Where does the escargot? Tracking marine gastropod larvae using statolith
and protoconch
Danielle ZacherlDepartment of Ecology, Evolution and Marine Biology
University of CaliforniaSanta Barbara, CA 93106
They move fast….really….
Adult Kelletia kelletii lays eggs at ‘natal’ reef
Planktonic veliger larvae hatch out
Oceanic transport?
Larvae ‘settle’ onto benthic habitat, metamorphose intojuveniles
“closed population”
Larvae settle elsewhere…..
“open population”
•Where do incoming larvae originate? •What is the extent of connectivity between spatially separated populations?
Dissolved trace elements
Larval uptake Otolith incorporation
Otoliths as ‘recorders’ of elemental composition
CaCO3 + Ba2+ BaCO3+ Ca2+
10 m200 m
Statolith and protoconch (larval shell) of veliger Kelletia kelletii
Can invertebrate larval hard parts ‘record’ their source of production?
•Point Conception
•Monterey Bay
•Punta Eugenia
Historic range
Extension
Kelletia kelletii
100 Km
• Hopkins Marine Life Refuge (HMLR)McAbee’s Beach
•Diablo Canyon
•Big Creek
JalamaCoho
IV ReefNaples Reef
•Pt. Loma
•La Bufadora
•Punta San Carlos # whelks/m2
0 0.2 0.4 0.6 0.8 1 1.2 1.4
HMLR
Big Creek
Diablo
Jalama
Coho
Naples
Isla Vista
Pt Loma
La Bufadora
Punta San Carlos
0
25
50
0
25
50
% p
opul
atio
n
0
25
50
20 30 40 50 60 70 80 90 100 110 1200
25
50La Bufadora (n=361)
0
25
50
0
25
50
0
25
500
25
50
HMLR (n=129)
Diablo Canyon (n=50)
Jalama (n=72)
Coho (n=515)
Naples Reef (n=337)
IV Reef (n= 225)
Pt. Loma (n=487)
25
50
0
25
50
0
25
50
0
25
50
0
25
50
% p
opul
atio
n
0
25
50
0
25
50
0
25
50
20 30 40 50 60 70 80 90 100 110 1200
25
50
McAbee's Beach (n=87)
HMLR (n=38)
Diablo Canyon (n=52)
Jalama (n=66)
Coho (n=406)
Naples Reef (n= 630)
IV Reef (n=230)
Pt. Loma (n=132)
La Bufadora (n=187)
•Point Conception
•Monterey Bay
•Punta Eugenia
100 Km?
?
Relevant to:•Population ecologists •Biogeographers•Introduced species experts•Resource managers
Sea surface temperature (SST) – June 2001 (monthly composite)
J F M A M J J A S O N D
Monthly mean seawater temperature (30 yr average) at 10 m depth
Baja Ca. N
San Diego
Santa Barbara Channel SSanta Barbara Channel N
Pt. Conception
Diablo Canyon
Big Sur
Monterey
Central Baja Ca. 10
11
12
13
14
15
16
17
How does this affect metal (Me) incorporation?
•Upwelled water is Me rich, Me conc. can affect incorporation
•Upwelled water is cold, temperature can affect Me incorporation
•Do differences in Barium (Ba) concentration in seawater and temperature affect the Ba signal in larval hard parts?
•Are Kelletia kelletii larval hard parts produced north of Point Conception chemically distinguishable from those produced in the Santa Barbara Channel?
•Do differences in Barium (Ba) concentration in seawater and temperature affect the Ba signal in larval hard parts?
Is Ba concentration in protoconch and larval statolith influenced by seawater temperature and Ba concentration?
1x 2x 4x 6x 1x 2x 4x 6x
Cold (11-12° C) Warm (16.5-17.5° C)
Protoconch and statolith samples analyzed separately using ICP-MS
Ba incorporation into protoconch (larval shell)
0
5
10
15
20
25
0 5 10 15 20
Ba/Ca mol/mol seawater
Ba/
Ca
m
ol/m
ol p
roto
con
ch
11-12° C16.5-17.5° C
y = 1.1082x + 0.2218
R2 = 0.9999
y = 0.7585x + 1.3877
R2 = 0.9898
Seawater X Temp
P = 0.0021
Ba incorporation into larval statolith
Seawater X Temp
P = 0.0050
0
5
10
15
20
25
30
0 5 10 15 20
Ba/Ca mol/mol seawater
Ba/
Ca
mol
/mol
sta
toli
th
16.5 - 17.5°C
11 - 12°C
y = 1.4322x + 1.9066
R2 = 0.9966
y = 1.2543x + 0.429
R2 = 0.9964
•Do differences in Ba concentration in seawater and
temperature affect the Ba signal in larval hard parts?
