Plastics Comprise 85 Percent of Trash Accumulating in the Earth’s Oceans
Marine litter—first recognized, anecdotally, in the 1960s—has been a serious environmental concern since the 1980s, according to the 2015 book, Marine Anthropogenic Litter. But while today’s sources of litter are many and its effects are still growing, major efforts are underway to address the issue. Individuals, organizations, communities, and nations can all lend a hand.
What is Marine Litter or Debris?
Marine litter (or marine debris) refers to objects made of anything manufactured. It includes small pieces of trash, like cigarette butts, grocery bags, and plastic bottles, and massive items, like construction waste, commercial fishing tackle, and even ships.
In the U.S., marine debris is legally defined as “any persistent solid material that is manufactured or processed and directly or indirectly, intentionally or unintentionally, disposed of or abandoned into the marine environment or the Great Lakes” (33 U.S. Code § 1956).
The vast accumulation and ongoing supply of debris presents a threat to oceans and other water bodies. It can wipe out the lives of all kinds of marine life, from individual mammals, fish, and plants to entire ecosystems, as emphasized by Stephen Guertin, deputy director at the U.S. Fish and Wildlife Service, Department of the Interior, in 2019. The loss is not only felt in the natural world; it also impacts the livelihoods and lives of those who live, work, or play on or near the water.
Sources of Marine Litter
Marine litter finds its way into the planet's oceans and beaches through many avenues, such as being blown in by winds, being deliberately abandoned in the water, pumped in as sewage, and as river trash carried oceanward by stormwater. Natural events like hurricanes or tornados contribute to loads of marine litter ending up in the oceans.
About 80% of ocean plastic pollution is from land-based sources, while the remaining 20% is from water-based sources, including offshore industrial operations, offshore drilling, and aquaculture, as well as shipping containers or vessels themselves.
The three major sources of marine debris are, therefore, land, water-based sources, or a natural disaster, such as a major weather or geological event.
The biggest type of marine debris is plastics, which account for 85% of all marine waste, according to the United Nations Environment Programme’s (UNEP) 2021 report. About 80% of ocean plastic pollution is from land-based sources, while the remaining 20% is from water-based sources, including offshore industrial operations, offshore drilling, and aquaculture, as well as shipping containers or vessels themselves.
Debris arising from seagoing activities can include large shipping containers that fall or get blown off seagoing cargo vessels. Other types of debris are the nets, lines, floats, buoys, and crab pots familiar to fishing enthusiasts, and items also seen with land-based activities, including plastic containers and other common, everyday household items.
How Ocean Plastics Can Affect Marine Life
Ocean plastics are grouped according to size. Macroplastics float on the surface or sink to the ocean floor. Animals can ingest macroplastics or become tangled up in ropes, fishing lines, and plastic bags. Marine habitats and individual plants suffer, too. Mangroves, the shrubs and trees in coastal, brackish water, and plants from the wetlands edging the oceans can be damaged by debris carried in ocean currents as it brushes up against them. Coral reefs can be broken apart or smothered by plastic sheeting and bags that come to rest on them. Oyster beds, seagrass beds and deep-water habitats are subjected to a similar fate.
Plastic debris creates an environment favorable for algae blooms, which can be economically damaging and biologically deadly. Ocean plastics are so pervasive that they have created their own microbial habitat: the plastisphere.
Ocean plastics are so pervasive that they have created their own microbial habitat: the plastisphere.
Microplastics (typically less than 5 mm (0.2 in) in size) are carried along water currents where they are eaten or absorbed. Some can introduce heavy metals in aquatic environments. Much to the harm of all, plastics break down, releasing the chemicals used to manufacture them.
Ocean plastic has become so prevalent that vast amounts have merged and grown into aptly named ocean “garbage patches” —gigantic trash collections. Among these is the Great Pacific Garbage Patch (GPGP), which is mostly composed of microplastics but still can cause entanglement, ghost fishing, ingestion, and transport of non-native species.
Neither are people immune from harm. They can ingest phthalates and bisphenol when they eat fish or other sea life that consumed microplastics. Continued exposure to such toxins can damage reproductive systems, promote metabolic diseases like diabetes, harm the thyroid, induce breathing problems, and decrease the body's response to vaccinations.
Hope on the Horizon
Once it became obvious in the 1980s that marine debris was creating problems, scientists, researchers, environmental advocates, marine and other business owners, and concerned citizens began taking action. For example, a global assessment of solutions was conducted in 2021 to provide recommendations for the prevention, monitoring, and cleanup of marine litter worldwide.
New developments in the U.S. include eight programs recently instituted to answer the issues created by marine litter. Several of them are funded in part or whole by the U.S. National Oceanic and Atmospheric Administration (NOAA). The Clean Water Fund with its “ReThink Disposable” program, for example, aims to reduce the single-use packaging waste generated by food and beverage operations. Then there is the Ocean Conservancy's project designed to initiate preventative practices for the food service and convenience outlets in Miami-Dade County in Florida. Another program funds the Parley Foundation so they can organize cleanups along Hawaiian beaches.
Other organizational programs cover a range of activities:
The U.S. EPA's Trash Free Waters spreads knowledge of marine litter issues. It also supports installing litter capture devices and improved solid waste management globally.
The Commission for Environmental Cooperation developed a program to help find local solutions to marine litter. They wrote a guide called “Reducing Marine Litter Through Local Action: A Toolkit for Community Engagement.” It's intended to help North American communities ensure that their trash does not become marine debris.
NOAA’s Marine Debris Program, created to manage issues related to ocean pollution, provides a website with emergency response guides, a blog, and newsletters. The site contains booklets, activities, and guides for educators, schoolkids, and the general public. Funding is also available.
The United Nations Educational, Scientific, and Cultural Organization, or UNESCO, lists 13 private and nonprofit organizations active in solving issues related to marine debris. For example:
The Public Benefit Corporation 4Ocean is a Certified B Corp that employs individuals to clean marine litter. (Public benefit corporations exist “to generate social and public good” in a sustainable manner. They include both governmental agencies and corporations operating for profit.)
The Ocean Cleanup puts its engineers, researchers, scientists, and others to work on removing plastics from the world's oceans.
The previously mentioned Ocean Conservancy also works on programs that cover trash-free seas, encourage sustainable fisheries, protect regional locations such as the Arctic, and address issues like climate change.
Everyone Can Help
With plastics composing most of marine litter, individuals can take steps to help make a difference, such as those suggested by the Oceanic Society:
Reduce the use of single-use plastics, and recycle plastics when possible (See The Earth & I, August 2023)
Support legislation that limits the use of plastics
Participate in clean-up projects
Avoid products containing microbeads
Spread awareness of the issue and its causes
Support organizations addressing the issue
The Problem of Marine Litter Is Not Irreversible
People's actions on or around the seas have created many problems that affect marine life and those who live on the land. But while the situation is dire, there are solutions. Become informed, spread the word, and take action before it is too late.
*Cassie Journigan is a writer who lives in the north-central region of Florida in the United States. She focuses on issues related to sustainability. She is passionate about numerous topics, including the Earth's changing climate, pollution, social justice, and cross-cultural communications.