November 19, 2024 • 42 mins
For most of our planet’s existence, the Earth was quiet. The boisterous sounds of life we know today are a recent development, one that the growing field of bioacoustics is helping us understand and interpret. In this episode, we travel to Australia to listen to dolphins and meet the microbes that helped usher in life on the planet.
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Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Amy Martin (00:00):
Hi, I know you just pressed play on this episode,
but I'm about to ask you to stoplistening to me. Yes, this is a
strange way to start a newseason of our show, I know, but
this is my request or myinvitation. If you're so
inclined, in just a moment,please press pause and spend 10
(00:24):
or 15 seconds listening towhatever you can hear around
you. All the voices, anythingmaking any sort of noise at all,
and then press play again. Thatpart's crucial. Please do come
back. Okay. Are you ready?Three, two, one.
(00:47):
What did you hear? Could youhear any sounds that weren't
made by people? If so, consideryourself lucky, because human
beings have become very, veryloud.
Flight Attendant (01:09):
In preparation for takeoff, may we now remind
you to fasten your seatbelts.
Amy Martin (01:17):
This relentless noise we make. It's not normal.
For most of our time on thisplanet, we humans have been very
good listeners, tuning incarefully to the movements of
water, changes in the weather,the voices of other animals. But
now many of us move through ourdays or even our entire lives
(01:41):
hearing almost nothing but thesounds of just one species. Our
own. If the planet is a dinnerparty, we're the guests who are
ruining the conversation,talking over everyone, assuming
(02:04):
that our voices are the mostimportant ones in the room.
We're drowning out essentialcommunication between other
creatures, forcing them to spendtheir lives shouting to each
other in order to be heard, orworse, we're silencing them
forever. And our noise doesn'tonly threaten other beings.
(02:30):
We're endangering ourselves, andwe know things are out of
balance. We feel isolated andcut off because we are.With
multiple ecological crisesmounting around us, many of us
feel desperate to help, andthere is unquestionably so much
(02:50):
work to be done, but maybe thefirst step is slowing down and
letting the voices of our planetmates back in.
What if being useful starts withbeing quiet? What if saving the
(03:18):
world begins with listening toit? What changes when we
remember to listen to the morethan human world? That's the
question at the heart of thisseason of our show. Despite all
(03:43):
the damage that's already beendone, there is still a vast
planetary choir singing aroundus. It's right there waiting for
us, if we turn our attention toit.
All over the world, people arehearing those voices and
responding. We are in the midstof a listening emergency, but
(04:07):
also a listening Renaissance. Inthis season, we'll meet people
who are devoting their lives tolistening, reconnecting with old
traditions, or creating newones, and building tools that
might someday allow us tocomprehend what other animals
are saying in ways we've onlydreamed of in the past. It's
(04:32):
going to be a fun journey and afascinating one, but I'm going
for something deeper than thewow factor of cool nature
sounds. I chose to make thisseason now because I think all
of our ecological crises,climate, extinction, pollution,
are essentially breakdowns inrelationship, and the first step
(04:56):
in healing any brokenrelationship is listening. So
what happens when we do that?Welcome to threshold. I'm Amy
Martin, and this is season five.Hark.
(05:58):
It's seven o'clock on a sunnymorning, and I'm on a boat
heading into Shark Bay, a hugemarine reserve off the Western
Australian coast. This isMalgana country, one of hundreds
of Aboriginal groups inAustralia, and in malgana, the
name of this place isGathaagudu, which means "two
waters."
Dr. Stephanie King (06:19):
Dolphins straight ahead.
Amy Martin (06:21):
We've barely left the jetty, and Dr. Stephanie
King has already spotted adolphin. It surfaced and
disappeared again in a flash,but that was enough time for her
to identify it. It was a femalenamed Gindy.
You knew who it was that fast?
Laura Palmer (06:36):
Yeah, she does.
Amy Martin (06:37):
Wow.
Laura Palmer (06:38):
She's great.
Amy Martin (06:39):
That's Laura Palmer, she's working on her PhD, and
the other person with us isresearch assistant Amelia Clark.
All three of these scientistsare from the University of
Bristol in the UK. Stephanie isthe leader of the expedition and
the current captain of the boat.
How did you know?
Dr. Stephanie King (06:57):
Because of the markings on the dorsal fin.
She has an uncle who has asimilar fin to her. You can see
the three small nicks, thelittle break marks at the top.
Each nick is kind of similarlyspaced along the fin, almost
equidistant from each other. Soeach dolphin has a unique dorsal
fin, like we say, like afingerprint, but it's far more
obvious than that, I guess, likea human face. So they're very
(07:20):
distinctive. If you've beenworking with them a long time,
then then you recognize all theindividuals.
Amy Martin (07:26):
Shark Bay and its surrounding coastal areas are
listed as a UN World HeritageSite, and it's easy to see why.
The water is a clear turquoiseblue and huge sea grass meadows
provide food and shelter for anabundance of wildlife. Sea
turtles, dugongs, and more than300 species of fish, including
(07:46):
the namesake sharks. But thesuperstars here are the
dolphins. The scientists ofShark Bay Dolphin Research have
been studying them continuouslysince 1982, making this one of
the most carefully observedcommunities of dolphins on the
planet. Stephanie is one of thecurrent co directors.
(08:07):
Do you know how many dolphinsare here, roughly?
Dr. Stephanie King (08:10):
Two to 3000 I mean, there's about 1800 that
we have in our catalog that wework on, and that's just in our
core study area, in the easternGulf. There's far more than
that.
Amy Martin (08:19):
And of those 1800 how many of them can you
identify on site like you justidentified that one in two
seconds?
Dr. Stephanie King (08:25):
I've never tested myself, but maybe we
could do that. I know a lot.More, way more than 200.
Amy Martin (08:33):
And when did you first come here?
Dr. Stephanie King (08:35):
I first came to Shark Bay in 2014, so 10
years ago now.
Amy Martin (08:40):
And have you been coming almost every year since
then?
Dr. Stephanie King (08:43):
Every year. I think 2020 was the only year
because of COVID, but I comeevery year, and it's a really
important part of my, I guessjust part of my life, coming
here, spending time with theanimals, being inspired for the
next questions that we want toanswer, seeing who's still
around, who's had a calf, howare the males doing, who's
(09:05):
allying with who? I think thisis certainly where I'm at my
most happiest as a fieldbiologist. It's where I'd like
to be most of the time, if Icould.
Amy Martin (09:14):
Yeah.
Stephanie studies these dolphinsusing every non invasive tool,
she can find (09:21):
drone videography, DNA sampling, and especially
bioacoustics. Recording andanalyzing the sounds the
dolphins make.
Dr. Stephanie King (09:32):
Sounds is the primary way that they
communicate, and a lot of ourresearch now is starting to
uncover exactly what some ofthese sounds mean and how
they're used.
Amy Martin (09:41):
Bioacoustics is the name for a fast growing field of
science, or really an approachto scientific research that's
being used across many fields.Sometimes it's also called
ecoacoustics, or acousticecology. All of these labels
have slightly differentmeanings, but they're all based
around listening to the morethan human world, and they're
(10:02):
all booming right now. Over thecourse of this season, we're
going to meet bioacousticsresearchers working with all
kinds of different creatures,but we're going to dive deep
with dolphins. Pun intended.We'll be returning to Shark Bay
in several episodes in hopes ofreally getting to know this team
and the way these remarkableanimals are using sound
(10:24):
Stephanie says that starts withlearning about the dolphins
world overall, their habitats,their relationships, their needs
and preferences.
Dr. Stephanie King (10:33):
So we look at behavioral complexity in
bottlenose dolphins, and thatcan take the form of foraging
specializations and tool use,which is a great example of
animal culture, but we alsospend a lot of time looking at
cooperation. This is reallywhere my passion lies,
understanding how animals usecommunication to mediate complex
(10:55):
social behaviors likecooperation.
