As unlikely as it may seem, your drive to the supermarket is responsible for a lot of noise pollution in our oceans – and a lot of stress to marine life as a result.
Of course, it’s not the specific sound of your car trundling along the street that the fish and whales hear. But many of the products that feature in your weekly shop – from the goods you buy, to the petrol you burn, to your car’s component parts – contribute to marine noise pollution.
Let’s start with the oil. Before we can drill the oil or turn it into fuel to drive our cars, oil companies have to discover it.
Companies look for oil using high-pressure airguns. These machines are towed across the surface of the ocean, firing off sounds to determine the make-up of sediment layers in the seafloor. These are some of the loudest human-created sounds – researchers working in the middle of the Atlantic Ocean have been able to record the sounds produced from coastal oil surveys.
These sounds are problematic for marine life. Whales and other animals that rely heavily on sound for communicating and finding food are most affected. Hearing is to these animals much the same as vision is to humans. Unusually loud sounds can disturb whales’ behaviour and, if they are close enough, can damage their hearing. There is even some suggestion that the airguns can cause whale strandings, although this is not yet completely certain.
Currently, one-third of all oil comes from offshore sources and this proportion is expected to increase. This can only mean more bad news for our marine life.
What about the metal box that consumes all the oil? Parts for the car are sourced from all over the world and have to be shipped across our oceans. In turn, the raw materials needed to make these parts are usually shipped in from yet more places. The commercial shipping needed for all this represents another problematic source of ocean noise.
The contributions of individual ships may seem trivial in comparison to the loud noise from airguns. However, the world merchant fleet includes around 52,000 ships. Collectively, these increase the ambient noise levels in our oceans. In fact, the amount of low-frequency sound in some parts of our oceans has doubled each decade over the past 60 years.
Humans perceive only some of this sound, because of the very low pitches involved. But these sounds are well within the frequency range used by baleen whales. Recent work suggests that this constrains the communication ranges in whales, causing chronic stress and potentially interrupting mating behaviour.
Oh, and most of your groceries are shipped around the world at some point too, as are many other consumer items – including the battery in your hybrid car, if you have one. Around 90% of world trade is carried by commercial ships at some stage. Not all of this ends up in your shopping bag, but a large proportion enters the consumer market at some point.
Certain grocery items, such as fish, originate from the oceans themselves. Like cargo ships, fishing vessels produce noise from their engines and propellers, but they also have noisy fish-finding sonars and winches as well.
The good news is that noise pollution, unlike chemical pollution, dissipates quickly. This means that the future for underwater noise remains bright. If you want to give the whales a break, just drive a little less, or support higher efficiency standards for vehicles. This will not only reduce oil consumption, but also the wear and tear on your car, meaning that fewer replacement parts will need to be shipped in.
You can also buy locally produced items and support the local economy too. That way everyone wins.
No matter how connected we think everything is, the situation is generally even more complicated than we can imagine. So next time you walk to the shops and buy an apple grown in your state, you should allow yourself a moment to feel good about yourself, safe in the knowledge that you have helped to make the oceans a tiny bit quieter.
Air guns used for marine oil and gas exploration are loud enough to affect humpback whales up to 3km away, potentially affecting their migration patterns, according to our new research.
Whales’ communication depends on loud sounds, which can travel very efficiently over distances of tens of kilometres in the underwater environment. But our study, published today in the Journal of Experimental Biology, shows that they are affected by other loud ocean noises produced by humans.
As part of the BRAHSS (Behavioural Response of Humpback whales to Seismic Surveys) project, we and our colleagues measured humpback whales’ behavioural responses to air guns like those used in seismic surveys carried out by the offshore mining industry.
Air guns are devices towed behind seismic survey ships that rapidly release compressed air into the ocean, producing a loud bang. The sound travels through the water and into the sea bed, bouncing off various layers of rock, oil or gas. The faint echoes are picked up by sensors towed by the same vessel.
During surveys, the air guns are fired every 10-15 seconds to develop a detailed geological picture of the ocean floor in the area. Although they are not intended to harm whales, there has been concern for many years about the potential impacts of these loud, frequent sounds.
