December 26, 2025 • 39 mins
What would a snail scientist do with a blank check? What can we learn from snails and their kin? Why is the ocean getting more acidic, how do we know, and why does that matter? Featuring Tim Pearce, Curator of Mollusks at Carnegie Museum of Natural History.
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Episode Transcript
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Michael Pisano (00:09):
You're listening to the Anthropocene Archives, a
presentation of We Are Nature.
In this special series ofstories, we're delving deep into
Carnegie Museum of NaturalHistory's 22 million collection
items, raiding cabinets andcases, sifting through objects
and organisms in search ofstories of stewardship,
solutions, and scientificwonder.
On today's episode, Solidaritywith the small and slimy,
(00:35):
assisted mollusk migration, andsome wisdom from slow-rolling
role models.
Today we're taking the scenicroute.
Let's escargot.
Welcome to We Are Nature, ashow about natural history and
(00:55):
movable futures presented byCarnegie Museum of Natural
History.
I'm your host, amateur slimetrail follower Michael Pisano,
and today I'm joined by aprominent professional mollusk
joke author.
Would you just please introduceyourself?
Tim Pearce (01:07):
I'm Tim Pearce here at Carnegie Museum of Natural
History.
I'm assistant curator ofmollusks, and I take care of the
shell collection.
Michael Pisano (01:15):
I am just so excited for you to join us
today.
We've also got a third guestwho we'll maybe get to, a
professional mollusk, maybe wecould say.
So thank you both for joiningus today and taking us behind
the scenes of the malacologycollection here.
To kick us off, could you tellme a little bit about the
Carnegie's mollusk collections?
Tim Pearce (01:33):
Oh, right.
So we've got a huge shellcollection.
Um it's been here for since1895, I think.
So that's what, 130 years?
Are we there yet?
And um it's the 10th or 11thlargest shell collection in the
United States.
Oh wow.
So that's pretty amazing.
We've got we are particularlystrong in land snails from the
(01:54):
Appalachian area from theeastern United States.
That makes sense.
But we also are really strongin the freshwater mussels.
The guy who literally wrote thebook on them was a former
curator, and we've got hiscollection.
Michael Pisano (02:05):
Lucky, lucky, lucky.
What kind of species diversityare we talking about represented
in the collection here?
Tim Pearce (02:10):
There might be maybe 80,000 species of molluscs in
the world, and we have probably18 to 20,000 species represented
in our collection.
There's no museum that has themall.
Sure.
And that's partly because someof them are just described from
a single specimen.
Incredible.
That means one museum and onlyone museum can have that
(02:30):
species.
Period, right.
Michael Pisano (02:32):
What about locally?
What's our biodiversity, ourmollusk biodiversity like here?
Tim Pearce (02:36):
My specialty are the land snails.
And so we have about 130species of land snails in
Pennsylvania.
And we also have maybe 60 to 65of the freshwater mussels and
maybe 15 or 20 of the freshwaterclams.
Sorry, freshwater snails.
Well, we do have a few of thetiny clams too.
I'm not sure how many eight toten species of those.
(02:57):
Gotcha.
Michael Pisano (02:58):
Just to get right away into the things
you've brought us, I wonder ifmaybe we can start with this
very enticing one.
Mackenzie Kimmel (03:07):
Collection item one lives in a translucent
plastic tub.
Rich, moist soil fills thetub's bottom third.
Moss, bark, and a sortedorganic detritus is scattered
across the surface, evoking alonely forest floor.
(03:29):
The collection item housed hereis not one single organism, but
rather a colony.
Individuals range in size fromheartbreakingly tiny youth to
adults that measure an inch indiameter.
Each of their friendly facessports four tentacles.
(03:51):
Each of their backs holds aspiral structure made of calcium
carbonate adorned in white andorange stripes.
Can you identify collectionitem one?
Tim Pearce (04:07):
Well, this is a tub.
It's a plastic tub with atight-fitting lid that has holes
in the lid.
And inside is some soil andsome bark and some living
snails.
The common name for these istiger snail.
The Latin name is Anguispiraalternata.
(04:27):
And these are this is a colonythat I've had for I think about
2013 or 2014.
I collected in northernMichigan.
But I think this species haslived in Frick Park, one of our
local parks.
And so I'm trying to getpermission to release these and
(04:49):
start the colony in Frick Parkand maybe follow it to see how
successful recolonizing FrickPark is.
Michael Pisano (04:55):
Can you tell me a little bit more about the
organism?
I mean, what what's a tigersnail's day like?
What's their lifestyle?
Tim Pearce (05:01):
For the for your eyes only people, I don't know
if you can see this, but thereyou can see the snail, it's a
coil, and then out the bottom ofit is this body, and it's just
putting its eyes out there.
Yeah.
So it has four tentacles outthe front.
The two lower ones are forsmelling and tasting, and these
two upper ones have balls on thetips.
Those are actually eyeballs.
(05:22):
Yeah.
And so it's got eyes on thetips of its upper tentacles.
They don't have very goodvision, so they probably
couldn't tell you and me apart.
Michael Pisano (05:31):
No, that's okay.
Tim Pearce (05:32):
But they can tell light and dark.
Michael Pisano (05:33):
Okay, that seems more important as a foundation.
Tim Pearce (05:36):
And they are very good at smelling, so they could
probably smell us apart.
Michael Pisano (05:39):
And what are they smelling for in their
environment?
Tim Pearce (05:41):
Oh gosh, I don't know.
Probably food, but maybe alsomates.
Sure, sure, sure, sure.
It was possibly trying to stayaway from predators, but I'm not
sure that they would do much ofthat smelling.
Michael Pisano (05:53):
And when we're talking about food, what what
are they eating?
What's their diet like?
Tim Pearce (05:57):
That's a very interesting question because for
almost all of the snails, wedon't know what they eat.
Oh, no kidding.
We just make a guess that, oh,they're eating detritus, they're
eating dead leaves.
Um, and in most cases that'sprobably true.
But then again, get evendeeper, please.
There's eating and then there'sabsorbing.
(06:18):
So a lot of these creatures areeating a lot of things that
just comes through, comes outthe other end, looking pretty
much like it went in.
Okay.
So then the question is, whatare they actually, how are they
staying alive?
Michael Pisano (06:31):
What are they taking out of that stream?
Tim Pearce (06:33):
And so we believe, again, this is a belief we don't
we don't have the evidence yet,but we think that they're
eating and absorbing thebacteria and the fungus that are
growing on the they're helpingto decompose the leaves.
So the leaves themselves mightnot be contributing much
nutrition.
So have you heard ofenvironmental DNA?
(06:54):
Please.
Oh, so environmental DNA ismostly used in water.
Creatures that are living inthe water are leaking DNA just
through their slime, throughtheir waste products or their
gills.
And so a person can take asample of water and analyze it
for the DNA and see whichspecies are living there.
Speaker 3 (07:14):
So awesome.
Tim Pearce (07:15):
So that's pretty cool.
So one idea about trying tofigure out what the snails are
eating, I've tried to get somepeople interested in looking at
the snail poo to see what DNAcan we find in the poo to get an
idea of what they're eating.
So again, this doesn't get atwhat they're actually absorbing,
but it will get at what they'reeating at.
Michael Pisano (07:35):
What's coming in and coming out.
Tim Pearce (07:36):
So far, we haven't had much luck with the looking
at the poo.
One person that I did get tolook at that found an awful lot
of human DNA.
And so the one conclusion couldbe they're eating humans, but
the other conclusion is she hadcontaminated her sand.
Right, right, right, right.
That makes maybe more sense,but I wouldn't put anything
here.
I think that that's reallyfascinating that mollusks are
(07:58):
the second largest phylum in theworld.
That's right.
After Arthropods, for most ofthe mollusks, we don't know what
they eat.
That's incredible.
Michael Pisano (08:13):
One of the things I wanted to talk about
with our tiger snails today wasbroadening out to the land snail
kind of State of the Union,thinking about the Anthropocene,
thinking about some of theother stories this season.
I'm curious about kind of howthey're doing these days.
Tim Pearce (08:30):
Well, so yes, I have been studying tiger snails for
probably 10 years now.
They are or have been the mostcommon large land snail east of
the Mississippi.
And what that means is thereare lots of specimens in
museums.
Right.
Because people can find themand bring them in.
And museums are amazing becausethey've got all of this
(08:52):
information over time.
Yes.
And so it can tell you what wasliving where, when.
And so I was looking at themuseum and I was noticing, hey,
we're finding fewer of themnowadays.
And the museum allowed me tosee, hey, they're doing pretty
well, pretty well, pretty well.
And so around 1960, theystarted to disappear in
(09:14):
different places.
And I've been, I'm I'm notfinished with my studies yet,
but I'm approaching it from twodifferent angles.
Okay.
One is acid rain.
Yep.
And the mid-1960s is about whenacid rain started going up.
And so acid rain could havecontributed to their decline.
But then also global uh warmingor climate warming.
(09:36):
So if these snails are alreadyliving near the southern edge of
their limit or living as low onthe mountain as they can, if
the climate then warms, thenthey have to move north or they
have to move up the mountain.