Amy Martin (10:58):
Highly social animals like dolphins, elephants
and people have special needsfor communication. We make
decisions together, like whereto find food or how to respond
to a threat. We maintain longterm relationships that we
depend on in times of need, andwe pass on information to our
young. All of this cooperationdemands that we develop complex
(11:22):
communication skills.
Dr. Stephanie King (11:24):
And in Shark Bay, we have male dolphins that
form long term alliances. Sothese are really significant
relationships for these animals.They're investing heavily in
these cooperative relationshipswith each other, and I'm really
fascinated by the ways that theydo that. So what vocal signals
are they using to mediate theserelationships? How do they keep
(11:45):
track of each other? How do theycoordinate their behavior? So
these are all the types ofquestions that we aim to answer
in our work in Shark Bay.
Amy Martin (11:54):
Is the cooperation that they're engaged in, how
much of that is happeningthrough sound?
Dr. Stephanie King (12:01):
It's mostly happening through sound, and
that's because it's a speciesthat lives underwater, right? So
vision is restricted becauselight doesn't travel that far.
They have good visual acuity,they've got good vision, but
they don't rely on visionbecause they can't see that far
underwater. But sound travelsreally far.
Amy Martin (12:20):
Dolphins use other forms of communication too, of
course.
Dr. Stephanie King (12:23):
They can be quite tactile with each other,
so they'll spend time pettingand rubbing each other, and
that's a way of reaffirming orestablishing or maintaining
relationships.
Amy Martin (12:31):
But Stephanie says sound is central.
Dr. Stephanie King (12:34):
They use sound for all important aspects
of their life, to navigate theirenvironment, to find food, and,
importantly, to communicate witheach other. So it's their
primary modality, it's sound,it's not vision, it's not
gestures. And by sharinginformation through vocal
signals, they can let each otherknow where they are, maybe if
(12:56):
they plan to move, if they wantto reunite this type of
information.
Amy Martin (13:02):
When I visited the team in May of 2023, they were
just getting started for theyear. Amelia, who goes by
Millie, is a recent master'sgraduate who's here to get
experience as a researchassistant. Laura is a PhD
student collecting data for herthesis work.
Laura Palmer (13:18):
This is my first time in Shark Bay, so I've only
been here a week now. We've hadlots of amazing days on the
water, so certainly very lucky.It was a good time to come.
Amy Martin (13:28):
Laura and Millie are under some pressure because they
only have a few weeks withStephanie, then she has to
leave, and they'll do everythingon their own. One of the key
things they need to learn is howto take a survey of every
dolphin they meet.
Dr. Stephanie King (13:42):
By survey, I mean, we photograph the group,
and we stay with them for atleast five minutes, and we write
down their predominant behavior.So are they socializing,
traveling, resting, and then welook at who are they with. And
by doing that throughout theseason, over multiple years, and
we've been doing it for 40 yearsnow, we have this incredible
picture of who associates withwho, who has strong friendships,
(14:03):
which dolphins avoid each other.And we can, like, map the social
network, if you like, and we canlook at the structure and maybe
link some of that information tofitness measures, like, does
being more sociable mean thatyou're more successful and you
have more offspring, forexample.
Amy Martin (14:20):
You got dolphins, Laura?
Laura Palmer (14:21):
No, not yet. But there's splashing basically at
zero degrees.
Amy Martin (14:26):
While I've been peppering Stephanie with
questions, Laura and Millie arescanning the water for anything
that looks remotely dolphin-ish.Laura said she saw some splashes
at zero degrees, meaningstraight ahead. So she moves to
the bow with a boat to get abetter look.
Dr. Stephanie King (14:42):
If we see splashes, we'll check just to
make sure it's not dolphinsforaging anything that looks
like it could be a dolphin, orindicate dolphin behavior we'll
check with the binos and maybeeven go a bit closer.
Amy Martin (14:53):
I quickly get obsessed with dolphins spotting
myself, which was a littledangerous. Stephanie told me
that if someone says they see adolphin and it turns out to be a
bird, they have to bakesomething for the rest of the
group back at the ResearchStation.
Laura Palmer (15:07):
Yeah, yeah.
Dr. Stephanie King (15:08):
Yeah?
Amy Martin (15:10):
But then Laura calls from the bow, there's definitely
dolphin activity up ahead.
We're in business!
The dolphins are constantly inmotion, and they are fast.
Stephanie needs to move usquickly or we'll lose them. But
she also wants to maintain somedistance so we don't disturb
(15:30):
them. It's a bit of a dance tofind that just-right spot.
Ooh, I just saw a fin.
Everyone has a job to do.Stephanie's in the captain's
chair, Laura will try to getclear photographs of every
dolphin we see. Millie willwrite down notes, and I'll just
try to stay out of the way.
Dr. Stephanie King (15:48):
We have Zeppelin and Blimey.
Amy Martin (15:52):
Hands on the steering wheel and eyes on the
water, Stephanie calls out thename of each dolphin to put into
the notes.
Dr. Stephanie King (15:58):
Z-E-P, and B-L-M. Yeah, you got them. They
might come again they're stilljust beneath the surface.
Amy Martin (16:14):
They're so close!
Stephanie is mindful of keepingsome distance, but the dolphins
aren't as concerned about therules. They swim close to the
boat, zipping around and seemingto check us out. When they swim
over dark patches of sea grass,they can all but disappear, and
then all of a sudden, they popup again to grab a quick breath.
(16:40):
Even though I can see themcoming, it's delightfully
startling every time they crestthe surface. These are
Indo-Pacific bottlenosedolphins, smaller than some
other species, but still big.They average around two and a
half meters long, or more thaneight feet, with a maximum
weight of about 230 kilograms,or about 500 pounds. But all
(17:03):
that bulk doesn't limit theirgrace. It's actually hard to
call what they do swimming. Itlooks more like dancing or
flying. Their smooth, shinybodies roll past us in a
heartbeat as Laura tries to geta clear portrait of each one.
Laura Palmer (17:20):
I'm going to try to get Blimey one more time.
Amy Martin (17:24):
As if she heard Laura's request, Blimey pops up
and looks right at us, and Laurapresses down on the shutter.
Laura Palmer (17:32):
Thanks, Blimey!
Amy Martin (17:36):
With the visuals taken care of, it's time to move
on to sound.
So Laura's pulling out herrecorder, plugging in the
hydrophones.
A hydrophone is just awaterproof microphone attached
to a long cable. This team hasfour of them. As Laura gets
everything connected and readyto record, Stephanie keeps the
(17:58):
boat following the dolphins froma distance, they seem to be on
the move towards something orsomeone.
Dr. Stephanie King (18:05):
We have another dolphin up ahead, I
think it's Juicy. Blimey's onthe bow. Hey guys. Both on the
bow.
Amy Martin (18:19):
Oh wow, right under the surface.
And then they're gone again.It's shocking how quickly a
group of 500 pound animals canjust disappear. The four of us
stand in the boat looking infour different directions,
waiting, watching. We knowthey're nearby, but we don't
(18:43):
know exactly where or when theymight pop back up to take a
breath. Stephanie uses thetemporary pause in activity to
look over Millie's notes andtell her what needs to be added.
Dr. Stephanie King (18:54):
So the five minute information would be
travel. There are two otheranimals here.
Amy Martin (18:59):
They're back. Stephanie interrupts herself to
call to Laura, telling her thatJuicy is not the only dolphin
that has joined this group.There's another one, so far
unidentified. Then she quicklyturns back to Millie.
Dr. Stephanie King (19:11):
Travel, regular, straight, slow, tight.
Amy Martin (19:21):
There's a lot happening all at once, with
dozens of these kinds ofteachable moments every hour.
And Stephanie has to find abalance between making sure the
data get collected correctly andgiving the younger researchers
freedom to do things themselves.
Laura Palmer (19:35):
So there's just going to be cables running on
the back as well.
