Geology concepts and applications

Oceans & Plastic Pollution

The growing mass of plastic debris that is polluting many of the world's oceans is of great concern to scientists, governments, and environmentally inclined ordinary citizens -- and should be of grave concern to every inhabitant of this planet. What is the nature of the problem? How severe is the degree of degradation to the species that use the ocean as habitat? What are the laws that apply to the debasement of the world's oceans vis-a-vis plastic pollution? These questions will be addressed in this paper.

How serious is the plastic-related problem? What's the impact on marine species?

In a recent book by noted environmental author Marquita K. Hill, the retired professor of chemical engineering (University of Maine) explains that when it comes to marine environments "Truly pristine locales no longer exist" (Hill, 2010, p. 257). Plastic bags, bottle tops, and polystyrene foam coffee cups "have been found in the stomachs of dead sea lions, dolphins, sea turtles, and birds" and seagulls in the North Sea "…had an average of 30 pieces of plastic in their stomachs, according to a 2004 study," she continues. And moreover plastic debris "…is estimated to kill a million seabirds and 100,000 marine mammals and turtles each year" because they ingest the plastic material, or become entangled in plastic fishing line, plastic bags, plastic six-pack holders and string from balloons (Hill, 257).

Charles Moore, writing in the journal Natural History, was shocked at the proliferation of plastic in the Pacific Ocean. He and his crew set out from Point Conception, California, in 1998, heading northwest in their aluminum-hulled catamaran research vessel Alguita. At about 800 miles offshore, they dropped their "manta trawl" overboard and allowed it to skim the surface for three plus miles. "What we saw amazed us," Moore writes (Moore, 2003, p. 3). They witnessed a "rich broth of minute sea creatures mixed with hundreds of colored plastic fragments -- a plastic plankton soup" (Moore, 2003, p. 3). Among the harvest of plastic bits and pieces, they also recovered "a menacing medusa of tangled net lines," Moore continues (p. 3). Their research revealed that for every pound of existing zooplankton, there are "…six pounds of plastic floating in the North Pacific subtropical gyre…" (Moore, 2003, p. 3).

Professor Stelios Katsanevakis reports that that plastic pollution on the ocean is just the tip of the iceberg, so to speak. Using data from the North Sea and the ocean waters around Australia (and other environments) "…it has been estimated that up to 70% of the marine litter that enters the sea ends up on the seabed… 15% is found on beaches and the rest (another 15%) floats on the water surface" (Katsanevakis, 2008, p. 59). The professor has conducted intensive research on the impact that plastic pollution has had (is having) on sea life. The most vulnerable marine species are the pinnipeds (Seals and Sea Lions); getting entangled in marine debris has been reported for "at least 20 pinniped species," Katsanevakis asserts (p. 64). The seals and sea lions have been found strangled / entangled in packing tape, plastic strapping, plastic rings and ropes, fragments of fishing nets and monofilament lines (Katsanevakis, 2008).

At least 14 species of Cetaceans (whales) are known to become entangled in "derelict fishing gear" mostly from "ghost driftnets" (those nets that are no longer connected to a fishing vessel but have either been cut loose or have broken free) (Katsanevakis, 2008, p. 66). There was some very telling evidence found in 2006, in the stomach a dead sperm whale that was found floating in the Aegean Sea in the Mediterranean, Katsanevakis explains on page 73; "Dozens of plastic bags… net fragments and pieces of rope were found…" (p. 73).

As for marine turtles (loggerhead, green, leatherback, hawksbill, hawksbill and Kemp's ridley), the most frequent cause of mortality is "derelict fishing gear" (either through entanglement or ingestion), Katsanevakis explains (p. 68). In fact, the necropsies that were performed on 73 turtle carcasses that had been stranded along the Texas coast (1986-87) revealed that "marine debris was ingested in 32.9% of the turtles" -- and "plastics" dominated the debris found (Katsanevakis, p. 75). The list of plastic trash found in those turtles is too long to include in this research.

Seabirds (especially pelicans, gannets and gulls) often fall prey to "monofilament line"; albatrosses, petrels, penguins and grebes are not found entangled in plastic fishing line or other plastic debris as often as pelicans and gulls (Katsanevakis, 2008, p. 69). What is particularly insidious about plastic is when it is ingested by marine animals is releases "toxic chemicals" due to the chemical additives that are added to the plastic during the manufacturing process. Once in the abdomen of the animal the toxic materials can block the digestive tract and block "gastric enzyme ingestion, diminished feeding stimulus, nutrient dilution, reduced growth rates, lowered steroid hormone levels, delayed ovulation and reproductive failure," Katsanevakis asserts (p. 71).

There is lethal danger for small marine organisms as well, when it comes to "microscopic plastic particles" that lodge in sediments and surface waters of oceans, Katsanevakis explains (p. 71). After these microscopic particles are ingested by small marine organisms (lugworms, bivalves, barnacles and amphipods), and these organisms are in turn consumed by larger species, the poisons move up the food chain, the author goes on (p. 71).

What are the sources of these massive quantities of plastic in the oceans?

Professor Katsanevakis teaches in the Zoology / Marine Biology departments at the University of Athens, Greece; his lengthy, scholarly essay in the 2008 book Marine Pollution: New Research offers an invaluable wealth of information on ocean pollution with specific reference to plastics. The main sources of marine litter are "…merchant shipping, ferries and cruise liners, fishing vessels, military fleets and research vessels, pleasure craft, offshore oil and gas platforms, and aquaculture installations," Katsanevakis explains (p. 56). The main sources of land-based plastic pollution are waste dumps (landfills) near the coast, storm water discharges, "unregulated disposal of litter due to absence of waste services or landfills in urban or rural areas, the plastic industry and other industrial facilities," and tourism / beachgoers (Katsanevakis, 2008, p. 56).

What international laws apply to issues of ocean pollution?