the biological response to in situ southern ocean iron fertilization. richard t. barber and sofex...
TRANSCRIPT
The biological response to in situ Southern Ocean iron fertilization.
Richard T. Barber
and SOFeX Team
SOFeX: Southern Ocean Iron Experiments, An Overview of the Biological Responses
Richard Barberand the SOFeX Group
Primary productivity, photosynthetic performance and quantum yield team on the three ships:
R/V Revelle: Barber, Lance, Stuebe
R/V Melville: Hilting, Hiscock, Apprill, Delizo, Tanner
USCG Polar Star: Van Hilst
FRRF data provided by Sasha Tozzi.
PAM data provided by Jill Peloquin.
POC flux data provided by Ken Buesseler.
North PatchTemp. 7.5ºC
Si(OH)4 2.0μMNO3 21μM +Fe 1.2nM
South PatchTemp. -0.5ºC Si(OH)4 63μM NO3 27μM+Fe 0.7nM
NP SP
Underway nutrients and temperature figure provided by W. T. Hiscock, U. Miami.
Sur
face
Chl
(m
g C
hl m
-3)
0
1
2
3
4
Year Day
20 25 30 35 40 45 50 55
SOFeX ProductivityDUKE - MBARI - VIMS - SIO
South Patch
Fertilization
Melville
Revelle
Polar Star
South Patch
Year Day
20 25 30 35 40 45 50 55
Pop
t (m
mol
C m
-3 d
-1)
0
1
2
3
4
SOFeX ProductivityDUKE - MBARI - VIMS - SIO
MelvilleRevelle
Fertilization
South In
0.5 1.0 1.5 2.0 2.5 3.0 3.5
South Out
Prim. Prod. GF/F (mmol C m -3 d-1 )
0.5 1.0 1.5 2.0 2.5 3.0
0
20
40
60
80
North Out
1 2 3 4 5 6 7
0204060
80100120140160
Initial "Pre" PP profileFinal "Out" PP profile
North In
1 2 3 4 5 6 7
Earliest "In" PP profileFinal "In" PP profile
Zm
orel (
m)
Zm
orel (
m)
South In
0.5 1.0 1.5 2.0 2.5 3.0
South Out
Prim. Prod. (mmol C m-3 d-1)
0.5 1.0 1.5 2.0 2.5 3.0
Zm
ore
l (m
)
0
20
40
60
80
North Out
Prim. Prod. (mmol C m-3 d-1)1 2 3 4 5 6 7
Zm
ore
l (m
)
0
20
40
60
80
100
120
140
160Initial "Pre" PP profileSubsequent "Out" PP profilesFinal "Out" PP profile
North In
1 2 3 4 5 6 7
Earliest "In" PP profileSubsequent "In" PP profilesFinal "In" PP profile
-169.7 -169.5 -169.3 -169.1-54.5
-54.4
-54.3
-54.2
-54.1
-54
0
0.04
0.08
0.12
0.16
0.2
0.24
0.28
0.32
0.36
Fe (nM )N o. Patch R evisit
-169.7 -169.5 -169.3 -169.1-54.5
-54.4
-54.3
-54.2
-54.1
-54
N orth Patch SF6Feb. 8-9
0.032
0.036
0.04
0.044
0.048
0.052
0.056
0.06
0.064
0.068
0.072
-169.7 -169.5 -169.3 -169.1-54.5
-54.4
-54.3
-54.2
-54.1
-54
2
4
6
8
10
12
14
16
C hloro. F luorN o. Patch R evisit
-169.7 -169.5 -169.3 -169.1-54.5
-54.4
-54.3
-54.2
-54.1
-54
6.55
6.65
6.75
6.85
6.95
7.05
O xygen (m l/L)
No. Patch revisit by Revelle.
SOFeX ProductivityDUKE - MBARI - VIMS - SIO
North Patch
Year Day
10 15 20 25 30 35 40 45 50
Sur
face
Chl
(m
g C
hl m
-3)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
MelvilleRevelleFertilization
North Patch
Year Day
10 15 20 25 30 35 40 45 50
Pop
t (m
mol
C m
-3 d
-1)
0
1
2
3
4
5
6
7
SOFeX ProductivityDUKE - MBARI - VIMS - SIO
MelvilleRevelle
Fertilization
Ed(
0- ) (m
ol q
ua
nta
m-2 d
-1)
0
10
20
30
40
50
60
Pri
m.
Pro
d.
