Pollution's Impact On Marine Life: A Kid's Guide

Marine life is under immense pressure from plastic, rising temperatures, acidification, fishing, and more. Pollution can be devastating for marine life, which is often sensitive to changes in their environment.

Plastic Pollution

Plastic pollution is a huge problem for marine life. Plastic waste does not biodegrade, and can persist in the environment for a millennium, polluting beaches, entangling marine life, and being ingested by fish, whales, turtles, and seabirds.

The Great Pacific Garbage Patch is a floating body of garbage of immense size – at 620,000 square miles, it is twice the size of Texas.

Chemical Pollution

Chemical pollution is also a big problem for the oceans. Before 1972, copious toxic chemicals, industrial waste, untreated sewerage, and even millions of tons of heavy metals and radioactive material were dumped into the sea. Although regulations have increased, chemical pollution continues to be a problem, with animal agriculture being a lead cause.

Other Types of Pollution

Shallow waters near urban environments suffer from light pollution, which interferes with the circadian rhythms of coastal organisms that regulate their feeding, migratory, and reproductive habits.

Noise pollution, from sonar devices, oil rigs, and large ships, also poses problems. Mass beachings of various species of whales have been attributed to loud artificial noises caused by seismic human activity.

How does plastic pollution affect marine life?

Plastic pollution is having a devastating impact on the oceans and the animals that live there. It is estimated that up to 13 million metric tons of plastic end up in the ocean each year, and it is predicted that by 2050, plastic will outweigh all the fish in the sea.

Plastic is harmful to marine life because it does not biodegrade. It can take hundreds of years to break down, and even then, it only breaks down into tiny pieces called microplastics, which are still dangerous. These microplastics can be swallowed by marine animals, who mistake them for food. This can lead to suffocation or starvation, as the plastic fills up their stomachs with no nutritional value. It is estimated that half of all sea turtles worldwide have ingested plastic, often mistaking plastic bags for jellyfish. Plastic can also cause internal injuries and death in marine animals, as well as transferring toxic chemicals up the food chain to bigger fish, marine mammals, and eventually humans.

Large pieces of plastic can entangle marine animals, trapping and injuring them and making them more vulnerable to predators. An estimated 300,000 whales, dolphins, and porpoises die each year from becoming entangled in discarded fishing gear. Plastic debris can also smother and break coral reefs, preventing their healthy growth.

The impact of plastic pollution on marine life is widespread and severe. It affects at least 800 species worldwide, including 86% of all sea turtle species, 44% of all seabird species, and 43% of all marine mammal species. It is important to reduce, recycle, and reuse plastic to help mitigate the harmful effects of plastic pollution on marine ecosystems.

How does noise pollution affect marine life?

Noise pollution in the ocean has increased dramatically over the last few decades. As most marine species are highly dependent on sound for their survival, this type of pollution is extremely damaging to marine wildlife. It interferes with the key life functions of these animals and can even cause death.

Many marine animals are highly dependent on underwater sound. Visibility is often low, but sound is transmitted extremely well through water. As a result, sound has evolved as an important sensory signal for marine wildlife, particularly for marine mammals such as whales, dolphins, and porpoises. They rely on sound to communicate, locate mates and prey, avoid predators, navigate, and even defend their territories.

Noise pollution in the marine environment is threatening the natural soundscape of the ocean. Ships, seismic surveys, explosions, construction, and sonar devices have turned the once peaceful environment into a loud, chaotic home which is extremely damaging for marine wildlife.

• Hearing loss: Very loud sounds can harm marine mammals. If the animal is too close to the source of the sound, they panic and ascend too quickly to escape the noise. This has been known to cause decompression sickness, which can lead to tissue damage from gas bubble lesions.
• Behavioural changes: A foreign sound can disrupt the natural behaviour of marine mammals. They might move away from the noise, adjust their activities to avoid the noisy times of day, or increase their anti-predatory behaviour.
• Interference with communication: Noise pollution can interfere with the detection of acoustic signals in the marine environment. This means that the sound we are creating in the ocean is masking the sounds produced by marine wildlife. This can lead to changes in individual and social behaviour, altered metabolisms, and hampered population recruitment, which in turn can affect the health and service functions of marine ecosystems.
• Death: In some cases, noise pollution can even cause death in marine wildlife.

How does chemical pollution affect marine life?

