Effects of Ocean Pollution on Marine Life

Annette McDermott
oil-covered starfish

If you're worried about the effects of ocean pollution on marine life, you are not alone. The increase of pollutants in the world's oceans is affecting the variety of creatures that live there.

Various Pollutants

There are many of types of ocean pollutants that endanger marine life. Some of them are more obvious than others, but all contribute to an unhealthy ocean and many times, the death of its creatures.

Effects of Oil on the Ocean

Although the big oil spills from offshore drilling get a lot of attention, there are millions of gallons of oil dumped into the world's oceans every year from other sources. According to National Oceanic and Atmospheric Administration (NOAA), there are four main ways oil pollution occurs, and man-made causes account for more than half of it. These are

  • Natural oil seeps originating from the ocean beds spreads into the seas and accounts for 45% of oil pollution.
  • Consumption of oil in various phases such as storage, and waste production like municipal and industrial waste, and urban runoff causes 37% og pollution.
  • Oil transportation by sea causes 10% of oil pollution. Included here are the small and major oil spills that people usually associate with ocean pollution.
  • Offshore oil extraction processes release 3% of oil also into the ocean.

Oil is dangerous to marine life in several ways. According to the NOAA , if fur-bearing mammals or birds get oil on their fur or feathers, they may not fly or move properly, maintain body temperature, or feed. The oil washes up on beaches and contaminates nesting areas and feeding grounds. As marine mammals try to clean themselves, they may ingest oil which can poison them.

Although fish and shellfish aren't impacted in deep seas, those living, feeding or spawning in shallow waters can be vulnerable resulting ultimately in death. Fish can also get contaminated from oil residues and become unfit for human consumption, according to the University of Delaware and Office of Environmental Health Hazard Assessment.

Coral Reef Impact

Oil may impact coral reefs in a negative way. These reefs are not only beautiful, they provide a habitat for many sea creatures. NOAA indicates the impact of oil on coral reefs is difficult to predict. Oil also clogs up the gills of the fish that live there and suffocates them. When oil floats on the surface, it blocks sunlight and prevents marine plants from using light for photosynthesis. These plants are important parts of the food chain and the reef habitats found in the oceans.

Toxic Materials

Toxic materials are a side effect of modern living. Thanks to water's solvency, toxic pollution often ends up in the ocean, sediment, and the sea surface micro-layer. Eight percent of pollution has non-point sources and comes from land, reports the World Wide Fund for Nature (WWF). Toxic pollution sources, according to MarineBio, include:

  • Industry waste
  • Sewage discharge
  • Radioactive waste from power plants, nuclear dumps, and nuclear submarines
  • Fertilizers and manure waste
  • Household cleaning products

Pollutants find their way into the ocean and sink to the bottom. Bottom feeding organisms ingest these chemicals and contaminates the food chain. The smaller fish is eaten by the larger fish, which is then eaten by a human. Toxins build up in the tissues of the people who eat the contaminated fish and may lead to illnesses like cancer, reproductive disorders, birth defects, and other long-term health problems. The National Resources Defense Council offers a guide to fish you should avoid due to high mercury and PCB content. Fertilizers, sewage, and household waste loaded with phosphorus and nitrogen cause nutrient pollution points out Environmental Protection Agency (EPA) that cause dead zones in seas.

Trash and Other Debris

polluted beach

Plastic bags, balloons, medical waste, soda cans, and milk cartons all find their way into the oceans of the world. These items float in the water and wash up on beaches. According to the WWF, marine debris creates health hazards for marine life.

Ocean mammals get entangled in old nets and drown because they cannot get to the surface for air. Birds, turtles, and fish ingest a variety of plastic items, especially micro-beads and their digestive systems become clogged, reports The Guardian. Sea turtles are attracted to floating plastic bags which appear to be jellyfish, one of their favorite treats. The plastic bags block their digestive system and cause a slow and painful death.

Various pieces of trash cause entanglement, starvation, drowning, and strangulation. When the trash washes up onto beaches and into marshes and wetlands, it ruins breeding grounds and habitats. Marine plants may be strangled by debris and die. Debris removal efforts may alter ecosystems.

How much plastic is in the ocean? Daily Mail in 2017 reports there are 5.25 trillion pieces of plastic in oceans around the world and 8 million tons of waste is added each year.

Other forms of ocean pollutions like noise, acid rain, climate change and ocean acidification can also take their toll on marine life.

Statistics on the Effects of Ocean Pollution

Statistics on the effects of ocean pollution on fish and other marine life are difficult to determine because of the number of animals involved and the size of the ocean. Scientifically, there are many unknowns. However, there have been some interesting studies done in small areas of the ocean and test groups of marine life.

  • A 2015 scientific review found that 693 marine species encounter marine debris. Plastic made up 92% of the debris they encountered.
  • The same study found that the survival of 17% of the species on the IUCN Red List were threatened by marine debris.
  • Man-made debris was found in 55-67% of all marine species according to a Nature study.
  • A 2017 scientific review reports that "233 marine species, 100% of marine turtles, 36% of seals, 59% of whales, and 59% of seabirds, as well as 92 species of fish and 6 species of invertebrates" had plastic in them. This lead to starvation, stomach problems and even the death of the animal.
  • Entanglement was reported in 344 species, "100% of marine turtles, 67% of seals, 31% of whales, and 25% of seabirds, as well as 89 species of fish and 92 species of invertebrates," according to the 2017 review. This leads to injury, deformations, restriction in movement making them vulnerable to predators, drowning or starvation.
  • A Center for Biological Diversity report states that within a year of the British Petroleum oil spill in the Gulf of Mexico, 82,000 birds of 102 species were likely harmed or killed. In addition, approximately 6,165 sea turtles, 25,900 marine mammals, and an unknown number of fish were harmed or killed. As of mid-June, 2010, the spill contributed to the death of 658 sea birds, 279 sea turtles, 36 sea mammals, and countless fish.
  • Five species of turtles living in the Gulf of Mexico are now endangered. Embryos of two fishes have heart defects, loons and whales have very high concentrations of toxins in them, and 900 dolphins were found dead according to National Geographic.
  • Coastal habitats of marine birds and animals is being contaminated or destroyed by the marine debris that floats and deposits on isolated islands far from regions of dense human populations according a Guardian report in 2017. So ocean pollution impacts all regions of the marine world as ocean currents move water around the world.

Research Helps Protect Ocean Life

The amount of research done by marine biologists, environmentalists, and others is staggering. There is worldwide concern over the growing problem of ocean and other water pollution and no clear and easy resolution to the problem in sight. The oceans are an important part of the earth's environment, and it is imperative they are protected and kept clean to protect marine health and ultimately, human health.

Effects of Ocean Pollution on Marine Life