(upbeat music)
- My name's Dave Mellinger.
I'm a professor at Oregon State University
and I study Marine Acoustics,
especially marine mammal acoustics.
This project was one done for the US Navy
and the Western Pacific near the Mariana Islands
and especially over the Mariana Deep.
Well, Mariana Trench is the deepest point
in the world's ocean.
We have made recordings deep in the Mariana Trench
but we have by no means explored the whole thing.
So we went to Guam to put the gliders in the water
and deployed two of them on two different tracks
around the Mariana Islands.
What an ocean glider is,
this cool robotic instrument that works by buoyancy changes
and it makes itself denser than water
and it has wings on the sides
so it actually flies down in the water.
We have a hydrophone attached to the glider
and the sound gets recorded onto
some internal chips inside the glider.
We don't know what the sounds are
until we get the gliders back home and in the lab.
When we started listening to these sounds
we heard some relatively familiar sounds
like humpback whales and dolphin sounds
but we also ran across this very strange, unusual sound
which we later called the Western Pacific Biotwang.
We started hearing it and we're like,
what the heck is that sound?
(deep low frequency vibration)
We just had not heard this kind of thing before.
And so, we started looking for it,
listening for it in our recordings
and found all these Western Pacific Biotwangs
occurring all over the place.
(sound twanging)
We really didn't know what this was
but we started finding more and more of them.
So it was a mystery sound,
we didn't know what was making it,
nobody had ever reported this kind of sound before.
(sound twanging)
One of the characteristics about it
was that it was pretty irregular
and so that made us think
that it was an animal of some sort.
Manmade sounds tend to be very regular and repeatable,
like things like sonar sounds that are made by ships
and submarines and whatnot,
and this was not perfectly repeating every time
but the complexity of this call kind of ruled out fish.
Fish don't make very complex sounds
and this sound was very complex,
one of the most complex ones we've ever seen.
And then we looked at the frequency range of the sound.
It's got a lot of low
frequency components
and so that made us
think Baleen whale.
There're two basic large groups of whales
which are the Baleen whales and the Toothed whales
and the Baleen whales make, are the big ones,
like Blue whales and so on,
and they make the lowest frequency sounds.
(sound twanging)
Some of the portions of the sound
resembled that of Minke whales
which had been heard in other parts of the Pacific.
But other components of this call
did not match Minke whales at all,
and so we were really not sure what we had.
And you realize that there's a lot
that we don't know about the oceans out there,
so it's really cool to run across one of these things
and be able to say,
okay, this is something new to science,
here, let's document it and report as much
as we can find out about it
and maybe other people will find out even more.
The ocean's a huge place, you know,
it's 70% of the Earth's surface.
If you think about say,
the number of vertebrates that are out there,
5,000 mammals or maybe 10,000 species of birds
and a few thousand reptiles and amphibians.
But fish, fish, there are more than
30,000 species of fish known.
And fish do make sounds
and the amount of variety present in different kinds
of fish sounds is staggering,
we know very little about that.
The amount of variety out there is just mind blowing.
The amount of stuff left to discover
about the oceans is just incredible.
So it's a pretty exciting area to be doing research in.
(upbeat music)