Although it sounds like a simple experiment to expose whales to air guns and see what they do, it is logistically difficult. For one thing, the whales may respond to the presence of the ship towing the air guns, rather than the air guns themselves. Another problem is that humpback whales tend to show a lot of natural behavioural variability, making it difficult to tease out the effect of the air gun and ship.
There is also the question of whether any response by the whales is influenced more by the loudness of the air gun, or how close the air blast is to the whale (although obviously the two are linked). Previous studies have assumed that the response is driven primarily by loudness, but we also looked at the effect of proximity.
We used a small air gun and a cluster of guns, towed behind a vessel through the migratory path of more than 120 groups of humpback whales off Queensland’s sunshine coast. By having two different sources, one louder than the other, we were able to fire air blasts of different perceived loudness from the same distance.
We found that whales slowed their migratory speed and deviated around the vessel and the air guns. This response was influenced by a combination of received level and proximity; both were necessary. The whales were affected up to 3km away, at sound levels over 140 decibels, and deviated from their path by about 500 metres. Within this “zone”, whales were more likely to avoid the air guns.
Each tested group moved as one, but our analysis did not include the effects on different group types, such as a female with calf versus a group of adults, for instance.
Our results suggest that when regulating to reduce the impact of loud noise on whale behaviour, we need to take into account not just how loud the noise is, but how far away it is. More research is needed to find out how drastically the whales’ migration routes change as a result of ocean mining noise.
Ask most people about pollution, and they will think of rubbish, plastic, oil, smog, and chemicals. After some thought, most folks might also suggest noise pollution.
We’re all familiar with noise around us, and we know it can become a problem – especially if you live near an airport, train station, highway, construction site, or DIY-enthusiast neighbour.
But most people don’t think that noise is a problem under water. If you’ve read Jules Verne’s Twenty Thousand Leagues Under the Sea you might imagine that, maelstroms excepted, life is pretty quiet in the ocean. Far from it.
When we put a hydrophone (essentially a waterproof microphone) into the water, no matter where in the world’s oceans, it’s never quiet. We hear wind blowing overhead and rain dropping onto the ocean surface – even from hundreds of metres deep. In Australian waters we can also detect the far-off rumbles of earthquakes and the creaking of Antarctic ice thousands of kilometres away.
Water is much denser than air, so its molecules are packed tighter together. This means that sound (which relies on molecules vibrating and pushing against one another) propagates much further and faster under water than in air.
This also applies to human-produced sound. Under water we can hear boats and ships and even aeroplanes. Large vessels in deep water can be detected tens of kilometres away. We can be far offshore doing fieldwork, the only people around, with nothing in sight but water in any direction. Yet when we switch the engines off and put a hydrophone into the water, we hear ship noise. Sometimes, whole minutes later, the vessel we heard might appear on the horizon.
Seafarers have known about another source of sound for thousands of years: marine life. Many animals produce sound, from the tiniest shrimp to the biggest whales. Many fish even communicate acoustically under water – during the mating season, the boys start calling. Whales do it, too.
Light doesn’t reach far under water. Near the surface, in clear water, you might be able to peer a few metres, but in the inky depths you can’t see at all. So many marine animals have evolved to “see with sound”, using acoustics for navigation, for detecting predators and prey, and for communicating with other members of their species.
The thing is that man-made sound can interfere with these behaviours.
The effects of noise on marine animals are similar to those on us. If you’ve ever been left with ringing ears after a rock concert, you’ll know that loud noise can temporarily affect your hearing or even damage it permanently.
Noise interferes with communication, often masking it. Can you talk above the background noise in a busy pub? Long-term exposure to noise can cause stress and health issues — in humans and animals alike.
Excessive noise can change marine creatures’ habits, too. Like a person who decides to move house rather than live next door to a new airport, animals might choose to desert their habitat if things get too noisy. The question is whether they can find an equally acceptable habitat elsewhere.
There is a lot more research still to be done in this field. Can we predict what noises and vibrations might be released into the marine environment by new machinery or ships? How does sound propagate through different ocean environments? What are the long-term effects on marine animal populations?
One positive is that even though noise pollution travels very fast and very far through the ocean, the moment you switch off the source, the noise is gone. This is very much unlike plastic or chemical pollution, and gives us hope that noise pollution can be successfully managed.