And some of thesedisappearances could be
consistent with climate warmingplaying a role also.
So I'm still I'm at the pointI'm trying to tease out which,
(10:00):
if either of those factors iscausing this.
Michael Pisano (10:02):
I mean, I think they're both great working
theories to start with.
So, you know, I think for asnail to migrate, to imagine
being at that scale, movingthrough a landscape, many, many
challenges, and some that aremore novel than others, perhaps.
So maybe we could talk abouthuman modification of the
landscape and what that has donefor snails trying to move to
(10:25):
chase a climate or for otherreasons.
Tim Pearce (10:27):
Absolutely, yeah, that's absolutely true.
That um something that we justtake for granted, you know,
walking across the street, thatcan be a barrier for a snail.
If a snail requires forest andwe've got an agricultural field
between this forest and thatforest, it's really hard for the
snail to get across.
Right, right, right.
So but but no, it's true.
(10:47):
A path or a road can be abarrier to a snail migration.
We've we've started to thinkabout assisted migration.
Yeah, well, if if the snail'sliving at the top of the
mountain, there is no more up,but there's another mountain
far, far away.
We can carry them to the newmountain and uh and start a new
(11:08):
colony there.
So that's that's something thatpeople are talking about.
Sure.
We need to do it carefullybecause we don't want to mess up
existing ecology that's goingon there.
Michael Pisano (11:17):
Yes, I think there's kind of a fraught
history of well-intentioned, wepicked something up and moved it
over and put it somewhere else.
Can you kind of speak to theopen questions in that
possibility?
Because I a lot of episodesthis season we've talked about
the need to move from a passiveidea of conservation where it's
just you set aside the land andeverything will flourish and
(11:38):
everything will be fine, butrather we're at a point where
maybe we need to be a little bitmore active and participatory.
Can you just kind of speak tohow that uh affects this
scenario?
Tim Pearce (11:48):
I think predictive modeling would be relevant here.
So with predictive modeling,you look at where the species
lives now, and you look at abunch of variables like the
climate and the rainfall and thetemperature, maybe the habitat,
what kind of vegetation it has,maybe the underlying rock type,
those kinds of things.
And then using all thatinformation, you can predict
(12:11):
other places that it might befound right right now.
Um so you could go and look andtest your test your hypothesis.
But the power is you can alsodial it forward and say, all
right, right, in a in a climatewarming world or uh with with
modified rainfall, where mightwe predict it would be in the
(12:32):
future?
Right.
And then you could say, do theexisting reserves adequately
protect this species, or wouldwe need to move them, or would
we need to make create newreserves?
Sure.
Michael Pisano (12:45):
I am curious about other ways to maybe make
space for safe snail passage,and you know, maybe thinking
about that a little more broadlyabout more welcoming landscapes
for the small and thevulnerable, right?
Like maybe this is a good timeto talk a little bit about the
charisma of the snail, which Ithink you probably uh have some
(13:06):
takes on, but you know,generally when we're talking
about the undergrowth, the mud,the small things crawling around
in them, it's not a typicaldefinition of charisma.
What do you find, you know,endearing, nice, exciting about
these?
Tim Pearce (13:20):
I guess one of my favorite things about mollusks
is that I can keep up with them.
They're not too fast for me.
Um, I just I just love them.
They're um nice to be with.
They uh they don't make a lotof noise.
That's true.
They're mellow, um, good rolemodels.
Michael Pisano (13:38):
What can we learn from snails?
Tim Pearce (13:41):
Take it easy.
Yeah.
Take it easy.
Enjoy the enjoy the scenery.
Michael Pisano (13:46):
Sure.
Tim Pearce (13:46):
Um, be friendly.
Michael Pisano (13:49):
All very good lessons, and yeah, not maybe not
always worrying about growth ormore.
But uh, yes.
I am curious, I guess, about,you know, it kind of an
(14:15):
extension of this same questionabout charisma and what you see
as, you know, not justendearing, but also valuable uh
about these small creatures.
Like how is the success of theland snail, let's say, defined
very broadly, connected to humansuccess.
Tim Pearce (14:33):
Right.
On the charisma topic, I thinkmost people don't find snails
and slugs very charismatic.
And I think that that'sunfortunate because there are so
many creatures in the worldthat are maybe less charismatic
than things with big eyes.
Speaker 3 (14:50):
That's right.
Tim Pearce (14:51):
In utilitarian terms, uh, they do perform a lot
of functions for us.
Okay.
I mean, they help to chew upthe leaves that fall down to
return the nutrients to thesoil, the plants can grow again.
If if things didn't chew up theleaves, we'd be up to our neck
or even deeper in leaves.
Snails, land snails, are reallyimportant in the food web.
They provide uh essentialcalcium to a lot of creatures
(15:15):
and and food.
I mean, think about birds.
Mother birds are laying eggscoated with a shell of calcium
carbonate.
Right.
And she gets it from eating thesnail shells.
Wow.
And and fireflies, babyfireflies, eat snails, sometimes
nothing but snails.
So if you love fireflies, andwe all do, let's not so well,
then you've got to love snails.
(15:36):
So yeah, they do play reallyimportant roles in the
ecosystem.
Snails and other lesscharismatic creatures.
So we do need to appreciatethem.
Michael Pisano (15:46):
I do appreciate that you kind of set out this
ecosystem services, you know,version of this.
What are they doing for theecology for us?
But I think you're also hintingat, and maybe this is just me
reaching, you know, an inherentvalue.
I I guess for me, you know, Igrew up as a certified bug nerd,
right?
And I loved a lot of thingsthat many people didn't really
(16:06):
see as charismatic.
And it wasn't because I wasaware of all the important roles
they play in an ecosystem, it'sbecause of just something
special about them.
And I, you know, I kind of seethe same spark in your eyes when
you look at our tiger snailshere.
I am kind of curious about whatyou think happens, you know,
culturally, let's say, in ahuman world where we learn to
(16:27):
look past that charismaticmegafauna system of conservation
or of narrative, really, right?
Because of course, to protect awhale, you're protecting
habitat, which maybe protectsthe snails that are in the
habitat to some degree, butit's, you know, the poster child
is the poster child.
It doesn't escape me, I guess,that, you know, like you said,
the species have big human eyesthat you can kind of read in a
(16:50):
an emotion into.
They feel very human.
So we're we're relating toanother organism.
But what happens, you know,kind of culturally for us when
we can say, actually, there'svalue to that which is foreign
that does not look like us, thatis small, vulnerable, squishy,
slimy.
Tim Pearce (17:07):
I I completely agree.
I'm not sure what else to add.
Um I you know, you could youcould talk at it from a
religious perspective.
Sure.
So almost all the religions ofthe world say we should be
stewards.
Sure.
And so it's it's really ourobligation to take care of
creation, and these are part ofcreation.
Sure.
I don't know, every livingcreature is worthy of respect.
(17:29):
On the charisma idea, it's notjust the big eyes that are
charismatic.
Yeah, tell me more.
Butterflies are charismatictoo.
Michael Pisano (17:36):
That's true.
Why?
Why do you think that is?
Tim Pearce (17:38):
We love color color and we love movement.
Michael Pisano (17:41):
And I think they are associated with flowers and
with beautiful, you know,beautiful kind of landscapes
that we can create.
Not necessarily, you know, agarden, right, is a very
controlled piece of nature tosay, ooh, beautiful.
But for now, I'd like to moveon to this other uh collection
item you've brought.
Mackenzie Kimmel (18:03):
Collection item two splits into two halves,
a top and a bottom thatinterlock neatly the satisfying.
The exterior of both halves ismottled white and gray and
covered in wavy organic ridgesthat suggest an accretion of
(18:25):
layers over time.
The interior of the halves isluminous bright white and
smooth, with one small patch ofruddy color on each face.
The whole collection item fitscomfortably into the curve of a
hand.
What is collection item two?
Tim Pearce (19:02):
I've brought along an oyster.
It's actually a bivalve, so itlooks like a clam, but this
particular one, a very misshapenclam.
So it's not at all regular, andit would be hard to describe
how it's misshapen.
It looks kind of like a leaf,maybe.
But it has the two halves, andthe two halves fit together very
(19:23):
nicely.
And um, interestingly, on theinside, it's got one patch of
color on each of the shells.
That's actually the musclescar.
And so these uh these oystershave one muscle, and when it
wants to close, then it willpull its muscles shut and close
the shell.
Most clams have two muscles,but the oysters and many other
(19:43):
uh mollusks have just one.
Scallops also have just onemuscle scar.
Michael Pisano (19:48):
Okay, tell me about this specimen.
Where where is this from?
Tim Pearce (19:51):
This one is um this is a Northern Europe species.
Okay, okay.
Um this one is Neopicnodonticochlear.
Cochlear refers to ear.
Neo is new and Pycnodonti, I'mnot sure what that means.
Um, but these would be eaten innorthern Europe.
Michael Pisano (20:07):
Gotcha.
