When it comes to pollution, the literal tons of plastic floating in the ocean tend to grab all the headlines. Although that issue is of great importance, the other forms of pollution, such as noise pollution, should not be overlooked. For far too long, the honking of cars and the roaring of plane engines have dominated the once-peaceful nighttime hours. This constant noise echoes throughout the environment and disrupts animals large and small, aquatic and terrestrial.
#10 — Trouble Finding Mates
There are a number of animals that rely on mating calls to attract partners. Whether it be frogs or birds, the problems caused by noise pollution are quite similar. The most obvious problem is that the mating calls cannot be heard over the sound of heavy traffic. A prime example of this is the pobblebonk frog. In an environment free from anthropogenic noise, or simply noise caused by human activity, the pobblebonk frog’s call can be heard from over 2,500 feet away. The screeching of tires can reduce that range to as little as 50 feet. Another problem is the frequency of the mating call. Some birds prefer a low-frequency call. However, these same low-frequency calls are the hardest to hear over noise pollution. This puts the male birds between a rock and a hard place. If they make a low-frequency call, they may go unheard. If they make a high-frequency call, they may be ignored.
#9 — Indecisive Arthropods
Arthropods, including insects and spiders, showed mixed reactions to noise pollution. Some, such as spiders and velvet ants, fled noisy areas, while their prey moved in and multiplied. Though the reaction varies greatly among arthropods, the concerns are the same. Should the above scenario happen, some insects could grow to uncontrollable levels and eat away at the surrounding environment. Of course, the environment included the fields of groups planted by people. Should the reverse happen, and spiders and velvet ants begin to greatly outnumber their prey, there may not be enough insects to participate in pollination and decomposition. Bees, which fall under the arthropod umbrella, pollinate over 80% of our cultivated crops. With the human population steadily growing, keeping the noise down may be our only hope in feeding all of those mouths.
# 8 — Blinding Bats
Bats hunt by using echolocation. Essentially, bats have the ability to make a sound and gain a sense of the environment by listening to the resulting echoes. As you can imagine, the echoes can be difficult to interpret when the sounds of human activity are mixed in. A study found that the amount of time spent searching by bats that hunted near a highway was five times greater than the time spent by bats in silent environments. To make matters worse, the bats that hunted near the highway saw a success rate that was 40% lower than their silent environment counterparts. In short, bats are hunting for longer while having less overall success.
# 7 — Putting Prairie Dogs on Edge
For some animals, sound dictates behavior. The prairie dogs of Colorado, for example, showed a drastic change in behavior when exposed to extended periods of artificial sound. The sound essentially put the prairie dogs on high alert as the number of prairie dogs above ground dropped by 21%. Continued exposure to sound saw the number of prairie dogs on the lookout for predators raise by 48% while the number of prairie dogs resting and socializing dropped by a similar 50%. If the sound was maintained for months on end, it is possible that the prairie dogs could see a decline in population due to a lack of food as the focus shifted away from foraging and towards security.
#6 — The Whale in the Room
Marine mammals of all kinds, including whales and dolphins, use sound to navigate and commute. Unfortunately, the sound produced by military sonar, shipping traffic, and oil exploration can disrupt these messages. In the worst case scenarios, noise pollution can lead to mass strandings as marine mammals either mistake artificial noise for a fellow species member or struggle to interpret a message through the cacophony produced by machinery. Though the exact reason is still unclear, the Scientific Committee of the International Whaling Commission concluded, “The weight of accumulated evidence now associates mid-frequency, military sonar with atypical beaked whale mass strandings.”
The marine mammals that manage to find their way are still impacted by noise pollution. Noises of extreme volumes, such as the high-intensity sonar, can produce sounds well over 235 decibels. To put that into perspective, that is as loud as a rocket launching into the sky. Sounds of such high levels can directly damage the hearing of marine mammals. Some whales have even shown a tendency to descend rapidly upon hearing these loud sounds. Diving at such a rapid rate can lead to internal bleeding and over time may result in fatal injuries.
#5 — Suffering Cephalopods
Cephalopods, some of which are squids, octopuses, and cuttlefish, come equipped with an organ called a statocyst. The statocyst is a small, balloon-like structure filled with hairs and nerves that helps the cephalopod know its position and balance itself accordingly. Essentially, statocysts are the cephalopod version of the semicircular canals found in the human ear. When exposed to low-intensity, low-frequency sounds, statocysts can become swollen and even rupture. This gives the cephalopod a permanent case of vertigo which makes the organism unable to hunt, avoid predators, and reproduce.
#4 — That’s Not a Reef
The biodiversity of coral reefs is second only to the tropical rainforest. With thousands of species constantly swirling around the reef, some fish choose to lay their eggs elsewhere as a means of protection against predators. Once the babies are ready to swim through the waters of the ocean, they first look for the nearest coral reef. The task is usually quite easy as the life surrounding the reef makes noise in the same way you can tell you are approaching the city by the sound of car horns. With noise now reaching the fish from all directions, be it from seismic surveys or underwater mining, the coral reef has become quite elusive.
#3 — Distracted Prey Theory
Being able to hear a predator approaching boosts an animal’s chances of survival. Though the main concern would be noise pollution drowning out the noise of predators on the prowl, scientists from Vassar College found that noise pollution can interrupt and lead to a form of sensory overload. They found this out by observing the behavior of hermit crabs. When switching shells, hermit crabs are vulnerable to predators as their squishy bodies are no match for the jaws of hungry fish. Knowing this, the hermit crabs that were given a visual predator cue by the scientists chose shells faster than the hermit crabs that received no visual cue. Basically, if a hermit crab sees a predator, it will quickly jump into a shell as expected. However, when scientists played ship noise, the difference between the two groups greatly diminished. Essentially, noise pollution can “blind” some organisms in the same way multitasking can make humans less productive.
#2 — Harming Human Health
Humans also share in the suffering brought on by noise pollution. The Harvard Medical School states that “noise pollution not only drives hearing loss, tinnitus, and hypersensitivity to sound but can cause or exacerbate cardiovascular disease; type 2 diabetes; sleep disturbances; stress; mental health and cognition problems, including memory impairment and attention deficits; childhood learning delays; and low birth weight.” To make matters worse, there are a number of research studies underway that are looking for a connection between noise pollution and other conditions, such as dementia. With more and more people moving into cities, the noise will only grow in intensity and frequency, which brings our collective health into question. For this very reason, the United States Environmental Protection Agency called noise pollution “a growing danger to the health and welfare of the Nation’s population.”
#1 — Ecosystem Collapse
When we think about the environment, we often fixate on a single animal or a group of animals. The reality is that all of the plants and animals within an ecosystem are connected. Because of this, removing or harming one species can cause a domino effect which will in turn harm other species. For example, if trees are removed from an area, the animals living within the trees or in their branches will have to move elsewhere. The animals that feed on the leaves may starve as they now have to compete against the animals that are accustomed to eating the plants that grow closer to the ground. This competition has the potential to reduce both populations which in turn limits the amount of food available for carnivorous predators. With enough misfortune, the ecosystem could completely collapse