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Co-Limitation of Phytoplanktonby Light and Multiple Nutrients
Hein de Baar, Klaas Timmermans, Loes Gerringa, Erik Buitenhuis, Patrick Laan;
Christiane Lancelot, Olivier Aumont, Geraldine Sarthou, Andy Bowie, Stephane Blain, Paul Worsfold
and many others in European research teams of MERLIM, CARUSO, IRONAGES
Koninklijk Nederlands Instituut voor Onderzoek der ZeeRoyal Netherlands Institute for Sea Research
Europese UnieEuropean Union
Contents
• Building Blocks for Life• Concepts of Limitation• Observations in the Sea• Growth Experiments• Ironages• GEOTRACES (GEOSECS II)• Summary
Abundance of Chemical Elements
HeO
Mg
O
-3
-2
-1
0
1
2
3
4
5
6
7
8
9
10
11
0 10 20 30 40 50 60 70 80 90 100
Ar
Ti
Cr
UTh
H
He
Li
Be
B
C
N
F
NeSi
S
Ca
Fe
Ni
ZnMn
CoCu
Ag
CdHg
Pb
Mg
NaAl
PCl
10 L
og(A
bund
ance
)
Atomic Number
O
Major Bio-ElementsAbundances versus one million Si atoms
• Carbon• Nitrogen• Silicon• Phosphor
us• Iron
• 10 x 106
• 3 x 106
• 1 x 106
• 1 x 104
• 0.9 x 106
Metals Abundance & Biological Evolution
Evolution used abundant metals: essentialLow abundant metals no bio-functions: toxic
Pb315
Hg0.34
Cd ?1.61
Ag0.49
Zn1260
Cu522
Ni49300
Co2250
Fe900000
Mn9550
numbers of atoms versus 1 million Si atoms
Photosynthetic Oxygen Captured in Iron Formations
0
1
2
3
4
5
6
7
3.8 3.3 2.8 2.3 1.8 1.3 0.8 0.3
Time before present [Gyrs = 109 years]
1017
kg
Fe2O3 formed
4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0
4 Fe(II)dissolved + 3 O2 2 (Fe2O3)deposit
oxygen in the air
photosynthesisDumb algaetook away
theirown iron supply
2. Concepts of limitation [nutrient]------- = ----------------------------max ( Knutrient + [nutrient] )
Michaelis, M. & Menten, M.L. (1913) Kinetics of invertase action. Zeitschrift f. Biochemie, 49, 333.Monod, J. (1942) Recherches sur la croissance des cultures bacteriennes. Paris, Herrmann. Emiliania huxleyi
in pristine natural seawater
driven into iron limitation by siderophore addition
Timmermans et al., in prep.
Multiple Limitations in Real Ocean
• Caveats– static (steady state) equation applied to
dynamic wax and wane of plankton blooms– limitations presumed independent while within
living cell they are all interacting
de Baar and Boyd (2000) JGOFS Midterm Synthesis Book
[N] [P] [Fe] [Si]----- = {(1-exp(aI/Kmax)}{-----------}{----------}{------------}{-----------} max (KN+ [N]) (KP+[P]) (KFe+[Fe]) (KSi+[Si])
growth light nitrate phosphate iron silicategrowth light nitrate phosphate iron silicate
Moreover terms for Mn, Cu, Zn, Co to be included as well !?
Some examples of interactions
within the plant cell
• Iron-light co-limitation– electron transfer in photosystems
• Iron essential for nitrate uptake– nitrate reductase, nitrite
reductase
• Zinc - bicarbonate co-limitation– carbonic anhydrase
3. Observations in the Sea
• Zn and silicate• Cd and phosphate• Cu and Ag and silicate• Fractionations Zn/Cd and Cu/Ag• Anomalies of major nutrients
Zinc resembles SilicateD
epth
[m
] Zn [nM]
North PacificOcean(33°N, 145°W)
Bruland (1980)-5000
-4500
-4000
-3500
-3000
-2500
-2000
-1500
-1000
-500
00 2 4 6 8 10
Zn [nM]
0.053 Si [uM]
Cadmium resembles PhosphateCd [nM]
Dep
th [
m]
North PacificOcean(33°N, 145°W)
Bruland (1980)-5000
-4500
-4000
-3500
-3000
-2500
-2000
-1500
-1000
-500
00 0.2 0.4 0.6 0.8 1 1.2
Cd [nM]0.331 PO4
Improved accuracy of both Cd and PO4 is crucial for further progress
Loscher, vander Meer, de Baar, Saager, de Jong (1998) The global Cd/phosphate relationship in deep ocean waters and the need for accuracy. Mar Chem., 59, 87-93
Global Cd/phosphate dataset for waters >1000m depth.