Amy Martin (19:38):
Okay.
Laura is about to startrecording.
Dr. Stephanie King (19:42):
Blimey just ahead. Juicy's here.
Amy Martin (19:48):
So are there four here?
Dr. Stephanie King (19:50):
Yes, so that's Juicy. She's got a really
gnarly peduncle, like an oldshark bite wound, makes it very
scarred.
Laura Palmer (19:58):
Love juicy. Juicy showed up on a few days now,
becoming a firm favorite.
Amy Martin (20:03):
How old is she, roughly?
Dr. Stephanie King (20:05):
Juicy was born in 2001, so she's about 22
years old, and her calf is aboutthree and a half, so she's still
quite young, you know?
Amy Martin (20:14):
Yeah, Twenty-something. Oh, wow, three
just all came up.
Young dolphins like this calf,named Jungle, usually stay with
their mothers for around fouryears. At first they depend on
mom for milk, but even afterthey're weaned, they usually
(20:34):
stick around perfecting theirhunting skills and learning how
to fit in to dolphin society. Ican't help but notice some
parallels between the animals inthe water and us humans up in
the boat. All together, we're atotal of eight mammals working
in two teams using acousticcommunication to learn from our
(20:54):
leaders. And then for me, cameone of the more magical moments
of this experience.
We have a speaker! So we'rehearing in the hydrophone.
Laura has flipped on a speakerin the boat, so we can hear, in
real time, the conversations thedolphins are having in the water
(21:15):
around us. Suddenly, we're withthem in a completely different
way.
Laura Palmer (21:26):
I love these guys.
Amy Martin (21:34):
I'd heard recordings of dolphin sounds before this
trip, and you probably have too,but this was the moment I
learned the enormous differencebetween hearing a random
recording of some anonymousdolphins and being with actual
living individual creatures andhearing their voices as they fly
through the water all around me.
Dr. Stephanie King (22:09):
Juicy.
Laura Palmer (22:10):
Juicy. Juicy is at 230 degrees.
Dr. Stephanie King (22:16):
That might be the calf.
Amy Martin (22:21):
That high-pitched swoop is called a whistle, and
it's one of the most importantsounds in dolphin communication.
Laura is overjoyed to hear it,because whistles are at the
center of her research for thistrip. She wants to learn more
about how they're used betweenmothers and calves, like Jungle
and Juicy are doing right now.
Laura Palmer (22:44):
Juicy at 20 degrees. With calf in BP.
Amy Martin (22:50):
BP stands for "baby position," meaning right next to
mom and moving in tandem withher. It's another quick way of
noting how the dolphins aregrouped and relating to each
This is so cool, you guys, it'smaking me cry!
other.
Laura Palmer (23:07):
I could cry with joy as well. This is a great
recording for me.
Amy Martin (23:16):
I brought my own hydrophone on this trip, and I'm
eager to get it in the water.But soon this group of dolphins
disperses, and Laura pulls hergear back up into the boat.
What do you call those kinds ofsounds?
Laura Palmer (23:30):
Oh, so they were buzzes. So when they're
foraging, it's very rapid rateecholocation. They're basically
using it to gain a lot ofinformation on their
environment, right andpotentially the prey items that
they're tracking. And we alsoheard a lot of whistles, which
are predominantly social signalsas well, so it's likely they're
communicating with each other,or, you know, potentially the
(23:51):
other animals that we'veinitially saw that are not with
us right now.
Amy Martin (23:57):
We head off to a new spot across the bay, and as the
boat picks up speed, it's harderto talk. So I settle in and
watch the waves for a while.This team has been gracious
enough to let me tag along forseveral days, so there'll be
time for more of my questionslater, and I have a lot of them.
I want to know everything aboutthese whistles, what they mean,
(24:19):
why they matter. I want to askStephanie a lot more about the
male alliances that she studiedand how they use sound, but
right now, it's time to take adeep breath and appreciate where
I am and what I'm getting towitness. I don't have to
understand at all to know that Ihave just been visited by
(24:41):
wondrous beings, creatures fullof beauty and power and
intelligence, and they'vesurvived on this planet for
millions of years by listeningto each other. We'll have more
(25:08):
after this short break.
Hey, I want to take a minute tothank you for listening to
Threshold and to explain howimportant you are in getting the
show made. Most podcasts raisemoney by selling advertising,
and that pushes them to make alot of episodes as quickly as
(25:30):
possible. But that's just notwho we are. Our show is about
thinking deeply about how humansare fitting into the rest of the
web of life. We take you placesand craft stories that are
intellectually challenging andemotionally rich. That's the
kind of show we want to make,and that's the kind of show
(25:50):
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(26:12):
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(26:34):
the donate button and give whatyou can and again, thank you so
much for listening.
Dallas Taylor (26:46):
I'm Dallas Taylor, host of 20,000 Hertz, a
podcast that reveals the untoldstories behind the sounds of our
world. We've uncovered theincredible intelligence of
talking parrots.
Basically, "bird brain" was apejorative term, and here I had
this bird that was doing thesame types of tasks as the
primates.
(27:06):
We've investigated the bondingpower of music.
There's an intimacy there incommunicating through the medium
of music that can be really apowerful force for bringing
people together.
We've explored the subtlenuances of the human voice.
We have to remember that humans,over many hundreds of thousands
of years of evolution, havebecome extremely attuned to the
(27:28):
sounds of each other's voices.
And we've revealed why a famouscomposer wrote a piece made
entirely of silence.
Unknown (27:35):
I think that's a really potentially quite useful and
quite profound experience tohave.
Dallas Taylor (27:40):
Subscribe to 20,000 Hertz right here in your
podcast player. I'll meet youthere.
Amy Martin (27:48):
Welcome back to Threshold, I'm Amy Martin, and
for the rest of this episode,we're gonna do some time travel.
We're going back to a world longbefore dolphins, before
dinosaurs, before there were anyanimals or plants. If we could
transport ourselves back to thevery early Earth, we would find
(28:12):
a barren world blanketed intoxic gas. The atmosphere had
almost no oxygen in it. Therewas no life at all. The only
thing making sound was theplanet itself, storms,
earthquakes, ocean waves,volcanos. And that's how things
(28:38):
were for a really long time. TheEarth is around four and a half
billion years old, and for about90% of those years, nothing
existed that was capable ofintentionally making a sound or
receiving it. So how do we getfrom that world to this one? How
(29:03):
did the Earth transform itselffrom a place of such
unfathomable quiet into a nonstop symphony of sound? We're
going to spend the rest of theseason telling that story,
tracing the sonification of theEarth roughly in the order in
which life evolved. It allstarted with a silence too long
(29:24):
for us to truly comprehend, butI wanted to try, and it turns
out one of the best places to dothat is just down the Western
Australian coast from where Imet the dolphin researchers.
Okay, I'm just in the parkinglot. Pardon me, just in the
(29:44):
parking lot for the Hamelinpool.
I leave behind one talkativeAustralian Raven and a small
flock of chiming wedgebills andwalk the short distance out to
the edge of Hamelin pool, a bigbay with a surface smooth as
glass.
I just want to try to listenhere for a little while. The
(30:13):
water is so still. There's not aripple, there's not a there's no
birds landing on it. There's nobubbles or any sign of movement.
It's early, and I'm alone. Butthose aren't the only reasons
this place is so silent. HamelinPool has an inner stillness.
(30:39):
It's extremely salty, twice assalty as the open ocean, which
means it's hard for plants andanimals to survive here and
against this canvas of quiet,every sound made by a living
thing pops out, a bird peep, afly buzz. For most of our
(31:01):
planet's history, this kind ofsilence reigned supreme.
Just think about the entireearth being that quiet. There
was nothing, breathing, flying,walking, crawling, a whole
(31:23):
planet with nothing that had avoice.
