Jet Noise Pollution: Impact On Natural Habitats

Aircraft noise pollution is a pressing issue that has been associated with several negative health effects, from sleep disorders to cardiovascular disorders. It is caused by a variety of factors, including engine and mechanical noise, aerodynamic noise, and noise from aircraft systems. This noise can have a significant impact on both human health and the environment.

Aircraft noise can disrupt the lives of animals, leading to changes in their natural behaviours and even relocation to quieter areas. These changes can have flow-on effects for entire ecosystems. Marine animals, in particular, are affected by noise from commercial vessel traffic, oil and gas exploration, seismic surveys, and military sonar.

The impact of aircraft noise pollution on biodiversity is a growing area of concern, with studies indicating that it can affect a range of biological groups such as birds, amphibians, reptiles, fish, mammals, and invertebrates. It can also influence their communication, reproduction, and space use, among other things.

To mitigate the effects of aircraft noise pollution, governments have implemented extensive controls and procedures, and aircraft designers, manufacturers, and operators have developed quieter aircraft and better operating procedures. Additionally, noise reduction technologies and satellite-based navigation systems have been employed to reduce noise levels.

Impact on birds

Noise pollution has a significant impact on birds, affecting their physical and mental well-being. While birds have endured loud natural sounds for centuries, human-made noise pollution is a relatively new phenomenon that has various effects on birds, including physical harm, behavioural changes, and disruptions to their reproductive cycles.

Physical Harm

Birds exposed to persistent noise pollution have exhibited symptoms similar to those of humans suffering from post-traumatic stress disorder, including skewed stress hormone levels, increased anxiety, distraction, and hypervigilance. High levels of noise can also lead to long-term physical effects on birds, such as cardiovascular diseases, feather loss, and weight loss.

Behavioural Changes

Noise pollution can impact the behaviour of birds, including their feeding and reproductive behaviours. Some birds may prolong their state of awareness instead of focusing on finding food, resulting in direct interference with their feeding behaviour. Noise can also affect the acoustic communication of birds, as it masks vocalizations and other sounds that birds rely on to communicate with one another. This can lead to a reduction in bird diversity, as only species that can adapt to the noise may thrive in noisy environments.

Disruptions to Reproductive Cycles

Prolonged stress caused by noise pollution can trigger a range of physical reactions in birds, such as heightened heart rate, hormonal imbalances, and weight loss. It can also hinder their immune systems, leading to reduced reproductive success. Noise pollution has been found to impact egg-laying, breeding, and abandonment, as well as mating and parental communication. As a result, some bird species have experienced a decline in population numbers.

Changes in Habitat Selection

Noise pollution decreases the quality of habitats for birds, as fewer birds choose to stay in noisy areas. This habitat degradation results in a decrease in the bird population, which can have consequences for the entire ecosystem.

Impact on marine life

Marine life is extremely sensitive to sound, even low-frequency noise, which is inaudible to humans. Marine mammals rely on underwater sounds for essential life functions like searching for prey, avoiding predators, locating offspring, and finding a mate. Therefore, insufficient mechanisms to safeguard them against underwater noise pollution can be detrimental to marine life.

Anthropogenic noise pollution, also known as ocean noise, is the sounds from human activities that act as stressors to the marine ecosystem. It impacts marine mammals, their behaviour, physiology, and reproduction cycle and directly affects their mortality rates.

Ocean noise has a much greater impact on marine life than previously understood. More than 500 studies have established that humans are responsible for altering the ocean soundscape. Harsh noises have impacted marine animals, causing them to flee their original habitats and move away from their feeding grounds, resulting in death or injury.

The death of marine animals can occur hours after exposure to extreme underwater noise. For example, whales can die soon after due to strandings. A relatively common environmental impact of noise pollution is breaching themselves shortly after a tactical sonar exercise. Such beaching has been reported in regions like Greece, Madeira, Hawaii, Spain, and the coastal US, where sonar exercises are common.

Underwater noise pollution is painful for marine animals. Most are alarmed by the alien sounds, which can cause internal damage, such as hemorrhages, changed diving patterns, migration to new places, damage to internal organs, and an overall panic response to the foreign sounds.

Noise pollution also disrupts the regular communication between marine animals. Animals prone to noise pollution are unable to call their mates, look for food, or even make a cry for help.

Many marine animals, such as rockfish, herring, eel, cod, and blue whiting, show extensive damage to their ears upon exposure to seismic air guns, even when several kilometres away. Exposure to noise during the embryonic stage increases the sensitivity of fish to noise impact, increasing mortality rates at birth and the development of genetic anomalies.

The migration to new areas affects marine diversity balance and indirectly affects humans too. A decrease in the catch of many fish species, like herring, cod, and blue whiting, has been noticed, especially in areas susceptible to noise pollution from ships.

The sensitivity of marine animals to ocean noise pollution varies. While whales and dolphins may show greater resistance, soft-shelled species like molluscs, prawns, and fish are much more sensitive. However, as many as 24 whale species have shown adverse effects of noise pollution in the ocean.

