Garbage in the Ocean, by Julia Hill
Marine debris or garbage consists of man-made materials that collect in our oceans. Plastics, wood, metal, and other manufactured products are now found throughout the world’s oceans where, after being carried by wind and currents, they often form large garbage patches within circular ocean currents or gyres. There are several of these garbage patches worldwide with the largest in the Indian Ocean, North and South Atlantic, and North and South Pacific. The North Pacific Gyre or Great Pacific Garbage Patch, stretching between Japan and California, is so large that it is divided into eastern (between Hawaii and California) and western (near Japan) segments. While these “garbage patches” conjure up images of floating islands of trash, they are often composed of smaller particles that cloud the water and larger pieces of debris that sink to the ocean floor. Current estimates show that there are over 5.25 trillion pieces of garbage in marine environments worldwide. These garbage patches continue to grow as plastics and other goods make their way to our oceans.
How garbage reaches our oceans
Most of this garbage, about 80%, comes from land. Inefficient industrial practices and over-taxed sewage or waste removal centers allow garbage from our streets to reach waterways. Whether carried by rivers or floods, these items then make their way to the ocean. The remaining 20% is dumped directly by ocean vessels like fishing trawlers and cargo ships as well as offshore oil drilling rigs. Cruise ships are one of the biggest culprits representing less than 1% of the global merchant fleet but producing about 25% of merchant vessel waste.
Impacts on ecosystems
For marine animals, most harm from marine debris revolves around ingestion and entanglement. Sea turtles have been known to mistake floating plastic bags for jellyfish. Sea-faring birds such as albatrosses confuse floating plastic pellets with fish eggs and feed them to their young, resulting in compacted digestive tracts, ruptured organs, and starvation. Whales, sharks, and sea lions drown after becoming entangled in discarded fishing nets.
Debris collecting on the ocean surface can interrupt sun exposure and growth of plankton and algae that form the base of the marine food chain. Disruption at this level causes problems for smaller fish all the way up to whales and sharks. This same debris can also act as a vessel for non-native species to reach new habitats, disrupting isolated environments on islands and coral reefs.
Last, but not least, is the impact of pollutants on the marine environment. Plastics can leach harmful chemicals while also absorbing others. When marine animals ingest this polluted material they may suffer directly (i.e., liver toxicity) or indirectly as these toxins make their way up the oceanic food chain. Concentrations of these pollutants in the water column damage overall ecosystem health and result in less stable environments.
What is currently being done and how we can help
Cleaning up debris once it has reached our oceans is no easy task. Organizations such as The Ocean Cleanup are working on ways to tackle this problem with the goal of removing 50% of the Great Pacific Garbage Patch within the next five years. Oceana uses its global reach to protect our oceans by targeting government policy changes in countries with the most influence. Since this issue starts on land, focus on stronger sewage and waste removal systems alongside recycling programs can produce positive results. Beach cleanups and recycling programs are effective at the community level while individuals can have an impact by taking more care in the products they purchase. Less consumption and more recycling will have a positive influence on all environments and result in less debris reaching our oce