But although Hamelin Pool may bea profoundly quiet place, it
(31:47):
isn't actually as lifeless as itseems. There's a lot of
mysterious blackish gunkcarpeting the beach in front of
me, almost like a bathtub ringof slime growing where the water
meets the shore. These arecommunities of microbes. They go
by sexy names like gelatinousmicrobial mats or pustular
(32:08):
sheets, and they built a bridgebetween the barren early Earth
and the lush, loud, fruitfulworld we enjoy today. Ancient
microbes were the inventors ofwhat is arguably the most
important technology of alltime, photosynthesis. A couple
(32:30):
of billion years ago, theystarted to tap into the sun's
energy and produce oxygen, andthat changed everything. Bit by
bit, they pumped that oxygeninto the sea.
Dr. Erica Suosaari (32:44):
You know, and after a while, then all that
oxygen created by photosynthesisfrom microbes, eventually
saturates the ocean, the oceancan't hold anymore. Where does
the oxygen go? It goes into theatmosphere.
Amy Martin (32:55):
This is Dr. Erica Suosaari.
Dr. Erica Suosaari (32:58):
The atmosphere becomes oxygenated,
which essentially that allowsfor evolution, which then here
we go, and finally get to us.
Amy Martin (33:08):
The slimy mats I saw growing in Hamelin Pool were
microbes still performing theseancient rituals, doing the work
that led to all other life onEarth. They don't look like much
at all, but they hold the originstory of every call, cry,
squawk, or song ever heard.
Dr. Erica Suosaari (33:30):
This is a living system still doing this,
still doing these same processesthat were happening billions of
years ago. There is no placeelse on the planet that
represents that in its entirety.It is really this window into
the ancient.
Amy Martin (33:49):
I'm curious about you, like, what, what stage in
your development did yourealize, I really want to learn
a whole lot more about goo?
Dr. Erica Suosaari (34:03):
I guess technically I'm a marine
geologist. I'm a carbonatesedimentologist, but I look at
marine rocks.
Amy Martin (34:09):
Erica is based at the Smithsonian Institution's
National Museum of NaturalHistory in Washington, DC. She
first visited Hamelin Pool whileworking on her PhD, and she was
so blown away by the glimpse itprovided into the early Earth
that she moved to WesternAustralia and lived close by for
several years, just so she couldcontinue studying the place.
Dr. Erica Suosaari (34:31):
So I have sort of this obsession with
time. I've always had thisobsession with time and kind of
infinity and what it means andthe big picture and how
significant our lives are andwhat we do, because the time is
so big, and it's like, you know,kind of figuring out the puzzle
(34:53):
of what life means on hugescales.
Amy Martin (34:59):
And key pieces of that puzzle can be found in
these communities of microbes atHamelin. Erica is one of the
world's leading experts on themand the stony structures they
create, which are called-
Dr. Erica Suosaari (35:11):
Microbiolites, which are basically rocks
created by microbes.
Amy Martin (35:16):
We don't tend to think of microbes as creating
anything except infections,maybe, but at some point, way
back in time, they started tomake rocks: clotted
thrombolites, brancheddendrolites and layered
stromatolites. The world'soldest fossilized stromatolites
(35:36):
found in Western Australia arealmost three and a half billion
years old, and the microbes atHamlin pool are still making
these rocks today. It's thelargest known collection of
living marine stromatolites inthe world.
Dr. Erica Suosaari (35:53):
What Hamelin represents is, is, I don't even
have a word for what Hamelinrepresents. It's just, it's a
really spectacular place. It's aliving laboratory.
Amy Martin (36:07):
The stromatolites are kind of like the Machu
Picchu or Egyptian pyramids ofthe microbial world. These are
structures made by communitiesof living things with a story to
tell. They grow close to theedges of Hamelin pool in the
shallow water, maybe a foot ortwo high. Some of them look a
little bit like toadstools,others resemble stubby fingers
(36:30):
or brainy mounds. But whateverform they take, there's
something about them thatsignals life. You can see
familiar, organic patterns inthem, you can sense that they
grew, and this is how it allbegan, even though the microbes
themselves are very quiet,without them, there would be no
(36:51):
voices to speak or ears tolisten. Erica says one of the
essential ingredients in thisprocess is a coding the microbes
make and cover themselves with.
Dr. Erica Suosaari (37:04):
It's called EPS. It's exo-polymeric
substance.
Amy Martin (37:07):
Exo-polymeric substance. I asked her to
translate that into non-sciencylanguage.
Dr. Erica Suosaari (37:14):
It's like a, it's this. It's this. It's the
slime of life. You know? It'slike a, it's a goo.
Amy Martin (37:23):
It's a goo. We've got a microbe that makes a goo.
Dr. Erica Suosaari (37:25):
Yeah.
Amy Martin (37:28):
As sediment in the water floats by, some of it
sticks to this goo, kind of likedust sticking to fly paper. It
builds up layer after layer intostone.
Dr. Erica Suosaari (37:39):
And you build up kind of this laminated
structure. So that's astromatolite.
Amy Martin (37:44):
The EPS can actually do all kinds of cool stuff. It
helps the microbes communicatewith each other. It acts as a
sunscreen. It even changes thechemistry of the water, which
helps in the stromatolitebuilding process.
So it's a it's a self producedgoo that does chemistry.
Dr. Erica Suosaari (38:02):
Yes, or has chemistry happening. Yeah, all
around it.
Amy Martin (38:07):
Okay, there's like, a lot going on.
Dr. Erica Suosaari (38:10):
Oh yeah, there's a lot going on.
Amy Martin (38:11):
I like to think of these microbial communities as
the world's first cities, withthe bacteria in them bustling
around, working as architectsand engineers, carpenters and
chemists. They farmed sunlightand produced oxygen, the oxygen
that led to me talking to youright now.
Dr. Erica Suosaari (38:34):
These lineages of bacteria, life
persisting for billions ofyears.
Amy Martin (38:44):
While everything changed around them again and
again and again, these microbescarried life forward, passing it
on and on and on, one generationafter another.
Dr. Erica Suosaari (38:58):
It's not a timeline that I still think I
can wrap my mind around, but Ifind it sort of comforting that
there is this long stretch oftime that these rocks represent,
and I am drawn to that.
Amy Martin (39:15):
What do you think the world sounded like when the
only living things were thesemicrobes.
Dr. Erica Suosaari (39:23):
Cashing waves. I don't know. A lot of
water. But underwater,there'ssomething about silence. I can't
imagine. I mean, silence. Whatdoes that sound like for oxygen
(39:44):
bubbles to rise to the surface,crashing waves? Kind of
meditative and calm, which iscrazy, because it's a time in
Earth's history where it's verychaotic, and, and yet, you know,
there's like the kind of thepeace that life brings.
Amy Martin (40:05):
As I stood on the beach at Hamelin Pool, I tried
to imagine more than 3 billionyears of that silence. Eons of
(40:30):
ear splitting emptiness. Andrhen finally, the planet began
to sing. Every song or call orcry made on Earth happened in
(41:06):
just the last tenth of theplanet's existence. The
cacophony of life that we takefor granted is actually
exceptional. Silence is the normon our planet, or any planet
that we know of. Erica's work isbeing used in the search for
(41:27):
life on Mars, and maybe somedaywe'll receive communication from
some extraterrestrial being. Butso far, we Earthlings are
singing together into the void.The only voices we've ever heard
(41:50):
are each others'.
(42:31):
This episode of Threshold waswritten, recorded and produced
by me, Amy Martin, with helpfrom Erika Janik and Sam Moore.
Music by Todd Sickafoose.Post-production by Alan Douches.
Fact-checking by Sam Moore.Special thanks to Tim Lamont and
Miles Parsons. This show is madeby Auricle Productions, a
(42:52):
non-profit organization poweredby listener donations. Deneen
Weiske is our executivedirector. You can find out more
about our show atthresholdpodcast.org.
