Ferries And Water Pollution: Understanding The Impact

Ferries are a significant contributor to water pollution, despite their eco-friendly reputation. The shipping sector, including ferries, currently accounts for about 3% of global greenhouse gas emissions, with ferries releasing carbon dioxide and other greenhouse gases into the atmosphere. In addition, ferries generate sewage and greywater, which contains oils, detergents, heavy metals, and fecal particles, posing a threat to marine life and ecosystems. The improper management of fuel and oil can also lead to spills that harm the environment and wildlife. Furthermore, ferries contribute to noise pollution, which disturbs and harms marine animals and mammals. To mitigate these issues, ferry companies are adopting new technologies and environmentally friendly fuels, such as biofuels, to reduce their carbon footprint and promote a more sustainable travel experience.

Ferries contribute to ocean acidification

Carbon dioxide (CO2) is a colourless and odourless gas that is naturally present in the Earth's atmosphere. It is released into the atmosphere through human activities such as burning fossil fuels and deforestation. The ocean absorbs a significant portion of the excess CO2, which then reacts with water molecules to form carbonic acid. This increase in acidity has direct impacts on marine life, especially those that rely on carbonate to build their shells and skeletons. As the ocean becomes more acidic, the availability of carbonate decreases, making it more challenging for these organisms to survive.

Ferries, as a mode of transportation, contribute to the release of carbon dioxide and other greenhouse gases. The use of fossil fuels, such as low-sulfur fuel oil or biodiesel, by ferry companies leads to emissions that contain carbon dioxide. While some ferry operators have implemented environmentally conscious policies and technologies, such as LNG engines and waste recycling, there is still a significant impact on the environment. The emissions from ferry engines contribute to the overall increase in atmospheric CO2 levels, which directly influences the acidity of the ocean.

In addition to the direct release of carbon dioxide, ferries also contribute to ocean acidification through indirect means. The operation of ferries can lead to the introduction of invasive species into new ecosystems. These "aquatic hitchhikers" can include noxious weeds, feral cats, and insects, which can have detrimental effects on the local marine life and ecosystems. Additionally, ferries generate waste, including sewage and greywater, which can contain harmful substances such as oils, detergents, heavy metals, and fecal particles. When this waste is discharged into the ocean, it can contribute to increased nutrient levels, spread pathogenic bacteria, and deplete oxygen, further impacting the ecosystem and marine life.

The impact of ferries on ocean acidification is significant enough that organisations like the NOAA have implemented monitoring programs. These programs utilise Ships of Opportunity (SOPs) or Volunteer Observing Ships (VOSs) to collect data on ocean acidification parameters in remote areas. By understanding the dynamics and impacts of ocean acidification, researchers and conservationists can develop strategies to mitigate its effects and preserve the health of marine ecosystems and the people who depend on them.

Greywater discharge harms marine life

Greywater, or grey water, is wastewater from bathroom and kitchen sinks, bathtubs, water fountains, and wash basins. While greywater is generally considered safe for reuse in irrigation on land, it poses a threat to marine life when discharged into the ocean.

Ferries and other ships generate and discharge large volumes of greywater into the ocean. Passenger vessels, in particular, produce significant amounts of greywater due to the high number of people on board. Greywater can contain various contaminants, including oils, detergents, heavy metals, bacteria, pharmaceuticals, personal care products, chemicals, and microplastics. These contaminants can have harmful effects on marine ecosystems and marine life.

One of the main concerns with greywater discharge is the spread of pathogenic bacteria and viruses. The high levels of bacteria and nutrients found in greywater can lead to oxygen depletion and the growth of toxic algal blooms, creating dead zones that disrupt marine food chains. These disturbances can impact both marine organisms and humans who consume seafood.

In addition, the chemicals and microplastics present in greywater can be ingested or entangled with by marine animals, causing harm and even death. Microplastics, in particular, can take hundreds to thousands of years to break down, posing a long-term threat to marine life.

While there are local regulations governing greywater discharge, such as in Alaska, there is currently no internationally enforced requirement. Organizations are advocating for stricter regulations, such as revisions to the International Convention for the Prevention of Pollution from Ships (MARPOL), to better protect marine environments from the harmful effects of greywater discharge.

Invasive species are introduced

Ferries and other vessels can introduce invasive species to new environments, causing environmental disturbances and leading to ecological degradation. Invasive species are plants and animals that invade an ecosystem where they don't belong, and they can have a range of detrimental effects. Firstly, they can consume native species, compete for food and space, and introduce diseases, which can lead to the extinction of native plants and animals and a reduction in biodiversity. For example, the introduction of lionfish, native to the Indo-Pacific, into the Atlantic Ocean through the aquarium trade has resulted in the decimation of native coral reef fish populations. Similarly, the introduction of zebra mussels, native to the Black and Caspian Sea, into North American waters has disrupted freshwater ecosystems as they outcompete native species for food and space.