And aside from eating uhoysters, you know, I think we
would be remiss in not talkingabout oysters kind of incredible
ecosystem services bit.
What what do they do for theecology around them?
Tim Pearce (20:19):
I I'll probably uh fail to tell you something, but
they do an awful lot.
One of them is that they doclean a lot of the water.
So they're filtering a lot ofuh food particles out of the
water.
So they're using their gillsfor breathing, but also for
eating.
And so as the food particles goover the gills, the little
cilia is sending the food oneway toward the mouth and the
(20:40):
non-food somewhere else.
And so it actually gets boundup into little strings.
So they're cleaning debris outof the water.
Another thing that they'redoing is they are they're
building reefs with theirshells.
So their their shells, afterthey finish living, they might
die.
But then over time it builds upthis these huge reefs, which
are really important wavebreaks.
(21:02):
They help to protect us fromhurricanes and huge waves.
And then they also providehabitat for the new oysters to
settle on.
There actually has been aproblem because humans have been
harvesting oysters for so manyyears and piling them up on the
shore.
And so then the reeves.
Speaker 2 (21:21):
Yeah, I like it.
Tim Pearce (21:23):
The reefs have been disappearing and it's not
providing substrate for new babyoysters to live.
So there's been a lot of effortto build new reefs out there on
the on the seashore.
And uh so they've been gettingsometimes artificial structures,
but sometimes they've just beengetting oyster shells and
putting them out there.
And so, yeah, they're comingback really, really
(21:44):
successfully.
It's a real success story.
Michael Pisano (21:47):
I also understand there's a more local
success story with freshwater uhmussels that is maybe uh
something you could speak tobecause I I do love a local
story.
Uh I guess what I'm reallygetting for is like Clean Water
Act and the way that maybediversity had gone down to a an
almost zero in some of therivers around here.
And can you speak to that kindof uh um local part?
Tim Pearce (22:11):
Yeah, when you when you first said success story, I
wasn't sure which one.
Um but yes, right here in inPittsburgh proper, uh the water
quality was really bad.
And so they probably perishedbecause of the bad water
quality.
But in many other parts of theeastern United States, um it
hasn't been water quality somuch, but siltation.
(22:33):
So by by building dams, we turnflowing rivers into lakes, and
that changes which species canlive there.
Down in the Tennessee ValleyAuthority, they channelized and
straightened out a lot ofrivers, which took away a lot of
the habitat.
So the siltation and thechannel and the habitat change
that really dated a lot of theclams.
(22:53):
But they're starting to undosome of that and they're coming
back.
But yeah, in Pittsburgh,cleaning up the water did allow
the fish to return.
So there's this bizarre lifecycle of the fish.
Speaker 3 (23:04):
Oh, tell me, I love it.
Yeah, yeah, yeah.
Tim Pearce (23:06):
So the freshwater mussels, um, they're they
actually are parasites on fishfor a couple of weeks as larvae.
So the females of thesefreshwater mussels, they're
doing triple duty with theirgills.
They're breathing with theirgills, they're eating with their
gills, and they keep theirbabies in their gills.
Incredible.
Triple duty, amazing.
So they hold the babies in overthe winter, and then when it's
(23:30):
in the springtime, they waituntil there's a fish nearby and
squeeze out some babies, andthey're little tiny, tiny things
with little hooks, and theygrab onto the fish's gills or
their fins, and then they suckthe fish's juices for a few
weeks until they metamorphoseand fall off.
And in the in the process, thefish has moved them to new
areas.
The fish is the rapid transitfor the for these mussels to
(23:53):
find new areas to live.
So when the water quality wasreally bad, it was bad for the
fish too.
Right.
But now fish are moving back inand the mussels are moving back
in.
And in fact, some species ofmussels have moved back in that
weren't here before.
Incredible.
Um not invasion, they've justbeen able to migrate further
upstream.
So, yes, it is a success story.
Michael Pisano (24:14):
Yeah.
Um, not to turn us towards anongoing, not great story, but I
would like to talk a little bitabout um problems in, I think,
well, I'll I'll I'll let youtell me exactly how widespread
this is, but there's an issue ofacidification that's impacting
creatures with shells like this.
Tim Pearce (24:32):
In freshwaters, there's acid mine drainage, and
that's wreaking havoc with allsorts of things.
But no, in the ocean, that oneis more directly related to um
carbon dioxide in theatmosphere.
So when you have more carbondioxide in the atmosphere, then
more of it dissolves in thewater, and then that makes
carbonic acid, which makes theocean more acidic.
(24:54):
So for creatures that arebuilding shells out of calcium
carbonate, more acidic water,makes it more difficult to build
them and more difficult to keepthem.
They will actually dissolve.
So this is causing a lot ofproblems for a bunch of
mollusks, and with the oystersin particular, you know, a lot
of the oysters we eat are comingfrom oyster farms, and the
(25:14):
farmers there actually buy babyoysters.
It's called spat.
They buy the baby oysters andbring them in and then they
plant them in their farms.
Well, the baby spat, the babyoysters are really sensitive to
this ocean acidification, andfarmers are having a lot of
difficulty.
So they actually have tomeasure the pH of the water
before they plant their oysters,or else they might all die.
(25:37):
Wow.
So that that's making itdifficult for the oyster farm.
And for you, if you like to eatraw oysters.
Michael Pisano (25:43):
Sure.
Well, and I think probably morebroadly in the ecology, can you
kind of speak to what thisacidification is doing?
You know, not in too muchdetail, but it's not just a
problem, I imagine, forcreatures with shells like this.
Tim Pearce (25:56):
But well, so right, a lot of creatures are having
difficulty building theirshells, and the pteropods are
microscopic.
Well, some of them are biggerthan microscopic, but they're
small snails, actually, thatspend their whole life in the
plankton, floating in theplankton, float around in the
currents, and they are reallyimportant in the food web.
Lots of creatures are eatingthem from other plankton,
(26:19):
fishes, and even whales, thebaline whales are eating these
teropods.
By the way, terrapod is spelledwith a P.
And the joke is you cannot hearthem going to the bathroom
because the P is silent.
So pteropods are reallyimportant in the food web.
(26:39):
Yes, but they're also reallysusceptible to this ocean
acidification.
And some of them, their shellsare dissolving, it's more
difficult for them to grow themand to keep them.
And we don't know what that'swhat's going to happen.
Sure.
And what what will the declineof pteropods do to the food web?
It's a really good question.
You know, if all thesecreatures are depending on, and
(27:00):
it's a large fraction of theirfood, so we don't know.
But it's potentially badthings.
Michael Pisano (27:07):
Yeah, I mean, I'm reminded to bring this back
to my comfort zone of insectsand the idea of their population
declines, biodiversity declinesthat we're seeing terrestrially
now.
And it is this huge unknownthat I think makes a lot of
people very nervous when theylearn about it.
I certainly, yeah, was feelinguh a little hopeless, I would
even say, when this beautifullydiverse group of creatures that
(27:29):
I grew up with thinking of asthey're, you know, ubiquitous
and kind of unstoppably teemingall around, you know, when those
are in trouble and when itseems like it's going to have
such an impact as thisfoundation falls out from
underneath food webs or otherparts of topology.
That's right, insectigedon somesense.
Insectigetton.
Like, how do we orientconservation and maybe
(27:51):
conservation narratives as wellto target those losses that
we're seeing of these smallcreatures?
Tim Pearce (28:00):
Well, for the for the insects, I think you need to
under we need to understandwhat the issue is.
You know, is it the is it thepesticides or you know what is
causing it?
And then we can address it.
For the terrapods, I think weknow it's ocean acidification.
So we need to stop driving ourcars so much.
Or we need to drive electriccars more.
Michael Pisano (28:20):
Sure.
So I mean there is thisindividual kind of scale action,
right?
Of, you know, at a culturallevel, we have to shift away
from reliance on fossil fuelsand these things that are
putting more carbon into theair, which is making the ocean
more acidic.
But what about, you know, Iwonder what you think about at
larger scales, at communityscales, policy scales.
Is there any sort ofconservation effort that you
(28:41):
would like to see?
Tim Pearce (28:42):
Oh my goodness, are you giving me the million-dollar
check question?
Michael Pisano (28:46):
Yeah.
Tim Pearce (28:46):
If I had million dollars, how would I change
politics?
Get in there.
Tell us about it.
I would put more scientists inpolitics.
Sure.
Except I'm a scientist and Idon't want to be a politician.
Michael Pisano (28:58):
That's okay.
Well, I think that's thereinlies part of the cultural issue,
right?
Is that politics seems likekind of a bad uh pursuit.
Tim Pearce (29:05):
I want politicians to know more science.
I think that that would.
I mean, if if politiciansunderstood science, they would
understand what the issue is andwhy they need to act in a
certain way.
I guess that's what I would dowith my million dollars.
Okay.
Michael Pisano (29:21):
Well, you might have a little left over.
So is there anything else youmight do?
Uh, you know, I think sothere's there's like a science
literacy question that you havehave brought up.
Um is there any kind ofspecific uh policy that you
think would be helpful whenwe're talking specifically about
acidification?