Chemical pollution is a major problem for the oceans and has devastating effects on marine life, which is often sensitive to changes in its environment. Chemical pollution can enter the ocean through various sources, such as industrial waste, untreated sewage, and agricultural runoff. Here are some ways in which chemical pollution impacts marine life:

• Toxicity: Chemical pollution can be toxic to marine organisms, causing harm or even death. For example, pollutants like mercury and pesticides can accumulate in the tissues of fish and other marine creatures, leading to health issues and population declines.
• Disruption of Food Webs: Chemical pollution can disrupt the marine food web by affecting the health and abundance of various species. For instance, pollutants may reduce the population of certain species, leading to a decrease in the number of predators or causing an increase in the population of prey species.
• Alteration of Ocean Chemistry: Chemical pollution can alter the chemistry of the ocean, such as increasing acidity levels, which can have detrimental effects on marine life. For instance, increased ocean acidification can dissolve the shells of marine organisms like mussels and oysters.
• Bioaccumulation and Biomagnification: Some chemicals can accumulate in the tissues of marine organisms over time, leading to higher concentrations in predators at higher trophic levels. This process, known as bioaccumulation, can result in toxic effects on marine life, especially top predators.
• Harmful Algal Blooms (HABs): Chemical pollution, particularly nutrient runoff from agriculture, can contribute to the growth of harmful algal blooms. These blooms can produce toxins that are harmful to marine life and can also impact oxygen levels in the water, leading to "dead zones" where marine life cannot survive.
• Impacts on Coral Reefs: Chemical pollution can have detrimental effects on coral reefs, which are vital habitats for a diverse range of marine species. For example, pollutants can cause coral bleaching, impair the development of coral reefs, and increase their vulnerability to diseases.
• Disruption of Marine Ecosystems: Chemical pollution can disrupt the delicate balance of marine ecosystems, leading to changes in species composition and biodiversity. This can have far-reaching consequences for the entire food web and the overall health of the ocean.
• Threats to Human Health: Chemical pollution in the ocean can also pose risks to human health. Contaminated seafood, for example, can lead to the ingestion of harmful chemicals, posing risks to consumers.

How does light pollution affect marine life?

Light pollution is a human-made alteration of outdoor light levels from those occurring naturally. It has harmful effects on wildlife and ecosystems, energy and climate change. Sources of light pollution include streetlights, greenhouses, and satellites.

Light pollution interferes with the natural light cues that marine organisms rely on for essential activities such as eating, mating, and camouflage. It can also disrupt their natural rhythms, threatening their habitats.

For example, light pollution lures sea turtle hatchlings away from the ocean, causing them to perish from exhaustion or predators. It also inhibits the reproduction of coral reefs, which provide food and shelter for many sea creatures.

Additionally, light pollution can alter the behavior of zooplankton, a foundational organism in aquatic food chains. It can also impact the feeding, schooling, and migration of radiated fin fish, which depend on specific light intensities.

The widespread use of LED lighting exacerbates the problem, as LEDs typically produce light with shorter wavelengths that can penetrate deeper into the water.

Efforts to reduce light pollution can include enforcing ordinance laws that require residents to turn off beach-facing lights at night, incorporating environmentally friendly lighting systems, adopting automatic lighting systems, and erecting coastal barriers to contain light pollution.

It is important to address light pollution through better lighting practices and the creation of Dark Sky Reserves to preserve essential marine habitats.

How does water pollution affect marine life?

Water pollution has a devastating impact on marine life, which is often sensitive to changes in its environment. Water pollution can be defined as the unwanted waste released into water bodies by human activity. Water pollution can take many forms, including plastic pollution, chemical pollution, noise pollution, and light pollution.

Plastic pollution

Plastic pollution is one of the most pressing issues facing marine life. Plastic waste does not biodegrade and can persist in the environment for up to a millennium, polluting beaches, entangling marine life, and being ingested by fish, whales, turtles, and seabirds. Plastic pollution can also lead to the death of marine mammals, such as whales, as they mistake plastic bags for jellyfish and eat them. Plastic pollution can also release toxic chemicals into the water, which can be harmful to marine life.

Chemical pollution

Chemical pollution is another major issue, with animal agriculture being a leading cause. Fertilizers, herbicides, and pesticides from farms can leak into rivers and eventually make their way into the ocean. Other chemical pollutants include crude oil, which has been responsible for oil spills such as the Deepwater Horizon disaster. Chemical pollution can have devastating effects on marine life, causing toxic algae blooms that can kill marine life and create "dead zones" hundreds of miles long.

Noise pollution

Noise pollution from human activities such as sonar devices, oil rigs, and large ships can also harm marine life. Mass beachings of whales have been attributed to loud artificial noises, which can panic and disorient the animals.

Light pollution

Light pollution, particularly in shallow waters near urban areas, can interfere with the circadian rhythms of coastal organisms, affecting their feeding, migration, and reproductive habits. It can also make it easier for predators to hunt small fish and damage the breeding capabilities of reef fish.

Frequently asked questions