Cut Noise

Noise: The Neglected Green Issue of our Age?

Extracts from Why Noise Matters (2011)

by Stewart et al

The threat to the planet’s sound systems is silently passing the world by

This blog makes the case for noise as a green issue. It draws a parallel between the way in which climate change is threatening to alter the planet’s eco-systems and ‘man-made’ or human noise is threatening the planet’s natural sound systems. These natural systems, which have evolved over the centuries, are fragile and complex. The sounds of the oceans, the forests, the deserts and the prairies send important signals to marine and wildlife. When human noise distorts or destroys these sounds, the very survival of the species which depend on them can be threatened. Although there is some evidence of adaptation to new, noisy situations – such as urban birds singing more loudly – there are also signs that human noise has become so intrusive that it is threatening to destroy the delicate balance of nature’s sound systems on which so many species depend. As a general rule, the noise impact on marine and wildlife depends on the extent to which noise disrupts a functioning eco-system or a natural sound system.

Noise has the greatest effect on the marine and wildlife which rely most heavily on auditory signals for survival. Increases in background noise levels can interfere with, or mask, communication signals which animals, birds and mammals use in their daily lives: in courtship, to warn of danger (often critical to survival) or to stake out territory.

It is in the oceans and forests that the natural sound systems are being most dramatically distorted.

The natural sounds of the ocean are magnificent in their range, beautiful in their delivery and stunningly varied. But these sounds are in danger of being overwhelmed by human noises and vibrations as never before in recorded history. It is estimated that during the past 50 years underwater noise has doubled each decade. Scientists and conservationists are increasingly concerned that noise pollution poses a significant threat to whales, dolphins and other marine wildlife.

The sounds of the jungle rival those of the ocean. They are at once beautiful and frightening, awesome and awe-inspiring. But they are under threat. As the jungle is chopped down or invaded, its natural noise rhythms are disappearing. Dr Bernie Krause, the eminent American acoustician who has recorded nature’s sounds for the past forty years, estimates that in that time nearly a third of the ecosystems he has captured have become aurally “extinct” because of habitat loss or the presence of noise-making machines .

Sonar testing is having an impact on mammals and fish.

However, it is ships which are responsible for the majority of the human-induced noise in the oceans. The noisiest ships are the huge vessels which carry oil, food and manufactured goods between ports all over the world. It is the propellers which are the cause of most of the noise from ships. As the blades turn, they create thousands of tiny bubbles, a process known as ‘cavitation’. It is the sound of these bubbles bursting which causes the noise. Ship engines are a distant secondary contributor.

We are all familiar with the phase ‘dumb animals’. It comes from the days when we assumed that animals couldn’t talk to each other. We now know differently. Dr Bernie Krause, the musician turned acoustician, coined a word for this: biophony. It is what the world sounds like in the absence of humans. It is quite remarkable. Krause has found that animals divide up the acoustic spectrum so they don’t interfere with one another’s voices. It is like a musical score for an orchestra, with each instrument in its place. No two species are using the same frequency. Krause told Wired Magazine: ‘That’s part of how they co-exist so well.’ When they issue mating calls or warning cries, they aren’t masked by the noises of other animals. This is best illustrated in the rainforest.

When human noise - what Krause calls anthropony – intrudes on this natural symphony, the information flow of the animal world is disturbed. It is increasingly happening: from cars, lorries, aircraft, logging, drilling. It doesn’t take much to disrupt the delicate balance of a natural soundscape.

It is interesting, though, that this threat to the planet’s sound systems is silently passing the world by. Though there is concern amongst individuals and some campaigning groups, it has generated nothing to match the vibrant, worldwide movement urging action to stop runaway climate change. The lack of interest is almost certainly a by-product of the way that society has failed to tackle noise problems closer to home over the past decades. Noise hasn’t been regarded as a major pollutant. It still isn’t seen as a key problem. But nature is telling us something different. How long will we remain deaf to its dying call?

