes in Paris, Copenhagen, and St. Gallen, Switzerland. The findings were published in the journal Science of the Total Environment.

This research highlights the potential for biological solutions to address the pervasive problem of plastic pollution in the ocean. As Vaksmaa stated, 'Marine fungi can break down complex materials made of carbon. There are numerous amounts of marine fungi, so it is likely that in addition to the four species identified so far, other species also contribute to plastic degradation.'

The discovery of Parengyodontium album offers a glimpse of hope in the fight against oceanic plastic pollution. With further research, the identification and utilization of more plastic-degrading organisms could significantly mitigate the environmental impact of plastic waste.

Key Takeaways

• Marine fungus Parengyodontium album breaks down polyethylene (PE) plastic in the ocean.
• Fungus decomposes PE at 0.05% per day under lab conditions, requiring UV light to initiate breakdown.
• Breakdown process converts PE into carbon dioxide, which is then excreted by the fungus.
• This fungus is one of only four known marine fungi that can degrade plastic.
• Discovery offers hope for biological solutions to mitigate oceanic plastic pollution.