What is Marine Debris?

There are 400 billion stars in the Milky Way while 5.25 trillion pieces of plastic reside in our oceans (13 times more).

Any trash, from glass bottles to aluminum cans to plastic bags, can find its way into the ocean becoming “marine debris.”  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. 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.

Plastics overwhelming dominate the composition of marine debris. Within a square mile of the Great Pacific Garbage Patch, scientists collected nearly 1.9 million bits of plastic, and it is estimated that plastic comprises 60-80% of marine debris in the world’s oceans. Plastics enter the ocean as fragments of manufactured plastic products or as pre-production plastic pellets, called “nurdles.” 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.”

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.

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.”

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

Plastic does not decompose. After coming into contact with the sun, plastic products continue to break into smaller and smaller pieces called “micro-plastics.”

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.

Economic Impacts

Marine debris has serious negative consequences on beach tourism and real estate property values.

A study of New Jersey estimated the state lost billions of dollars in tourism revenue as a result of marine debris washing ashore. A similar study demonstrated that New York forwent anywhere from $950 million to $2 billion.

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.

Like tourism, housing values also suffer from the distasteful appearance and stench of trash floating nearby waterfront homes and cluttering the streets and alleys of neighborhoods. As a prime beach tourism destination and real estate hub, south Florida must take measures to limit the amount of marine debris washing upon our beaches and reefs by investing in both public education to reduce single-use plastic consumption and in cleanups.