Transcriber: Herronson James Reviewer: David DeRuwe
This is an underwater soundscape.
(Underwater sounds)
What you can hear are the sounds beneath the surface of a stream.
(Underwater sounds)
You can hear the stream flowing.
(Stream flowing)
You can listen to insects talk.
(Insects talking)
Sometimes fish swim by and grunt.
(Fish grunting)
And if you’re lucky, you can listen to sediments or plants release gas.
(Laughter)
Fun, right?
But why should we listen to streams?
Let me ask you a question.
Why do you listen to your friends?
I would hope you want to know how they feel and how they are.
And that was my goal.
I wanted to know whether, by just listening,
I could learn more about streams.
I didn’t want to use traditional methods where you step into the creek
and you scoop out the insects and you electrocute the fish,
just to learn more about the streams.
It didn’t make sense to me that in order to protect the environment,
I would have to invade it.
So I decided to listen.
I got a microphone - no, I got a hydrophone -
which is a small waterproof microphone,
and I placed it in the water.
And the world I discovered was just amazing.
Some streams are active during the day,
others during the night,
and some are singing and buzzing 24 hours.
And the best thing is?
A hydrophone doesn’t seem to bother the little creatures.
They’re even curious about it.
What you can see here are two spangled grunters
being very curious about that hydrophone while talking.
(Spangled grunters’ sounds)
I discovered that much like a bird chorus in the morning
or an insect orchestra at night,
so do streams have a 24-hour cycle.
They have a unique soundscape,
a unique voice that repeats every 24 hours.
Let me show you what I mean.
This is the Delaneys Creek in Southeast Queensland.
(Creek sounds)
And this is the Cainbable Creek in Southeast Queensland.
(Creek sounds)
Pretty different, right?
But streams not only have a 24-hour cycle, they also have a lunar cycle.
Insects don’t seem to appreciate the moonlight very much.
The fuller the moon, the quieter they become.
That’s probably because they don’t want to get eaten by predators.
The moonlight exposes them,
so they go into hiding and are not that active anymore.
And then there are the seasons.
Let me take you back, April 2018.
I was sitting next to the Whirl Creek, listening.
(Creek sounds)
And I began to wonder:
“Would I always hear these sounds, or would they differ?”
So I decided to go back six months later.
And that year was particularly dry,
and on my way there, I saw somebody pumping out water onto their fields.
And when I arrived at the creek,
water level had dropped, and everything looked very dry.
So I got worried about the little creatures in the stream,
and when I submerged the hydrophone,
this is what I heard:
(Silence)
What had happened?
I wasn’t sure.
Was it nature’s course?
Or was it climate change
finally striking down on this lovely creek?
Was I watching the slow death of a friend?
I wasn’t sure.
So I decided to come back six months later,
and this is what I heard:
(Creek sounds)
They were back!
(Laughter)
Similar to seasonal changes that we see on land
when birds and other creatures migrate or mate,
so did creeks have a seasonal pattern in their sound.
And although their sounds differ
through the seasons and through the moon cycle
and even through the day,
there’s one extra factor
that can influence the sounds underneath the surface.
Can you guess what it is?
Let me give you a hint.
During the pandemic, have you noticed how quiet your surroundings became?
No planes flying over your head.
No cars driving through the cities, on the highways.
Everything became just a little bit more ... quiet.
And that is it.
Sounds produced by humans not only affect us as humans,
but also the creatures we share this planet with.
Noise pollution is known to increase blood pressure
and causes sleeping disorders in humans.
And animals are equally stressed.
Just listen to what a boat can sound like underwater.
(Underwater boat sounds)
This was a very mild version because I didn’t want to shock you.
And it was only 10 seconds.
Imagine listening to it for hours and having nowhere to go.
Would you be stressed?
Noise underwater increases the stress levels in fish,
and it can lead to hearing loss.
And even if fish haven’t lost their hearing,
they still have a hard time hearing each other.
Try asking somebody out on a date
while standing next to a construction site.
You would probably have a hard time too.
And even if fish found a mate and laid eggs,
they tend to protect those eggs less when loud noise is around.
All in all, scientists know
that loud noise has a negative impact on fish health and fish fitness.
And it’s time that we see it as a pollution,
similar to chemicals and plastics.
But we don’t have to be passive listeners.
We could learn how to listen to help the environment.
We could listen to the sediments being transported by the creek.
We could listen when a creek is about to dry out
or a riverbank is crumbling.
We could step in and help if it’s necessary.
We could also listen for disturbances,
such as illegal water pumping or the arrival of an invasive species.
We could protect our waterways by detecting those disturbances early on
and catch those culprits in the act.
We could also listen for
the spawning activities of endangered species.
We could find out when and where they arrive
and protect that area and help that species to survive.
We could learn so much more,
and we could help the environment so much more if we just started listening.
Thank you for listening.
(Applause)