(29:42):
Like, are there any otherthings we can do to mitigate?
Because it's it's I think my myunderstanding about change um
in our time, uh like systemchange is that it is varied in
its approach.
There's local thrusts, there'sactivism, there's politics and
policy, right?
There's kind of an ecosystemthat's required to make change.
So, what else kind of fits intothat for you uh when we're
(30:05):
talking about conserving?
And I'll open it up to kind ofmollusk biodiversity, mollusk
health.
Tim Pearce (30:10):
Two avenues.
Two one I would I would say,yeah, more funding for research.
Just basic research.
Like I said, we don't even knowwhat most of them eat.
That's true.
And there's you know, there'sjust so many, especially tiny
species, those are the ones thatreally make me happy.
I think the average land snailis about an eighth of an inch.
Wow, so we.
Three millimeters.
(30:31):
You know, that means half thespecies are smaller than that.
unknown (30:34):
Wow.
Tim Pearce (30:34):
So that's one avenue.
And then I think on a practicallevel, I think we really do
need to get the the carbonsuckers, things that will bring
the carbon out of theatmosphere.
I mean, trees are doing it forfree if we would stop cutting
them down.
Sure.
Um, but I mean, one crazy idea.
Yeah, well carbon dioxideactually freezes.
(30:56):
So carbon dioxide goes from gasto solid without going through
a liquid.
Okay.
Speaker 3 (31:01):
Yep.
Tim Pearce (31:01):
And carbon dioxide freezes at a higher temperature
than nitrogen and oxygen, whichis the bulk of our air.
So if we could just make theair cold enough, really cold, we
would get carbon dioxide snow.
And I mean, it's it's not, Imean, yes, it's cold.
It would take a lot of energyto get down there.
So I propose to go to someplace that's already cold.
(31:22):
Okay.
Like Antarctica.
Sure, it's cold.
And build these big factoriesthat would bring air in, make it
cold, and the carbon dioxidewould snow out, and then bring
in some more, and it would snowout, and then you'd collect all
this carbon dioxide.
Michael Pisano (31:35):
That was my next question.
What do you do with the snow?
Tim Pearce (31:37):
Okay, well, now it gets even crazier.
Michael Pisano (31:39):
Okay, great.
Tim Pearce (31:40):
Well, diamonds are just compressed carbon.
So you take all this carbondioxide snow, compress it into
diamonds, and then sell thediamonds to fund the operation.
I love it.
Michael Pisano (31:53):
It's circular, so that's something.
Tim Pearce (31:55):
I have a feeling it would not be economically
feasible, but still it's a coolidea.
It is.
Michael Pisano (32:00):
I love hearing ideas like that.
And I guess my feeling is like,of course, there's an element
of fantasy, and there's a lot ofthings that would have to work
out for that to, you know,realistically work out.
But what is the kind of valueof thinking big and thinking
outside of kind of the normalconstraints?
Because, you know, I think onething you mentioned within that
to me was there were two kind ofinstances where you said, oh,
(32:22):
this is my million dollars, youknow, that I get to spend my if
money's no object, and you alsosaid, well, economically it
wouldn't be very feasible.
But when kind of the future ofthe planet is on the line, what
are economics?
What is the point of economics?
Is it to you know consolidatewealth?
That's another wholeconversation, or is it to create
a livable space for all of us?
(32:43):
Or, you know, just just Iwonder what your kind of
thoughts are on the state oflike imaginative thinking within
the constraints uh that we findourselves in and this
challenge.
Tim Pearce (32:52):
I think that humans have a discontent gene.
Michael Pisano (32:56):
Okay, I'm listening.
Tim Pearce (32:58):
I'm not content with the way that things are.
I'm gonna invent something andmake it better.
And then we're not content withthat, and we want to make it
better.
And so this non-content geneforces us into progress.
Sure.
Which, you know, don't get mewrong, yeah, I'm actually
enjoying my life.
(33:18):
Right.
But I'm wondering, is thatreally for the better?
Speaker 3 (33:23):
Right.
Tim Pearce (33:24):
You know, there's lots of other creatures out
there that are doing just fineand they don't have this
discontent gene in their head.
Is it better to have morestuff?
Is it better to have morecontrol over the world, or is it
better to be happy with whatyou have?
Michael Pisano (33:40):
I think we're coming back to some lessons that
snails can give us, right?
About contentedness, but alsothe pace of things, right?
I think what you're sayingreminds me of things that I have
read uh and said probably atparties about growth versus
degrowth as a kind of model forthe economy and for the point of
(34:01):
um endeavor, let's say.
Uh like moonshot, right, aslike a kind of concept is you
know, the idea that something isvery challenging, but if we
come together and a lot ofpeople lend their varied
expertises, a lot of things arepossible.
You can get to the moon.
Can you talk about kind of someof the role that you think
science can play, the kind ofscience that you do, and that
(34:24):
you would hope, you know, peoplecoming into careers in science
might contribute towards solvingsome of these problems of our
age for snails, for people, forthe planet?
Tim Pearce (34:34):
Just in one sentence, if we don't do it,
it's going to be done to us.
And and we are smart, we cansee what's happening, we can see
the solution, we can choose todo it, or it will be done to us.
Michael Pisano (34:47):
I love uh I love having an active role in you
know, some way in playing out uhmy future and the future of the
people I love and the placesthat I care about.
So I accept.
How would you suggest peopleget involved in supporting
mollusks, their local snailpopulations?
What could you do to be abetter neighbor to the mollusks
(35:10):
in your neighborhood?
Tim Pearce (35:11):
Well, so earlier when we were talking about
migration, sure, you didn't usethe word corridor, but you could
have used the word corridor.
Because corridors, I mean,corridors are recognized as
important for large mammals tomigrate between habitat,
sections, areas of habitat.
Um, but it's also true formollusks too.
So if you had continuous forestbetween these two areas, then
(35:35):
the mollusk could slowly underits own power, the mollusk could
actually migrate.
Speaker 3 (35:40):
But where's the rush?
Tim Pearce (35:41):
Where's the rush?
But yes.
Um, corridors actually areimportant.
But then I don't want to sayforests are the only thing
because there are mollusks whoalso live in open areas.
And so there, you know, theymight be in a limestone area,
and it's not nothing to do withhumans.
That's just the landscape.
This is a limestone hill, andthere's a limestone hill.
(36:02):
Yeah.
How do they get from one to theother?
But uh no, so corridors andproviding habitat for mollusks
is probably a good idea.
I was downtown last night andit's pretty sterile.
Concrete, um, there are someplantings here and there, but
not a lot of mollusks.
Speaker 3 (36:18):
Yeah.
Tim Pearce (36:18):
So providing good natural habitat is good in your
own yard.
You probably have non-nativespecies, but you know, you get
philosophical about do wewelcome non-native species into
our yards or not?
Um you can try to welcome, Imean, I'm battling the slugs
(36:38):
right now.
But um we can try to welcomethe the slugs and and have you
know some sort of naturalgarden, or at least a part of
your yard might have some bushesrather than just mown lawn.
Although mown lawn also hassnails in it.
Um so yes, welcome welcomediversity, welcome nature, and
(36:59):
and appreciate it.
Michael Pisano (37:01):
Yeah, yeah, on that appreciation note, maybe
this can kind of take us out.
I I wonder, you know, maybeit's an obvious question, but I
think you might have a goodanswer to it anyway.
Um what is you know the valueof inviting diversity into your
life in in this biologicalsense, maybe more broadly if
we're still feelingphilosophical.
(37:21):
But you know, why should thecity not be a sterile
environment?
Why should your yard uh havehabitat?
Why should you go out of yourway to, you know, put a little
bit of something out for theslugs?
Tim Pearce (37:33):
Well, that's it's tough because you know it is
it's nice to have tidiness.
It's nice to have, it's nicenot to have bugs in your house.
You know, they are part ofthey're part of creation, but
they're part of the diversity.
Diversity is what makes theworld go round.
Who are we to exclude them?
Michael Pisano (37:52):
That's a great question.
I think there's plenty ofbenefits to just the simple act
of uh like hanging out with somesnails.
And so I really appreciate youbringing these friends by for
today.
Uh is there any oh actually,you know what?
I would be probably remiss inmy hosting duties if I didn't
ask you to uh close us out onmaybe one more of your favorite
(38:14):
jokes.
Tim Pearce (38:15):
Barack Obama Halloween's coming up, Barack
Obama went to a Halloween partygiving his wife a piggyback
ride.
Okay.
And the host said, Welcome, Mr.
President.
Um, what are you dressed up as?
And Barack said, I'm a snail.
This is Michelle on my back.
Michael Pisano (38:36):
That's very good.
Thank you again so much forjoining me.
Tim Pearce (38:40):
It's been great.
Thank you.
Michael Pisano (38:51):
20,000 thanks to Tim for inviting us into the
Carnegie's Malacologycollection, and to the 20,000
mollusks therein for remindingus to slow down, take it easy,
and enjoy the scenery.