In total, about 55 marine species have suffered due to exposure to sound at varying frequencies. These include several whale species, sea bass, snapper, goldfish, cod, tuna, squid, and invertebrates like lobster, crabs, and shrimp.

Mass strandings of sea turtles and dolphins became common on the beaches near the Gulf of Mexico when explosives were deployed to remove oil platforms in offshore waters.

Addressing the problem

Several organisations have assessed underwater noise in busy international waterways and seas, such as the Mediterranean. Managing sea traffic could be one way of limiting the impact of noise on marine life. For example, the Vancouver Fraser Port Authority in British Columbia has developed a unique and workable program. Ships are encouraged to take a different route, away from the endangered southern native killer whales' feeding grounds. Volunteers suggest slow speeds for large ships crossing certain waters in southwest British Columbia.

A review by 25 international researchers, who studied 10,000 academic papers on the issue of anthropogenic noise, revealed that while noise cannot be ended altogether, sufficient measures can be taken to decrease it considerably.

Shipping engineers suggest using propellers to decrease cavitation or tiny bubbles that make a loud noise when they burst. Most cruise ships have electric motors to drive propellers and reduce noise levels. Additionally, most ship-quieting technologies increase the vessel's fuel efficiency and decrease its environmental impact.

Impact on human health

Jet noise pollution has been associated with several negative health effects on humans, from sleep disorders to cardiovascular disorders. Here is an in-depth look at the impact on human health:

Sleep Disturbances

Jet noise pollution has been linked to sleep disturbances, with studies showing that noise from aircraft, roads, and other sources can lead to difficulties in falling asleep, increased wakefulness, and reduced sleep quality. This can have a significant impact on overall health and well-being, as sleep plays a crucial role in maintaining physical and mental well-being.

Cardiovascular Diseases

Jet noise pollution has also been associated with cardiovascular issues, including hypertension, ischaemic heart disease, and an increased risk of heart attacks. The stress and annoyance caused by jet noise can trigger physiological responses, such as the activation of the cardiovascular system and the release of stress hormones, which can have negative consequences over time.

Mental Health and Well-being

Jet noise pollution can impact mental health and well-being. Studies have found that higher levels of jet noise are associated with lower levels of happiness and well-being. Additionally, jet noise can contribute to psychological distress and an increased risk of depression and anxiety. The constant exposure to jet noise can lead to a continuous state of stress, affecting an individual's ability to cope and recover.

Annoyance

Annoyance is a significant factor in the relationship between jet noise exposure and health outcomes. It is considered a stress response and can be described as the feeling of being forced to deal with unwanted noise, leading to cognitive, emotional, and behavioural reactions. Jet noise can trigger annoyance, which in turn can contribute to or mediate other adverse health outcomes.

Hearing Impairment

While jet noise pollution has been linked to various health issues, studies suggest that it does not directly cause hearing impairment in the general public. However, prolonged exposure to loud noises, including jet noise, can potentially lead to hearing loss over time.

Other Health Effects

Jet noise pollution has also been associated with an increased risk of obesity, waist circumference, and type 2 diabetes. Additionally, there are indications that jet noise may impact cognitive functioning, particularly in children, affecting reading skills and oral comprehension.

Impact on amphibians

Amphibians are highly threatened species, and noise pollution is likely a contributing factor. Frogs and toads rely on sound to communicate, and their calls can be masked by anthropogenic noise. Frogs and toads have been observed to alter their calls in response to noise pollution. For example, male frogs may change the frequency of their calls to be heard over the noise, but this may make them less attractive to females.

Amphibians are sensitive to noise in the 20-1000 Hz range, and some species can hear sounds up to 15,000 Hz. Studies have shown that noise pollution can reduce the ability of amphibians to detect and locate prey, and can also affect their reproductive success. For example, noise pollution has been linked to reduced hatching rates in frog eggs.

Amphibians are also affected by noise from aircraft, including planes, helicopters, and sonic booms.

Impact on invertebrates

The impact of jet noise pollution on invertebrates is not well understood, with limited research having been conducted on the topic. However, invertebrates are known to be sensitive to sound, and noise pollution can affect their ability to hear, detect prey, and communicate. Some studies have shown that invertebrates alter their natural behaviours or relocate to avoid noisy areas.

Invertebrates are sensitive to particle motion rather than sound pressure, and changes in their behaviour can have flow-on effects for whole ecosystems.

• A 2014 study found that invertebrates can be sensitive to anthropogenic noise and indicated that this sensitivity may have an influence on ocean biodiversity.
• A 2023 study found that invertebrates can produce and use sounds to reveal their presence and for a broad variety of behaviours. They can generate the sound unintentionally during moving or feeding or deliberately for communication.
• A 2020 study found that invertebrates are the least studied taxonomic group in terms of the impact of noise pollution.
• A 2016 study found that invertebrates are mainly sensitive to the particle motion of sound, rather than the sound pressure.
• A 2010 study found that invertebrates have evolved around the extraction of information from soundscapes.
• A 2008 study found that invertebrates have specially adapted to the natural noises in their environment.

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