calcification and transparent exopolymer particles (tep) production in batch cultures of emiliania...
TRANSCRIPT
Calcification and transparent exopolymer particles (TEP) production in batch
cultures of Emiliania huxleyi exposed to different pCO2
Caroline De Bodt, Quentin d’Hoop, Jérôme Harlay
and Lei Chou
Core theme IVBiogeochemical feedbacks on the oceanic carbon sinks
2nd annual CarboOcean meeting
Outline of the presentation
- Introduction- Description of the experiment- Results of chl a, calcification and TEP for
the 3 cultures- Calcification in relation to the Ωcalcite
- Correlation between TEP, particulate organic and inorganic carbon
- Conclusions
Outline of the presentation
- Introduction- Description of the experiment- Results of chl a, calcification and TEP for
the 3 cultures- Calcification in relation to the Ωcalcite
- Correlation between TEP, particulate organic and inorganic carbon
- Conclusions
Outline of the presentation
- Introduction- Description of the experiment- Results of chl a, calcification and TEP for
the 3 cultures- Calcification in relation to the Ωcalcite
- Correlation between TEP, particulate organic and inorganic carbon
- Conclusions
Outline of the presentation
- Introduction- Description of the experiment- Results of chl a, calcification and TEP for
the 3 cultures- Calcification in relation to the Ωcalcite
- Correlation between TEP, particulate organic and inorganic carbon
- Conclusions
Outline of the presentation
- Introduction- Description of the experiment- Results of chl a, calcification and TEP for
the 3 cultures- Calcification in relation to the Ωcalcite
- Correlation between TEP, particulate organic and inorganic carbon
- Conclusions
Outline of the presentation
- Introduction- Description of the experiment- Results of chl a, calcification and TEP for
the 3 cultures- Calcification in relation to the Ωcalcite
- Correlation between TEP, particulate organic and inorganic carbon
- Conclusions
The coccolithophore E.huxleyi
http://www.soes.soton.ac.uk/staff/tt/
(Engel et al., 2004a)
-- Photosynthesis: sink for CO2
106CO2 ↓ + 16NO3
- + H2PO4
- + 17H
+ +
122H2O
↔ (CH2O)106(NH3)16H3PO4 + 138O2
-- Calcification: source of CO2
CaCa2+2+
+ 2HCO + 2HCO33-- ↔ CaCO3 + CO2↑ + H2O
- Extracellular release (Transparent exopolymer particles, TEP)
Description of the Experiment
- Cultures were grown in filtered seawater enriched with NO3 and PO4
- Irradiance : 150 µmol m-2 s-1
- Temperature : 13°C- Light/Dark cycle : 14h/10h
Culture 1 Culture 2 Culture 3
Vol. batch reactor (L)
2 8 8
Initial pCO2 (µatm)
490 630 930
Measured parameters
- pH- Total alkalinity- Nutrient concentrations (NO3 and PO4)
- Chlorophyll a- TEP - POC
pCO2, Ωcalcite
Evolution of the pCO2
0
100
200
300
400
500
600
700
0 10 20 30 40 50 60
day
pC
O2
(µa
tm)
Results
0
5
10
15
20
25
30
35
40
0 10 20 30 40 50 60
day
Ch
loro
ph
yll a
(µ
g L
-1)
490 µatm 630 µatm 930 µatm
Results
0
5
10
15
20
25
30
35
40
0 10 20 30 40 50 60
day
Ch
loro
ph
yll a
(µ
g L
-1)
490 µatm 630 µatm 930 µatm
0
1
2
3
4
5
6
7
8
9
0 10 20 30 40 50 60
day
E.huxleyi
(x 1
05 ce
ll m
l-1)
Results
-10
0
10
20
30
40
50
60
70
80
0 10 20 30 40 50 60
day
Cu
mu
lati
ve
Ca
CO
3 (m
g k
g-1
)
0
5
10
15
20
25
30
35
40
0 10 20 30 40 50 60
day
Ch
loro
ph
yll a
(µ
g L
-1)
490 µatm 630 µatm 930 µatm
0
1
2
3
4
5
6
7
8
9