Hi, I know you just pressed play on this episode,
but I'm about to ask you to stoplistening to me. Yes, this is a
strange way to start a newseason of our show, I know, but
this is my request or myinvitation. If you're so
inclined, in just a moment,please press pause and spend 10
(00:24):
or 15 seconds listening towhatever you can hear around
you. All the voices, anythingmaking any sort of noise at all,
and then press play again. Thatpart's crucial. Please do come
back. Okay. Are you ready?Three, two, one.
(00:47):
What did you hear? Could youhear any sounds that weren't
made by people? If so, consideryourself lucky, because human
beings have become very, veryloud.
Flight Attendant (01:09):
In preparation for takeoff, may we now remind
you to fasten your seatbelts.
Amy Martin (01:17):
This relentless noise we make. It's not normal.
For most of our time on thisplanet, we humans have been very
good listeners, tuning incarefully to the movements of
water, changes in the weather,the voices of other animals. But
now many of us move through ourdays or even our entire lives
(01:41):
hearing almost nothing but thesounds of just one species. Our
own. If the planet is a dinnerparty, we're the guests who are
ruining the conversation,talking over everyone, assuming
(02:04):
that our voices are the mostimportant ones in the room.
We're drowning out essentialcommunication between other
creatures, forcing them to spendtheir lives shouting to each
other in order to be heard, orworse, we're silencing them
forever. And our noise doesn'tonly threaten other beings.
(02:30):
We're endangering ourselves, andwe know things are out of
balance. We feel isolated andcut off because we are.With
multiple ecological crisesmounting around us, many of us
feel desperate to help, andthere is unquestionably so much
(02:50):
work to be done, but maybe thefirst step is slowing down and
letting the voices of our planetmates back in.
What if being useful starts withbeing quiet? What if saving the
(03:18):
world begins with listening toit? What changes when we
remember to listen to the morethan human world? That's the
question at the heart of thisseason of our show. Despite all
(03:43):
the damage that's already beendone, there is still a vast
planetary choir singing aroundus. It's right there waiting for
us, if we turn our attention toit.
All over the world, people arehearing those voices and
responding. We are in the midstof a listening emergency, but
(04:07):
also a listening Renaissance. Inthis season, we'll meet people
who are devoting their lives tolistening, reconnecting with old
traditions, or creating newones, and building tools that
might someday allow us tocomprehend what other animals
are saying in ways we've onlydreamed of in the past. It's
(04:32):
going to be a fun journey and afascinating one, but I'm going
for something deeper than thewow factor of cool nature
sounds. I chose to make thisseason now because I think all
of our ecological crises,climate, extinction, pollution,
are essentially breakdowns inrelationship, and the first step
(04:56):
in healing any brokenrelationship is listening. So
what happens when we do that?Welcome to threshold. I'm Amy
Martin, and this is season five.Hark.
(05:58):
It's seven o'clock on a sunnymorning, and I'm on a boat
heading into Shark Bay, a hugemarine reserve off the Western
Australian coast. This isMalgana country, one of hundreds
of Aboriginal groups inAustralia, and in malgana, the
name of this place isGathaagudu, which means "two
waters."
Dr. Stephanie King (06:19):
Dolphins straight ahead.
Amy Martin (06:21):
We've barely left the jetty, and Dr. Stephanie
King has already spotted adolphin. It surfaced and
disappeared again in a flash,but that was enough time for her
to identify it. It was a femalenamed Gindy.
You knew who it was that fast?
Laura Palmer (06:36):
Yeah, she does.
Amy Martin (06:37):
Wow.
Laura Palmer (06:38):
She's great.
Amy Martin (06:39):
That's Laura Palmer, she's working on her PhD, and
the other person with us isresearch assistant Amelia Clark.
All three of these scientistsare from the University of
Bristol in the UK. Stephanie isthe leader of the expedition and
the current captain of the boat.
How did you know?
Dr. Stephanie King (06:57):
Because of the markings on the dorsal fin.
She has an uncle who has asimilar fin to her. You can see
the three small nicks, thelittle break marks at the top.
Each nick is kind of similarlyspaced along the fin, almost
equidistant from each other. Soeach dolphin has a unique dorsal
fin, like we say, like afingerprint, but it's far more
obvious than that, I guess, likea human face. So they're very
(07:20):
distinctive. If you've beenworking with them a long time,
then then you recognize all theindividuals.
Amy Martin (07:26):
Shark Bay and its surrounding coastal areas are
listed as a UN World HeritageSite, and it's easy to see why.
The water is a clear turquoiseblue and huge sea grass meadows
provide food and shelter for anabundance of wildlife. Sea
turtles, dugongs, and more than300 species of fish, including
(07:46):
the namesake sharks. But thesuperstars here are the
dolphins. The scientists ofShark Bay Dolphin Research have
been studying them continuouslysince 1982, making this one of
the most carefully observedcommunities of dolphins on the
planet. Stephanie is one of thecurrent co directors.
(08:07):
Do you know how many dolphinsare here, roughly?
Dr. Stephanie King (08:10):
Two to 3000 I mean, there's about 1800 that
we have in our catalog that wework on, and that's just in our
core study area, in the easternGulf. There's far more than
that.
Amy Martin (08:19):
And of those 1800 how many of them can you
identify on site like you justidentified that one in two
seconds?
Dr. Stephanie King (08:25):
I've never tested myself, but maybe we
could do that. I know a lot.More, way more than 200.
Amy Martin (08:33):
And when did you first come here?
Dr. Stephanie King (08:35):
I first came to Shark Bay in 2014, so 10
years ago now.
Amy Martin (08:40):
And have you been coming almost every year since
then?
Dr. Stephanie King (08:43):
Every year. I think 2020 was the only year
because of COVID, but I comeevery year, and it's a really
important part of my, I guessjust part of my life, coming
here, spending time with theanimals, being inspired for the
next questions that we want toanswer, seeing who's still
around, who's had a calf, howare the males doing, who's
(09:05):
allying with who? I think thisis certainly where I'm at my
most happiest as a fieldbiologist. It's where I'd like
to be most of the time, if Icould.
Amy Martin (09:14):
Yeah.
Stephanie studies these dolphinsusing every non invasive tool,
she can find (09:21):
drone videography, DNA sampling, and especially
bioacoustics. Recording andanalyzing the sounds the
dolphins make.
Dr. Stephanie King (09:32):
Sounds is the primary way that they
communicate, and a lot of ourresearch now is starting to
uncover exactly what some ofthese sounds mean and how
they're used.
Amy Martin (09:41):
Bioacoustics is the name for a fast growing field of
science, or really an approachto scientific research that's
being used across many fields.Sometimes it's also called
ecoacoustics, or acousticecology. All of these labels
have slightly differentmeanings, but they're all based
around listening to the morethan human world, and they're
(10:02):
all booming right now. Over thecourse of this season, we're
going to meet bioacousticsresearchers working with all
kinds of different creatures,but we're going to dive deep
with dolphins. Pun intended.We'll be returning to Shark Bay
in several episodes in hopes ofreally getting to know this team
and the way these remarkableanimals are using sound
(10:24):
Stephanie says that starts withlearning about the dolphins
world overall, their habitats,their relationships, their needs
and preferences.
Dr. Stephanie King (10:33):
So we look at behavioral complexity in
bottlenose dolphins, and thatcan take the form of foraging
specializations and tool use,which is a great example of
animal culture, but we alsospend a lot of time looking at
cooperation. This is reallywhere my passion lies,
understanding how animals usecommunication to mediate complex
(10:55):
social behaviors likecooperation.
Amy Martin (10:58):
Highly social animals like dolphins, elephants
and people have special needsfor communication. We make
decisions together, like whereto find food or how to respond
to a threat. We maintain longterm relationships that we
depend on in times of need, andwe pass on information to our
young. All of this cooperationdemands that we develop complex
(11:22):
communication skills.
