What is Marine Debris?

 Any trash, from glass bottles to aluminum cans to plastic bags, can find its way into the ocean becoming “marine debris.” [1] The waste comes from landfills when it is blown into nearby rivers and streams that lead to the sea, boats that purposefully or accidentally dump garbage off board, or beachgoers who lose their belongings. [2]  Massive quantities of marine debris circulate within currents across the globe. One of these floating piles of trash, the Great Pacific Garbage Patch, lies in the North Pacific Ocean spanning nearly 7 million square miles. [3] 

Marine debris accumulates heavily along the uninhabited islands in Biscayne National Park (BNP). This photo was taken on April 16, 2016 9nm offshore in BNP during one of Debris Free Oceans' cleanups.

Marine debris accumulates heavily along the uninhabited islands in Biscayne National Park (BNP). This photo was taken on April 16, 2016 9nm offshore in BNP during one of Debris Free Oceans' cleanups.

Plastics overwhelming dominate the composition of marine debris. [4] Within a square mile of the Great Pacific Garbage Patch, scientists collected nearly 1.9 million bits of plastic, [5] and it is estimated that plastic comprises 60-80% of marine debris in the world’s oceans. [6] Plastics enter the ocean as fragments of manufactured plastic products or as pre-production plastic pellets, called “nurdles.” [7] Frighteningly, some geologists claim that we may be able to precisely mark our era as the Plasticozoic, "the place in the sands of time when bits of plastic first appeared." [8]

From interfering with food webs, ghost fishing, and transferring toxins up the food chain, this marine debris significantly interferes with ecosystem and human health, and it has many socioeconomic impacts. The eradication of marine debris is essential to the wellbeing of our current and future generations, and the unique characteristics of marine debris as an environmental problem require an innovative approach to its eradication.

Environmental Impacts

Overall ecosystem health is gravely affected by the accumulation of trash and plastics in our oceans. Marine debris ingestion and entanglement directly impacts marine life.  Additionally, the mere presence of marine debris can disrupt an entire food web through its indirect impacts.

On an island in the Pacific Ocean, Albatross birds have been suffering from starvation after consuming too much plastic. The position of the islands subjects them to ocean currents that push massive quantities of trash onshore leaving the Albatross with little food except plastic to consume. Click the photo to learn more.

On an island in the Pacific Ocean, Albatross birds have been suffering from starvation after consuming too much plastic. The position of the islands subjects them to ocean currents that push massive quantities of trash onshore leaving the Albatross with little food except plastic to consume. Click the photo to learn more.

Studies show that “ingested marine debris is quite common in samples of dead and captured seabirds and turtles,” indicating that many marine organisms mistake small bits of plastic and trash for food. Ingestion of marine debris causes various effects in marine life, including “reducing the absorption of nutrients in the gut, reducing the amount of space for food in the gizzard and stomach, uptake of toxic substances that comprise the debris or have been adsorbed into the debris, ulceration of tissues, and mechanical blockages of digestive processes.”

A grouper never found its way out of an abandoned fishing net lost at sea.

A grouper never found its way out of an abandoned fishing net lost at sea.

Aside from consuming the marine debris, many marine organisms become entangled in the debris, which is suspected to result in significant direct physical harm and mortality in marine species. Derelict fishing gear is particularly harmful as it often results in “ghost fishing.” Ghost fishing occurs when lost or abandoned fishing gear continues to catch fish that then goes to waste. Debris entanglement can also have damaging effects on marine habitats, such as corals reef and sea grass destruction resulting from contact with derelict fishing gear. 

Marine debris also results in more indirect disruptions of ecological functions. For instance, smaller plastics collect together on the surface of the ocean blocking sunlight to the autotrophs below it. Autotrophs are small marine organisms that feed off sunlight and provide food to the bottom of the food chain. Once the autotrophs’ productivity collapses so does the productivity of all other larger marine organisms up the food chain.

Human Health Impacts

Because nurdles are light and difficult to restrain, over 250 billion pounds of nurdles transported by trucks and ships each year are susceptible to blowing into the ocean during transportation.

Because nurdles are light and difficult to restrain, over 250 billion pounds of nurdles transported by trucks and ships each year are susceptible to blowing into the ocean during transportation.

After coming into contact with the sun, manufactured plastic products that enter the ocean just continue to break into smaller and smaller pieces, called “micro-plastics.” The products break into micro-pastics because plastic does not decompose. Pre-production plastics, or “nurdles,” are small plastic pellets that are later melted and molded to produce everyday plastic products. Massive quantities of nurdles often spill off ships and into the sea.

Scientists are concerned that plastics, particularly microplastics and nurdles, “are able to adsorb, concentrate, and deliver toxic compounds to organisms that ingest them or to benthic communities.  In fact, studies have demonstrated that plastics readily absorb contaminants with greater ease than natural sediments like rocks and sand. The contaminants that plastics absorb include polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT).

DDT and PCBs are persistent organic pollutants (POPs) that “can accumulate and pass from one species to the next through the food chain.” POPs have been linked with “reproductive, developmental, behavioral, neurologic, endocrine, and immunologic adverse health effects” in humans. Because microplastics and nurdles are easily ingested by species at the bottom of the food chain, humans are in danger of ingesting large quantities of POPs when consuming larger species, like tuna and wahoo.

