Chemical Pollution: Marine Life's Silent Killer

Marine pollution is a growing concern, with chemicals and trash from human activities on land and at sea causing severe damage to marine habitats. Chemical pollution, such as nutrient runoff from farms and factories, crude oil, and pesticides, has detrimental effects on marine life and ecosystems. These pollutants can lead to toxic algal blooms, reduce oxygen levels, and poison marine animals and humans. Plastic pollution, including microplastics, is also a significant issue, with plastic debris smothering and entangling wildlife, altering habitats, and being ingested by marine organisms, leading to health issues and death. The accumulation of chemicals and plastics in the food chain further exacerbates the problem, impacting larger animals and humans who consume contaminated seafood. Additionally, light pollution from coastal urban areas disrupts the physiological behaviours of marine wildlife, affecting migration, reproduction, and feeding patterns. The combination of chemical and plastic pollution poses a severe threat to the health and biodiversity of marine habitats, with far-reaching consequences for both marine life and human communities.

Plastic pollution

One of the biggest threats posed by plastic pollution to marine habitats is the ingestion of plastic by marine organisms. Marine species, from seabirds to whales, fish, and turtles, mistake indigestible plastic waste for food. This leads to internal injuries, starvation, and suffocation. Research indicates that half of the sea turtles worldwide have ingested plastic, and it is estimated that plastic contributes to the death of more than 100,000 marine mammals every year.

Another threat is the entanglement of marine organisms in plastic debris, such as discarded fishing nets and abandoned vessels. This can restrict their movement, cause injury, and make them more vulnerable to predators. Plastic debris can also smother and crush coral reefs, preventing their healthy growth.

In addition, microplastics, which are plastic particles smaller than 5 mm, have been detected in a range of marine species, including plankton, mussels, and whales. As these small organisms are eaten by larger animals, the toxic chemicals from the plastic become part of their tissues, migrating up the food chain and eventually reaching humans.

To address plastic pollution, global efforts are needed to reduce plastic production, phase out harmful products and chemicals, and improve waste management practices. Many countries have already taken action, with over sixty enacting regulations to limit or ban disposable plastic items.

Oil spills

Cleanup efforts after oil spills can also impact wildlife. For example, the use of dispersants to increase the rate of oil degradation can further harm bird feathers and cause oil particles to disperse deeper into the water column, affecting benthic animals in deeper waters.

Eutrophication

Cultural eutrophication, or man-made eutrophication, occurs when sewage, industrial wastewater, fertilizer runoff, and other nutrient sources are released into the environment. Nutrient pollution is a major cause of eutrophication, leading to algal blooms and excess growth of aquatic plants. Phosphorus and nitrogen are the two main nutrients that cause cultural eutrophication as they enrich the water, promoting the growth of algae. When soluble nitrogen becomes limiting and phosphorus inputs remain significant, the formation of floating algal blooms is commonly observed as nitrogen-fixing cyanobacteria.

The increased growth of algae and plants can lead to overcrowding and competition for sunlight, space, and oxygen. When algae and plants die, their decomposition by bacteria consumes oxygen, creating hypoxic or anoxic conditions that can be harmful to fish and other aquatic organisms. This process can also alter the overall plant community by shading out benthic plants. Additionally, the selection for algal and aquatic plant species that thrive in nutrient-rich conditions can cause structural and functional disruption to aquatic ecosystems and their food webs, resulting in a loss of habitat and biodiversity.

To combat eutrophication, various policies and approaches have been introduced, including the United Nations Development Program's sustainability development goals. Preventing and minimizing point source pollution from sewage and agriculture, as well as reducing nutrient inputs, are crucial steps in managing eutrophication.

Industrial chemicals

Marine pollution is a growing concern, with chemicals and trash entering the ocean and causing damage to the environment, wildlife, and human health. Industrial chemicals are a significant contributor to this issue.

Industrial pollution refers to waste generated from industries, such as factory runoff and chemical contamination. This type of pollution includes a range of harmful substances, such as acids, alkaline, scrap metals, sludge, and coal ash. Industrial chemicals can enter water bodies through runoff from factories, farms, and other industrial sites. For example, nonpoint source pollution occurs when rain or snow moves pollutants from roads, farms, or industrial sites into nearby waterways that eventually flow into the ocean.

One of the most well-known examples of industrial chemical pollution is the use of pesticides, such as DDT, which accumulate in the food chain. These chemicals climb up the food chain, causing diseases and killing birds that consume marine animals. The accumulation of these chemicals in top predators like bald eagles led to their inclusion on the endangered species list in the United States.

Another significant impact of industrial chemicals is the contamination of water with nutrients, leading to eutrophication and algal blooms. Excessive nutrients, such as nitrogen and phosphorus from fertilizer runoff, stimulate the rapid growth of algae, resulting in harmful algal blooms or "red tides." These blooms can be toxic to marine life and humans, and when they die off, they deplete oxygen levels in the water, creating "dead zones" where marine organisms struggle to survive.

Additionally, industrial chemicals can have toxic effects on marine life and ecosystems. For instance, personal care products contain cryptic chemicals that negatively impact coral health and reproduction. Oxybenzone, a common ingredient in sunscreens, has been found to harm coral reefs, which are vital habitats supporting diverse communities of plants, fish, and other organisms.

Furthermore, industrial chemicals can also affect human health. Per- and polyfluoroalkyl substances (PFAS) are human-made chemicals resistant to biodegradation. These chemicals have been found in water sources and can enter the human body through contaminated marine mammals. PFAS compounds can disrupt the life cycles of aquatic organisms and potentially impact human health.

Light pollution

Research scientist Christopher Kyba notes that the introduction of artificial light is "the most drastic change human beings have made to their environment." Light pollution turns night into day, impacting the behaviour of predators and prey. It also affects the breeding rituals of amphibians and interferes with the nocturnal activity of birds, drawing them off course and towards dangerous landscapes.

Sea turtles are another example of a species negatively impacted by light pollution. Female sea turtles avoid artificial light when looking for a spot to lay their eggs, sometimes avoiding coming ashore altogether. Hatchlings are drawn towards inland lights instead of the moonlight reflecting on the water, leading to dehydration and starvation.

With the increasing urbanisation and coastal development, light pollution is expected to grow, causing more harm to marine ecosystems. It is imperative to address this issue and reduce light pollution to protect the health of marine environments and the species that depend on them.

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