to 1
% (
mm
ol C
m-2 d
-1)
0
20
40
60
80
100
120
140
Ed(
0- ) (m
ol q
ua
nta
m-2 d
-1)
0
10
20
30
40
50
60
Ch
l (m
g m-3
)
0
1
2
3
4
5
Ed(
0- ) (m
ol q
ua
nta
m-2 d
-1)
0
10
20
30
40
50
60
Pop
t (m
mo
l C
m-3 d
-1)
0
2
4
6
8
Ed(0-) at -54.0oS
Ed(0-) at -66.0oS
AESOPS 1997-1998
Chl
Popt
PP
Ed(
0- ) (m
ol qu
an
ta m-2
d-1)
0
10
20
30
40
50
60
Prim
. P
rod
. to
1%
(m
mo
l C
m-2 d
-1)
0
20
40
60
80
100
120
140
Ed(
0- ) (m
ol qu
an
ta m-2
d-1)
0
10
20
30
40
50
60
Ch
l (m
g m
-3)
0
1
2
3
4
5
Ed(0
- ) (m
ol qu
an
ta m-2
d-1)
0
10
20
30
40
50
60
Po
pt (
mm
ol C
m-3 d
-1)
0
2
4
6
8
Ed(0-) at -54.0oS
Ed(0-) at -66.0oS
AESOPS 1997-1998SOFeX North OutSOFeX South Out
A
B
C
Ed(0
- ) (m
ol quanta
m-2 d
-1)
0
10
20
30
40
50
60
Prim
. P
rod
. to
1%
(m
mo
l C
m-2 d
-1)
0
20
40
60
80
100
120
140
Ed(0
- ) (m
ol quanta
m-2 d
-1)
0
10
20
30
40
50
60
Chl (m
g m-3
)
0
1
2
3
4
5
Ed(0
- ) (m
ol quanta
m-2 d
-1)
0
10
20
30
40
50
60
Po
pt (
mm
ol C
m-3 d
-1)
0
2
4
6
8
Ed(0-) at -54.0oS
Ed(0-) at -66.0oS
AESOPS 1997-1998SOFeX North OutSOFeX South OutSOFeX North InSOFeX South In
A
B
C
Weeks Post First Fertilization
1 2 3
Bin
ned
Int
PP
(m
mol
C m
-2 d
-1)
10
20
30
40Out 10%In 10%
50m flux
Weeks post 1st Iron addition
PO
C F
lux
(mM
C m
-2 d
-1)
0
2
4
6
8
10
12
14
16
18
INOUT
1 2 3 4
100m flux
Weeks post 1st Iron addition
PO
C F
lux
(mM
C m
-2 d
-1)
0
2
4
6
8
10
12
14
16
18
1 2 3 4
50m
Weeks Post Fertilization
1 2 30
20
40
60
80
Out Flux/Out PPIn Flux/In PP
100m
Weeks Post First Fertilization
1 2 30
20
40
60
80
% o
f In
teg
rate
d P
rim
. P
rod
. a
s P
OC
Flu
x South Patch (10% PP)
South Patch (10% PP)
Out In
m, m
ol C
(m
ol p
hoto
ns)-1
0.00
0.01
0.02
0.03
0.04
Melville: South GF/F
SOFeX 1° ProductivityDuke MBARI VIMS SIO
Out In Out In
m, m
ol C
(m
ol p
hoto
ns)-1
0.00
0.01
0.02
0.03
0.04GF/F 5 m 20 m
PAR (mol photons m-2 s-1)
10 100 1000
Qua
ntum
Yie
ld (
mol
C /
mol
pho
tons
)
0.000
0.005
0.010
0.015
0.020
0.025
0.030
0.035
Iron additionControl
Time elasped since first Fe enrichment (hours)
0 50 100 150 200 250 300
Fv/
Fm
0.30
0.35
0.40
0.45
0.50
0.55
0.60
PAM- bulk assemblage for South Patch, bars are iron additions, circled data are OUTs. Cells never reached photochemical maximum for 20 m water for PAM (0.70).
Outs
SOFeX and IronEx Fv/Fm's
Patch Day-3 0 3 6 9 12
Fv/
Fm
0.2
0.3
0.4
0.5
0.6
IronExI IronExII SOFeX NI SOFeX SI
South
10 15 20 25 30 35 40 45 50
1
2
3
4
<20m>20m
Ch
l (m
g m
-3) 0.5
1.0
1.5
2.0
2.5 North
Year Day
<20m>20m
South
Year Day
10 15 20 25 30 35 40 45 50
1
2
3
4
Ch
l (m
g m
-3) 0.5
1.0
1.5
2.0
2.5 North<5m
>5m
<5m
>5m
Results
• 10x increase in Chl in both N and S patch• 10x increase in productivity (Popt) in both N and S patch• 3 to 4x increase in integrated primary productivity• 3 to 4x increase in quantum yield in South patch, but
no differential enhancement of quantum yield in large (> 20 μm) phytoplankton
• Big change in size composition in N patch despite low Si conditions, but only modest change in size composition in S patch with high Si conditions
• In patch POC flux about 30% of In patch PP integrated to 10% light level; Out flux about 40% of Out PP integrated to 10% light level
Remaining Questions
1. Depth of export
2. Fate of exported organic carbon at depth
3. Cellular mechanism of “fast” photosynthetic efficiency response to Fe
4. Nature of temperature vs. photosynthetic efficiency relationship
North Patch
Year Day
10 15 20 25 30 35 40 45 50
%P
opt
>20
m
0
10
20
30
40
SOFeX ProductivityDUKE - MBARI - VIMS - SIO
MelvilleRevelle
Fertilization
South Patch
Year Day
20 25 30 35 40 45 50 55
% P
opt
>20
μm
0
10
20
30
40
50
60
70
80
SOFeX ProductivityDUKE - MBARI - VIMS - SIO
MelvilleRevelle
Fertilization
South In
1 2 3 4 5 6 7
South Out
1 2 3 4 5 6 7
Zm
ore
l (m
)
0
20
40
60
80
North Out
1 2 3 4 5 6 7
Zm
ore
l (m
)
0
20
40
60
80
100
120
140
160
Initial "Pre" PP profileFinal "Out" PP profile
North In
1 2 3 4 5 6 7
Earliest "In" PP profileFinal "In" PP profile
Prim Prod (mmol C m-3 d-1)