DJ Thermos makes the music,Mackenzie Kimmel describes the
(39:15):
collection items, and GarrickSchmidt and Michael Pizzano,
that's me, edit the podcast.
Thanks for listening.
You're listening to the Anthropocene Archives, a
presentation of We Are Nature.
In this special series ofstories, we're delving deep into
Carnegie Museum of NaturalHistory's 22 million collection
items, raiding cabinets andcases, sifting through objects
and organisms in search ofstories of stewardship,
solutions, and scientificwonder.
On today's episode, Solidaritywith the small and slimy,
(00:35):
assisted mollusk migration, andsome wisdom from slow-rolling
role models.
Today we're taking the scenicroute.
Let's escargot.
Welcome to We Are Nature, ashow about natural history and
(00:55):
movable futures presented byCarnegie Museum of Natural
History.
I'm your host, amateur slimetrail follower Michael Pisano,
and today I'm joined by aprominent professional mollusk
joke author.
Would you just please introduceyourself?
Tim Pearce (01:07):
I'm Tim Pearce here at Carnegie Museum of Natural
History.
I'm assistant curator ofmollusks, and I take care of the
shell collection.
Michael Pisano (01:15):
I am just so excited for you to join us
today.
We've also got a third guestwho we'll maybe get to, a
professional mollusk, maybe wecould say.
So thank you both for joiningus today and taking us behind
the scenes of the malacologycollection here.
To kick us off, could you tellme a little bit about the
Carnegie's mollusk collections?
Tim Pearce (01:33):
Oh, right.
So we've got a huge shellcollection.
Um it's been here for since1895, I think.
So that's what, 130 years?
Are we there yet?
And um it's the 10th or 11thlargest shell collection in the
United States.
Oh wow.
So that's pretty amazing.
We've got we are particularlystrong in land snails from the
(01:54):
Appalachian area from theeastern United States.
That makes sense.
But we also are really strongin the freshwater mussels.
The guy who literally wrote thebook on them was a former
curator, and we've got hiscollection.
Michael Pisano (02:05):
Lucky, lucky, lucky.
What kind of species diversityare we talking about represented
in the collection here?
Tim Pearce (02:10):
There might be maybe 80,000 species of molluscs in
the world, and we have probably18 to 20,000 species represented
in our collection.
There's no museum that has themall.
Sure.
And that's partly because someof them are just described from
a single specimen.
Incredible.
That means one museum and onlyone museum can have that
(02:30):
species.
Period, right.
Michael Pisano (02:32):
What about locally?
What's our biodiversity, ourmollusk biodiversity like here?
Tim Pearce (02:36):
My specialty are the land snails.
And so we have about 130species of land snails in
Pennsylvania.
And we also have maybe 60 to 65of the freshwater mussels and
maybe 15 or 20 of the freshwaterclams.
Sorry, freshwater snails.
Well, we do have a few of thetiny clams too.
I'm not sure how many eight toten species of those.
(02:57):
Gotcha.
Michael Pisano (02:58):
Just to get right away into the things
you've brought us, I wonder ifmaybe we can start with this
very enticing one.
Mackenzie Kimmel (03:07):
Collection item one lives in a translucent
plastic tub.
Rich, moist soil fills thetub's bottom third.
Moss, bark, and a sortedorganic detritus is scattered
across the surface, evoking alonely forest floor.
(03:29):
The collection item housed hereis not one single organism, but
rather a colony.
Individuals range in size fromheartbreakingly tiny youth to
adults that measure an inch indiameter.
Each of their friendly facessports four tentacles.
(03:51):
Each of their backs holds aspiral structure made of calcium
carbonate adorned in white andorange stripes.
Can you identify collectionitem one?
Tim Pearce (04:07):
Well, this is a tub.
It's a plastic tub with atight-fitting lid that has holes
in the lid.
And inside is some soil andsome bark and some living
snails.
The common name for these istiger snail.
The Latin name is Anguispiraalternata.
(04:27):
And these are this is a colonythat I've had for I think about
2013 or 2014.
I collected in northernMichigan.
But I think this species haslived in Frick Park, one of our
local parks.
And so I'm trying to getpermission to release these and
(04:49):
start the colony in Frick Parkand maybe follow it to see how
successful recolonizing FrickPark is.
Michael Pisano (04:55):
Can you tell me a little bit more about the
organism?
I mean, what what's a tigersnail's day like?
What's their lifestyle?
Tim Pearce (05:01):
For the for your eyes only people, I don't know
if you can see this, but thereyou can see the snail, it's a
coil, and then out the bottom ofit is this body, and it's just
putting its eyes out there.
Yeah.
So it has four tentacles outthe front.
The two lower ones are forsmelling and tasting, and these
two upper ones have balls on thetips.
Those are actually eyeballs.
(05:22):
Yeah.
And so it's got eyes on thetips of its upper tentacles.
They don't have very goodvision, so they probably
couldn't tell you and me apart.
Michael Pisano (05:31):
No, that's okay.
Tim Pearce (05:32):
But they can tell light and dark.
Michael Pisano (05:33):
Okay, that seems more important as a foundation.
Tim Pearce (05:36):
And they are very good at smelling, so they could
probably smell us apart.
Michael Pisano (05:39):
And what are they smelling for in their
environment?
Tim Pearce (05:41):
Oh gosh, I don't know.
Probably food, but maybe alsomates.
Sure, sure, sure, sure.
It was possibly trying to stayaway from predators, but I'm not
sure that they would do much ofthat smelling.
Michael Pisano (05:53):
And when we're talking about food, what what
are they eating?
What's their diet like?
Tim Pearce (05:57):
That's a very interesting question because for
almost all of the snails, wedon't know what they eat.
Oh, no kidding.
We just make a guess that, oh,they're eating detritus, they're
eating dead leaves.
Um, and in most cases that'sprobably true.
But then again, get evendeeper, please.
There's eating and then there'sabsorbing.
(06:18):
So a lot of these creatures areeating a lot of things that
just comes through, comes outthe other end, looking pretty
much like it went in.
Okay.
So then the question is, whatare they actually, how are they
staying alive?
Michael Pisano (06:31):
What are they taking out of that stream?
Tim Pearce (06:33):
And so we believe, again, this is a belief we don't
we don't have the evidence yet,but we think that they're
eating and absorbing thebacteria and the fungus that are
growing on the they're helpingto decompose the leaves.
So the leaves themselves mightnot be contributing much
nutrition.
So have you heard ofenvironmental DNA?
(06:54):
Please.
Oh, so environmental DNA ismostly used in water.
Creatures that are living inthe water are leaking DNA just
through their slime, throughtheir waste products or their
gills.
And so a person can take asample of water and analyze it
for the DNA and see whichspecies are living there.
Speaker 3 (07:14):
So awesome.
Tim Pearce (07:15):
So that's pretty cool.
So one idea about trying tofigure out what the snails are
eating, I've tried to get somepeople interested in looking at
the snail poo to see what DNAcan we find in the poo to get an
idea of what they're eating.
So again, this doesn't get atwhat they're actually absorbing,
but it will get at what they'reeating at.
Michael Pisano (07:35):
What's coming in and coming out.
Tim Pearce (07:36):
So far, we haven't had much luck with the looking
at the poo.
One person that I did get tolook at that found an awful lot
of human DNA.
And so the one conclusion couldbe they're eating humans, but
the other conclusion is she hadcontaminated her sand.
Right, right, right, right.
That makes maybe more sense,but I wouldn't put anything
here.
I think that that's reallyfascinating that mollusks are
(07:58):
the second largest phylum in theworld.
That's right.
After Arthropods, for most ofthe mollusks, we don't know what
they eat.
That's incredible.
Michael Pisano (08:13):
One of the things I wanted to talk about
with our tiger snails today wasbroadening out to the land snail
kind of State of the Union,thinking about the Anthropocene,
thinking about some of theother stories this season.
I'm curious about kind of howthey're doing these days.
Tim Pearce (08:30):
Well, so yes, I have been studying tiger snails for
probably 10 years now.
They are or have been the mostcommon large land snail east of
the Mississippi.
And what that means is thereare lots of specimens in
museums.
Right.
Because people can find themand bring them in.
And museums are amazing becausethey've got all of this
(08:52):
information over time.
Yes.
And so it can tell you what wasliving where, when.
And so I was looking at themuseum and I was noticing, hey,
we're finding fewer of themnowadays.
And the museum allowed me tosee, hey, they're doing pretty
well, pretty well, pretty well.
And so around 1960, theystarted to disappear in
(09:14):
different places.
And I've been, I'm I'm notfinished with my studies yet,
but I'm approaching it from twodifferent angles.
Okay.
One is acid rain.
Yep.
And the mid-1960s is about whenacid rain started going up.
And so acid rain could havecontributed to their decline.
But then also global uh warmingor climate warming.
(09:36):
So if these snails are alreadyliving near the southern edge of
their limit or living as low onthe mountain as they can, if
the climate then warms, thenthey have to move north or they
have to move up the mountain.
And some of thesedisappearances could be
consistent with climate warmingplaying a role also.