We all need energy, some of which comes from oil and gas; most of our consumer goods are shipped across the seas on container vessels; and many of us enjoy eating seafood caught by noisy fishing boats, some of which even use dynamite to catch fish. We want to protect our borders, making naval operations a necessity. Then there’s the ever growing industry of marine tourism, much of it aboard ever-bigger cruise ships which need large ports in which to berth.
There are a lot of stakeholders in the marine environment, and all speak a different language, all make different claims, and all make noise. Knowing precisely how much noise they make, and how it affects marine life, will help to ensure our oceans and their resources last well into the future.
September 3-11 is SeaWeek 2016, the Australian Association for Environmental Education Marine Educators’ national public awareness campaign.
In a radio interview this morning, Prime Minister Tony Abbott raised what he described as the “potential health impacts” of wind farms.
Yesterday’s article in The Australian by Liberal Democrat senator David Leyonjhelm highlighted some very good points about wind turbine noise and its effect on people living near them. People are complaining of a range of health related problems and are attributing them to wind turbines. The question is: what is the cause of these health problems?
Many blame the production of infrasound from wind turbines, yet this has not been proven to date. What is needed is new, comprehensive research to determine the true cause.
These concerns are currently being aired through a Senate Committee on wind farms and regulations, chaired by independent senator John Madigan.
Earlier this year the National Health and Medical Research Council found that there was no evidence that wind turbines directly affect health, but called for further research, particularly on the effects within 1.5 km of turbines.
I have been interested in how wind turbines produce noise, through a variety of research projects spanning several years. The most recent was an ARC Discovery project focusing on the fundamental noise-producing physics of wind turbine blades and the development of techniques to link personal annoyance with noise levels inside homes. My group and I have also investigated ways to reduce wind turbine noise by changing the shape of the blades and to steal ideas from owls, who have the ability to fly and hunt silently.
So are Leyonjhelm’s claims correct? Let’s run through them.
Claim: “Wind turbines emit infrasound and low-frequency noise.”
Wind turbines undoubtedly create infrasound. It is created by the movement of the blades through the air, as the blades pass the tower and, depending on the construction of the turbine, by the gearbox.
Claim: “Inappropriate levels of infrasound, regardless of the source, cause adverse health impacts.”
However, most experts believe that the level of infrasound produced by wind turbines is too low to be heard or create health problems. Recent measurements show that infrasound can propagate many kilometres from a wind farm – what we don’t know is if these very low level sounds can cause health effects.
Previous studies on the effects of infrasound on health have focused on the exposure of high levels of infrasound from industrial sources. These studies show that perception or physiological effects occur at levels that are many times those generated by wind farms.
Claim: “Research by NASA … established wind turbines could generate surprisingly high levels of infrasound and low frequency noise.”
While it is true that early designs of wind turbines created large amounts of low-frequency noise that was annoying (the so-called “downwind” turbines of the 1980s which were reported on by NASA), modern designs that place the rotors upwind of the tower have greatly reduced this problem and made wind turbines quiet enough for widespread use.
There have also been many years of intensive research and development into the design of quiet wind turbine rotors and operational methods to reduce noise. This is not to say that wind farm noise is not responsible for reported health problems.
The effect of sensitization after long exposure to low-level noise, the effects on sleep and the role of moderating factors must be considered along with noise generation and propagation effects to properly understand why so many people are complaining of health problems near wind farms.
Claim: “Wind farms are not required to limit or even monitor their infrasound emissions.”
There are no requirements for infrasound to be monitored near wind farms because it occurs at a very low level and is not expected to be heard by most people. It is also very difficult to measure, especially in the presence of wind that will also generate infrasound of the same or higher level when it passes through trees or blows over a house.
Even when we do record it, we don’t yet know what level is responsible for causing health problems.
What is needed is new multi-disciplinary research linking engineers with medical and health scientists where noise data and health information are recorded simultaneously for people living close to and far from wind farms. Only such detailed research can help provide an answer to this challenging and perplexing problem.
The link below is to an article that reports on the decline of city birds, due to noise pollution.
The following link is to an article that looks into how noise pollution impacts squids and octopuses. An enlightening article on an issue that is becoming clearer all of the time.