When I was a boy one of the songs I often heard on the radio (a precursor to the iPhone) was by Max Bygraves – What Noise Annoys An Oyster? It was just a humorous ditty with a catchy tune I could sing along to. The song answered its own question. ‘A noisy noise annoys an oyster most.’
What that noisy noise was is not elaborated
upon in the song.
Recently, I have begun pondering the source of noisy
noises. What constitutes a noisy noise? Moreover, what is the noisiest
noise? There would appear to be at least two ways to answer the first of these.
A noisy noise could be the loudest noise.
Or, a noisy noise could be one that is unrelenting.
One that keeps nagging away at your eardrums.
I did some research. The loudest natural sound is that
of the Blue Whale, whose mating call can be as great as 188 dB (decibel) and
heard from hundreds of kilometres away underwater. The loudest sound ever in
recorded history is said to have been the Tunguska Meteor in Siberia in 1908. This
meteor exploded some 5 – 10 km above the Earth’s surface, so leaving no impact
crater, but emitted a noise of 300 dB or more. The Krakatoa eruption in 1883 produced
a similar noise level and was heard 2,000 km away. Sailors within 60 km had
their eardrums shattered, and thousands of people close by were killed. In
comparison, an earthquake of magnitude 5 on the Richter scale can be as much as
230 dB.
All these are sudden events of relatively short
duration – although I have not checked how long the mating season is for a Blue
Whale.
They are also all extremely loud. A level of 85 dB is
often quoted as the maximum level of toleration for a human before hearing damage
is done. Normal human speech is around 55-65 dB, and a human scream can be from
80 – 120 dB. Upper safe noise levels for humans are usually set at around 75 –
80 dB.
But, what of continuous and unrelenting noise?
Unsurprisingly perhaps, the species on Earth that is
the noisiest in this regard is us. We humans are incredibly noisy. Most of that
noise is not from our voices, but from our technology.
Household technologies such as vacuum cleaners and
dishwashers are close to the safe threshold for humans, at around 70 – 75 dB.
Other everyday technologies however are above the safe
zone. Consider a few examples: Leaf blower 80 – 90 dB., lawn mower approx. 95
dB., and chainsaws around 105 dB. No wonder your ears hurt each weekend when
the neighbourhood starts mowing lawns, blowing leaves around, or cutting up
firewood.
Yet, even these are not our noisiest creations. A
pneumatic drill for example produces 110 dB. Our city streets are extremely
noisy. A car horn registers 120 dB as does the siren of an emergency vehicle.
Sporting events and music concerts have levels of up to 110 dB. Go out to an
airport and you’ll hear a jet aircraft take off at 130 dB.
City dwellers are beset by a continuous noise level of
60 dB or more. This constant noise level is enough to lift blood pressure and
raise heart rates above normal levels. Chronic noise of this level can elevate
stress levels, cause loss of concentration, and be a factor in sleep
deprivation. Simply put, living in cities can be unhealthy for you.
Sadly, unhealthy noise levels are not restricted to
cities.
What of the other life forms on this planet? Does the ever-present
noise generated by humans have an impact?
It sure does.
Our noisy noise detrimentally affects the
mating, communication, and navigation patterns of many animals. Even supposedly
protected nature areas are not immune to the presence of human noise. Noise
levels can be 2 – 10 times the normal background noise levels in these areas.
The effect of human noise upon animals has only
recently begun being studied and analysed. However, already the damage is being
witnessed. A 2019 research paper looked at data from more than 100 species
(including amphibians, arthropods,
birds, fish, mammals, molluscs and reptilians.)1 The paper
concluded that: ‘We found clear evidence that anthropogenic noise affects a
wide range of species from a variety of different taxonomic groups.’
Disturbingly, the
researchers noted that, ‘it is likely that we underestimate the effect of
noise.’
The oyster in Max
Bygraves’ song was correct. Noisy noises do annoy oysters – and just about
every other animal (including us humans) on the planet.
Note:
1. Hansjoerg P Kunc and Rouven Schmidt. The effects of anthropogenic noise on animals: a meta-analysis, The Royal Society: Biology Letters, November 2019. https://royalsocietypublishing.org/doi/10.1098/rsbl.2019.0649 accessed 16 July 2024
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