•YES! Ba incorporation increases with increasing Ba SW concentration
•Effect is greater at colder seawater temperatures
•Are Kelletia kelletii larval hard parts produced north of Point
Conception chemically distinguishable from those produced in the
Santa Barbara Channel?
•Do differences in trace metal concentration in seawater and temperature affect the elemental signal in larval hard parts?
•Are Kelletia kelletii larval hard parts produced north of Point Conception chemically distinguishable from those produced in the Santa Barbara Channel?
•Isla Vista (n=21)
Ellwood (n=27)Tajiguas (n=4)
Cojo(n=25)
•Diablo (n=22)
•Monterey (n=37)
•Yellowbanks, SCI (n=7)
Egg mass collection sites
...
Monterey (n=37)
Diablo (n=22)
Tajiguas (n=4)Ellwood (n=27)
Isla Vista (n=21)
Yellowbanks, SCI (n=7)
Elements analyzed: Mg, Li, Sr, Pb, Mn, Cr, Ce, Cd, U, Zn, Ba
Cojo(n=25)
QuickTime™ and aGraphics decompressorare needed to see this picture.
Ba/Ca mol/mol Mg/Ca mmol/mol
Ce/
Ca m
ol/m
ol
Southern samples
Northern samples
Trace elemental composition of K. kelletii protoconchs from two regions
•Using all 11 elements-Canonical Discriminant Analysis shows significant site discrimination (p<.0001)•Serial deletion validation predicts 89% correct, 93% in northern region
•Do differences in trace metal concentration in seawater and
temperature affect the elemental signal in larval hard parts?
•Are Kelletia kelletii larval hard parts produced north of Point
Conception chemically distinguishable from those produced in the
Santa Barbara Channel?
• Yes!
Invertebrate larvae can be ‘naturally’ tagged at their origin
•Finer resolution?
What next?
•Temporal stability?
•Other species, other systems
~ 50 mm
Concholepas concholepas
0
20
40
60
80
100
Antofagasta Las Cruces0
1
2
3
4
5Ba/CaZn/Ca
Ba/
Ca m
ol/m
ol
Zn/
Ca
mm
ol/m
ol
Me/Ca in Concholepas concholepas larval statoliths from two Chilean sites
**Data above generated in collaboration with Juan Carlos Castilla and Patricio Manriquez of Pontificia Universidad Católica de Chile
Acknowledgements
Most especially: Steve Gaines, Steve Swearer, David Lea, Georges Paradis
Financial support: Partnership for Interdisciplinary Studies of Coastal OceansLerner Grey Foundation, Sigma Xi
A league of dive buddies and lab helpers: Steve Lonhart, Chris Faist, Brian Cheng, Alison Haupt, Sarah Kleinshmidt, Jessica Van Leuven, Marina Salonga,
Andrea Hsu, Bryce Wolcott,Alex Pappas, Elsie Tanadjaja, Clara Svedlund, Tiffany Jenkins,Catrina Mangiardi, Alex Wyndham, Ben and Stephanie Best,
Eric Hessel, Mike Hickford, Mauricio Gomez, Mike Behrens
Understanding friends: Rafe Sagarin, P McConnell, Ben Heying, Zorba the cat
Godlike others: Chris Gotshalk, Jenn Caselle, Dotti Pak, Cynthia CudabackShane Anderson, Terry Marciando, Bob Warner
Is Ba concentration in protoconch and larval statolith influenced by seawater temperature and Ba concentration?
1x 2x 4x 6x 1x 2x 4x 6x
Cold (11-12° C) Warm (16.5-17.5° C)
•Egg masses collected, inspected, and randomly assigned to treatment•Three replicates per treatment•Cultures changed every other day•Maintained through maturity•Frozen storage
Egg capsule (~800 larvae each)
50 shells(1 sample)
10 statoliths(10 samples)
Solution ICP-MS
Laser ICP-MS
(peroxide dissolution of organics)
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
3
3.2
Yellow
banks,
SCI
Isla
Vist
a
Ellwoo
d
Tajig
uas
Cojo
Diablo
Can
yon
Mon
terey
Pro
toco
nch
Ba/
Ca
mol
/mol
Yes, but not entirely…..
10
12
14
16
18
051015
Monterey
Diablo
Cojo
Ellwood
Ylbnks, SCI
Days before collection
° C
Subtidal seawater temperature (14 m) during larval ‘hard part’ formation
Sea surface temperature (SST) – July 2001 (monthly composite)
*