As fisheries contribute greater than 20 percent of the average per capita animal protein intake for more than 1.5 billion people,  these bioaccumulation effects are significant. Particularly at risk are the populations of small island states and developing nations who derive 90% of their animal protein from fish.  POPs can also affect the next generation because they are transferred to developing offspring through the placenta and breast milk.

While the consumption of marine species may result in serious indirect impacts on human health, marine debris that washes ashore may also immediately and directly injure beachgoers. Debris such as glass and aluminum may cut people walking on the beach. More threatening, however, is the possibility of hazardous medical waste, like needles, washing ashore and injuring the public.

Socioeconomic Impacts

Marine debris has demonstrated serious effects on beach tourism, the fishing industry, and recreational boating and fishing. [1] When marine debris washes ashore, it causes serious economic effects and diminishes enjoyment of our beaches. A study in 1988 estimated that “New Jersey lost between $379 million and $3.6 billion in tourism and other revenue as a result of marine debris washing ashore.” A similar study demonstrated that New York forwent anywhere from $950 million to $2 billion in revenue as a result of marine debris washing ashore. This decline in economic revenue stems from tourists foregoing ventures to the beach because of its distasteful appearance. For instance, a South African study concluded that 10 pieces of marine debris “per meter of beach would deter 40 percent of foreign tourists.”

Major cities lose billions of dollars per year as a result of marine debris littering their coastlines. Read the study at Balance, A., Ryan, P.G., and J.K. Turpie, How Much is a Clean Beach Worth? The impact of litter on beach users in the Cape Peninsula, South Africa, South Africa Journal of Science 5:210-213 (2000). 

Major cities lose billions of dollars per year as a result of marine debris littering their coastlines. Read the study at Balance, A., Ryan, P.G., and J.K. Turpie, How Much is a Clean Beach Worth? The impact of litter on beach users in the Cape Peninsula, South Africa, South Africa Journal of Science 5:210-213 (2000). 

More than 43.5 million people work as fishermen, and an additional 200 million do associated work, including fish processing, marketing, distribution, and supply. A 2007 study by the Natural Resources Consultants, Inc. quantified the cost of ghost fishing on this large industry and the subsequent benefits to the industry from derelict fishing gear removal. While the removal for each acre of net cost $4,960, the benefits of removing the gear resulting in $6,285 per acre value of species saved. Thus, nearly $6,000 worth of marine life per acre is lost from debris entanglement, and a significant financial benefit is derived from its removal.

Read more about yachtsman Ivan Macfadyen's journey by clicking the photo above. You will be redirected to an article by The Guardian.

Read more about yachtsman Ivan Macfadyen's journey by clicking the photo above. You will be redirected to an article by The Guardian.

While marine debris poses a physical threat to marine life, it also causes physical harm to commercial and recreational boats “from fouling of propellers and jet intakes as well as damage to hulls.” For example, yachtsman Ivan Macfadyen feared “entangling [his boat’s] propeller in the mass of pieces of rope and cable” when he sailed from Melbourne, Australia to Osaka, Japan. Macfadyen could only turn his motor on in the daytime so that he would be able weave around the debris, which ranged from the size of a water bottle to “the size of a big car or truck.” At the end of his voyage, Macfadyen’s “hull was scratched and dented all over the place.”

When people intrinsically value healthy ecosystems, they also suffer from the mere loss of the existence of marine life and overall degradation of marine ecosystems. The fish and birds Mcfadyen heard and saw on the same 3000 mile voyage 10 years ago had disappeared and been replaced with “muffled thuds and bumps and scrapes” from debris knocking against his boat’s hull and “every kind of throwaway domestic item you can imagine, from broken chairs to dustpans, toys and utensils.” During his voyage, Macfadyen “felt sick to his heart,” and he stated “with stunned disbelief ... the ocean is broken” and “dead.” This sense of death and brokenness overcoming the sea affects individuals who value healthy marine ecosystems for their own sake.

Citations

[1] A 2008 U.S. Ocean Studies Board Report defined “marine debris” as “any persistent, manufactured, or processed solid material that is directly or indirectly, intentionally or unintentionally, disposed of or abandoned into the marine environment.”

[2]  Sylvia Earle. “The World is Blue.” National Geographic Society. Chapter 4. Kindle Edition. 

[3]  National Geographic Education. Encyclopedic Entry. “Great Pacific Garbage Patch.” http://education.nationalgeographic.com/education/encyclopedia/great-pacific-garbage-patch/?ar_a=1

[4] National Geographic, Great Pacific Garbage Patch, Education (last visited November 2013), http://education.nationalgeographic.com/education/encyclopedia/great-pacific-garbage-patch/?ar_a=1. 

[5] Id. 

[6] United States Environmental Protection Agency, Pacific Southwest/Region 9, MARINE DEBRIS IN THE NORTH PACIFIC: A SUMMARY OF EXISTING INFORMATION AND IDENTIFICATION OF DATA GAPS, 1 (2011), http://www.epa.gov/region9/marine-debris/pdf/MarineDebris-NPacFinalAprvd.pdf

[7] Id. 

[8] Sylvia Earle, THE WORLD IS BLUE, National Geographic Society, Ch. 4. Kindle Edition.