a

Add

ing

a N

ew D

imen

sion

to th

e S

tudy

of C

alca

reou

s P

lank

ton

Res

pons

e to

Oce

an A

cidi

ficat

ion

Ros

ie L

. Oak

es1 ,

Jeffr

ey M

. Urb

ansk

i2 , an

d Ti

mot

hy J

. Bra

low

er1

1 Dep

artm

ent o

f Geo

scie

nces

, The

Pen

nsyl

vann

ia S

tate

Uni

vers

ity, U

nive

rsity

Par

k, P

A, U

SA

2 GE

Mea

sure

men

t & C

ontro

l, Le

wis

tow

n, P

A, U

SA

PP

11A

- 132

3

• A

nthr

opog

enic

act

iviti

es a

re in

crea

sing

at

mos

pher

ic c

arbo

n di

oxid

e le

vels

at

unpr

eced

ente

d ra

tes

• It

is th

ough

t tha

t, si

nce

1800

, ~30

% o

f th

is c

arbo

n di

oxid

e ha

s be

en a

bsor

bed

into

the

ocea

ns (

Sabi

ne e

t al.,

200

4)•

The

dis

solu

tion

of c

arbo

n di

oxid

e in

to

the

ocea

n af

fect

s oc

ean

chem

istr

y by

de

crea

sing

the

conc

entr

atio

n of

car

bona

te

ions

and

dec

reas

ing

the

pH•

Pter

opod

s ar

e ho

lopl

akto

nic

gast

ropo

d m

ollu

scs

whi

ch li

ve in

the

surf

ace

ocea

ns

and

form

thei

r sh

ells

out

of

arag

onite

, the

m

ore

solu

ble

form

of

calc

ium

car

bona

te.

• B

ecau

se p

tero

pods

for

m a

rago

nite

sh

ells

, the

y w

ill b

e am

ong

the

firs

t or

gani

sms

to b

e im

pact

ed b

y oc

ean

acid

ific

atio

n.•

Cul

ture

and

incu

batio

n ex

peri

men

ts

have

sho

wn

that

ele

vate

d ca

rbon

dio

xide

le

vels

and

dec

reas

ed c

arbo

nate

ion

conc

entr

atio

ns (

or s

atur

atio

n) a

re

detr

imen

tal t

o pt

erop

od c

alci

fica

tion

(Com

eau

et a

l., 2

009,

201

0, B

edna

ršek

et

al.,

2012

a, 2

012b

). T

here

are

eve

n so

me

pter

opod

s in

the

mod

ern

ocea

n fe

elin

g th

e ef

fect

s of

thes

e ch

angi

ng c

ondi

tions

(B

erna

ršek

et a

l., 2

014)

.

The

Que

stio

n30

00

2500

2000

1500

1000

500

0

60O

40O

20O

0O 20O

40O

60O

30OE

60OE

90OE

120O

E15

0OE

180O

150O

W12

0OW

90OW

60OW

30OW

0O

JR27

1

Caria

co

JR27

4

• W

e ar

e in

tere

sted

in h

ow p

lank

ton

reac

ted

to p

ast c

hang

e an

d th

eref

ore

be a

ble

to p

redi

ct h

ow th

ey m

ay

resp

ond

to f

utur

e ch

ange

. In

orde

r to

do

this

, we

firs

t nee

d to

und

erst

and

wha

t the

ir c

ondi

tion

is in

the

mod

ern

ocea

n.H

ow d

oes

the

shel

l thi

ckne

ss a

nd s

hell

volu

me

of p

tero

pods

var

y w

ith

vary

ing

ocea

n ch

emis

try

in t

he

mod

ern

ocea

n?•

Thu

s fa

r th

e co

nditi

ons

of m

oder

n pt

erop

ods

and

cultu

red

pter

opod

s ha

ve b

een

asse

ssed

usi

ng li

ght

mic

rosc

opy

and

SEM

imag

ery

(e.g

. Ger

hard

t and

Hen

rich

, 200

1, B

edna

ršek

et a

l., 2

012a

, 201

2b, 2

014)

. •

Futu

re c

hang

es in

pte

ropo

d sh

ell m

orph

olog

y ar

e lik

ely

to b

e sm

all a

nd n

on-l

etha

l (B

edna

ršek

et a

l., 2

012b

).

• A

dvan

ces

in c

ompu

ter

tom

ogra

phy

mea

n th

at it

is n

ow p

ossi

ble

to im

age

thes

e sh

ells

in 3

D a

t mic

ron

scal

e re

solu

tion,

add

ing

a ne

w d

imen

sion

to th

e st

udy

of m

oder

n pt

erop

ods.