Dr. Stephanie King (11:24):
And in Shark Bay, we have male dolphins that
form long term alliances. Sothese are really significant
relationships for these animals.They're investing heavily in
these cooperative relationshipswith each other, and I'm really
fascinated by the ways that theydo that. So what vocal signals
are they using to mediate theserelationships? How do they keep
(11:45):
track of each other? How do theycoordinate their behavior? So
these are all the types ofquestions that we aim to answer
in our work in Shark Bay.
Amy Martin (11:54):
Is the cooperation that they're engaged in, how
much of that is happeningthrough sound?
Dr. Stephanie King (12:01):
It's mostly happening through sound, and
that's because it's a speciesthat lives underwater, right? So
vision is restricted becauselight doesn't travel that far.
They have good visual acuity,they've got good vision, but
they don't rely on visionbecause they can't see that far
underwater. But sound travelsreally far.
Amy Martin (12:20):
Dolphins use other forms of communication too, of
course.
Dr. Stephanie King (12:23):
They can be quite tactile with each other,
so they'll spend time pettingand rubbing each other, and
that's a way of reaffirming orestablishing or maintaining
relationships.
Amy Martin (12:31):
But Stephanie says sound is central.
Dr. Stephanie King (12:34):
They use sound for all important aspects
of their life, to navigate theirenvironment, to find food, and,
importantly, to communicate witheach other. So it's their
primary modality, it's sound,it's not vision, it's not
gestures. And by sharinginformation through vocal
signals, they can let each otherknow where they are, maybe if
(12:56):
they plan to move, if they wantto reunite this type of
information.
Amy Martin (13:02):
When I visited the team in May of 2023, they were
just getting started for theyear. Amelia, who goes by
Millie, is a recent master'sgraduate who's here to get
experience as a researchassistant. Laura is a PhD
student collecting data for herthesis work.
Laura Palmer (13:18):
This is my first time in Shark Bay, so I've only
been here a week now. We've hadlots of amazing days on the
water, so certainly very lucky.It was a good time to come.
Amy Martin (13:28):
Laura and Millie are under some pressure because they
only have a few weeks withStephanie, then she has to
leave, and they'll do everythingon their own. One of the key
things they need to learn is howto take a survey of every
dolphin they meet.
Dr. Stephanie King (13:42):
By survey, I mean, we photograph the group,
and we stay with them for atleast five minutes, and we write
down their predominant behavior.So are they socializing,
traveling, resting, and then welook at who are they with. And
by doing that throughout theseason, over multiple years, and
we've been doing it for 40 yearsnow, we have this incredible
picture of who associates withwho, who has strong friendships,
(14:03):
which dolphins avoid each other.And we can, like, map the social
network, if you like, and we canlook at the structure and maybe
link some of that information tofitness measures, like, does
being more sociable mean thatyou're more successful and you
have more offspring, forexample.
Amy Martin (14:20):
You got dolphins, Laura?
Laura Palmer (14:21):
No, not yet. But there's splashing basically at
zero degrees.
Amy Martin (14:26):
While I've been peppering Stephanie with
questions, Laura and Millie arescanning the water for anything
that looks remotely dolphin-ish.Laura said she saw some splashes
at zero degrees, meaningstraight ahead. So she moves to
the bow with a boat to get abetter look.
Dr. Stephanie King (14:42):
If we see splashes, we'll check just to
make sure it's not dolphinsforaging anything that looks
like it could be a dolphin, orindicate dolphin behavior we'll
check with the binos and maybeeven go a bit closer.
Amy Martin (14:53):
I quickly get obsessed with dolphins spotting
myself, which was a littledangerous. Stephanie told me
that if someone says they see adolphin and it turns out to be a
bird, they have to bakesomething for the rest of the
group back at the ResearchStation.
Laura Palmer (15:07):
Yeah, yeah.
Dr. Stephanie King (15:08):
Yeah?
Amy Martin (15:10):
But then Laura calls from the bow, there's definitely
dolphin activity up ahead.
We're in business!
The dolphins are constantly inmotion, and they are fast.
Stephanie needs to move usquickly or we'll lose them. But
she also wants to maintain somedistance so we don't disturb
(15:30):
them. It's a bit of a dance tofind that just-right spot.
Ooh, I just saw a fin.
Everyone has a job to do.Stephanie's in the captain's
chair, Laura will try to getclear photographs of every
dolphin we see. Millie willwrite down notes, and I'll just
try to stay out of the way.
Dr. Stephanie King (15:48):
We have Zeppelin and Blimey.
Amy Martin (15:52):
Hands on the steering wheel and eyes on the
water, Stephanie calls out thename of each dolphin to put into
the notes.
Dr. Stephanie King (15:58):
Z-E-P, and B-L-M. Yeah, you got them. They
might come again they're stilljust beneath the surface.
Amy Martin (16:14):
They're so close!
Stephanie is mindful of keepingsome distance, but the dolphins
aren't as concerned about therules. They swim close to the
boat, zipping around and seemingto check us out. When they swim
over dark patches of sea grass,they can all but disappear, and
then all of a sudden, they popup again to grab a quick breath.
(16:40):
Even though I can see themcoming, it's delightfully
startling every time they crestthe surface. These are
Indo-Pacific bottlenosedolphins, smaller than some
other species, but still big.They average around two and a
half meters long, or more thaneight feet, with a maximum
weight of about 230 kilograms,or about 500 pounds. But all
(17:03):
that bulk doesn't limit theirgrace. It's actually hard to
call what they do swimming. Itlooks more like dancing or
flying. Their smooth, shinybodies roll past us in a
heartbeat as Laura tries to geta clear portrait of each one.
Laura Palmer (17:20):
I'm going to try to get Blimey one more time.
Amy Martin (17:24):
As if she heard Laura's request, Blimey pops up
and looks right at us, and Laurapresses down on the shutter.
Laura Palmer (17:32):
Thanks, Blimey!
Amy Martin (17:36):
With the visuals taken care of, it's time to move
on to sound.
So Laura's pulling out herrecorder, plugging in the
hydrophones.
A hydrophone is just awaterproof microphone attached
to a long cable. This team hasfour of them. As Laura gets
everything connected and readyto record, Stephanie keeps the
(17:58):
boat following the dolphins froma distance, they seem to be on
the move towards something orsomeone.
Dr. Stephanie King (18:05):
We have another dolphin up ahead, I
think it's Juicy. Blimey's onthe bow. Hey guys. Both on the
bow.
Amy Martin (18:19):
Oh wow, right under the surface.
And then they're gone again.It's shocking how quickly a
group of 500 pound animals canjust disappear. The four of us
stand in the boat looking infour different directions,
waiting, watching. We knowthey're nearby, but we don't
(18:43):
know exactly where or when theymight pop back up to take a
breath. Stephanie uses thetemporary pause in activity to
look over Millie's notes andtell her what needs to be added.
Dr. Stephanie King (18:54):
So the five minute information would be
travel. There are two otheranimals here.
Amy Martin (18:59):
They're back. Stephanie interrupts herself to
call to Laura, telling her thatJuicy is not the only dolphin
that has joined this group.There's another one, so far
unidentified. Then she quicklyturns back to Millie.
Dr. Stephanie King (19:11):
Travel, regular, straight, slow, tight.
Amy Martin (19:21):
There's a lot happening all at once, with
dozens of these kinds ofteachable moments every hour.
And Stephanie has to find abalance between making sure the
data get collected correctly andgiving the younger researchers
freedom to do things themselves.
Laura Palmer (19:35):
So there's just going to be cables running on
the back as well.
Amy Martin (19:38):
Okay.
Laura is about to startrecording.
Dr. Stephanie King (19:42):
Blimey just ahead. Juicy's here.
Amy Martin (19:48):
So are there four here?
Dr. Stephanie King (19:50):
Yes, so that's Juicy. She's got a really
gnarly peduncle, like an oldshark bite wound, makes it very
scarred.