 

 

 

Cacophony of human noise is hurting all marine life, scientists warn

A major assessment concludes that ocean soundscape is being drowned out by human activity

 - An article by Damian Carrington which appeared in The Guardian 4/2/21

A natural ocean soundscape is fundamental to healthy marine life but is being drowned out by an increasingly loud cacophony of noise from human activities, according to the first comprehensive assessment of the issue. The damage caused by noise is as harmful as overfishing, pollution and the climate crisis, the scientists said, but is being dangerously overlooked. The good news, they said, is that noise can be stopped instantly and does not have lingering effects, as the other problems do.

Marine animals can hear over much greater distances than they can see or smell, making sound crucial to many aspects of life. From whales to shellfish, sealife uses sound to catch prey, navigate, defend territory and attract mates, as well as find homes and warn of attack. Noise pollution increases the risk of death and in extreme cases, such as explosions, kills directly. Carbon dioxide emissions from fossil fuel burning are also making the oceans more acidic, meaning the water carries sound further, leading to an even noisier ocean, the researchers said.

But the movement of marine mammals and sharks into previously noisy areas when the Covid-19 pandemic slashed ocean traffic showed that marine life could recover rapidly from noise pollution, they said. “Everything from the tiniest plankton up to sharks sense their acoustic environment,” said Prof Steve Simpson at the University of Exeter in England, and part of the review team. “As a result, the animals have to produce sound to communicate, but also to receive sound.” He said noise pollution was like an “acoustic fog” in the ocean. “Marine animals can only see across tens of metres at most, and can smell across hundreds of metres, but they can hear across entire ocean basins,” said Prof Carlos Duarte at King Abdullah University of Science and Technology in Saudi Arabia, who led the review.

Duarte said major assessments of the health of the ocean were ignoring noise: “Yet the scientific literature, when read carefully, provides compelling evidence of human-caused noise being a major source of disruption to the marine ecosystem.” The review, published in the journal Science, analysed more than 500 studies that assessed the effects of noise on sea life. About 90% of the studies found significant harm to marine mammals, such as whales, seals and dolphins, and 80% found impacts on fish and invertebrates. “Sound is a fundamental component of ecosystems, [and noise] impacts are pervasive, affecting animals at all levels,” the analysis concluded.

The most obvious impact is the link between military sonar and seismic survey detonations and deafness, mass strandings, and deaths of marine mammals. But many uses of sound can be harmed, such as the hums that male toadfish use to attract females and the honks that cod use to coordinate spawning. Baleen whales produce calls to help group cohesion and reproduction that can travel across ocean basins, and humpback whales sing complex mating songs that have regional dialects. Sperm whales and various dolphins and porpoises use sonar to echolocate prey. Other animals use sound to feed: some shrimps produce a “snap” sound to stun prey.

However, over the past 50 years, increased shipping has raised low-frequency noise on major routes by 32 times, the review said. Fishing vessels use sonar to find shoals of fish and bottom trawlers create rumbling noise. The construction and operation of oil rigs and offshore windfarms also cause noise pollution, as does the detonation of second world war bombs in the North Sea. “Fish, clams, crabs and corals all hear sound and use it to find healthy places to make their home,” said Simpson. “So shipping or construction noise takes away that homing sense. It also means that whales that might have lived in a family and hunted over hundreds of miles have to live within 10 miles of each other to be able to communicate. “We find that animals are directly stressed by noise as well, and so they make poor decisions that often lead to death,” he said, noting that noise from motorboats on the Great Barrier Reef in Australia leads to double the mortality from predators. “Underwater noise is a serious concern and it is growing,” said Prof Daniel Pauly at the University of British Columbia in Canada, who was not part of the review team. “The level of noise marine mammals are exposed to is devastating … Underwater sound waves are far more violent than sound waves in air.”

