Ships' Impact: Polluting The Sea And Destroying Marine Life

Ships can pollute the sea in several ways, causing significant harm to marine life and ecosystems. One of the most well-known forms of ship pollution is oil spills, which can have devastating and long-lasting effects on the marine environment. In addition to accidental spills due to collisions or groundings, intentional spills also occur when ship operators illegally dump oily residues or wash their tanks at sea to cut costs. Another way ships pollute the sea is through ballast water discharges, which can introduce non-native species that cause ecological and economic damage to aquatic ecosystems. Noise pollution from ships can disrupt marine species that rely on sound for communication, orientation, and feeding. Air pollution from ships, including emissions of nitrogen oxides and sulfur oxides, contributes to global warming and poses risks to human health. Solid waste, plastic pollution, sewage, and greywater discharges from ships also contaminate the oceans, endangering marine life and damaging ecosystems such as coral reefs.

Ships can physically damage marine life

Cruise ships, in particular, pose a significant threat to marine life. Their entertainment activities produce high levels of noise pollution, which can harm the sensitive hearing of marine mammals such as killer whales and dolphins. The large amounts of solid waste generated by cruise ships can also injure or kill marine animals through ingestion or entanglement. Furthermore, the anchoring of cruise ships has led to several incidents involving the destruction of coral reefs, which are vital for providing shelter to marine organisms and protecting coastlines from erosion and storms.

Ships can cause noise pollution

Noise pollution from ships can have a detrimental impact on marine life. The noise produced by ships can travel long distances and harm marine species that rely on sound for orientation, communication, and feeding.

Sources of noise pollution

The sources of noise pollution in the ocean include ship engines, underwater blasts, sonar, and oil drilling. These sounds can be extremely loud and disruptive to marine life.

Impact on marine life

Noise pollution can cause behavioural changes in marine animals, such as altered movement patterns, changes in vocalisations, and increased stress levels. It can also lead to physical damage, such as hearing loss and internal organ damage.

Marine mammals, such as whales and dolphins, are particularly vulnerable to noise pollution as they rely heavily on sound for essential life functions. Noise pollution can disrupt their communication, feeding, and mating behaviours.

Mitigation strategies

Some measures have been implemented to reduce noise pollution from ships, such as using sound-absorbing ship technologies and avoiding the breeding grounds of certain marine species. Additionally, organisations like the International Maritime Organization have issued guidelines to reduce noise pollution resulting from military sonars, seismic surveys, propellers, and other sources.

Ships can cause air pollution

Secondly, ships' engines emit unwanted air pollutants, similar to vehicle exhaust tanks on roads. Research has found that the air quality on the aft areas of cruise ships, in terms of particulate matter pollution, is comparable to the air quality in major cities like Beijing. This means that the air pollution from ships can affect both the marine environment and human health, especially for the 40% of Europeans living within 50 kilometers of the sea.

Thirdly, cruise ships, in particular, contribute heavily to marine noise pollution due to their entertainment activities on board. This noise pollution disturbs and harms the sensitive hearing of marine animals and mammals, such as killer whales and dolphins, often leading to their death and causing an overall loss to the ecosystem.

Finally, while some ships have equipment called 'scrubbers' fitted to clean exhaust gases, these can end up pumping pollution into the sea instead of reducing air pollution. Therefore, it is essential to address air pollution from ships to protect both the marine environment and human health in coastal areas.

Ships can cause water pollution

Secondly, ships contribute to solid waste pollution, including plastics, paper, food waste, glass, and metals. This waste can become marine debris, posing threats to marine organisms, coastal communities, and industries that depend on marine waters.

Thirdly, ships are responsible for oil pollution, which is considered the most well-known form of environmental pollution by ships. Oil spills can occur due to accidents, such as ship collisions or groundings, or intentional discharges of oily residues and ballast water. Oil pollution has devastating and irreversible effects on marine ecosystems and biodiversity, impacting the development, reproduction, and disease resistance of marine life.

Additionally, ships generate plastic pollution through cargo losses and the illegal dumping of plastic waste into the ocean. This plastic pollution breaks down into microplastics, which disperse throughout the marine environment and are ingested by marine organisms, leading to bioaccumulation and further damaging marine ecosystems.

Furthermore, ships produce ballast water pollution. Ballast water, used to stabilise ships during travel, is often taken on in coastal waters and discharged in other regions, introducing non-native species and causing ecological and economic damage to aquatic ecosystems, as well as human health issues.

Lastly, ships emit toxic chemicals and pollutants from their engines and operations, including nitrogen oxides, sulfur oxides, and carbon dioxide. These emissions contribute to air pollution and can have indirect effects on water quality and marine life.

Overall, the impact of ships on water pollution is significant, and it is important to address and mitigate these issues to protect marine ecosystems and human health.

Ships can pollute with plastic waste

The shipping industry is a major contributor to plastic pollution in the oceans, which can be categorised as either direct or indirect. Direct plastic pollution includes cargo losses and the illegal dumping of plastic waste into the sea. Some vessels violate international regulations by discharging plastic waste directly into the ocean, while others improperly manage waste during routine operations, leading to the disposal of food packaging and other plastic items into the marine environment. Indirect plastic pollution comes from land-based sources such as trash and debris from construction, ports, marinas, and commercial and industrial facilities.

A study published in the Journal of Maritime & Transportation Science indicates that plastics make up 60-80% of marine debris. The Great Pacific Garbage Patch, a collection of marine debris in the North Pacific Ocean, is largely made up of synthetic fishing nets, ropes, bags, boxes, and other abandoned gear. While most people imagine a pile of floating garbage, around 70% of the plastics in this patch have sunk to the ocean floor.

Plastic pollution causes irreparable damage to the ocean and its ecosystems. It injures and kills fish, seabirds, and marine mammals, and has impacted at least 267 species worldwide, including sea turtles, seabirds, and marine mammals. It also pollutes the human food chain, as fish ingest plastic fragments and debris.

To address plastic pollution from shipping, a multi-level governance framework has been established, involving international organisations, national governments, businesses, and civil society. Key policies and agreements include the International Convention for the Prevention of Pollution from Ships (MARPOL), which specifically prohibits the direct discharge of plastic waste into the sea. Regional initiatives such as the Paris Memorandum of Understanding (MoU) and the EU's Marine Strategy Framework Directive (MSFD) also play a crucial role in preventing shipping-related plastic pollution.

Despite these efforts, existing mitigation measures face significant challenges. Many port waste reception facilities need improvement to effectively recycle plastic waste. Additionally, there is a lack of data and impact studies on marine biota, and the design of plastic products needs to be improved to reduce environmental harm.

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