Where does the escargot?
Tracking marine gastropod larvae using statolith
and protoconch
Danielle Zacherl
Department of Ecology, Evolution and Marine Biology
University of California
Santa Barbara, CA 93106
zacherl@lifesci.ucsb.edu
They move fast….really….
Oceanic transport?
Larvae settle elsewhere…..
“open population”
Planktonic veliger larvae hatch out
Larvae ‘settle’ onto benthic
habitat, metamorphose into
juveniles
“closed population”
Adult Kelletia kelletii lays
eggs at ‘natal’ reef
•Where do incoming larvae originate?
•What is the extent of connectivity between spatially
separated populations?
Otoliths as ‘recorders’ of elemental composition
Dissolved trace
elements
Larval uptake
Otolith
incorporation
CaCO3 + Ba2+  BaCO3+ Ca2+
Can invertebrate larval hard parts ‘record’
their source of production?
200 mm
Statolith and protoconch (larval shell) of veliger
Kelletia kelletii
10 mm
•Monterey Bay
100 Km
Extension
•Point Conception
Kelletia kelletii
Historic range
•Punta Eugenia
McAbee’s Beach
• Hopkins Marine Life Refuge (HMLR)
•Big Creek
HM LR
•Diablo Canyon
Jalama
Coho
Naples Reef
IV Reef
Big Creek
Diablo
Jalama
Coho
Naples
Isla Vista
•Pt. Loma
Pt Loma
La Bufadora
•La Bufadora
Punta San Carlos
0
0.2
0.4
0.6
0.8
# whelks/m2
1
1.2
1.4
•Punta San Carlos
50
HMLR (n=129)
25
0
50
Diablo Canyon (n=50)
25
0
50
Jalama (n=72)
25
% population
0
50
Coho (n=515)
25
50
0
Naples Reef (n=337)
25
0
50
IV Reef (n= 225)
25
0
50
Pt. Loma (n=487)
25
0
50
La Bufadora (n=361)
25
0
20 30 40 50 60 70 80 90 100 110 120
50
McAbee's Beach (n=87)
25
50
HMLR (n=38)
25
0
50
Diablo Canyon (n=52)
25
0
50
Jalama (n=66)
% population
25
0
50
Coho (n=406)
25
0
50
Naples Reef (n= 630)
25
0
50
IV Reef (n=230)
25
0
50
Pt. Loma (n=132)
25
0
50
La Bufadora (n=187)
25
0
20 30 40 50 60 70 80 90 100 110 120
?
•Monterey Bay
100 Km
•Point Conception
?
Relevant to:
•Population ecologists
•Biogeographers
•Introduced species experts
•Resource managers
•Punta Eugenia
Sea surface temperature (SST) – June 2001 (monthly composite)
Monthly mean seawater temperature (30 yr average)
at 10 m depth
Monterey
17
Big Sur
Diablo Canyon
Pt. Conception
Santa Barbara Channel N
Santa Barbara Channel S
16
15
14
San Diego
Baja Ca. N
13
12
11
Central Baja Ca.
JF MAM J JASO N D
10
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?
Is Ba concentration in protoconch and larval statolith influenced
by seawater temperature and Ba concentration?
1x
2x
4x
6x
Cold (11-12° C)
1x
2x
4x
6x
Warm (16.5-17.5° C)
Protoconch and statolith samples analyzed separately using ICP-MS
Ba incorporation into protoconch (larval shell)
Ba/Ca m mol/mol protoconch
25
20
Seawater X Temp
y = 1.1082x + 0.2218
R2 = 0.9999
P = 0.0021
15
11-12° C
16.5-17.5° C
10
y = 0.7585x + 1.3877
R2 = 0.9898
5
0
0
5
10
15
Ba/Ca m mol/mol seawater
20
Ba incorporation into larval statolith
Ba/Ca m mol/mol statolith
30
y = 1.4322x + 1.9066
R2 = 0.9966
25
Seawater X Temp
20
P = 0.0050
15
16.5 - 17.5°C
11 - 12°C
y = 1.2543x + 0.429
R2 = 0.9964
10
5
0
0
5
10
15
Ba/Ca m mol/mol seawater
20
•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?
Egg mass collection sites
•Monterey
Monterey (n=37)
Diablo (n=22)
•Diablo
Tajiguas (n=4)
Ellwood (n=27)
Cojo
(n=25)
...
•Isla
Isla Vista (n=21)
•Yellowbanks,
Yellowbanks, SCI (n=7)
Elements analyzed: Mg, Li, Sr, Pb, Mn, Cr,
Ce, Cd, U, Zn, Ba
Ce/Ca mmol/mol
Trace elemental composition of K. kelletii protoconchs
from two regions
Southern samples
Northern samples
•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
What next?
•Finer resolution?
•Temporal stability?
•Other species, other systems
Concholepas concholepas
~ 50 mm
Me/Ca in Concholepas concholepas
larval statoliths from two Chilean sites
Ba/Ca
Zn/Ca
5
80
4
60
3
40
2
20
1
0
0
Zn/Ca mmol/mol
Ba/Ca mmol/mol
100
Antofagasta Las Cruces
**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 Oceans
Lerner 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 Cudaback
Shane Anderson, Terry Marciando, Bob Warner
Is Ba concentration in protoconch and larval statolith influenced
by seawater temperature and Ba concentration?
1x 2x
4x
Cold (11-12° C)
6x
1x 2x
4x
6x
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)
(peroxide dissolution of organics)
Solution
ICP-MS
50 shells
(1 sample)
10 statoliths
(10 samples)
Laser
ICP-MS
Yes, but not entirely…..
Protoconch Ba/Ca mmol/mol
3.2
3
2.8
2.6
2.4
2.2
2
1.8
1.6
1.4
Subtidal seawater temperature
(14 m) during larval ‘hard part’ formation
18
16
Monterey
Diablo
Cojo
Ellwood
Ylbnks, SCI
14
°C
12
10
15
10
5
Days before collection
0
Sea surface temperature (SST) – July 2001 (monthly composite)
*