Laura Palmer (19:58):
Love juicy. Juicy showed up on a few days now,
becoming a firm favorite.
Amy Martin (20:03):
How old is she, roughly?
Dr. Stephanie King (20:05):
Juicy was born in 2001, so she's about 22
years old, and her calf is aboutthree and a half, so she's still
quite young, you know?
Amy Martin (20:14):
Yeah, Twenty-something. Oh, wow, three
just all came up.
Young dolphins like this calf,named Jungle, usually stay with
their mothers for around fouryears. At first they depend on
mom for milk, but even afterthey're weaned, they usually
(20:34):
stick around perfecting theirhunting skills and learning how
to fit in to dolphin society. Ican't help but notice some
parallels between the animals inthe water and us humans up in
the boat. All together, we're atotal of eight mammals working
in two teams using acousticcommunication to learn from our
(20:54):
leaders. And then for me, cameone of the more magical moments
of this experience.
We have a speaker! So we'rehearing in the hydrophone.
Laura has flipped on a speakerin the boat, so we can hear, in
real time, the conversations thedolphins are having in the water
(21:15):
around us. Suddenly, we're withthem in a completely different
way.
Laura Palmer (21:26):
I love these guys.
Amy Martin (21:34):
I'd heard recordings of dolphin sounds before this
trip, and you probably have too,but this was the moment I
learned the enormous differencebetween hearing a random
recording of some anonymousdolphins and being with actual
living individual creatures andhearing their voices as they fly
through the water all around me.
Dr. Stephanie King (22:09):
Juicy.
Laura Palmer (22:10):
Juicy. Juicy is at 230 degrees.
Dr. Stephanie King (22:16):
That might be the calf.
Amy Martin (22:21):
That high-pitched swoop is called a whistle, and
it's one of the most importantsounds in dolphin communication.
Laura is overjoyed to hear it,because whistles are at the
center of her research for thistrip. She wants to learn more
about how they're used betweenmothers and calves, like Jungle
and Juicy are doing right now.
Laura Palmer (22:44):
Juicy at 20 degrees. With calf in BP.
Amy Martin (22:50):
BP stands for "baby position," meaning right next to
mom and moving in tandem withher. It's another quick way of
noting how the dolphins aregrouped and relating to each
This is so cool, you guys, it'smaking me cry!
other.
Laura Palmer (23:07):
I could cry with joy as well. This is a great
recording for me.
Amy Martin (23:16):
I brought my own hydrophone on this trip, and I'm
eager to get it in the water.But soon this group of dolphins
disperses, and Laura pulls hergear back up into the boat.
What do you call those kinds ofsounds?
Laura Palmer (23:30):
Oh, so they were buzzes. So when they're
foraging, it's very rapid rateecholocation. They're basically
using it to gain a lot ofinformation on their
environment, right andpotentially the prey items that
they're tracking. And we alsoheard a lot of whistles, which
are predominantly social signalsas well, so it's likely they're
communicating with each other,or, you know, potentially the
(23:51):
other animals that we'veinitially saw that are not with
us right now.
Amy Martin (23:57):
We head off to a new spot across the bay, and as the
boat picks up speed, it's harderto talk. So I settle in and
watch the waves for a while.This team has been gracious
enough to let me tag along forseveral days, so there'll be
time for more of my questionslater, and I have a lot of them.
I want to know everything aboutthese whistles, what they mean,
(24:19):
why they matter. I want to askStephanie a lot more about the
male alliances that she studiedand how they use sound, but
right now, it's time to take adeep breath and appreciate where
I am and what I'm getting towitness. I don't have to
understand at all to know that Ihave just been visited by
(24:41):
wondrous beings, creatures fullof beauty and power and
intelligence, and they'vesurvived on this planet for
millions of years by listeningto each other. We'll have more
(25:08):
after this short break.
Hey, I want to take a minute tothank you for listening to
Threshold and to explain howimportant you are in getting the
show made. Most podcasts raisemoney by selling advertising,
and that pushes them to make alot of episodes as quickly as
(25:30):
possible. But that's just notwho we are. Our show is about
thinking deeply about how humansare fitting into the rest of the
web of life. We take you placesand craft stories that are
intellectually challenging andemotionally rich. That's the
kind of show we want to make,and that's the kind of show
(25:50):
you've told us you want to hear.That's why we created an
independent, non profit mediacompany, and why nearly all of
our funding comes from listenerslike you. This is not the
easiest way of funding a show,but it is the way that's most
aligned with our mission, andit's worked so far thanks to
(26:12):
people who decide to support it.Our year-end fundraising
campaign is happening nowthrough December 31 and each
gift will be matched by ourpartners at NewsMatch. That
means, if you can give $25,we'll receive 50. You can make
your donation online atthresholdpodcast.org. Just click
(26:34):
the donate button and give whatyou can and again, thank you so
much for listening.
Dallas Taylor (26:46):
I'm Dallas Taylor, host of 20,000 Hertz, a
podcast that reveals the untoldstories behind the sounds of our
world. We've uncovered theincredible intelligence of
talking parrots.
Basically, "bird brain" was apejorative term, and here I had
this bird that was doing thesame types of tasks as the
primates.
(27:06):
We've investigated the bondingpower of music.
There's an intimacy there incommunicating through the medium
of music that can be really apowerful force for bringing
people together.
We've explored the subtlenuances of the human voice.
We have to remember that humans,over many hundreds of thousands
of years of evolution, havebecome extremely attuned to the
(27:28):
sounds of each other's voices.
And we've revealed why a famouscomposer wrote a piece made
entirely of silence.
Unknown (27:35):
I think that's a really potentially quite useful and
quite profound experience tohave.
Dallas Taylor (27:40):
Subscribe to 20,000 Hertz right here in your
podcast player. I'll meet youthere.
Amy Martin (27:48):
Welcome back to Threshold, I'm Amy Martin, and
for the rest of this episode,we're gonna do some time travel.
We're going back to a world longbefore dolphins, before
dinosaurs, before there were anyanimals or plants. If we could
transport ourselves back to thevery early Earth, we would find
(28:12):
a barren world blanketed intoxic gas. The atmosphere had
almost no oxygen in it. Therewas no life at all. The only
thing making sound was theplanet itself, storms,
earthquakes, ocean waves,volcanos. And that's how things
(28:38):
were for a really long time. TheEarth is around four and a half
billion years old, and for about90% of those years, nothing
existed that was capable ofintentionally making a sound or
receiving it. So how do we getfrom that world to this one? How
(29:03):
did the Earth transform itselffrom a place of such
unfathomable quiet into a nonstop symphony of sound? We're
going to spend the rest of theseason telling that story,
tracing the sonification of theEarth roughly in the order in
which life evolved. It allstarted with a silence too long
(29:24):
for us to truly comprehend, butI wanted to try, and it turns
out one of the best places to dothat is just down the Western
Australian coast from where Imet the dolphin researchers.
Okay, I'm just in the parkinglot. Pardon me, just in the
(29:44):
parking lot for the Hamelinpool.
I leave behind one talkativeAustralian Raven and a small
flock of chiming wedgebills andwalk the short distance out to
the edge of Hamelin pool, a bigbay with a surface smooth as
glass.
I just want to try to listenhere for a little while. The
(30:13):
water is so still. There's not aripple, there's not a there's no
birds landing on it. There's nobubbles or any sign of movement.
It's early, and I'm alone. Butthose aren't the only reasons
this place is so silent. HamelinPool has an inner stillness.
(30:39):
It's extremely salty, twice assalty as the open ocean, which
means it's hard for plants andanimals to survive here and
against this canvas of quiet,every sound made by a living
thing pops out, a bird peep, afly buzz. For most of our
(31:01):
planet's history, this kind ofsilence reigned supreme.
Just think about the entireearth being that quiet. There
was nothing, breathing, flying,walking, crawling, a whole
(31:23):
planet with nothing that had avoice.
