Understanding Marine Life Pollutants: A Comprehensive Guide

Marine pollution is a pressing issue that poses a serious threat to the health and well-being of our planet. Oceans cover over 70% of the Earth's surface and are home to most of the life on the planet. However, human activities have led to the oceans being bombarded with various pollutants, including trash, noise, oil, and carbon emissions. One of the main types of pollution is plastic pollution, with single-use plastic items such as bags, bottles, and straws being a significant contributor. These plastics can take hundreds of years to decompose, persisting in the environment and harming marine life. Other pollutants include chemical contamination, noise pollution, and oil spills, all of which have detrimental effects on marine ecosystems and the coastal economies that depend on them.

Plastic pollution

Sources of Plastic Pollution

Impact on Marine Life

Furthermore, plastic pollution affects the reproduction rates of sea turtles by altering the temperature of the sand where incubation occurs. Recent studies also indicate that corals that come into contact with plastic have an 89% chance of contracting diseases, compared to a 4% likelihood for corals that do not.

Addressing Plastic Pollution

The durability of plastic, which can take hundreds of years to degrade, exacerbates the long-term environmental impact. However, there are efforts to address this issue. The Global Partnership on Plastic Pollution and Marine Litter (GPML) was formed in 2012 to bring together various actors to strengthen coordination and scale up efforts to tackle plastic pollution worldwide. Additionally, encouraging recycling and reuse, as well as promoting biodegradable plastics and a "zero-waste" philosophy, are essential steps in mitigating the plastic pollution crisis.

Chemical pollution

Marine life is affected by a variety of chemical pollutants, which are released into the ocean through human activities. These chemical contaminants include pesticides, herbicides, fertilizers, detergents, oil, industrial chemicals, and sewage.

Pesticides, Herbicides, and Fertilizers

Farmlands are often treated with fertilizers, which can eventually find their way into local streams and estuaries. This excess of nutrients causes massive blooms of algae, which rob the water of oxygen, creating dead zones where marine life cannot survive. Herbicides and pesticides can also find their way into the ocean, harming marine life and disrupting the food chain.

Detergents and Industrial Chemicals

Detergents and industrial chemicals are also common pollutants that reach the ocean. These chemicals can be toxic to marine life and can accumulate in the water, leading to long-lasting environmental damage.

Oil and Sewage

Oil spills are a significant source of chemical pollution in the ocean. Oil can suffocate marine animals by permeating their gills and feathers, and it can also cause cancer and behavioural changes, impacting their ability to reproduce. Sewage overflow from water treatment systems can also introduce harmful bacteria and viruses into the marine environment, affecting both marine life and human health.

Microplastics

Microplastics, which are tiny plastic particles that break down from larger plastic items, are another form of chemical pollution. These microplastics are ingested by small organisms, which are then eaten by larger predators, allowing the chemicals to move up the food chain and eventually end up in the seafood we consume.

Long-term Impact

Many chemical pollutants are persistent in the environment and can remain in the ocean for long periods. They may break down very slowly or increase in concentration as they move up the food web. This can lead to long-term ecological damage and impact the health of marine ecosystems and human populations that depend on them.

Noise pollution

Ocean noise, or anthropogenic noise pollution, is caused by human activities such as commercial shipping, offshore construction, sonars, seismic surveys, explosions, and construction. These sounds act as stressors to the marine ecosystem, impacting the behaviour, physiology, and reproduction cycles of marine mammals, and directly affecting their mortality rates. Marine life is extremely sensitive to sounds, even low-frequency noises, which are hardly audible to humans.

The impact of noise pollution on marine life includes temporary or permanent hearing loss, behavioural and physiological changes, masking of acoustic signals, injury, and even death. Very loud noises can cause marine mammals to panic and ascend too quickly, leading to decompression sickness and tissue damage from gas bubble lesions. It can also cause mass breaching events, with one notable example being the mass stranding of beaked whales due to naval sonar activity.

Furthermore, noise pollution interferes with the detection of acoustic signals, disrupting communication between marine animals. It can lead to changes in individual and social behaviour, altered metabolisms, and hampered population recruitment, affecting the health and service functions of marine ecosystems. Noise pollution decreases the communication range of marine mammals and causes them to change their vocal behaviour. For instance, increased ship noise has caused bottlenose dolphins to simplify their vocal calls, which may reduce the effectiveness of their communication.

To mitigate the impact of noise pollution on marine life, policies and technologies are being developed to reduce propeller noise from ships and mitigate the sounds of sonar equipment, seismic air guns, pile driving, and construction. Some organizations have suggested managing sea traffic to limit noise exposure for marine life, such as rerouting ships away from endangered marine species' habitats and implementing speed limits for large ships in certain waters.

Oil pollution

Oil spills from tankers are particularly detrimental due to the large volume of oil released in a specific area. The complex composition of oil, including crude oil and refined petroleum products, poses a unique set of challenges for scientists. The behaviour and potential effects of these chemicals vary depending on their release into the marine environment, making each spill distinct.

The impact of oil pollution extends beyond the immediate effects on marine life. Oil forms a thick sludge in the water, suffocating fish and blocking light from reaching photosynthetic aquatic plants. It also disrupts the normal migration, reproduction, and feeding patterns of marine organisms by interfering with underwater communication.

Addressing oil pollution requires a combination of local, national, and international efforts. Specialists and veterinarians play a crucial role in cleaning, rehabilitating, and returning oiled wildlife to their natural environment. Preventative measures, such as improved waste management practices and responsible chemical use, are essential to protect marine ecosystems from the detrimental effects of oil pollution.

Carbon emissions

Ocean acidification has detrimental effects on marine life, particularly shellfish and other calcifying organisms. The decrease in carbonate ions makes it challenging for these organisms to build and maintain their shells and calcium carbonate structures. This process has been likened to osteoporosis, as it weakens the shells and skeletons of oysters, clams, lobsters, shrimp, and coral reefs. Additionally, acidified waters can cause harmful algal species to produce more toxins and bloom faster, which can be harmful to humans consuming contaminated shellfish and detrimental to fish and marine mammals.

The impacts of ocean acidification are far-reaching, threatening the food supply of humans and marine life. It is estimated that over a billion people worldwide rely on seafood as their primary source of protein, and disruptions to marine food chains can have significant consequences. Moreover, acidification can reduce the protective benefits provided by reefs, such as storm protection, and negatively impact tourism opportunities.

To address the issue of ocean acidification, it is crucial to reduce carbon emissions and transition to more sustainable energy sources. Efforts to monitor and observe the progression of acidification are also essential, as they provide valuable data for developing mitigation strategies and policies. By taking action to reduce carbon emissions and protect our oceans, we can help preserve the diverse marine life that depends on a stable and healthy ocean environment.

Climate change-induced events, such as marine heatwaves, dead zones, and coral bleaching, pose further threats to marine life. For example, a marine heatwave in 2014 caused the death of thousands of sea lion pups as their food sources moved to cooler waters. Additionally, warming waters can exacerbate the effects of acidification and hypoxia (low oxygen levels), creating a cascade of challenges for marine organisms.

To mitigate the impacts of climate change on marine life, it is essential to reduce carbon emissions and adapt fishery management practices. By lowering carbon emissions, we can help stabilize ocean temperatures and maintain the health of marine ecosystems. Additionally, diversifying fisheries through aquaculture can build resilience against the changing climate.

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