The Ocean's Plight: Understanding Sea Pollution Causes

The oceans are among the earth's most valuable natural resources, covering more than 70% of the planet. They are home to most of the life on earth, from microscopic algae to the blue whale, the largest animal on the planet. However, human activities are causing significant harm to marine ecosystems through pollution in the form of trash, noise, oil, carbon emissions, and more. This paragraph will explore the various causes of sea pollution and their impacts on the environment and human health.

Land-based pollution

Eighty percent of marine pollution comes from land-based sources. One of the biggest sources of this is 'runoff' pollution. This occurs when chemicals, oils, and other contaminants are washed from the land into the sea via sewer, drain, and river systems. For example, surface runoff from farming, urban areas, and construction can carry soil and particles laden with carbon, nitrogen, phosphorus, and minerals into the sea. This nutrient-rich water causes algal blooms, which reduce oxygen levels in the water and create "dead zones" where marine life cannot survive.

Another significant contributor to land-based sea pollution is waste and litter, particularly plastic. Plastic debris and waste are suffocating marine life and turning oceans into "trash soup". Plastic does not biodegrade quickly, so it accumulates in the sea, forming garbage patches. The Great Pacific Garbage Patch in the North Pacific Ocean is composed of two separate patches and is made up primarily of microplastics. However, the largest single type of plastic pollution is discarded and lost nets from the fishing industry.

Inland mining is another source of marine pollution. Soil from mining sites ends up in rivers that flow to the sea, and some of the minerals discharged during mining, such as copper, can interfere with the life history and development of coral polyps. Mining has a poor environmental track record, with the United States Environmental Protection Agency reporting that mining has contaminated portions of the headwaters of over 40% of watersheds in the western continental US.

Excess chemical fertilisers also contribute to land-based sea pollution. These fertilisers eventually make their way into the oceans, where they can cause algal blooms. Single-use plastic bottles, eating utensils, and straws are also massive ocean polluters.

Noise pollution is another form of land-based sea pollution. An increasing barrage of human-generated noise is altering the underwater acoustic landscape and harming marine species worldwide. For example, the constant din of commercial tanker and container ships, as well as high-intensity sonar used by the U.S. Navy, has been linked to mass whale strandings.

Oil spills

Cleanup operations for oil spills can be challenging and time-consuming, requiring expensive management and disrupting port activity. While techniques such as skimming, in situ burning, and chemical dispersants can be used to remove oil from the water's surface, they may never completely eliminate all traces of the spill. It is crucial for ports to manage and mitigate oil spills effectively to limit the potential damage to ships and shipping operations.

To address the problem of oil spills, regulations and innovations have been implemented. For instance, MARPOL made it mandatory for large tankers to be fitted with double hulls, significantly reducing the number and volume of oil tanker spills. The Oil Pollution Act of 1990 also established that those responsible for oil spills can be held accountable for paying cleanup and restoration costs.

Marine debris

One of the primary sources of marine debris is littering and poor waste management practices. Plastic pollution, in particular, is a pressing issue, with plastics such as bottle caps, balloons, lighters, and microplastics ending up in the ocean. These plastics are often mistaken for food by marine wildlife, leading to internal injuries, intestinal blockages, and even death. Additionally, debris such as packing bands, balloon strings, and six-pack rings can cause entanglement and strangulation.

Another source of marine debris is ocean-based activities, including fishing and shipping. Derelict or lost fishing gear, such as nets and lines, can continue to capture and kill marine animals, damage sensitive habitats, and interfere with active fishing gear. Similarly, shipping activities contribute to marine debris through the release of crude oil during oil spills, which can have long-lasting impacts on the marine environment.

The accumulation of marine debris in the ocean leads to the formation of garbage patches, which are influenced by ocean currents and winds. These garbage patches can be found from the surface of the ocean to the ocean floor and pose a significant threat to marine life and ecosystems. The ingestion and entanglement risks associated with marine debris harm various species, including sea turtles, seabirds, and marine mammals.

The impacts of marine debris extend beyond the immediate harm to wildlife. It can also cause economic losses to the fishing and maritime industries, degrade the quality of life in coastal communities, and threaten human health and safety. Additionally, the breakdown of plastics in the ocean can release toxic chemicals, further contaminating the marine environment and entering the food chain.

Addressing the issue of marine debris requires a combination of local, national, and international efforts. Public awareness and education play a crucial role in preventing marine debris through responsible waste management and reduced pollution. Additionally, legislative actions, such as the Save Our Seas Act, aim to promote international cooperation and response to marine debris.

Noise pollution

Marine mammals, such as whales, dolphins, and porpoises, are highly dependent on underwater sound for critical activities like breeding, foraging, maintaining social structure, and avoiding predators. Noise pollution interferes with their ability to detect natural acoustic signals, disrupting their natural behaviours and communication. For example, increased ship noise has caused bottlenose dolphins to simplify their vocal calls, potentially reducing the information content of their calls and hindering effective communication.

The effects of noise pollution extend beyond the directly impacted species. As marine ecosystems are interconnected, altering the behaviour of one species can have indirect consequences for others. For instance, if noise pollution drives whales away from their usual feeding grounds, it can affect the species that depend on the whales' presence for their own food sources or ecological balance.

To mitigate the impacts of noise pollution on marine life, several actions have been proposed. These include implementing policies to reduce propeller noise from ships, mitigating the sounds of sonar equipment, and developing quieter technologies. By addressing these issues, we can improve the ocean soundscape and potentially enable the recovery of marine life, ensuring their survival and well-being.

Sewage and septic systems

Once sewage enters the ocean, it can have devastating effects on marine life and ecosystems. Sewage can contain high levels of nutrients, such as nitrogen and phosphorus, which can cause excessive growth of algae, known as algal blooms. These algal blooms can reduce oxygen levels in the water, creating "dead zones" where marine life cannot survive. The excess nutrients and chemicals in sewage can also contaminate waterways, making them toxic to aquatic life and entering the food chain as predators consume contaminated prey.

Additionally, sewage can introduce harmful bacteria, viruses, and parasites into the marine environment, posing risks to both marine organisms and human health. High levels of pathogens in sewage can lead to waterborne diseases and infections, affecting marine life and humans who come into contact with contaminated water.

To prevent sewage-related sea pollution, proper maintenance and management of septic systems are crucial. This includes regular inspections, timely repairs, and responsible waste disposal practices. It is essential to educate communities about the impacts of improper waste disposal and to implement measures to reduce sewage discharge into the ocean, such as improved wastewater treatment processes and stricter regulations.

Furthermore, investing in infrastructure upgrades and adopting sustainable practices can help mitigate the impact of sewage on marine environments. By implementing natural or organic alternatives to chemical fertilizers, we can reduce the excess nutrients that contribute to algal blooms. Individual actions, such as reducing single-use plastic products and properly disposing of waste, can also play a significant role in minimizing sewage-related sea pollution.

Frequently asked questions