•

We

are

wor

king

tow

ards

mak

ing

a hi

gh r

esol

utio

n, m

oder

n da

y ba

selin

e da

tase

t to

whi

ch f

utur

e ch

ange

s ca

n be

com

pare

d.

Intr

oduc

tion

Met

hods

• Pt

erop

ods

wer

e st

udie

d fr

om th

ree

loca

tions

: the

Arc

tic O

cean

(JR

271)

(L

eaky

et a

l., 2

012)

, the

Car

iaco

Bas

in

(Thu

nell

lab)

, and

the

Sout

hern

Oce

an

(JR

274)

(Ta

rlin

g et

al.,

201

3).

• In

divi

dual

pte

ropo

ds w

ere

wei

ghed

on

a M

ettle

r To

ledo

mic

roba

lanc

e (a

ccur

ate

to +

/- 0

.1μ

g) a

nd im

aged

in

two

dim

ensi

ons

on a

Zei

ss S

tem

i 20

00-C

ligh

t mic

rosc

ope

usin

g a

Can

on

Pow

ersh

ot G

9.•

Indi

vidu

al s

peci

men

s w

ere

then

m

ount

ed o

nto

carb

on ta

pe a

nd s

cann

ed

usin

g a

phoe

nix

v|to

me|

x m

at G

E

Mea

sure

men

t & C

ontr

ol in

Lew

isto

wn,

PA

(Fi

gure

2d,

e).

• E

ach

scan

take

s ~1

hou

r an

d th

e da

ta

is ~

2 G

B. T

he v

oxel

siz

e is

1 –

2 μ

m

depe

ndin

g on

the

size

of

the

pter

opod

. •

Dat

a w

as r

econ

stru

cted

usi

ng G

E

Dat

os a

nd V

G S

tudi

o M

ax 2

.2 s

oftw

are.

Fig

ure

1: S

ampl

e lo

catio

ns f

or th

is s

tudy

ove

rlai

n on

a m

ap a

rago

nite

com

pens

atio

n de

pth

adap

ted

from

F

eele

y et

al,

(200

4)

Res

ults

• A

tota

l of 5

1 pt

erop

ods w

ere

scan

ned

from

thre

e lo

catio

ns.

• Th

ere

is n

o tre

nd b

etw

een

the

norm

alis

ed sh

ell v

olum

e an

d om

ega

arag

onite

(Fig

ure

3).

• Th

e sc

an im

ages

show

shel

ls c

ondi

tion

does

n’t s

eem

to c

orre

late

with

om

ega

arag

onite

.

• She

ll vo

lum

e is

cal

cula

ted

as th

e su

m o

f vo

xels

whi

ch f

all w

ithin

a s

elec

ted

grey

scal

e ra

nge.

• T

he s

elec

ted

grey

scal

e ra

nge

is d

iffe

rent

for

eac

h sa

mpl

e an

d is

des

igna

ted

usin

g th

e au

tom

atic

su

rfac

e de

term

inat

ion

mod

ule

in V

G S

tudi

o M

ax 2

.2 s

oftw

are.

• The

dia

met

er o

f the

shel

l is m

easu

red

acro

ss th

e w

ides

t par

t of t

he w

horl,

par

alle

l to

the

botto

m o

f th

e sh

ell u

sing

the

mea

sure

men

t too

l in

VG

Stu

dio

Max

2.2

softw

are.

Dis

cuss

ion

• A

ll pt

erop

od sa

mpl

es c

ame

from

are

as

of th

e oc

ean

whi

ch a

re c

urre

ntly

su

pers

atur

ated

(Ω a

rago

nite

>1)

. The

re

seem

s to

be n

o tre

nd in

nor

mal

ised

shel

l vo

lum

e w

ith in

crea

sing

ly su

pers

atur

ated

w

ater

s.•

Ther

e ar

e so

me

chan

ges i

n sh

ells

whi

ch

are

visi

ble

by e

ye (F

igur

e 3)

that

don

’t co

rrel

ate

to c

hang

es in

Ω a

rago

nite

. •

The

calc

ifica

tion

dept

h of

pte

ropo

ds is

st

ill u

nkno

wn.

We

focu

sed

on th

e w

ater

ch

emis

try a

t 5 m

and

100

m a

s pte

ropo

ds

are

know

n to

be

dom

inan

t in

the

top

hund

red

met

res (

Bat

hman

n et

al.,

199

1;

Soils

and

von

Wes

tern

hage

n, 1

978)

. H

owev

er, p

tero

pods

are

kno

wn

to h

ave

a st

rong

ver

tical

mig

ratio

n pa

ttern

s and

hav

e be

en fo

und

as d

eep

as 1

000

m (B

erna

ršek

et

al.,

201

2c).