So I'm still I'm at the pointI'm trying to tease out which,
(10:00):
if either of those factors iscausing this.
Michael Pisano (10:02):
I mean, I think they're both great working
theories to start with.
So, you know, I think for asnail to migrate, to imagine
being at that scale, movingthrough a landscape, many, many
challenges, and some that aremore novel than others, perhaps.
So maybe we could talk abouthuman modification of the
landscape and what that has donefor snails trying to move to
(10:25):
chase a climate or for otherreasons.
Tim Pearce (10:27):
Absolutely, yeah, that's absolutely true.
That um something that we justtake for granted, you know,
walking across the street, thatcan be a barrier for a snail.
If a snail requires forest andwe've got an agricultural field
between this forest and thatforest, it's really hard for the
snail to get across.
Right, right, right.
So but but no, it's true.
(10:47):
A path or a road can be abarrier to a snail migration.
We've we've started to thinkabout assisted migration.
Yeah, well, if if the snail'sliving at the top of the
mountain, there is no more up,but there's another mountain
far, far away.
We can carry them to the newmountain and uh and start a new
(11:08):
colony there.
So that's that's something thatpeople are talking about.
Sure.
We need to do it carefullybecause we don't want to mess up
existing ecology that's goingon there.
Michael Pisano (11:17):
Yes, I think there's kind of a fraught
history of well-intentioned, wepicked something up and moved it
over and put it somewhere else.
Can you kind of speak to theopen questions in that
possibility?
Because I a lot of episodesthis season we've talked about
the need to move from a passiveidea of conservation where it's
just you set aside the land andeverything will flourish and
(11:38):
everything will be fine, butrather we're at a point where
maybe we need to be a little bitmore active and participatory.
Can you just kind of speak tohow that uh affects this
scenario?
Tim Pearce (11:48):
I think predictive modeling would be relevant here.
So with predictive modeling,you look at where the species
lives now, and you look at abunch of variables like the
climate and the rainfall and thetemperature, maybe the habitat,
what kind of vegetation it has,maybe the underlying rock type,
those kinds of things.
And then using all thatinformation, you can predict
(12:11):
other places that it might befound right right now.
Um so you could go and look andtest your test your hypothesis.
But the power is you can alsodial it forward and say, all
right, right, in a in a climatewarming world or uh with with
modified rainfall, where mightwe predict it would be in the
(12:32):
future?
Right.
And then you could say, do theexisting reserves adequately
protect this species, or wouldwe need to move them, or would
we need to make create newreserves?
Sure.
Michael Pisano (12:45):
I am curious about other ways to maybe make
space for safe snail passage,and you know, maybe thinking
about that a little more broadlyabout more welcoming landscapes
for the small and thevulnerable, right?
Like maybe this is a good timeto talk a little bit about the
charisma of the snail, which Ithink you probably uh have some
(13:06):
takes on, but you know,generally when we're talking
about the undergrowth, the mud,the small things crawling around
in them, it's not a typicaldefinition of charisma.
What do you find, you know,endearing, nice, exciting about
these?
Tim Pearce (13:20):
I guess one of my favorite things about mollusks
is that I can keep up with them.
They're not too fast for me.
Um, I just I just love them.
They're um nice to be with.
They uh they don't make a lotof noise.
That's true.
They're mellow, um, good rolemodels.
Michael Pisano (13:38):
What can we learn from snails?
Tim Pearce (13:41):
Take it easy.
Yeah.
Take it easy.
Enjoy the enjoy the scenery.
Michael Pisano (13:46):
Sure.
Tim Pearce (13:46):
Um, be friendly.
Michael Pisano (13:49):
All very good lessons, and yeah, not maybe not
always worrying about growth ormore.
But uh, yes.
I am curious, I guess, about,you know, it kind of an
(14:15):
extension of this same questionabout charisma and what you see
as, you know, not justendearing, but also valuable uh
about these small creatures.
Like how is the success of theland snail, let's say, defined
very broadly, connected to humansuccess.
Tim Pearce (14:33):
Right.
On the charisma topic, I thinkmost people don't find snails
and slugs very charismatic.
And I think that that'sunfortunate because there are so
many creatures in the worldthat are maybe less charismatic
than things with big eyes.
Speaker 3 (14:50):
That's right.
Tim Pearce (14:51):
In utilitarian terms, uh, they do perform a lot
of functions for us.
Okay.
I mean, they help to chew upthe leaves that fall down to
return the nutrients to thesoil, the plants can grow again.
If if things didn't chew up theleaves, we'd be up to our neck
or even deeper in leaves.
Snails, land snails, are reallyimportant in the food web.
They provide uh essentialcalcium to a lot of creatures
(15:15):
and and food.
I mean, think about birds.
Mother birds are laying eggscoated with a shell of calcium
carbonate.
Right.
And she gets it from eating thesnail shells.
Wow.
And and fireflies, babyfireflies, eat snails, sometimes
nothing but snails.
So if you love fireflies, andwe all do, let's not so well,
then you've got to love snails.
(15:36):
So yeah, they do play reallyimportant roles in the
ecosystem.
Snails and other lesscharismatic creatures.
So we do need to appreciatethem.
Michael Pisano (15:46):
I do appreciate that you kind of set out this
ecosystem services, you know,version of this.
What are they doing for theecology for us?
But I think you're also hintingat, and maybe this is just me
reaching, you know, an inherentvalue.
I I guess for me, you know, Igrew up as a certified bug nerd,
right?
And I loved a lot of thingsthat many people didn't really
(16:06):
see as charismatic.
And it wasn't because I wasaware of all the important roles
they play in an ecosystem, it'sbecause of just something
special about them.
And I, you know, I kind of seethe same spark in your eyes when
you look at our tiger snailshere.
I am kind of curious about whatyou think happens, you know,
culturally, let's say, in ahuman world where we learn to
(16:27):
look past that charismaticmegafauna system of conservation
or of narrative, really, right?
Because of course, to protect awhale, you're protecting
habitat, which maybe protectsthe snails that are in the
habitat to some degree, butit's, you know, the poster child
is the poster child.
It doesn't escape me, I guess,that, you know, like you said,
the species have big human eyesthat you can kind of read in a
(16:50):
an emotion into.
They feel very human.
So we're we're relating toanother organism.
But what happens, you know,kind of culturally for us when
we can say, actually, there'svalue to that which is foreign
that does not look like us, thatis small, vulnerable, squishy,
slimy.
Tim Pearce (17:07):
I I completely agree.
I'm not sure what else to add.
Um I you know, you could youcould talk at it from a
religious perspective.
Sure.
So almost all the religions ofthe world say we should be
stewards.
Sure.
And so it's it's really ourobligation to take care of
creation, and these are part ofcreation.
Sure.
I don't know, every livingcreature is worthy of respect.
(17:29):
On the charisma idea, it's notjust the big eyes that are
charismatic.
Yeah, tell me more.
Butterflies are charismatictoo.
Michael Pisano (17:36):
That's true.
Why?
Why do you think that is?
Tim Pearce (17:38):
We love color color and we love movement.
Michael Pisano (17:41):
And I think they are associated with flowers and
with beautiful, you know,beautiful kind of landscapes
that we can create.
Not necessarily, you know, agarden, right, is a very
controlled piece of nature tosay, ooh, beautiful.
But for now, I'd like to moveon to this other uh collection
item you've brought.
Mackenzie Kimmel (18:03):
Collection item two splits into two halves,
a top and a bottom thatinterlock neatly the satisfying.
The exterior of both halves ismottled white and gray and
covered in wavy organic ridgesthat suggest an accretion of
(18:25):
layers over time.
The interior of the halves isluminous bright white and
smooth, with one small patch ofruddy color on each face.
The whole collection item fitscomfortably into the curve of a
hand.
What is collection item two?
Tim Pearce (19:02):
I've brought along an oyster.
It's actually a bivalve, so itlooks like a clam, but this
particular one, a very misshapenclam.
So it's not at all regular, andit would be hard to describe
how it's misshapen.
It looks kind of like a leaf,maybe.
But it has the two halves, andthe two halves fit together very
(19:23):
nicely.
And um, interestingly, on theinside, it's got one patch of
color on each of the shells.
That's actually the musclescar.
And so these uh these oystershave one muscle, and when it
wants to close, then it willpull its muscles shut and close
the shell.
Most clams have two muscles,but the oysters and many other
(19:43):
uh mollusks have just one.
Scallops also have just onemuscle scar.
Michael Pisano (19:48):
Okay, tell me about this specimen.
Where where is this from?
Tim Pearce (19:51):
This one is um this is a Northern Europe species.
Okay, okay.
Um this one is Neopicnodonticochlear.
Cochlear refers to ear.
Neo is new and Pycnodonti, I'mnot sure what that means.
Um, but these would be eaten innorthern Europe.
Michael Pisano (20:07):
Gotcha.
And aside from eating uhoysters, you know, I think we
would be remiss in not talkingabout oysters kind of incredible
ecosystem services bit.
What what do they do for theecology around them?
