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Plastic Waste is Killing Marine Biodiversity

Poisoning. Dismemberment. Disease. It sounds like a horror film in the making. But this is the reality faced by many beneath the ocean’s surface – and we are the reason behind it.

Open a new tab in your browser and conduct an image search for ‘plastic pollution’. The results will present countless images of plastic waste in, on and by our Earth’s waters. But tragically what we see is only the tip of the iceberg: the ocean floor hosts the 'vast majority of plastic in the ocean', and, in what a press release by Oxford University has this year called the 'most comprehensive survey to date', researchers have found that the amount of plastic debris increases with depth – meaning that even life in areas that we have barely explored cannot escape the clutches of our plastic addiction.

Among the victims of our dependency are biogenic habitat-forming species, such as corals, sponges and seagrasses. Not only are these species carbon storage sites, but they are also the pillars of life on the ocean floor: they create environments that are the shelters, hiding spots, nursery sites and home foundations for other lifeforms. But while they nurture life, we are accelerating their deaths.

Plastic Siege on Biodiversity

Our plastic weaponry relentlessly attacks biogenic habitat-forming species: plastic bottle fragments slash them, abandoned fishing gear ensnares them, and ingested microplastics poison them. Given the fundamental role of these species in marine ecosystems, a domino effect arises: by damaging them, our plastic waste destroys the habitats on which other organisms depend, thereby threatening the survival of other species. Although some may be strong enough to overcome this plastic encroachment, many others will not.

This negative impact on biodiversity is further accentuated by the potential arrival of invasive species, which are often cited as being a major threat to biodiversity. While some species have evolved to live on plastic debris, others merely hitch a ride – preferring to encroach and settle on territories outside their natural boundaries. Among other things, these unwelcome guests may displace native species, outcompete already struggling native species for food, disturb the natural ecosystem and spread disease.

And it is not a case of 'out of sight, out of mind'. Many biogenic habitat-forming species are filter feeders (i.e., they feed by filtering nutrients from the water) and are found at the bottom of the food chain. This means that the plastic they consume may bioaccumulate up the food chain and, ultimately, into humans. Studies have found, among other things, that microplastics can cause damage to human cells, including disfigurement and immune system disruption, and that inflammatory bowel disease is more severe in patients with higher concentrations of microplastics in their faeces. As such, not only is our plastic waste killing marine diversity, but we ourselves may fall victim to our own inaction too.

A Path to Redemption

A dire future appears to be on the horizon if changes to the status quo are not made. But it is not too late to act, and relevant regulatory instruments in this regard have been enacted, and guidance has been released. For instance, the EU Single-Use Plastics Directive aims to reduce the volume and mitigate the effects of plastic on the environment, the EU Marine Strategy Framework Directive establishes 11 qualitative descriptors to guide EU member states in achieving a 'Good Environmental Status', and the UK designation of 'Highly Protected Marine Areas' protects species, habitats and ecosystems of designated areas to aid natural recovery of those sites.

At a more local level, Oceana proposes three key actions to tackle the impacts of plastic:

  • Reduce consumption: this includes using reusable bottles and bags and avoiding excess food packaging.

  • Document the area: this involves gathering information about the marine habitats that are most susceptible to plastic pollution.

  • Take action: this involves outlining procedures to remove plastic from marine ecosystems, be it manually or mechanically.

Our plastic waste has already maimed and killed many lives underwater. But we have the power to put an end to this suffering. Can we commence our road to redemption? The choice is in our hands.


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school of fish in plastic - Photo by Naja Bertolt Jensen on Unsplash (ST ref: 1181)

coloured plastic straws - Photo by FLY:D on Unsplash (ST ref: 1180)

group sorts through plastic on the beach - Photo by OCG Saving The Ocean on Unsplash (ST ref: 1179)


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