The plastiphere and marine life: The impact of plastic in our oceans

Our oceans are full of plastic. Fishing nets, bottles, food wrappers, straws, the list goes on. Studies have shown that there could be up to 200 trillion tons of plastic floating around, with massive buildups like that of the Great Pacific Garbage Patch demonstrating the extent of the problem. All that plastic has a big impact on marine life.

As plastic breaks down, it releases microplastics into the water, which ends up being absorbed or eaten by countless marine organisms. Yet despite all odds, some marine species have adapted to their new reality. Plastic in the ocean is harming more than just our ocean species, but it’s finding its way into our food chain through our diet. Let’s take a deep dive into the impact of ocean plastic, and how we can be more conscious about what we throw away. 

How does plastic end up in the ocean?

Most of us throw away our trash and plastic responsibly, but somehow so much of it ends up in the ocean, so how does this happen? 

One of the biggest ways is through our rivers. When it storms or rains, water runs off streets and through built-up areas, picking up plastic and other waste and carrying it into storm drains. Heavy rain can also cause pick up trash from garbage facilities, causing it to travel into storm drains that lead directly into streams and rivers. 

Rivers then act like plastic highways, transporting the plastic all the way to the sea. Some of the world’s major rivers carry thousands of tons of plastic to our oceans annually. This is naturally made worse by increasingly unpredictable weather, flooding, and rainfall from a changing climate. A 2018 study found that 90% of all river-borne plastic that ends up in the ocean comes from just 10 rivers around the world, including China’s Yangtze River, the Nile in Africa, and the Austrian Danube. 

What is the impact of plastic on marine life?

The impact of all this plastic being dumped into the ocean is far-reaching and deadly. Roughly 100,000 marine creatures perish annually as a direct result of plastic waste. Entanglement, toxicity, ingestion, and habitat destruction are the biggest contributors.

Ingestion

We have all seen the dreadful images of seabirds, sharks, and other ocean animals with stomachs full of plastic. This happens when marine mammals mistake plastic for food. For example, sea turtles can mistake plastic bags for jellyfish and seabirds ingest floating plastic fragments, feeding them to their chicks.

Entanglement & suffocation

Fishing waste is by and large the most common type of plastic waste in the ocean. Thousands of miles of old nets, ropes, lines, and other fishing items are discarded at sea, sinking deep into the ocean and suffocating vital deep sea and coral ecosystems. Another byproduct of discarded fishing nets — known as “ghost nets” — is that mammals and birds sometimes get stuck while swimming, or become too interested in fish trapped in the nets, becoming trapped themselves. This is also common in massive commercial fishing, creating what’s known as bycatch*. Sustainable fishing is the only way to prevent this from happening. 

Microplastics & micro creatures

The most insidious thing about plastic is that it doesn't disappear, it just breaks down into billions of smaller and smaller pieces. Microplastics are nearly impossible to clean up, and are often consumed by tiny marine organisms like zooplankton*. As a result, microplastics move up the food chain, affecting larger predators and ultimately humans who eat seafood. Microplastics consumed by fish and shellfish accumulate and become toxic chemicals that disrupt their reproduction, growth, and hormone function.

As plastics have only been widely used since World War II, the long-term impact of microplastics is still unknown, but in the ocean, microplastics are being colonized by microbial communities. Fungi, diatoms*, and bacteria form biofilms on the plastic’s surface, creating a whole new man-made ecosystem.

Plastisphere: How has marine life adapted?

Despite all odds, ocean life has found ways to make use of our endless waste, which is a testament to the resilience and resourcefulness of the natural world. The so-called "plastisphere" is an entirely human-made miniature ecosystem formed on plastic debris. The composition of the plastisphere is influenced by environmental factors like temperature, salinity, oxygen, and water currents, as well as plastic type, nutrient availability, and geographic location. Larger marine species, like certain types of crabs, barnacles, and mussels that usually live in coastal areas are now surviving far offshore, using plastic to anchor themselves. 

So what does this mean? While new ecosystems and adaptation sounds promising, its existence poses a significant risk to marine life. Plastics can act like rafts, transporting harmful bacteria and invasive species across oceans where they can thrive in ecosystems they’re not supposed to, overwhelming the natural environment. 

The plastisphere acts differently from natural microbial communities that live on rocks, algae, and sediments. Some plastics attract certain types of bacteria, can create low-oxygen “dead zones” or produce toxic byproducts like hydrogen sulfide. These altered microbial byproducts can harm marine organisms and degrade water quality.

However, there may be one small silver lining to this evolution. While it’s still an active area of research, scientists have found that some marine bacteria and fungi have developed enzymes that can break down plastic polymers. This incredible discovery could mean that microbes could be evolving new metabolic pathways that use plastic as a food source, which could be used to develop new ways to recycle plastic and reduce pollution. However, we are still a long way off from being able to degrade all the plastic floating in our seas.

How can we clean up the oceans?

First and foremost, we need to buy and use less plastic. This is the number one thing any individual person can do to fight back against the trillions of tonnes of waste being pumped into the sea. Small, individual choices like opting for reusable water bottles, using paper bags instead of plastic bags, and recycling plastic where possible. It’s also important to be more conscious and informed about where our seafood is coming from. These small actions are what can make the most significant difference over time.

However, this doesn’t solve the problem we have right now — trillions of tons of waste adrift in our oceans. Unfortunately, once plastic reaches the ocean, it’s much harder to clear. In this case, prevention is often the best cure. That is why clearing those river “highways” might be a more effective first step. To take on this challenge, Planet Wild went to Albania to clear up one of Europe’s most polluted rivers.

By repurposing a weed harvester into a large waste-collecting boat, our partner Everwave is cleaning the river while also building a brand-new waste management facility to make sure what’s collected is disposed of properly. Thanks to the Planet Wild community, we’ve turned an abandoned building into a fully functioning recycling plant and stopped tons of plastic from reaching the sea. Solutions like this are the first step in reducing the amount of plastic waste getting dumped into the ocean, but much more needs to be done.

Ultimately, real change comes from government and policy changes. In fact, a global ban on single-use plastics could significantly reduce ocean plastic, because alongside fishing waste, single-use plastics make up 70% of plastics found on European beaches. This is a prime example of how individual actions can be a catalyst towards bigger change, showing policymakers that with proper recycling and ongoing education, we can save ocean ecosystems from suffocating beneath our need for convenience. 

Glossary of terms

Bycatch - When fishermen catch and discard animals they do not want, cannot sell, or are not allowed to keep.

Diatoms - Any member of a large group comprising several genera of algae, specifically microalgae, found in the oceans and waterways.

Zooplankton - Plankton consisting of small animals and the immature stages of larger animals.