Tim Pearce (20:19):
I I'll probably uh fail to tell you something, but
they do an awful lot.
One of them is that they doclean a lot of the water.
So they're filtering a lot ofuh food particles out of the
water.
So they're using their gillsfor breathing, but also for
eating.
And so as the food particles goover the gills, the little
cilia is sending the food oneway toward the mouth and the
(20:40):
non-food somewhere else.
And so it actually gets boundup into little strings.
So they're cleaning debris outof the water.
Another thing that they'redoing is they are they're
building reefs with theirshells.
So their their shells, afterthey finish living, they might
die.
But then over time it builds upthis these huge reefs, which
are really important wavebreaks.
(21:02):
They help to protect us fromhurricanes and huge waves.
And then they also providehabitat for the new oysters to
settle on.
There actually has been aproblem because humans have been
harvesting oysters for so manyyears and piling them up on the
shore.
And so then the reeves.
Speaker 2 (21:21):
Yeah, I like it.
Tim Pearce (21:23):
The reefs have been disappearing and it's not
providing substrate for new babyoysters to live.
So there's been a lot of effortto build new reefs out there on
the on the seashore.
And uh so they've been gettingsometimes artificial structures,
but sometimes they've just beengetting oyster shells and
putting them out there.
And so, yeah, they're comingback really, really
(21:44):
successfully.
It's a real success story.
Michael Pisano (21:47):
I also understand there's a more local
success story with freshwater uhmussels that is maybe uh
something you could speak tobecause I I do love a local
story.
Uh I guess what I'm reallygetting for is like Clean Water
Act and the way that maybediversity had gone down to a an
almost zero in some of therivers around here.
And can you speak to that kindof uh um local part?
Tim Pearce (22:11):
Yeah, when you when you first said success story, I
wasn't sure which one.
Um but yes, right here in inPittsburgh proper, uh the water
quality was really bad.
And so they probably perishedbecause of the bad water
quality.
But in many other parts of theeastern United States, um it
hasn't been water quality somuch, but siltation.
(22:33):
So by by building dams, we turnflowing rivers into lakes, and
that changes which species canlive there.
Down in the Tennessee ValleyAuthority, they channelized and
straightened out a lot ofrivers, which took away a lot of
the habitat.
So the siltation and thechannel and the habitat change
that really dated a lot of theclams.
(22:53):
But they're starting to undosome of that and they're coming
back.
But yeah, in Pittsburgh,cleaning up the water did allow
the fish to return.
So there's this bizarre lifecycle of the fish.
Speaker 3 (23:04):
Oh, tell me, I love it.
Yeah, yeah, yeah.
Tim Pearce (23:06):
So the freshwater mussels, um, they're they
actually are parasites on fishfor a couple of weeks as larvae.
So the females of thesefreshwater mussels, they're
doing triple duty with theirgills.
They're breathing with theirgills, they're eating with their
gills, and they keep theirbabies in their gills.
Incredible.
Triple duty, amazing.
So they hold the babies in overthe winter, and then when it's
(23:30):
in the springtime, they waituntil there's a fish nearby and
squeeze out some babies, andthey're little tiny, tiny things
with little hooks, and theygrab onto the fish's gills or
their fins, and then they suckthe fish's juices for a few
weeks until they metamorphoseand fall off.
And in the in the process, thefish has moved them to new
areas.
The fish is the rapid transitfor the for these mussels to
(23:53):
find new areas to live.
So when the water quality wasreally bad, it was bad for the
fish too.
Right.
But now fish are moving back inand the mussels are moving back
in.
And in fact, some species ofmussels have moved back in that
weren't here before.
Incredible.
Um not invasion, they've justbeen able to migrate further
upstream.
So, yes, it is a success story.
Michael Pisano (24:14):
Yeah.
Um, not to turn us towards anongoing, not great story, but I
would like to talk a little bitabout um problems in, I think,
well, I'll I'll I'll let youtell me exactly how widespread
this is, but there's an issue ofacidification that's impacting
creatures with shells like this.
Tim Pearce (24:32):
In freshwaters, there's acid mine drainage, and
that's wreaking havoc with allsorts of things.
But no, in the ocean, that oneis more directly related to um
carbon dioxide in theatmosphere.
So when you have more carbondioxide in the atmosphere, then
more of it dissolves in thewater, and then that makes
carbonic acid, which makes theocean more acidic.
(24:54):
So for creatures that arebuilding shells out of calcium
carbonate, more acidic water,makes it more difficult to build
them and more difficult to keepthem.
They will actually dissolve.
So this is causing a lot ofproblems for a bunch of
mollusks, and with the oystersin particular, you know, a lot
of the oysters we eat are comingfrom oyster farms, and the
(25:14):
farmers there actually buy babyoysters.
It's called spat.
They buy the baby oysters andbring them in and then they
plant them in their farms.
Well, the baby spat, the babyoysters are really sensitive to
this ocean acidification, andfarmers are having a lot of
difficulty.
So they actually have tomeasure the pH of the water
before they plant their oysters,or else they might all die.
(25:37):
Wow.
So that that's making itdifficult for the oyster farm.
And for you, if you like to eatraw oysters.
Michael Pisano (25:43):
Sure.
Well, and I think probably morebroadly in the ecology, can you
kind of speak to what thisacidification is doing?
You know, not in too muchdetail, but it's not just a
problem, I imagine, forcreatures with shells like this.
Tim Pearce (25:56):
But well, so right, a lot of creatures are having
difficulty building theirshells, and the pteropods are
microscopic.
Well, some of them are biggerthan microscopic, but they're
small snails, actually, thatspend their whole life in the
plankton, floating in theplankton, float around in the
currents, and they are reallyimportant in the food web.
Lots of creatures are eatingthem from other plankton,
(26:19):
fishes, and even whales, thebaline whales are eating these
teropods.
By the way, terrapod is spelledwith a P.
And the joke is you cannot hearthem going to the bathroom
because the P is silent.
So pteropods are reallyimportant in the food web.
(26:39):
Yes, but they're also reallysusceptible to this ocean
acidification.
And some of them, their shellsare dissolving, it's more
difficult for them to grow themand to keep them.
And we don't know what that'swhat's going to happen.
Sure.
And what what will the declineof pteropods do to the food web?
It's a really good question.
You know, if all thesecreatures are depending on, and
(27:00):
it's a large fraction of theirfood, so we don't know.
But it's potentially badthings.
Michael Pisano (27:07):
Yeah, I mean, I'm reminded to bring this back
to my comfort zone of insectsand the idea of their population
declines, biodiversity declinesthat we're seeing terrestrially
now.
And it is this huge unknownthat I think makes a lot of
people very nervous when theylearn about it.
I certainly, yeah, was feelinguh a little hopeless, I would
even say, when this beautifullydiverse group of creatures that
(27:29):
I grew up with thinking of asthey're, you know, ubiquitous
and kind of unstoppably teemingall around, you know, when those
are in trouble and when itseems like it's going to have
such an impact as thisfoundation falls out from
underneath food webs or otherparts of topology.
That's right, insectigedon somesense.
Insectigetton.
Like, how do we orientconservation and maybe
(27:51):
conservation narratives as wellto target those losses that
we're seeing of these smallcreatures?
Tim Pearce (28:00):
Well, for the for the insects, I think you need to
under we need to understandwhat the issue is.
You know, is it the is it thepesticides or you know what is
causing it?
And then we can address it.
For the terrapods, I think weknow it's ocean acidification.
So we need to stop driving ourcars so much.
Or we need to drive electriccars more.
Michael Pisano (28:20):
Sure.
So I mean there is thisindividual kind of scale action,
right?
Of, you know, at a culturallevel, we have to shift away
from reliance on fossil fuelsand these things that are
putting more carbon into theair, which is making the ocean
more acidic.
But what about, you know, Iwonder what you think about at
larger scales, at communityscales, policy scales.
Is there any sort ofconservation effort that you
(28:41):
would like to see?
Tim Pearce (28:42):
Oh my goodness, are you giving me the million-dollar
check question?
Michael Pisano (28:46):
Yeah.
Tim Pearce (28:46):
If I had million dollars, how would I change
politics?
Get in there.
Tell us about it.
I would put more scientists inpolitics.
Sure.
Except I'm a scientist and Idon't want to be a politician.
Michael Pisano (28:58):
That's okay.
Well, I think that's thereinlies part of the cultural issue,
right?
Is that politics seems likekind of a bad uh pursuit.
Tim Pearce (29:05):
I want politicians to know more science.
I think that that would.
I mean, if if politiciansunderstood science, they would
understand what the issue is andwhy they need to act in a
certain way.
I guess that's what I would dowith my million dollars.
Okay.
Michael Pisano (29:21):
Well, you might have a little left over.
So is there anything else youmight do?
Uh, you know, I think sothere's there's like a science
literacy question that you havehave brought up.
Um is there any kind ofspecific uh policy that you
think would be helpful whenwe're talking specifically about
acidification?
(29:42):
Like, are there any otherthings we can do to mitigate?
Because it's it's I think my myunderstanding about change um
in our time, uh like systemchange is that it is varied in
its approach.
