Ocean Pollution: Understanding The Devastating Impact On Marine Life

Oceans cover more than 70% of the Earth's surface and are pivotal to the health of our ecosystem. However, they are under serious threat from pollution, with billions of pounds of trash and other pollutants entering the ocean each year. This pollution has far-reaching consequences for both marine life and human health. The majority of marine pollution comes from land-based sources, including runoff from farms, construction, and ports, as well as littering and poor waste management practices. Marine animals are frequent victims, with oil spills ensnaring and suffocating them, and plastic debris often mistaken for food. The impact on humans is also significant, as toxins ingested by marine life make their way up the food chain, leading to potential long-term health issues. As the problem of ocean pollution worsens, it is essential to address it through collective efforts and individual actions to protect the health of our planet.

Oil spills and plastic pollution

Oil Spills

Oil spills occur when there is a release of liquid petroleum hydrocarbon into the ocean or other water bodies. These spills can have detrimental effects on marine life, including birds, mammals, fish, and shellfish. Oil spills can harm sea creatures by impairing their movement, destroying their insulating abilities, and causing toxicity. For example, oil can coat a bird's wings, leaving them unable to fly, or strip away the insulating properties of a sea otter's fur, making them susceptible to hypothermia.

Oil spills also have long-lasting consequences for ecosystems and economies, with clean-up and restoration efforts taking decades. The largest marine oil spill in American history, the Deepwater Horizon spill in 2010, resulted in an $8.8 billion settlement for restoration.

Plastic Pollution

Plastic pollution in the ocean is a pressing issue, with plastics taking thousands of years to decay. This pollution comes from various sources, including ships, offshore platforms, litter being blown into the sea, tides on beaches, and intentional dumping. As plastic breaks down, it releases toxic chemicals into the water and atmosphere, which are then ingested by fish and other sea creatures, ultimately entering the human food chain.

Plastics can also directly harm marine life through ingestion or entanglement. It is estimated that plastic kills over 100,000 sea turtles and birds annually. Furthermore, toxins from plastics can have adverse effects on human health, including direct toxicity from heavy metals such as lead, cadmium, and mercury, as well as health issues like cancer, birth defects, and immune system problems.

The accumulation of plastic in the ocean has led to the formation of garbage patches, with the Great Pacific Garbage Patch, located in the North Pacific Ocean, being the largest of them all. This garbage patch is composed of two separate patches, the Western Garbage Patch near Japan and the Eastern Garbage Patch between Hawaii and California, and is larger than the state of Texas.

Noise pollution

Marine mammals, such as whales, dolphins, and porpoises, are highly dependent on underwater sound for survival. They use sound to communicate, locate mates and prey, navigate, defend their territories, and avoid predators. Noise pollution interferes with these key life functions, disrupting their natural behaviours and impeding their ability to communicate. For example, increased ship noise has caused bottlenose dolphins to simplify their vocal calls, making it harder for them to effectively convey information and find mates.

Ocean noise can also disorientate animals, especially those that rely on echolocation, such as dolphins and toothed whales. Excessive noise can disrupt their echolocation signals, causing them to become disoriented and unable to hunt successfully. Additionally, very loud noises can induce panic in marine mammals, causing them to ascend too quickly to escape the noise, which can lead to decompression sickness and tissue damage from gas bubble lesions.

Noise levels in the ocean have been increasing at an alarming rate, with some areas doubling every decade since the 1950s. This rise in noise pollution is a growing concern for the survival of marine mammals, fish, and other ocean wildlife, as well as the health of marine ecosystems. While there are currently no international legal regulations on ocean noise pollution, organizations like the International Ocean Noise Coalition (IONC) are actively advocating for the recognition and regulation of this issue.

Chemical contamination

Marine pollution is a combination of chemical contamination and trash, most of which comes from land-based sources. Chemical contamination, or nutrient pollution, occurs when human activities, such as the use of fertilisers on farms, lead to the runoff of chemicals into waterways that ultimately flow into the ocean.

The increased concentration of chemicals, such as nitrogen and phosphorus, in the coastal ocean promotes the growth of algal blooms, which can be toxic to marine life and harmful to humans. This type of pollution can hurt local fishing and tourism industries.

A host of chemical pollutants are having a harmful effect on ocean health. These chemicals come from a range of sources, including crude oil and other petroleum products, antifoulants, pesticides, pharmaceuticals, and personal care products. It is estimated that the total amount of chemicals entering the ocean rose by 12% between 2003 and 2012.

