Human Impact: Ocean Pollution And Its Devastating Effects

Humans are the primary drivers of ocean pollution, whether they live near the coast or far inland. The ocean is being flooded with a variety of pollutants, including trash, noise, oil, carbon emissions, agricultural waste, chemical pollutants, light, and plastic. These pollutants enter the ocean through runoff, littering, poor waste management, storm winds, faulty factories, and water treatment systems. Plastic pollution is particularly problematic due to its long-lasting nature, with plastic items taking hundreds of years to decompose. Microplastics, which are tiny plastic particles, are ingested by marine life and accumulate in their tissues, eventually entering the human food chain. Chemical pollutants, such as mercury, lead, pesticides, and other heavy metals, contaminate water supplies and the food chain, leading to health issues in both marine life and humans. Ocean pollution has far-reaching consequences, damaging marine ecosystems, impairing atmospheric oxygen production, and posing risks to human health.

Agricultural pollution from farms and fish farming

Humans are the primary drivers of ocean pollution, regardless of whether the pollution comes from factories or farms. One of the main sources of ocean pollution is agricultural pollution, which includes both farms that raise crops and animals, as well as fish farms.

Farms

Agricultural pollution from farms occurs when manure, fertiliser, and other farm waste are washed into nearby water bodies during storms or when soil is saturated. This waste contains excess nutrients such as nitrogen and phosphorus, which can cause eutrophication. Eutrophication occurs when certain types of seaweed and algae grow rapidly due to the excess nutrients, depleting oxygen levels in the water and blocking sunlight from reaching underwater plants. This creates 'dead zones' where marine life cannot survive, affecting both wild and farmed fish.

Untreated sewage and manure from farms can also contaminate water supplies, posing risks to human health and the environment. Furthermore, farm waste can contain harmful chemicals such as antibiotics, which can contribute to the emergence of antibiotic-resistant bacteria and impact our ability to treat diseases.

Fish Farms

Fish farming, or aquaculture, is a significant contributor to ocean pollution, particularly when it occurs in open water systems. Fish farms allow parasites, waste, pesticides, fertilisers, and antibiotics to flow freely into the ocean. The waste produced by fish farms can smother plants and animals on the seabed, creating uninhabitable conditions for other species.

Additionally, fish farms can be breeding grounds for diseases, which can then spread to wild fish populations. The escape of farmed fish into the wild can also introduce alien species, create unnatural competition, and further transmit diseases.

The use of wild fish as feed for carnivorous farmed fish, such as salmon, further contributes to the depletion of wild fish stocks and can impact ocean ecosystems.

Governance and Solutions

The impact of agricultural pollution from farms and fish farming on coastal resources and marine life underscores the need for effective governance frameworks that address the interconnectedness of land and sea. Integrated land-sea management approaches are essential to mitigating the detrimental effects of human activities on coastal ecosystems.

To create a sustainable future for the fish farming industry, it is crucial to minimise pollution, disease, farmed fish escapes, and habitat damage. This can be achieved through regulatory enforcement, habitat protection, and the reduction of wild fish feed. The development of alternative diets, such as plant-based feeds, is also being explored to reduce the industry's environmental impact.

Chemical pollution from oil, mercury, pesticides, and other heavy metals

Marine pollution is a pressing issue, with chemicals and trash being the two main types of pollution. Chemical pollution from oil, mercury, pesticides, and other heavy metals has severely impacted the ocean and marine life.

Oil pollution is a significant concern, with point source pollution from oil spills being a major contributor. Point source pollution refers to pollution that comes from a single source, such as an oil or chemical spill. While these events are less frequent, they can have devastating impacts on the environment. Nonpoint source pollution, on the other hand, occurs as a result of runoff from various sources, such as septic tanks, vehicles, farms, and industrial discharge. This type of pollution can lead to the contamination of waterways and, ultimately, the ocean.

Mercury pollution is another critical issue affecting the ocean. Mercury is a toxic heavy metal that can have severe impacts on both human and animal health. The natural mercury cycle allows mercury to move across the globe, affecting various parts of the world. The ocean acts as a "storage closet" for mercury, and it has been estimated that a significant amount of anthropogenic mercury is present in waters shallower than 1000 meters, where consumable fish live. Mercury methylation, particularly in polar regions, has been linked to the production of methylmercury, a highly toxic compound that can bioaccumulate in marine food chains, ultimately reaching humans through seafood consumption.

