romberg tiburon center – san francisco state …...egg production (a), hatching success (b), and...
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INTRODUCTION
EFFECT OF OCEAN ACIDIFICATION ON THE NUTRITIONAL QUALITY OF PHYTOPLANKTON FOR COPEPOD REPRODUCTION
Morgan Meyers1*, William Cochlan1, Wim Kimmerer1, Ed Carpenter1
1Romberg Tiburon Center – San Francisco State University
METHODS
400 ppm CO2 air RHO SKE PRO ISO media
reservoir
fatty acid content
egg production
hatching success
naupliarsurvival
n=50 +
ASSESS COPEPOD REPRODUCTION
3 FEED COPEPODS2
Phytoplankton are the oceans’ primary producers of polyunsaturated fatty acids (PUFA), some of which are considered essential fatty acids (EFA) because animals cannot synthesize them de novo. These EFA support the health and reproduction of heterotrophic marine organisms at higher trophic levels. It is hypothesized that future ocean acidification (OA) conditions due to increased pCO2 could change the availability of phytoplankton PUFAs for ecologically significant consumers such as copepods, affecting their reproductive success in an increasingly acidified environment1.
RESEARCH QUESTIONS:
I. Does high pCO2 change the fatty acid composition of phytoplankton? II. Does this change in dietary phytoplankton fatty acid composition affect copepod reproductive success?
1 CULTURE PHYTOPLANKTON
*Contact presenting author at [email protected]
5A
1000 ppm CO2 air RHO SKE PRO ISO media
reservoir
400ppm phytoplankton
mixture
n=50 +
400ppm phytoplankton
mixture
Rhodomonas salina (RHO)Skeletonema marinoi (SKE)Prorocentrum micans (PRO)Isochrysis galbana (ISO)
RESULTS
CONCLUSIONSI. High pCO2 affects the FA composition of phytoplankton - Effect is species-dependent - EFA contents of cryptophytes (R. salina) and diatoms (S. marinoi) are more susceptible than dinoflagellates (P. micans) and haptophytes (I. glabana)
II. Feeding on a high pCO2 diet impacts copepod reproductive success - Some parameters are more sensitive to dietary changes than others - Differences in reproductive success could also be attributed to changes in feeding selectivity, sampled copepod population, and time of year
These results show the potential for future OA conditions to alter the EFA content of phytoplankton and affect the productivity of subsequent trophic levels.
0
20
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60
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400 1000 400 1000 400 1000
RHO SKE PRO
TOTA
L FA
TTY
ACID
PER
CEL
L (%)
Figure 1. December 2014 – Relative (A) and absolute (B) total fatty acid content in R. salina (RHO), S. marinoi (SKE), and P. micans (PRO) under low (400) and high (1000) pCO2 treatments.
0.000
0.004
0.008
0.012
0.016
0.020
400 1000
RHO
TOTA
L FA
TTY
ACID
PER
CEL
L (n
g)
0.000
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0.001
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400 1000
SKE
0.000
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PRO
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RHO SKE PRO
EFA
PER
CELL
(%)
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0.001
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400 1000
RHO
EFA
PER
CELL
(ng)
0
0.0001
0.0002
0.0003
0.0004
0.0005
400 1000
SKE
0
0.012
0.024
0.036
0.048
0.06
400 1000
PRO
1A 1B
2A 2B
Figure 2. December 2014 – Relative (A) and absolute (B) EFA content in R. salina (RHO), S. marinoi (SKE), and P. micans (PRO) under low (400) and high (1000) pCO2 treatments.
0
20
40
60
80
100
400 1000 400 1000 400 1000 400 1000
RHO SKE PRO ISO
TOTA
L FA
TTY
ACID
PER
CEL
L (%
)
Figure 3. June 2015 -Relative (A) and absolute (B) total fatty acid content in R. salina (RHO), S. marinoi (SKE), P. micans (PRO), and I. galbana (ISO) under low (400) and high (1000) pCO2 treatments.
0
0.05
0.1
0.15
0.2
0.25
400 1000
RHO
TOTA
L FA
TTY
ACID
PER
CEL
L (n
g)
0
0.005
0.01
0.015
0.02
0.025
400 1000
SKE
0
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400 1000
PRO
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0.006
0.012
0.018
0.024
0.03
400 1000
ISO
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400 1000 400 1000 400 1000 400 1000
RHO SKE PRO ISO
EFA
PER
CELL
(%)
0
0.01
0.02
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400 1000
RHO
EFA
PER
CELL
(ng)
0
0.0008
0.0016
0.0024
0.0032
0.004
400 1000
SKE
0
0.4
0.8
1.2
1.6
2
400 1000
PRO
3A 3B
4A 4B
0
0.00025
0.0005
0.00075
0.001
0.00125
400 1000
ISO
Figure 4. June 2015 -Relative (A) and absolute (B) EFA content in R. salina (RHO), S. marinoi (SKE), P. micans (PRO), and I. galbana (ISO) under low (400) and high (1000) pCO2 treatments.
0
10
20
30
40
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60
EGG
S PR
OD
UCE
D P
ER F
EMAL
E
Dec. 2014 June 2015
Median
0
20
40
60
80
100
% E
GG
S H
ATCH
ED P
ER F
EMAL
E
Dec. 2014 June 2015
0
20
40
60
80
100
% N
AUPL
IAR
SURV
IVAL
PER
FEM
ALE
400ppm 1000ppm
Dec. 2014 June 2015
Poisson regression odds ratios
June = 0.45 (95% CI 0.36, 0.56)
Dec. = 0.61 (95% CI 0.47, 0.79)
Logistic regression odds ratios
June = 0.55 (95% CI 0.42, 0.77)
Dec. = 0.02 (95% CI 0.01, 0.05)
Logistic regression odds ratios
June = 0.15 (95% CI 0.08, 0.27)
Dec. = 0.01 (95% CI 0.00, 0.04)
5A 5B
5C Figure 5. Egg production (A), hatching success (B), and naupliar survival (C) per female in December 2014 and June 2015 after being fed phytoplankton from either the low pCO2 treatment (black) or the high pCO2 treatment (gray). Each circle represents an individual female copepod. Error bars show Interquartile range.
Polyunsaturated FA (PUFA)
Monounsaturated FA (MUFA)
Saturated FA (SFA) Eicosapentaenoic acid (EPA) [20:5n-3]
Stearidonic acid (SDA) [18:4n-3]
Gamma-linolenic acid (GLA) [18:3n-6]
Docosahexaenoic acid (DHA) [22:6n-3]EFA
ACKNOWLEDGEMENTSI acknowledge the support I have received from Dr. Rodger Harvey (Old Dominion University), Dr. Anne Todgham, the Carpenter Lab, the Wilkerson/Dugdale Lab, the Cochlan Lab, Anne Slaughter, Toni Ignoffo, and RTC facilities. Partial funding was provided by the CSU Council on Ocean Affairs, Science and Technology (COAST) Graduate Research Award.
REFERENCES1. Rossoll D, Bermudez R, Hauss H, Schulz K, Riebesell U, Sommer U, Winder M. (2012) Ocean acidification-induced food quality deterioration constrains trophic transfer. PLoS ONE 7(4): e34737. doi:10.1371/journal.pone.0034737
CONTACTMorgan Meyers, MSc candidate(715) 220-1374 [email protected]
Carpenter LabRomberg Tiburon Center3150 Paradise Dr.Tiburon, CA 94920(415) 338-3756