But although Hamelin Pool may bea profoundly quiet place, it
(31:47):
isn't actually as lifeless as itseems. There's a lot of
mysterious blackish gunkcarpeting the beach in front of
me, almost like a bathtub ringof slime growing where the water
meets the shore. These arecommunities of microbes. They go
by sexy names like gelatinousmicrobial mats or pustular
(32:08):
sheets, and they built a bridgebetween the barren early Earth
and the lush, loud, fruitfulworld we enjoy today. Ancient
microbes were the inventors ofwhat is arguably the most
important technology of alltime, photosynthesis. A couple
(32:30):
of billion years ago, theystarted to tap into the sun's
energy and produce oxygen, andthat changed everything. Bit by
bit, they pumped that oxygeninto the sea.
Dr. Erica Suosaari (32:44):
You know, and after a while, then all that
oxygen created by photosynthesisfrom microbes, eventually
saturates the ocean, the oceancan't hold anymore. Where does
the oxygen go? It goes into theatmosphere.
Amy Martin (32:55):
This is Dr. Erica Suosaari.
Dr. Erica Suosaari (32:58):
The atmosphere becomes oxygenated,
which essentially that allowsfor evolution, which then here
we go, and finally get to us.
Amy Martin (33:08):
The slimy mats I saw growing in Hamelin Pool were
microbes still performing theseancient rituals, doing the work
that led to all other life onEarth. They don't look like much
at all, but they hold the originstory of every call, cry,
squawk, or song ever heard.
Dr. Erica Suosaari (33:30):
This is a living system still doing this,
still doing these same processesthat were happening billions of
years ago. There is no placeelse on the planet that
represents that in its entirety.It is really this window into
the ancient.
Amy Martin (33:49):
I'm curious about you, like, what, what stage in
your development did yourealize, I really want to learn
a whole lot more about goo?
Dr. Erica Suosaari (34:03):
I guess technically I'm a marine
geologist. I'm a carbonatesedimentologist, but I look at
marine rocks.
Amy Martin (34:09):
Erica is based at the Smithsonian Institution's
National Museum of NaturalHistory in Washington, DC. She
first visited Hamelin Pool whileworking on her PhD, and she was
so blown away by the glimpse itprovided into the early Earth
that she moved to WesternAustralia and lived close by for
several years, just so she couldcontinue studying the place.
Dr. Erica Suosaari (34:31):
So I have sort of this obsession with
time. I've always had thisobsession with time and kind of
infinity and what it means andthe big picture and how
significant our lives are andwhat we do, because the time is
so big, and it's like, you know,kind of figuring out the puzzle
(34:53):
of what life means on hugescales.
Amy Martin (34:59):
And key pieces of that puzzle can be found in
these communities of microbes atHamelin. Erica is one of the
world's leading experts on themand the stony structures they
create, which are called-
Dr. Erica Suosaari (35:11):
Microbiolites, which are basically rocks
created by microbes.
Amy Martin (35:16):
We don't tend to think of microbes as creating
anything except infections,maybe, but at some point, way
back in time, they started tomake rocks: clotted
thrombolites, brancheddendrolites and layered
stromatolites. The world'soldest fossilized stromatolites
(35:36):
found in Western Australia arealmost three and a half billion
years old, and the microbes atHamlin pool are still making
these rocks today. It's thelargest known collection of
living marine stromatolites inthe world.
Dr. Erica Suosaari (35:53):
What Hamelin represents is, is, I don't even
have a word for what Hamelinrepresents. It's just, it's a
really spectacular place. It's aliving laboratory.
Amy Martin (36:07):
The stromatolites are kind of like the Machu
Picchu or Egyptian pyramids ofthe microbial world. These are
structures made by communitiesof living things with a story to
tell. They grow close to theedges of Hamelin pool in the
shallow water, maybe a foot ortwo high. Some of them look a
little bit like toadstools,others resemble stubby fingers
(36:30):
or brainy mounds. But whateverform they take, there's
something about them thatsignals life. You can see
familiar, organic patterns inthem, you can sense that they
grew, and this is how it allbegan, even though the microbes
themselves are very quiet,without them, there would be no
(36:51):
voices to speak or ears tolisten. Erica says one of the
essential ingredients in thisprocess is a coding the microbes
make and cover themselves with.
Dr. Erica Suosaari (37:04):
It's called EPS. It's exo-polymeric
substance.
Amy Martin (37:07):
Exo-polymeric substance. I asked her to
translate that into non-sciencylanguage.
Dr. Erica Suosaari (37:14):
It's like a, it's this. It's this. It's the
slime of life. You know? It'slike a, it's a goo.
Amy Martin (37:23):
It's a goo. We've got a microbe that makes a goo.
Dr. Erica Suosaari (37:25):
Yeah.
Amy Martin (37:28):
As sediment in the water floats by, some of it
sticks to this goo, kind of likedust sticking to fly paper. It
builds up layer after layer intostone.
Dr. Erica Suosaari (37:39):
And you build up kind of this laminated
structure. So that's astromatolite.
Amy Martin (37:44):
The EPS can actually do all kinds of cool stuff. It
helps the microbes communicatewith each other. It acts as a
sunscreen. It even changes thechemistry of the water, which
helps in the stromatolitebuilding process.
So it's a it's a self producedgoo that does chemistry.
Dr. Erica Suosaari (38:02):
Yes, or has chemistry happening. Yeah, all
around it.
Amy Martin (38:07):
Okay, there's like, a lot going on.
Dr. Erica Suosaari (38:10):
Oh yeah, there's a lot going on.
Amy Martin (38:11):
I like to think of these microbial communities as
the world's first cities, withthe bacteria in them bustling
around, working as architectsand engineers, carpenters and
chemists. They farmed sunlightand produced oxygen, the oxygen
that led to me talking to youright now.
Dr. Erica Suosaari (38:34):
These lineages of bacteria, life
persisting for billions ofyears.
Amy Martin (38:44):
While everything changed around them again and
again and again, these microbescarried life forward, passing it
on and on and on, one generationafter another.
Dr. Erica Suosaari (38:58):
It's not a timeline that I still think I
can wrap my mind around, but Ifind it sort of comforting that
there is this long stretch oftime that these rocks represent,
and I am drawn to that.
Amy Martin (39:15):
What do you think the world sounded like when the
only living things were thesemicrobes.
Dr. Erica Suosaari (39:23):
Cashing waves. I don't know. A lot of
water. But underwater,there'ssomething about silence. I can't
imagine. I mean, silence. Whatdoes that sound like for oxygen
(39:44):
bubbles to rise to the surface,crashing waves? Kind of
meditative and calm, which iscrazy, because it's a time in
Earth's history where it's verychaotic, and, and yet, you know,
there's like the kind of thepeace that life brings.
Amy Martin (40:05):
As I stood on the beach at Hamelin Pool, I tried
to imagine more than 3 billionyears of that silence. Eons of
(40:30):
ear splitting emptiness. Andrhen finally, the planet began
to sing. Every song or call orcry made on Earth happened in
(41:06):
just the last tenth of theplanet's existence. The
cacophony of life that we takefor granted is actually
exceptional. Silence is the normon our planet, or any planet
that we know of. Erica's work isbeing used in the search for
(41:27):
life on Mars, and maybe somedaywe'll receive communication from
some extraterrestrial being. Butso far, we Earthlings are
singing together into the void.The only voices we've ever heard
(41:50):
are each others'.
(42:31):
This episode of Threshold waswritten, recorded and produced
by me, Amy Martin, with helpfrom Erika Janik and Sam Moore.
Music by Todd Sickafoose.Post-production by Alan Douches.
Fact-checking by Sam Moore.Special thanks to Tim Lamont and
Miles Parsons. This show is madeby Auricle Productions, a
(42:52):
non-profit organization poweredby listener donations. Deneen
Weiske is our executivedirector. You can find out more
about our show atthresholdpodcast.org.
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