Coastal Pollution: Impacting The Delicate Marine Ecosystem

Pollution has been affecting coastal and marine ecosystems since the beginning of human civilization. Over 80% of marine pollution comes from land-based sources, including industrial production, domestic sewage, and aquaculture activities. These activities lead to the destruction of habitats and reduced productivity of coastal wetlands.

One of the biggest sources of marine pollution is nonpoint source pollution, which occurs when runoff from sources like septic tanks, cars, farms, and boats carries contaminants into the ocean. This type of pollution can make water unsafe for humans and wildlife, even leading to beach closures after rainstorms.

Other sources of coastal pollution include oil spills, pipeline leaks, plastic waste, and sewage disposal. These various forms of pollution have severe impacts on marine life, including fish kills, algal blooms, and low-oxygen conditions.

As coastal pollution continues to increase, understanding pollution levels and trends is crucial for protecting marine ecosystems and resources.

Oil spills and leaks

Oil spills have devastating consequences for marine life. Oil can kill animals and birds by poisoning or suffocation, as well as affecting their natural buoyancy and waterproofing. It can also contaminate food supplies, leading to malnutrition and poisoning. Oil spills can affect breeding and reproduction, for example, by contaminating bird or turtle nests on shore, and can cause long-term damage to marine life, which can be irreparable.

Oil spills can be caused by a variety of factors, including human error, equipment malfunction, natural disasters, and deliberate acts. The response to an oil spill aims to stop the flow of oil, protect sensitive areas, and remove the oil from the environment as quickly and efficiently as possible. Various methods are used, including booms (floating physical barriers), skimmers, and other devices to contain and remove the oil.

Oil spills have far-reaching impacts on coastal and marine ecosystems, with over 80% of marine pollution originating from land-based sources such as industrial, agricultural, and urban activities. Oil spills contribute to the steady degradation of these ecosystems, with long-lasting effects on marine life and the environment.

Eutrophication

• It sets off a chain reaction in the ecosystem, as the excess algae and plant matter eventually decompose, producing large amounts of carbon dioxide.
• This leads to ocean acidification, which slows the growth of shellfish and can prevent shell formation in bivalve mollusks, impacting commercial and recreational fisheries.
• Eutrophication can create "dead zones" with low-oxygen (hypoxic) waters that kill fish and seagrass, further reducing essential fish habitats.
• It can also lead to harmful algal blooms, which can produce noxious toxins and pose risks to human health.
• Eutrophication can alter the species composition of an ecosystem, with certain species stimulated by the increased nutrient levels while others are negatively affected or even face mass mortality.
• The high rates of photosynthesis associated with eutrophication can deplete dissolved inorganic carbon and raise pH levels to extreme levels, impairing the chemosensory abilities of organisms that rely on chemical cues for survival.
• When the dense algal blooms die, microbial decomposition severely depletes dissolved oxygen, creating hypoxic or anoxic "dead zones" that cannot support most organisms.
• Eutrophication can also lead to economic losses, as it affects the productivity of coastal wetlands and fisheries.

Overall, eutrophication is a significant problem that affects coastal ecosystems and human activities alike. It is important to address this issue through effective pollution control measures and the implementation of best management practices to mitigate its negative impacts.

Air pollution

Ground-level Ozone (O3): Ground-level ozone is a significant pollutant that damages vegetation, including agricultural crops, forests, and plants. It reduces growth rates, lowers yields, and affects biodiversity and ecosystem services. Ozone enters plant leaves, reducing photosynthesis, slowing plant growth, and increasing vulnerability to pests and diseases. High levels of ground-level ozone contribute to the loss of species diversity and alterations in ecosystem structure and habitat quality. For instance, in 2019, economic losses due to the impact of ground-level ozone on wheat yields amounted to EUR 1,418 million across 35 European countries.

Nitrogen Compounds: Nitrogen oxides (NOx) and ammonia (NH3) in the air are deposited on land and in water bodies, leading to excessive nitrogen levels. In aquatic ecosystems, this contributes to eutrophication, promoting algal blooms and reducing oxygen availability. In sensitive terrestrial ecosystems, such as grasslands, excessive nitrogen deposition can lead to the loss of sensitive species, favouring species that thrive in high-nitrogen conditions, and altering ecosystem structure and function.

Sulphur Dioxide (SO2): The deposition of sulphur dioxide, along with nitrogen oxides and ammonia, leads to acidification, causing changes in the chemical composition of soils, lakes, rivers, and marine waters. Acidification disrupts ecosystems and leads to biodiversity loss. As SO2 emissions have decreased over the years due to regulations, the relative contribution of NH3 and NOx to surface water and soil acidification has increased.

Heavy Metals: Heavy metals, such as mercury, are toxic pollutants that travel long distances in the atmosphere and are deposited into ecosystems. They accumulate in soils and undergo bioaccumulation and biomagnification in the food chain. This contamination can build up in marine organisms, affecting both aquatic life and human health, as some of these contaminants end up in our food sources.

Ocean Acidification: Atmospheric pollution, particularly carbon dioxide (CO2), is absorbed by seawater, triggering chemical reactions that reduce seawater pH. This process, known as ocean acidification, can have far-reaching consequences for marine organisms and the overall structure of marine ecosystems. The accelerating pace of ocean acidification has become a growing concern for the scientific community.

Industrial production

Water Pollution

Water pollution is a significant issue caused by industrial production. Water is used in various industrial processes and often comes into contact with harmful substances such as metals, chemicals, and radioactive waste. This contaminated water is then discharged into rivers and oceans, leading to polluted ecosystems and freshwater sources. The release of pollutants into water bodies can have far-reaching consequences for both the environment and human health. Contaminated drinking water poses a direct threat to human health, and irrigation of crops with polluted water can also have detrimental effects.

Air Pollution

Industrial activities contribute significantly to air pollution, which has adverse effects on both the environment and human health. The burning of fossil fuels, such as coal and natural gas, releases pollutants into the atmosphere, including gases, smoke, and particulate matter. These pollutants reduce air quality and can cause respiratory and cardiovascular problems in humans and damage ecosystems worldwide. Additionally, contaminants in the air can lead to acid rain, which harms crops and acidifies freshwater sources.

Soil Pollution

Soil pollution is another consequence of industrial production. The use of chemical pesticides and fertilizers in agriculture, as well as the release of industrial waste, can result in elevated levels of chemicals in the soil. This contamination affects our ability to grow crops and can have detrimental effects on natural environments and human health. Polluted soil can also impact the health of animals and disrupt natural food chains.

Ecological Consequences

Climate Change

Domestic sewage

Untreated sewage may contain water, nutrients (nitrogen and phosphorus), solids (including organic matter), pathogens (including bacteria, viruses, and protozoa), helminths (intestinal worms and worm-like parasites), oils and greases, runoff from streets, parking lots, and roofs, heavy metals (including mercury, cadmium, lead, chromium, and copper), and many toxic chemicals including PCBs, PAHs, dioxins, furans, pesticides, phenols, and chlorinated organics.

The effects of this are varied and severe. Sewage pollution has been linked to significant numbers of infectious diseases, including gastroenteritis and upper respiratory disease, as well as illnesses such as diarrhea, cholera, dysentery, typhoid, and hepatitis A. It has also been linked to the creation of "dead zones", which are areas of anaerobic conditions at the sea bottom, due to increased amounts of nutrients. These zones have doubled since 1990. Sewage pollution has also been linked to the destruction of coral reefs, with eutrophication causing changes in the species composition of corals.

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