There are solutions, the review found, with a retrofit of five large container ships by shipping giant Maersk in 2015 showing that new propeller designs reduce noise and also increase fuel efficiency. Quieter propellers are the top priority, said Duarte; half of shipping noise comes from just 15% of vessels. Electric motors are another possible solution, as are small reductions in speed. For example, cutting the speeds of noisy vessels in the Mediterranean from 15.6 to 13.8 knots cut noise by 50% between 2007 and 2013. Seismic surveys can also be carried out using seabed vibrators, rather than sending noise waves through the whole water column. “Cutting noise is possibly the lowest-hanging fruit to make a difference and we can change that today,” said Simpson. “I have real hope that we will hear a healthier ocean in our lifetimes.”

Growing Ocean Pollution Is Impacting Dolphin Communication

“Nobody wants to live in a noisy neighborhood.”

by Joe McCarthy 26/10/18

reprinted from Global Citizen, 26/10/18

Noise pollution in the oceans causes mental and physical harm to marine animals and makes it difficult to carry out ordinary tasks like finding food. Imagine hearing a jackhammer outside your bedroom window as the sun rises every day — that would be annoying, wouldn’t it? That’s essentially what marine animals are contending with on a daily basis. In fact, the oceans have gotten so noisy that dolphins are changing how they speak with one another, according to a study from the University of Maryland Center for Environmental Science. 

A team of researchers, led by marine biologist Helen Bailey, installed underwater microphones at the bottom of the Atlantic Ocean off the coast of Maryland in 2016 to record ambient noise levels. They discovered that dolphins were adapting their communication sounds to be heard over the noise of boats in shipping lanes. “It’s kind of like trying to answer a question in a noisy bar and after repeated attempts to be heard, you just give the shortest answer possible,” Bailey said in a press release. “Dolphins simplified their calls to counter the masking effects of vessel noise.”

Bailey’s team found that dolphins were whistling at higher frequencies and with less complexity during periods of high noise pollution. Since dolphins have complex languages, this simplification could hinder the amount of information being conveyed and could therefore diminish their ability to navigate their environments. Additionally, noise pollution causes mental and physical problems in animals, just as it does in humans. This is especially true for marine animals because noises travel further underwater, and some animals can even die from prolonged exposure to harsh and loud sounds. The ocean advocacy website Marine Insight notes that noise pollution can cause hemorrhages, internal organ damage, and significant stress. Animals exposed to high levels of noise pollution have extensive damage to their ears.

Noise also causes animals to migrate to new areas, potentially disrupting their ability to mate and find food. “These whistles are really important,” Bailey said. “Nobody wants to live in a noisy neighborhood. If you have these chronic noise levels, what does this mean to the population?”

Marine noise pollution comes from a variety of sources. Boats create sound as they move through the water, and more sound when they honk or send sonic signals. Mining operations on the seafloor create a continuous roar of sound, and oil extraction efforts involve piercing bursts of noise. Additionally, fossil fuel companies often use powerful seismic blasting techniques to locate oil reserves and other resources, and military vessels contaminate the water with widespread sonar. Taken together, this constant noise pollution is causing immense harm to marine life of all kinds.

"The ocean is an acoustic world — a world of sound, not of sight — and marine mammals depend on their ability to hear and be heard for virtually everything they do in the wild,” Michael Jasny, director of the marine mammal protection project at the Natural Resources Defense Council, told Global Citizen in a 2017 interview on seismic blasting. “For foraging, for hunting, for finding mates, for navigating, for orienting themselves in the wild, everything they have to do to survive and thrive.”

"Noise travels very far underwater and seismic blasting sort of has a double whammy," he said. "It makes a loud, explosive sound that’s on par with dynamite every 10 seconds or so and that can cause very acute impacts in wildlife, but it also raises background levels of noise for hundreds, even thousands of miles, making it difficult for many species to hear and communicate." "It can also cause mortality in invertebrates and young fish," he added.

Bailey’s team said that regulations should be enacted to reduce noise levels throughout the oceans, and certain practices should be halted altogether because of the harm they cause to animals. Their research was published in the journal Biology Letters.