Ocean Pollution: World Atlas Of Human Impact

The ocean is a vital natural resource that provides humans with many economic benefits. However, due to human activities, the ocean is facing significant pollution, threatening marine life and ecosystems. Ocean pollution refers to the introduction of toxic materials and harmful pollutants such as agricultural and industrial waste, chemicals, oil spills, and plastic litter. The main causes of ocean pollution include the dumping of sewage, plastic waste, and thermal pollution from power plants and companies. The increase in carbon dioxide levels due to global warming is causing ocean acidification, which is detrimental to coral reefs and marine life. With an estimated 8-12 million tons of plastic entering the oceans annually, plastic pollution is one of the largest environmental problems. The World Wildlife Fund (WWF) has created an interactive map to visualize the issue, showing the concentration of plastic waste in the ocean and its sources.

Plastic pollution

Rain and wind carry macro plastics, such as plastic bags and bottles, into storm drains and rivers, which act as conveyor belts, dumping about 1.15-2.75 million metric tons of waste into the oceans annually. Sunlight and ocean waves help break down these macro plastics into microplastics, which have become a ubiquitous component of marine and freshwater ecosystems.

The volume of plastics in the ocean has been estimated at around 75-199 million tons, with 19-23 million tons of plastic waste leaking into aquatic ecosystems each year. A report by the United Nations predicts that by 2050, the plastic waste in the oceans will outweigh the fish.

Addressing plastic pollution is crucial for safeguarding ecosystems and preserving biodiversity. It also helps prevent the proliferation of microplastics through the food chain, protecting human health.

Sewage dumping

Sewage sludge contains a plethora of substances harmful to both the environment and humans. It includes wastewater from our houses, such as water used for showering, washing dishes, or watering the garden. It also contains industrial wastewater, which may include chemicals, acids, heavy metals, and surface runoff that collects substances like animal faeces, agricultural fertilisers, and car oil. When sewage systems get overwhelmed, authorities often release untreated sewage into rivers and oceans to prevent dirty water from flowing back up into our drains.

The dumping of untreated sewage has detrimental effects on the health of marine flora and fauna. It can cause "dead zones" where little is able to grow or survive. For example, antibiotics in sewage attack the natural community of bacteria that live on the surface of corals, leaving them open to disease. In Florida, an outbreak of white pox disease was attributed to viruses present in human sewage that was dumped untreated into the ocean, resulting in the death of 70% of the area's rare elkhorn corals.

Research has also shown that sewage dumping significantly affects the metabolism, diet, and composition of organisms living on the sea floor. For example, a study found that silver levels in sediment samples at a dumpsite were 20 times higher than in an unaffected area. Additionally, contaminants have been found to penetrate up to 5 cm below the sea floor as organisms burrow through contaminated sediments.

Positive change is on the horizon, however. In the UK, a water company was recently fined £90,000,000 for dumping raw sewage into the waters off Kent. This indicates a continued commitment to protecting oceans, even after the UK's exit from the EU, which had previously enforced environmental standards and fines for poor water quality.

Ocean acidification

Since the Industrial Revolution, the world's oceans have absorbed a significant portion of the CO2 emitted by human activities, resulting in a notable increase in ocean acidity. This absorption of CO2 forms carbonic acid in seawater, which is the primary driver of the declining pH levels. The impact of this process is evident in the approximately 30% increase in acidity since the beginning of the Industrial Revolution, with the average pH of seawater dropping from 8.19 to 8.05.

The effects of ocean acidification are far-reaching and detrimental to marine life, particularly for organisms that rely on calcium carbonate to build shells and skeletons. For example, shellfish, corals, mollusks, and some plankton species are vulnerable to the corrosive effects of increased acidity, which can dissolve their structures. This, in turn, can have cascading effects throughout the marine food web, impacting marine ecosystems, fisheries, and human societies that depend on marine resources.

Coral reefs, often regarded as centres of biodiversity, are also under threat from ocean acidification. The combination of ocean warming and acidification leads to coral bleaching, which has detrimental consequences for the numerous marine species that depend on these reefs for their life cycles. Additionally, the decline in pH can reduce the absorption properties of surface seawater, further endangering delicate coral reef ecosystems.

Larger animals, such as squid and fish, are not exempt from the impacts of ocean acidification. As carbonic acid concentrations rise in their body fluids, they may experience a condition called acidosis, which can cause respiratory, growth, and reproductive problems. These physiological changes can alter predator-prey relationships and have the potential to disrupt marine food chains.

Addressing ocean acidification requires a comprehensive understanding of the chemical processes involved and their effects on marine life. By working together, scientists and policymakers can develop strategies to mitigate the impacts and conserve our precious marine ecosystems.

Industrial chemicals

One of the main ways that industrial chemicals enter the ocean is through river and estuary systems. Rainwater, flooding, and stormwater can carry chemicals from land into nearby streams, rivers, and estuaries, which then flow into the ocean. This is often the result of factories and industrial sites allowing waste products to flow into these waterways. In addition, urban areas and agricultural activities are responsible for much of the industrial pollution that ends up in the ocean.

Another source of industrial chemical pollution in the ocean is the use of pesticides and insecticides, such as DDT. DDT has been widely used in agriculture and has been found to cause reproductive failure in some marine bird species. Despite being banned or restricted in most developed nations, its use remains unregulated in many underdeveloped countries, and it continues to contaminate marine waters.

Furthermore, chemicals used in the manufacturing of plastics, such as PFAS, phthalates, and bisphenol A (BPA), are also contributing to ocean pollution. These chemicals are endocrine disruptors and have been found to affect the reproduction and development of various aquatic organisms. In addition, as plastic degrades, it can release these chemicals into the surrounding environment, further exacerbating the problem.

The accumulation of industrial chemicals in the ocean can have far-reaching consequences. These chemicals can build up in the fatty tissues of aquatic fauna, leading to severe damage to their reproductive systems. Additionally, certain chemicals can cause coral bleaching, which has detrimental effects on marine life dependent on these reefs for their life cycles.

Addressing the issue of industrial chemical pollution in the ocean will likely require a collaborative effort between governments, industries, and consumers. It is important to recognize the potential long-term harm that these chemicals can cause to marine ecosystems and to take steps to regulate and reduce their use and release into the environment.

Oil spills

During times of conflict or war, deliberate oil spills may be used as a military tactic to block waterways or create environmental damage in enemy territories. Additionally, some companies or individuals may illegally dump oil to avoid proper disposal costs or regulations. These deliberate spills can have catastrophic consequences for marine and coastal ecosystems.

Preventing oil spills is of utmost importance as the consequences can be dire. Washington State, a major hub for oil refining and transportation, has invested heavily in spill prevention and preparedness. They have expanded oil spill response planning to cover sensitive areas near railroad lines and implemented measures such as using absorbent pads or fuel collars to catch drips during refueling.

When oil spills occur, cleanup and containment efforts are crucial. The U.S. Coast Guard is primarily responsible for cleaning up oil spills, while NOAA experts provide scientific support. Various equipment and tactics are used, such as booms, skimmers, in situ burning, and chemical dispersants. However, cleanup activities can never fully remove all the spilled oil, and care must be taken to avoid causing additional harm.

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