Ocean Pollution: Understanding The Human Impact

Oceans are incredibly valuable to the health and well-being of our planet, covering more than 70% of the Earth's surface. They govern the weather, clean the air, help feed the world, and provide a living for millions. However, human activities have led to ocean pollution, threatening the health of our planet. The majority of the garbage that enters the ocean each year is plastic, including single-use plastic bags, water bottles, and straws, which do not biodegrade and persist in the environment for a millennium. Other sources of ocean pollution include fossil fuels, oil spills, noise, sewage, industrial waste, and agricultural runoff. Ocean pollution has severe consequences for marine life and ecosystems, with animals frequently ingesting plastic or becoming entangled in it, and the chemistry of the ocean being altered.

Plastic pollution

Plastic waste in the ocean comes from both land-based and sea-based sources. Land-based sources include single-use plastic bags, water bottles, drinking straws, and yoghurt containers, which are dumped directly into the sea or make their way there gradually via storm drains, sewers, and rivers. Rivers are the main source of ocean plastic pollution, with coastal cities in middle-income countries being the world's plastic emissions hotspots. The closer a river is to the ocean, the more likely plastic in that river will reach the ocean. In addition, during storms and heavy rain events, plastic emissions can increase tenfold as trash is washed into waterways. Once plastic reaches coastal waters, it can take years to break free and reach the open ocean, but once it does, it can persist for centuries.

Plastic accumulates in huge subtropical oceanic areas called gyres, which are massive circular currents that trap floating plastic. The most well-known gyre is the Great Pacific Garbage Patch, located in the North Pacific Ocean between Hawaii and California. This garbage patch is estimated to be twice the size of Texas and is composed of two separate patches: the Western Garbage Patch near Japan and the Eastern Garbage Patch. While the Great Pacific Garbage Patch is the most polluted, other gyres in the Atlantic and Indian Oceans are also inundated with plastic, and smaller bodies of water are developing trash vortexes as well.

Fossil fuels

Oceans are incredibly valuable natural resources that cover more than 70% of the Earth's surface. They govern the weather, clean the air, help feed the world, and provide a living for millions. However, human activities have been polluting the oceans, and fossil fuels are a major contributor to this issue.

Burning fossil fuels like coal, oil, and natural gas releases carbon dioxide into the atmosphere, leading to an increase in global temperatures, extreme weather events, wildfires, and rising sea levels. This, in turn, melts glaciers and permafrost, releasing contaminants trapped in the ice. As a result, oceans absorb more carbon dioxide, causing ocean acidification. This process alters the pH of the water, making it more acidic. The increased acidity has severe ecological consequences, damaging coral reefs and calcium-containing creatures like plankton, which are at the bottom of the marine food chain. It also enhances the toxicity of heavy metals and chemicals, threatening both wildlife and human health.

In addition to carbon dioxide emissions, the extraction and use of fossil fuels introduce other harmful substances into the ocean. Oil spills, for example, have detrimental effects on marine water quality and wildlife. Even with improved technologies and policies, oil spills continue to occur, polluting the oceans and causing long-lasting damage. Furthermore, fracking, a method used to extract natural gas, has been linked to groundwater pollution, with significantly higher levels of methane found in drinking water sources.

The burning of fossil fuels also contributes to nitrogen deposition, which has significant impacts on marine ecosystems. In certain regions, atmospheric deposition from fossil fuel combustion accounts for a substantial proportion of nitrogen input into the water bodies. This leads to eutrophication, resulting in toxic algal blooms that deplete oxygen levels in the water and create "dead zones" where marine life struggles to survive.

The pollution caused by fossil fuels extends beyond the initial emissions. As oceans absorb the carbon dioxide, they take on a regulatory role in reducing atmospheric carbon dioxide concentrations. However, this comes at a cost, as the increased acidity disrupts the fundamental chemical balance of ocean and coastal waters, threatening marine life and ecosystems that millions of people depend on for food and livelihood.

Nonpoint source pollution

NPS pollution is primarily caused by land runoff, where rainfall or snowmelt moves over and through the ground, picking up and carrying natural and human-made pollutants. These pollutants are then deposited into nearby water bodies, including rivers, wetlands, and eventually, the ocean. For example, after a heavy rainstorm, water flowing off roads can carry oil left by cars into the ocean. Wind can also carry dirt and debris from nonpoint sources, depositing them on the ocean's surface.

The sources of NPS pollution are diverse and include residential, commercial, agricultural, and construction sites. Agricultural practices, in particular, can contribute significantly to NPS pollution through the use of fertilizers, pesticides, and manure, which can run off into nearby water bodies. In addition, stormwater runoff from urban areas can carry pollutants such as oil, grease, and chemicals from roads, parking lots, and industrial sites into storm drains and, ultimately, into the ocean.

The impacts of NPS pollution are far-reaching. It can affect drinking water supplies, fisheries, wildlife, and recreation. Coastal communities, including the commercial fishing industry and tourism, are particularly vulnerable to the effects of NPS pollution. If left unchecked, NPS pollution can lead to mass die-offs of fish, reduced water quality, and negative impacts on the overall quality of life in these communities, potentially driving down property values and affecting coastal economies.

Efforts to control NPS pollution are ongoing, with agencies such as the NOAA and the U.S. Environmental Protection Agency working to develop strategies to monitor, assess, and limit NPS pollution. Implementing best management practices, such as proper waste management, erosion control, and reducing the use of chemicals, can help mitigate the impacts of NPS pollution on ocean waters and the environment.

Oil spills

One of the most well-known oil spills is the Deepwater Horizon spill, which occurred in 2010 and had lasting impacts on the Gulf of Mexico. However, thousands of smaller oil spills occur each year, some releasing less than a barrel of oil. These minor spills contribute to chronic oil pollution and are often legal, as oil platforms are typically allowed a certain amount of discharge. Oil exploration, drilling, and production all pose risks to ocean ecosystems, including noise pollution and the release of dangerous chemicals.

To address oil spills and their consequences, various organizations and governments are taking action. Satellite technology, such as that pioneered by NOAA during the Deepwater Horizon spill, is being used to monitor and detect pollution. Additionally, campaigns and lawsuits have led to opposition to offshore drilling and the withdrawal of some waters from oil and gas leasing. These efforts are crucial in mitigating the impacts of oil spills and protecting marine life and ecosystems.

Light pollution

Coastal cities, offshore oil rigs, and ships flood the ocean with artificial light that impacts a wide range of sea creatures. From zooplankton to whales, light pollution disrupts natural rhythms and threatens marine habitats. Artificial light at night can interfere with natural processes, leading to confusion and reduced survival rates. For example, sea turtles have a hard time finding dark beaches for laying their eggs, and the lights of coastal cities confuse their hatchlings, often leading them away from the ocean to perish from exhaustion or predators.

Coral reefs, which are among the most diverse marine ecosystems, are also threatened by light pollution. Corals release their eggs based on the light cycle of the moon, and light pollution can trigger corals to spawn at less ideal times, reducing reproductive success and threatening the health and sustainability of coral reefs.

Addressing light pollution requires implementing better lighting practices and creating Dark Sky Reserves near sensitive marine habitats. Using red light is preferable as it doesn't penetrate as far into the water, and physical barriers can also be used to shield coastlines from artificial light.

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