Invasive species can also alter pollutants through bioaccumulation and the introduction of other contaminants into waterways. For instance, the introduction of the invasive water hyacinth in Lake Caohai, China, has affected nutrient cycling. Furthermore, human activities such as trade and the construction of reservoirs, ditches, and canals to address the impacts of climate change can facilitate the spread of invasive species and provide them with permanent habitats.

The prevention of invasive species introductions is crucial to mitigating their harmful effects. Proper cleaning of vessels and equipment, as well as the identification and reporting of invasive species, are essential strategies to prevent their establishment and spread. However, once an invasive species becomes established, it is challenging to eradicate, and management efforts often rely on pesticides, which can have negative ecological and human health consequences. Therefore, a comprehensive understanding of the direct and indirect effects of invasive species on ecosystems is necessary to develop effective prevention and control measures.

Fuel and oil spills harm the environment

Fuel and oil spills from ferries can have detrimental effects on the environment, wildlife, and humans. Large passenger vessels store significant amounts of fuel and oil, which, if spilled, can cause extensive ecological damage.

Oil spills can kill marine animals and birds through poisoning or suffocation, as well as by disrupting their natural buoyancy and waterproofing abilities. The feathers and fur of affected animals can become drenched in oil, impairing their ability to regulate body temperature and causing them to drown. Additionally, the ingestion of oil during preening can lead to gastrointestinal and organ damage in birds. Oil spills also impact the food sources of marine life, as contaminated food supplies can lead to malnutrition or gradual poisoning.

The effects of oil spills can persist for years, with toxic chemicals settling on the ocean floor and poisoning the sediment. Research has shown that even years after a spill, oil levels in the sediments of affected areas can remain significantly higher than pre-spill levels. This has severe consequences for deep-sea creatures that rely on the sediment surface for habitat and food. For example, a study on bottlenose dolphins exposed to the Deepwater Horizon oil spill revealed that the oil may have impacted their immune systems across generations, making them more susceptible to infections and diseases.

To mitigate the risk of fuel and oil spills, ferry operators should implement standard procedures and ensure staff have the necessary knowledge for proper fueling. This includes using distinct color caps for deck fills to easily distinguish them from water or other fills. Additionally, all vessels should be equipped with spill response kits, containing items such as absorbent pads, personal protective equipment, and containers for soiled items.

While ferries contribute to water pollution through fuel and oil spills, it is important to recognize that the ferry industry is also actively exploring more sustainable practices. Ferry companies are adopting new technologies and eco-friendly fuels to reduce their environmental footprint. Some companies are utilizing liquefied natural gas (LNG), a non-toxic liquefied fossil fuel, as it significantly reduces CO2 emissions compared to diesel. Others are exploring biofuels, such as biodiesel, which can decrease CO2 emissions by up to 80-90%. By investing in more sustainable practices and fuels, the ferry industry is taking steps toward minimizing its impact on water pollution.

Air pollution from ferry emissions

Ferry services are witnessing rapid expansion in many coastal regions, providing additional capacity to strained land-transport systems. This expansion has been accelerated by the introduction of high-speed craft, which can reduce commute times and offer new routes. However, this trend has also brought to light the environmental impact of ferries, particularly air pollution from their emissions.

Ferry emissions have become a notable issue for air quality management, especially in metropolitan transportation systems in coastal cities. Marine engines are a significant and growing source of air pollution in some locations, and the sparse data available makes it challenging to compare marine and on-land passenger travel emissions rigorously. Nevertheless, emissions from marine engines are starting to be regulated, and there is a growing trend of comparing ferry emissions to those of other transportation modes.

Emissions of NOX are a particular cause for concern, as all the technologies examined in one study led to increased NOX emissions due to ferry commuting. Even with the most advanced technologies, NOX emissions remain a problem. The study also reported emissions of five other compounds: non-methane hydrocarbons (NMHCs), particulate matter (PM), carbon monoxide (CO), sulfur dioxide (SO2), and carbon dioxide (CO2).

To address the environmental impact of ferry emissions, ferry companies are adopting cleaner fuels and technologies. For instance, some companies are using liquefied natural gas (LNG) as fuel, which significantly reduces CO2 emissions compared to diesel. LNG engines are also being implemented in high-speed vessels to improve their eco-friendliness. Additionally, biofuels like biodiesel, derived from biological waste, can reduce CO2 emissions by up to 90%. Other measures include equipping vessels with technologically advanced engines, filters, combustion engines, propellers, and hull coatings.

Furthermore, ferry companies are exploring ways to reduce water waste and solid and plastic waste. For instance, some companies are treating sewage waters, using filters for greywater, adopting non-toxic cleaners, and managing cargo residues. Overall, while ferry emissions are a growing concern, the industry is also witnessing efforts to mitigate their environmental impact through the adoption of cleaner technologies and fuels.

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