Human Impact: Ocean Pollution And Our Role

Humans are the primary drivers of ocean pollution, which comes in many forms, including agricultural, chemical, light, noise, and plastic pollution. Eighty percent of ocean pollution originates on land, caused by runoff from individual cars, boats, farms, and construction sites, as well as industrial releases of toxic waste. This pollution has severe consequences for marine life, such as oil spills that ensnare and suffocate animals, and plastic debris that is mistaken for food or entangles marine creatures. Additionally, it poses risks to human health, as seafood is often contaminated with plastics, toxic chemicals, and metals, leading to various diseases and disorders.

Agricultural pollution

Intensive livestock farming and aquaculture practices have widespread negative consequences on marine ecosystems. For example, concentrated waste from intensive fish farming can pollute the water and smother plants and animals on the seabed. Additionally, the overuse of chemical treatments, such as medicinal sea lice treatments and antibiotics, can negatively impact other marine life and contribute to the emergence of antibiotic-resistant bacteria, compromising our ability to treat human diseases.

Agricultural practices can also contribute to climate change, which exacerbates the impacts of ocean pollution. For example, the burning of coal releases mercury into the atmosphere, which eventually washes into the sea, leading to mercury pollution in the ocean. Additionally, population growth, industrialization, and climate change are driving fundamental changes in coastal ecosystems, highlighting the urgent need for integrated land-sea governance and sustainable practices.

Chemical pollution

Mercury pollution, for instance, is widespread and has multiple sources. Coal burning, industrial runoff, and coal power plant wastewater are significant contributors to mercury contamination in the oceans. When coal is burned, the mercury it contains vaporizes, eventually making its way into the ocean. Mercury accumulates in fish, particularly predator species, and poses risks to human health when consumed. This includes documented dangers to infants, children, and adults.

Cadmium and lead are other toxic metals released from plastics and industrial sources. These metals can reattach to plastic consumed by marine life and subsequently enter the human food chain. Oil pollution is another concern, with oil spills causing the suffocation and death of marine animals and impairing the ability of seabirds to fly or feed their young. Oil also breaks down into microplastic and nanoplastic particles, which can contain manufactured chemicals and further endanger marine life and humans.

Agricultural pollution, including chemical fertilizers, pesticides, and waste from fish farming, also contributes to chemical pollution in the oceans. Excess nitrogen and phosphorus from these sources lead to oxygen depletion in the ocean, creating dead zones where marine life struggles to survive. Furthermore, coastal pollution increases the frequency of harmful algal blooms (HABs), which produce toxins that accumulate in seafood and can cause serious illnesses, including dementia, amnesia, paralysis, and even death in humans who consume contaminated seafood.

"Forever chemicals", so-called due to their persistence in the environment, are another source of chemical pollution. These chemicals are found in a variety of products, from food packaging to fabrics, and have made their way into various marine species, including wild-caught fish. The complex mixture of toxic substances in the ocean poses a significant threat to both marine ecosystems and human health, underscoring the urgent need to address and reduce chemical pollution.

Light pollution

One of the most well-known examples of the impact of light pollution on marine life is the case of sea turtles. Artificial light from coastal cities disrupts the nesting sites of adult female sea turtles, who struggle to find suitably dark beaches for laying their eggs. The lights also confuse hatchling sea turtles, who become disoriented and struggle to find their way after emerging from their nests at night.

Additionally, light pollution has been found to cause stress in corals, and the fish that live in symbiosis with them experience sleep deprivation, leading to DNA damage in their brains. While some species may benefit from the increased light, such as nocturnal hunters, the overall impact on the ecosystem is disruptive.

The issue of light pollution in oceans is gaining recognition, with the United Nations adopting light pollution guidelines in 2020 as part of the Convention on the Conservation of Migratory Species of Wild Animals. Scientists continue to study the effects of artificial light on marine life, and coastal cities can play a role in mitigating these impacts by addressing the use, duration, and intensity of their lighting choices.

Noise pollution

Ocean noise pollution is a form of environmental pollution caused by human activities such as commercial shipping, oil exploration, seismic surveys, offshore wind turbine installation, and military sonar. These activities generate unnatural and excessive sound underwater, which can have detrimental effects on marine life.

Marine animals, such as dolphins, whales, and porpoises, rely heavily on sound for communication, locating mates and prey, navigating, and defending their territories. The excessive noise created by human activities can interfere with these natural sounds, disrupting their behaviours and communication abilities. For example, increased ship noise has led to bottlenose dolphins simplifying their vocal calls, potentially reducing the effectiveness of their communication.

To address this issue, there have been efforts to implement policies and regulations to reduce noise pollution. The European Commission, for instance, has set mandatory caps on underwater noise from human activities at sea. Local governments and individual ports have also established their own regulations, such as the Port of Vancouver offering discounts to vessels that comply with environmental guidelines.

Furthermore, there is a growing recognition of the need for quieter technologies and better maintenance of equipment to reduce noise at the source. By reducing anthropogenic noise in the marine environment, we can improve the ocean soundscape and potentially enable the recovery of marine life, making it easier for them to cope with other human-induced stressors.

Plastic pollution

The majority of plastic pollution in the ocean is caused by littering of disposable plastic items such as food wrappings, plastic bags, bottles, and razors. However, not all plastic waste in the ocean is due to littering; about 20% comes from industrial fishing, and a significant portion comes from manufacturing processes. In addition, plastic pollution in the ocean originates from land runoff, paint shed from shipping, discarded fishing gear, tyre abrasion, construction, and agriculture.

Plastic is extremely durable and can take hundreds of years to degrade, if it degrades at all. As a result, plastic pollution has severe consequences for marine life and human health. Marine animals such as birds, whales, fish, and turtles mistake plastic waste for food, leading to starvation, internal injuries, and reduced ability to swim and fly. As plastic breaks down into microplastics, they are easily ingested by marine life, including fish and shellfish, leading to physical harm and toxic exposure. These microplastics then move up the food chain, posing risks to human health. Consumption of seafood contaminated with microplastics has been linked to digestive issues, immune system effects, miscarriage, obesity, cardiovascular disease, and long-term risks like cancer.

To address plastic pollution in the ocean, a global plastics treaty is needed to reduce plastic production, phase out harmful products and chemicals, and implement strong national plans and compliance mechanisms. Banning single-use plastics and transitioning to renewable energy sources are also crucial steps in mitigating this issue.

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