Open circles deBaar et al. (1994);
Filled circles new data Loscher etal (1998).
Biological function for Cd after all
• Replacement of Zn by Cd in marine phytoplankton. Lee and Morel, Mar.Ecol.Prog.Ser., 127, 305-309, 1995
• A biological function for Cd in marine diatoms. Lane and Morel, Proc. Nat.Acad.Sci., 97, 4627-463, 2000
Pb315
Hg0.34
Cd ?1.61
Ag0.49
Zn1260
Cu522
Ni49300
Co2250
Fe900000
Mn9550
carbonicanhydrase
join theGreenParty
Silver (Ag) resembles Copper (Cu)
North PacificOcean(18°N, 108°W)
Martin et al. (1983)-1000
-900
-800
-700
-600
-500
-400
-300
-200
-100
00 1 2 3 4 5 6 7 8 9 10 11 12
Ag [pM] or tenfold Cu [nM]
Dep
th [
m]
10 x Cu [nM]Ag [pM]
Ag has better correlation with Si
Zhang, Amakawa & Nozaki (2001) Mar. Chem., 75, 151
Worldwide correlation Ag and Si
Zhang, Amakawa & Nozaki (2001) Mar. Chem., 75, 151
Ag/Si ratio increases from~1.2 10-6 in Atlanticto~2.7 10-6 in Pacific
Fractionations Cu/Ag and Zn/Cd
Periodic Table Group 1b Group 2b
Cu /Ag Zn / Cd
Crustal abundance ratio ~1060~780
Oceanic waters ratio ~8 + 3~91
Fractionation factor ~130~8.6
Pb315
Hg0.34
Cd ?1.61
Ag0.49
Zn1260
Cu522
Ni49300
Co2250
Fe900000
Mn9550
First row ‘real biometals’ have shorter ocean residence time than second row ‘abiotic’ metals
(Also differences inorganic speciation)
Nutrient anomalies Fragilariopsis kerguelensis blooms
Deep Sea Research II, 44, 229-260 (1997)
anomalous slope
Fragilariopsis kerguelensis with heavily silicified armor ‘pantzer’
More Fe co-limitations major nutrients
Study Fe-deplete Fe-repleteSouthern Ocean (Takeda, 1998) plankton community Si/N=2.3 Si/N = 0.95
N/P = 12 N/P = 14Chaetoceros dichaeta Si/N = 1.9 Si/N = 0.7Nitzschia sp. Si/N = 2.1 Si/N = 1.2
California upwelling (Hutchins et al., 1998)plankton community Si/N = 1.6 Si/N = 0.8
Si/N = 2.7 Si/N = 1.0Si/N = 3.0 Si/N = 1.0
Uptake by blooms in Ross Sea DiatomsPhaeocystisArrigo et al. (1999) N/P = 9.5 N/P = ~19
Three more recent cases of nitrate anomalies in Fragilariopsis blooms
Polarstern1999
Polarstern2000
SOIREE1999
Polarstern2000Polarstern1999
SOIREE1999
February 1999 SOIREE Nutrient Anomalies:
Fragilariopsis kerguelensis strikes again
Nutrients data courtesy Stuart Pickmere, NIWA, New Zealand
end of bloom season
Polarstern 1999 survey cruise:NOx/PO4 anomalies at stations
dominated by Fragilariopsis
Polarstern (2000) in situ Fe enrichment
y = 0.4756x + 16.394
R2 = 0.8868
y = 0.181x + 20.98
R2 = 0.7442
15.00
17.00
19.00
21.00
23.00
25.00
27.00
29.00
10.00 12.00 14.00 16.00
Si (uM)
NO3 (uM)