Pesticide pollution is a global concern, with an estimated 3-7 million tons of pesticides produced annually. Pesticides can contaminate water bodies through chemical runoff from improper storage, disposal, spills, and inappropriate application. Both point source and nonpoint source pollution contribute to the presence of pesticides in aquatic habitats. The toxicity of pesticides can lead to acute poisoning symptoms, such as stinging eyes, rashes, and nausea, as well as chronic health conditions that may manifest over time.

Heavy metals and other contaminants, including pesticides and microplastics, can accumulate in seafood, making it harmful for human consumption. Microplastics, plastic particles smaller than 5 mm, are ingested by marine organisms, which then become part of the food chain. As small organisms are eaten by larger animals, the toxic chemicals are transferred up the food chain, eventually reaching humans.

Light pollution from artificial sources like boats and offshore mining platforms

Light pollution is a human-made alteration of outdoor light levels from those occurring naturally. It has been found to negatively impact marine life. Coastal cities, ships, and offshore oil rigs are some of the sources of artificial light that flood the ocean, impacting a wide range of sea creatures, from zooplankton to whales.

Artificial night sky brightness can harm creatures that dwell in the ocean depths. Marine animals' natural rhythms are disrupted by light pollution, threatening their habitats. For example, sea turtles are disoriented by artificial light, and their offshore dispersal is compromised by light pollution from land-based or marine structures.

Light pollution from boats and ships can also affect seabirds. They can encounter extremely light-polluted areas associated with vessels or light-enhanced fisheries.

Offshore mining platforms can also contribute to light pollution. Deep-sea mining efforts may increase light levels to illuminate the bottom, affecting the environment of the mining sites as they are normally pitch-black. Shrimp found at hydrothermal vents suffered permanent retinal damage when exposed to submersible floodlights.

To address light pollution, it is important to consider the amount of artificial light needed and the appropriate colour. By applying these considerations, properly designed lighting can be beautiful, healthy, and functional.

Noise pollution from marine traffic and the fossil fuel industry

Humans are the primary drivers of ocean pollution, which can manifest in various forms, including agricultural, chemical, light, noise, and plastic pollution. Noise pollution, caused by marine traffic and the fossil fuel industry, has detrimental effects on marine life.

Marine traffic, including cargo ships and container carriers, tankers and small motorboats, contributes significantly to noise pollution in the ocean. As ship transportation increases, the sounds produced by these vessels alter the ocean soundscape and act as stressors for marine ecosystems. Studies have shown that while these noises may not impact humans, they can be extremely harmful to marine life, particularly cetaceans like whales and dolphins, which rely primarily on acoustics for communication and navigation.

The use of seismic airguns in the search for oil and gas deposits on the seafloor is a significant contributor to noise pollution from the fossil fuel industry. These airguns produce extremely loud blasts that can be repeated every few seconds, 24 hours a day, for extended periods. The blasts generate immense acoustic energy that propagates through the ocean, disrupting the lives of marine animals, including dolphins and whales.

The adverse effects of noise pollution on cetaceans have been well documented. Studies have shown that increased noise pollution leads to a decline in cetacean populations, with whales and dolphins struggling to communicate and navigate effectively. Additionally, noise pollution can cause stress in these acoustic animals, as evidenced by changes in hormone levels during quieter periods.

Plastic pollution from disposable and single-use plastic items

Plastic pollution is one of the most pressing environmental issues today. Humans are the primary drivers of ocean pollution, and plastic waste makes up 80% of all marine pollution. The production of disposable plastic products has increased exponentially, with plastic pollution being most visible in developing Asian and African nations, where garbage collection systems are often inefficient or non-existent. Even in the developed world, countries with low recycling rates struggle to properly collect discarded plastics.

The majority of plastic pollution in the ocean is caused by littering. Humans buy or use disposable plastic items such as food wrappings, plastic bags, razors, and bottles, and do not dispose of them properly, leading to their eventual journey into the ocean. Marine plastic debris often groups up in garbage patches in the center of the ocean's gyres. The biggest is the Great Pacific garbage patch, located between Hawaii and California.

Once in the ocean, sunlight, wind, and wave action break down plastic pollution into microplastics, often less than one-fifth of an inch across. These microplastics spread throughout the water column and have been found everywhere, from Mount Everest to the Mariana Trench. They are ingested by marine life, including fish and other species that filter their food from the water. These microplastics have also been found in humans, with particles present in our blood, lungs, and even feces.

To reduce plastic pollution, scientists and conservationists advocate for improved waste management systems, better recycling practices, product design changes, and a reduction in the manufacturing of single-use plastics. The best way to tackle this issue is to prevent plastics from entering waterways by addressing the root cause: the production and usage of disposable and single-use plastic items.

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