There's local thrusts, there'sactivism, there's politics and
policy, right?
There's kind of an ecosystemthat's required to make change.
So, what else kind of fits intothat for you uh when we're
(30:05):
talking about conserving?
And I'll open it up to kind ofmollusk biodiversity, mollusk
health.
Tim Pearce (30:10):
Two avenues.
Two one I would I would say,yeah, more funding for research.
Just basic research.
Like I said, we don't even knowwhat most of them eat.
That's true.
And there's you know, there'sjust so many, especially tiny
species, those are the ones thatreally make me happy.
I think the average land snailis about an eighth of an inch.
Wow, so we.
Three millimeters.
(30:31):
You know, that means half thespecies are smaller than that.
unknown (30:34):
Wow.
Tim Pearce (30:34):
So that's one avenue.
And then I think on a practicallevel, I think we really do
need to get the the carbonsuckers, things that will bring
the carbon out of theatmosphere.
I mean, trees are doing it forfree if we would stop cutting
them down.
Sure.
Um, but I mean, one crazy idea.
Yeah, well carbon dioxideactually freezes.
(30:56):
So carbon dioxide goes from gasto solid without going through
a liquid.
Okay.
Speaker 3 (31:01):
Yep.
Tim Pearce (31:01):
And carbon dioxide freezes at a higher temperature
than nitrogen and oxygen, whichis the bulk of our air.
So if we could just make theair cold enough, really cold, we
would get carbon dioxide snow.
And I mean, it's it's not, Imean, yes, it's cold.
It would take a lot of energyto get down there.
So I propose to go to someplace that's already cold.
(31:22):
Okay.
Like Antarctica.
Sure, it's cold.
And build these big factoriesthat would bring air in, make it
cold, and the carbon dioxidewould snow out, and then bring
in some more, and it would snowout, and then you'd collect all
this carbon dioxide.
Michael Pisano (31:35):
That was my next question.
What do you do with the snow?
Tim Pearce (31:37):
Okay, well, now it gets even crazier.
Michael Pisano (31:39):
Okay, great.
Tim Pearce (31:40):
Well, diamonds are just compressed carbon.
So you take all this carbondioxide snow, compress it into
diamonds, and then sell thediamonds to fund the operation.
I love it.
Michael Pisano (31:53):
It's circular, so that's something.
Tim Pearce (31:55):
I have a feeling it would not be economically
feasible, but still it's a coolidea.
It is.
Michael Pisano (32:00):
I love hearing ideas like that.
And I guess my feeling is like,of course, there's an element
of fantasy, and there's a lot ofthings that would have to work
out for that to, you know,realistically work out.
But what is the kind of valueof thinking big and thinking
outside of kind of the normalconstraints?
Because, you know, I think onething you mentioned within that
to me was there were two kind ofinstances where you said, oh,
(32:22):
this is my million dollars, youknow, that I get to spend my if
money's no object, and you alsosaid, well, economically it
wouldn't be very feasible.
But when kind of the future ofthe planet is on the line, what
are economics?
What is the point of economics?
Is it to you know consolidatewealth?
That's another wholeconversation, or is it to create
a livable space for all of us?
(32:43):
Or, you know, just just Iwonder what your kind of
thoughts are on the state oflike imaginative thinking within
the constraints uh that we findourselves in and this
challenge.
Tim Pearce (32:52):
I think that humans have a discontent gene.
Michael Pisano (32:56):
Okay, I'm listening.
Tim Pearce (32:58):
I'm not content with the way that things are.
I'm gonna invent something andmake it better.
And then we're not content withthat, and we want to make it
better.
And so this non-content geneforces us into progress.
Sure.
Which, you know, don't get mewrong, yeah, I'm actually
enjoying my life.
(33:18):
Right.
But I'm wondering, is thatreally for the better?
Speaker 3 (33:23):
Right.
Tim Pearce (33:24):
You know, there's lots of other creatures out
there that are doing just fineand they don't have this
discontent gene in their head.
Is it better to have morestuff?
Is it better to have morecontrol over the world, or is it
better to be happy with whatyou have?
Michael Pisano (33:40):
I think we're coming back to some lessons that
snails can give us, right?
About contentedness, but alsothe pace of things, right?
I think what you're sayingreminds me of things that I have
read uh and said probably atparties about growth versus
degrowth as a kind of model forthe economy and for the point of
(34:01):
um endeavor, let's say.
Uh like moonshot, right, aslike a kind of concept is you
know, the idea that something isvery challenging, but if we
come together and a lot ofpeople lend their varied
expertises, a lot of things arepossible.
You can get to the moon.
Can you talk about kind of someof the role that you think
science can play, the kind ofscience that you do, and that
(34:24):
you would hope, you know, peoplecoming into careers in science
might contribute towards solvingsome of these problems of our
age for snails, for people, forthe planet?
Tim Pearce (34:34):
Just in one sentence, if we don't do it,
it's going to be done to us.
And and we are smart, we cansee what's happening, we can see
the solution, we can choose todo it, or it will be done to us.
Michael Pisano (34:47):
I love uh I love having an active role in you
know, some way in playing out uhmy future and the future of the
people I love and the placesthat I care about.
So I accept.
How would you suggest peopleget involved in supporting
mollusks, their local snailpopulations?
What could you do to be abetter neighbor to the mollusks
(35:10):
in your neighborhood?
Tim Pearce (35:11):
Well, so earlier when we were talking about
migration, sure, you didn't usethe word corridor, but you could
have used the word corridor.
Because corridors, I mean,corridors are recognized as
important for large mammals tomigrate between habitat,
sections, areas of habitat.
Um, but it's also true formollusks too.
So if you had continuous forestbetween these two areas, then
(35:35):
the mollusk could slowly underits own power, the mollusk could
actually migrate.
Speaker 3 (35:40):
But where's the rush?
Tim Pearce (35:41):
Where's the rush?
But yes.
Um, corridors actually areimportant.
But then I don't want to sayforests are the only thing
because there are mollusks whoalso live in open areas.
And so there, you know, theymight be in a limestone area,
and it's not nothing to do withhumans.
That's just the landscape.
This is a limestone hill, andthere's a limestone hill.
(36:02):
Yeah.
How do they get from one to theother?
But uh no, so corridors andproviding habitat for mollusks
is probably a good idea.
I was downtown last night andit's pretty sterile.
Concrete, um, there are someplantings here and there, but
not a lot of mollusks.
Speaker 3 (36:18):
Yeah.
Tim Pearce (36:18):
So providing good natural habitat is good in your
own yard.
You probably have non-nativespecies, but you know, you get
philosophical about do wewelcome non-native species into
our yards or not?
Um you can try to welcome, Imean, I'm battling the slugs
(36:38):
right now.
But um we can try to welcomethe the slugs and and have you
know some sort of naturalgarden, or at least a part of
your yard might have some bushesrather than just mown lawn.
Although mown lawn also hassnails in it.
Um so yes, welcome welcomediversity, welcome nature, and
(36:59):
and appreciate it.
Michael Pisano (37:01):
Yeah, yeah, on that appreciation note, maybe
this can kind of take us out.
I I wonder, you know, maybeit's an obvious question, but I
think you might have a goodanswer to it anyway.
Um what is you know the valueof inviting diversity into your
life in in this biologicalsense, maybe more broadly if
we're still feelingphilosophical.
(37:21):
But you know, why should thecity not be a sterile
environment?
Why should your yard uh havehabitat?
Why should you go out of yourway to, you know, put a little
bit of something out for theslugs?
Tim Pearce (37:33):
Well, that's it's tough because you know it is
it's nice to have tidiness.
It's nice to have, it's nicenot to have bugs in your house.
You know, they are part ofthey're part of creation, but
they're part of the diversity.
Diversity is what makes theworld go round.
Who are we to exclude them?
Michael Pisano (37:52):
That's a great question.
I think there's plenty ofbenefits to just the simple act
of uh like hanging out with somesnails.
And so I really appreciate youbringing these friends by for
today.
Uh is there any oh actually,you know what?
I would be probably remiss inmy hosting duties if I didn't
ask you to uh close us out onmaybe one more of your favorite
(38:14):
jokes.
Tim Pearce (38:15):
Barack Obama Halloween's coming up, Barack
Obama went to a Halloween partygiving his wife a piggyback
ride.
Okay.
And the host said, Welcome, Mr.
President.
Um, what are you dressed up as?
And Barack said, I'm a snail.
This is Michelle on my back.
Michael Pisano (38:36):
That's very good.
Thank you again so much forjoining me.
Tim Pearce (38:40):
It's been great.
Thank you.
Michael Pisano (38:51):
20,000 thanks to Tim for inviting us into the
Carnegie's Malacologycollection, and to the 20,000
mollusks therein for remindingus to slow down, take it easy,
and enjoy the scenery.
DJ Thermos makes the music,Mackenzie Kimmel describes the
(39:15):
collection items, and GarrickSchmidt and Michael Pizzano,
that's me, edit the podcast.
Thanks for listening.
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