• If

pte

ropo

ds c

alci

fy d

eepe

r tha

n 10

0 m

, w

e w

ill m

iss t

he c

hem

ical

sign

al th

at is

dr

ivin

g th

is c

hang

e as

Ω a

rago

nite

doe

s no

t dec

reas

e lin

erly

with

dep

th.

• Pt

erop

ods h

ave

an a

nnua

l life

cycl

e an

d th

eref

ore

we

may

be

look

ing

at sh

ell

chan

ge e

ffect

s whi

ch w

ere

caus

ed b

y a

wat

er m

ass t

hat t

he p

tero

pod

was

in

cont

act w

ith m

onth

s bef

ore.

Con

clus

ions

• Th

ere

is n

o si

gnifi

cant

qua

ntifi

able

effe

ct

of Ω

ara

goni

te a

t 5m

or 1

00m

on

pter

opod

s sh

ells

from

supe

rsat

urat

ed w

ater

s.•

Shel

l thi

ckne

ss d

istri

butio

ns c

ould

be

used

to h

ighl

ight

spec

imen

s whi

ch a

re a

t ris

k of

bei

ng d

amag

ed.

• Spe

cim

ens f

rom

und

ersa

tura

ted

regi

ons

need

to b

e m

easu

red

to c

ompl

ete

this

stud

y.

• C

T sc

anni

ng w

ill b

e an

ess

entia

l too

l en

ablin

g us

not

onl

y to

mea

sure

cha

nge

but

to p

inpo

int t

he lo

catio

n of

this

cha

nge.

Fig

ure

3: V

olum

e of

ara

goni

te in

the

shel

l nor

mal

ised

to s

hell

diam

eter

fro

m th

ree

site

s co

mpa

red

to th

e om

ega

arag

onite

at 5

m (

open

sym

bols

) an

d 10

0m (

fille

d sy

mbo

ls).

The

3D

imag

es s

how

a

grad

ient

in s

peci

men

t qua

lity

at th

ese

omeg

a ar

agon

ite v

alue

s.

Fig

ure

2: S

ampl

e pr

epar

atio

n a)

ligh

t m

icro

scop

e im

age;

b)

mou

nt o

n ca

rbon

tape

; c)

raw

2D

dat

a fr

om C

T s

cann

er;

d) in

tern

al

set u

p of

sca

nner

; e)

ext

erna

l im

age

of

phoe

nix

v|to

me|

x m

Fig

ure

4: S

hell

thic

knes

ses

in s

ampl

es f

rom

the

Arc

tic O

cean

(L

imac

ina

hele

cina

) an

d th

e C

aria

co

Bas

in (

Lim

acin

a in

flat

a). T

he m

ode

valu

es b

etw

een

thes

e tw

o sa

mpl

e ar

e st

atis

tical

ly d

iffe

rent

.

Fig

ure

5: S

hell

thic

knes

s di

stri

butio

n in

one

sam

ple.

Sh

ells

with

hig

her

mod

e va

lues

(pu

rple

box

) lo

ok m

ore

pris

tine

than

thos

e w

ith lo

wer

mod

e va

lues

(re

d bo

x).

• W

ithin

eac

h sa

mpl

e, th

ere

is v

aria

tion

betw

een

diffe

rent

spec

imen

s.•

Pter

opod

s with

hig

her m

ode

valu

es (p

urpl

e bo

x)

look

mor

e pr

istin

e th

an th

ose

with

low

er m

ode

valu

es (r

ed b

ox).

• Th

is te

chni

que

seem

s to

be m

ore

diag

nost

ic a

t hi

ghlig

htin

g vu

nera

ble

spec

imen

s tha

n th

e no

rmal

ised

vol

ume

mea

sure

men

ts.

Shel

l thi

ckne

ss a

naly

sis

We

need

you

r hel

p!W

e w

ant t

o m

ake

a gl

obal

dat

abas

e of

the

stat

e of

pte

ropo

ds in

the

mod

ern

ocea

nD

o yo

u ha

ve:

• Pt

erop

od sa

mpl

es fr

om o

lder

co

llect

ions

?•

Pter

opod

sam

ples

from

upw

ellin

g zo

nes?

If so

, ple

ase

get i

n to

uch!

a b c

d e

Ack

now

ledg

emen

tsTh

e au

thor

s wou

ld li

ke to

than

k B

. M

arsh

all a

nd R

. Thu

nell

(USC

) for

sam

ples

fr

om th

e C

aria

co B

asin

, and

C. M

anno

, V.

Peck

and

G. T

arlin

g (B

AS)

for t

he A

rctic

an

d So

uthe

rn O

cean

sam

ples

.

Volu

me

Ana

lysi

s