The most dangerous pollutants are those that are persistent, bioaccumulative, and toxic. Even chemicals banned decades ago, like polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), are still found in high concentrations in deep-sea creatures. Since they do not break down easily, these chemicals accumulate in marine organisms, becoming more concentrated as they move up the food chain.

Pollutants recognised as endocrine disruptors and teratogens, which impact the ability of marine species to reproduce or reduce offspring survival rates, are a growing concern. Personal care products, in particular, contain cryptic chemicals that have a significant impact on human and ocean health. For example, oxybenzone, a common ingredient in sunscreens, has been found to negatively impact coral health and reproduction.

Another concern is the presence of per- and polyfluoroalkyl substances (PFAS), which are human-made chemicals that are resistant to biodegradation and have been found in ground, surface, and drinking water. PFAS has been found to accumulate in human and marine mammal blood.

Chemical pollution can also cause oxygen depletion in seawater. As excess debris in the ocean slowly degrades over many years, it uses oxygen, resulting in less oxygen in the ocean, which can lead to the death of ocean animals such as penguins, dolphins, whales, and sharks.

Eutrophication and algal blooms

Eutrophication is a process that occurs when the environment becomes enriched with nutrients, increasing the amount of plant and algae growth in estuaries and coastal waters. It is caused by an increased load of nutrients, such as nitrogen and phosphorus, which are essential elements for plant growth. However, when there is an excess of these nutrients in a body of water, it can stimulate an overgrowth of algae, leading to algal blooms.

Algal blooms, also known as "red tides", grow rapidly and produce toxic effects that can be harmful to marine life and sometimes even humans. They can also lead to hypoxia or dead zones, where oxygen levels are depleted, making it difficult for marine life to survive. Eutrophication sets off a chain reaction in the ecosystem, starting with an overabundance of algae and plants. As the excess algae and plant matter decompose, they produce large amounts of carbon dioxide, which lowers the pH of seawater, a process known as ocean acidification. This slow growth of fish and shellfish and can even prevent shell formation in bivalve mollusks, impacting commercial and recreational fisheries.

The increase in nutrient pollution is largely due to human activities such as agriculture, industry, and sewage disposal. Runoff from farms and fertilizer use can contribute to the excess nutrients in water bodies, triggering algal blooms. Climate change and human population growth are also predicted to further degrade water quality, intensifying the problem of eutrophication.

To address eutrophication, strategies such as nutrient diversion, altering nutrient ratios, physical mixing, and application of algaecides have been employed. However, these methods have often proven ineffective or costly, especially for large and complex ecosystems. Reducing nitrogen and phosphorus inputs into aquatic systems is crucial, but it can be challenging, especially in agricultural areas.

Overall, eutrophication and algal blooms have significant ecological, economic, and health impacts, and mitigating these issues requires collective efforts from scientists, policymakers, and citizens.

Climate change

Covering about 70% of the Earth's surface, the ocean has a two-way relationship with the climate. Oceans influence the weather on local to global scales, while changes in climate can alter many properties of the oceans. Oceans absorb a lot of heat from the sun and distribute it more evenly across the planet. They also absorb carbon dioxide from the Earth's atmosphere. As greenhouse gases trap more energy from the sun, the oceans absorb more heat, resulting in rising sea surface temperatures and sea levels.

The additional heat and carbon dioxide in the ocean can change the environment for the many plants and animals that live there. Warmer waters may promote the development of stronger storms in the tropics, causing property damage and loss of life. The impacts associated with sea level rise and stronger storm surges are especially relevant to coastal communities.

Although the oceans help reduce climate change by storing carbon dioxide, increasing levels of dissolved carbon are making the seawater more acidic. This increased ocean acidity makes it more difficult for certain organisms, such as corals and shellfish, to build their skeletons and shells. These effects could substantially alter the biodiversity and productivity of ocean ecosystems.

As the Earth's climate warms, the water also warms, melting sea ice. This warming could make the water less dense and less likely to sink. Without sinking cold water, the ocean currents could slow down or stop in some places. This could change the climate in places like Europe, which has a milder climate due to the warm currents in the oceans around it.

As the Earth warms, sea levels are rising. Water expands as it gets warmer, so warm water takes up more room in our oceans, leading to higher sea levels. Another reason for rising sea levels is the melting of land-based ice, which flows into the oceans and increases the volume of water.

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