0 10 20 30 40 50 60
day
E.huxleyi
(x 1
05 ce
ll m
l-1)
Results
-10
0
10
20
30
40
50
60
70
80
0 10 20 30 40 50 60
day
Cu
mu
lati
ve
Ca
CO
3 (m
g k
g-1
)
0
1000
2000
3000
4000
5000
6000
7000
0 10 20 30 40 50 60
day
TE
P (
µg
L-1
Xa
nth
an
eq
uiv
)
0
5
10
15
20
25
30
35
40
0 10 20 30 40 50 60
day
Ch
loro
ph
yll a
(µ
g L
-1)
490 µatm 630 µatm 930 µatm
0
1
2
3
4
5
6
7
8
9
0 10 20 30 40 50 60
day
E.huxleyi
(x 1
05 ce
ll m
l-1)
Results
-10
0
10
20
30
40
50
60
70
80
0 10 20 30 40 50 60
day
Cu
mu
lati
ve
Ca
CO
3 (m
g k
g-1
)
0
1000
2000
3000
4000
5000
6000
7000
0 10 20 30 40 50 60
day
TE
P (
µg
L-1
Xa
nth
an
eq
uiv
)
0
5
10
15
20
25
30
35
40
0 10 20 30 40 50 60
day
Ch
loro
ph
yll a
(µ
g L
-1)
490 µatm 630 µatm 930 µatm
0
1
2
3
4
5
6
7
8
9
0 10 20 30 40 50 60
day
E.huxleyi
(x 1
05 ce
ll m
l-1)
Link between calcification and Ωcalcite
CaCa2+ 2+
(aq) + CO(aq) + CO332-2- (aq) (aq) ↔ CaCO3
(s)
- Saturation state with respect to calcite:
'
23
2
sp
COCacal
K
mm
> 1 precipitation
< 1 dissolution
Link between calcification and Ωcalcite
CaCa2+ 2+
(aq) + CO(aq) + CO332-2- (aq) (aq) ↔ CaCO3
(s)
- Saturation state with respect to calcite:
'
23
2
sp
COCacal
K
mm
> 1 precipitation
< 1 dissolution
-10
0
10
20
30
40
50
60
70
0 10 20 30 40 50 60
day
Cu
mu
lati
ve C
aCO
3 (
mg
kg
-1)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
0 10 20 30 40 50 60
day
CaC
O3 s
atu
rati
on
sat
e
Link between calcification and Ωcalcite
Key value : Ωcalcite = 3
Culture 1 Culture 2 Culture 3
0
2
4
6
8
10
0 1 2 3 4
CaCO3 saturation state
0
2
4
6
8
10
0 1 2 3 4
0
2
4
6
8
10
0 1 2 3 4
Cal
cifi
cati
on
(m
g C
aCO
3 k
g-1
j-1
)
0
2
4
6
8
10
0 1 2 3 4
CaCO3 saturation state
C
alci
fica
tio
n
(mg
CaC
O3
kg-1
j-1
)
0
2
4
6
8
10
0 1 2 3 4
0
2
4
6
8
10
0 1 2 3 4
CaCO3 saturation state
Correlation between TEP and POC
- During the exponential growth phase, POC concentration increases linearly with chlorophyll a.
- After nutrient exhaustion, TEP continue to be produced and contribute to POC increase by 61%.
in the exponential growth phase
y = 0.072x + 0.051
R2 = 0.985
0123456789
0 10 20 30 40
chorophyll a (µg L-1)
PO
C (
mg
L-1
)
after nutrients exhaustion
y = 0.001x + 0.481
R2 = 0.698
0123456789
0 2000 4000 6000 8000 10000
TEP (µg L-1 xanthan equiv.)
PO
C (
mg
L-1
)
TEP production is strongly correlated with CaCO3 concentrations. → Calcification may be considered as a source of TEP.
Correlation between TEP and CaCO3
y = 61.239x + 513.373
R2 = 0.903
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
0 20 40 60 80
Cumulative CaCO3 (mg kg-1)
TE
P (
µg
L-1
xa
nth
an
eq
uiv
.)
omega calcite > 1
omega calcite < 1
Conclusions
- E. huxleyi is sensitive to pCO2
Conclusions
- E. huxleyi is sensitive to pCO2
- TEP concentrations continue to increase after the decline in E. huxleyi growth
Conclusions
- E. huxleyi is sensitive to pCO2
- TEP concentrations continue to increase after the decline in E. huxleyi growth
- Very good correlation between TEP and calcite production
Conclusions
- E. huxleyi is sensitive to pCO2
- TEP concentrations continue to increase after the decline in E. huxleyi growth
- Very good correlation between TEP and calcite production
- key value of 3 for the Ωcalcite
Thank you for your attention
This study was partially supported by the PEACE project,
funded the Belgian Science Policy Office.