NO3/Si insideNO3/Si-outside
y = 0.0298x + 1.192
R2 = 0.6564
y = 0.0012x + 1.6159
1.00
1.20
1.40
1.60
1.80
2.00
10.00 12.00 14.00 16.00
Si (uM)
PO4 (uM)
PO4/Si-insidePO4/S-outside
y = 2.9355x + 2085.6
R2 = 0.7627
y = 0.5991x + 2122.4
R2 = 0.3882
2100
2110
2120
2130
2140
2150
10.0012.0014.0016.00
Si (uM)
DIC (umol/kg)
DIC/Si-insideDIC/Si-outside
Bozec, Bakker, de Baar, Thomas, Bellerby and Watson (2003) submitted
y = 0.4756x + 16.394
R2 = 0.8868
y = 0.181x + 20.98
R2 = 0.7442
15.00
17.00
19.00
21.00
23.00
25.00
27.00
29.00
10.00 12.00 14.00 16.00
Si (uM)
NO3 (uM)
NO3/Si insideNO3/Si-outside
y = 0.0298x + 1.192
R2 = 0.6564
y = 0.0012x + 1.6159
1.00
1.20
1.40
1.60
1.80
2.00
10.00 12.00 14.00 16.00
Si (uM)
PO4 (uM)
PO4/Si-insidePO4/S-outside
y = 2.9355x + 2085.6
R2 = 0.7627
y = 0.5991x + 2122.4
R2 = 0.3882
2100
2110
2120
2130
2140
2150
10.0012.0014.0016.00
Si (uM)
DIC (umol/kg)
DIC/Si-insideDIC/Si-outside
y = 0.4756x + 16.394
R2 = 0.8868
y = 0.181x + 20.98
R2 = 0.7442
15.00
17.00
19.00
21.00
23.00
25.00
27.00
29.00
10.00 12.00 14.00 16.00
Si (uM)
NO3 (uM)
NO3/Si insideNO3/Si-outside
y = 0.0298x + 1.192
R2 = 0.6564
y = 0.0012x + 1.6159
1.00
1.20
1.40
1.60
1.80
2.00
10.00 12.00 14.00 16.00
Si (uM)
PO4 (uM)
PO4/Si-insidePO4/S-outside
y = 2.9355x + 2085.6
R2 = 0.7627
y = 0.5991x + 2122.4
R2 = 0.3882
2100
2110
2120
2130
2140
2150
10.0012.0014.0016.00
Si (uM)
DIC (umol/kg)
DIC/Si-insideDIC/Si-outside
Polarstern (2000) in situ Fe enrichment
Polarstern Ironex II RedfieldTakeda(2000) (1994) (1934) (1998)
-Fe +FeC/P 82 90 + 5 106C/N 5.9 6.2 + 0.2 6.6N/P 12 14.3 + 0.2 16 12 14C/Si 2.9 5.1 + 0.3Si/N 2.1 2.3 0.9
in the patch in the patch in bottlesplankton planktonplanktoncommunity community community
(Steinberg &Millero, 1998)
Bozec, Bakker, de Baar, Thomas, Bellerby and Watson (2003) submitted
4. Growth Experiments
• Pristine natural seawater medium• Fragilariopsis kerguelensis• Diatoms are Forever
– light & Fe co-limitation– small versus large Chaetoceros sp.
• Zn-HCO3 co-limitation Emiliania huxleyi
Different forms of Fe in seawater
AlgalCell
[Fe ] [Fe ]
[Fe(III)L]organic complexes
? ?
? ?photoreduction
sidero-phores
solidsFe2O3
Fe(OH)3FeOOHcolloids
photoreduction
[Fe(OH) ][Fe(OH) ]2+
+23+2+
[FeCO ]03
[FeOH ]+
[Fe(II)L]?
Gerringa, de Baar and Timmermans (2000), Marine Chemistry, 68, 335-346
EDTA dopewould disturball this
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0 2 4 6 8 10
Fragilariopsis kerguelensis
µ (
d-1
)
Fe dissolved (x10 -9 M )
Km Fediss: 0.44 x 10-9 Mµmax: 0.31 . d-1
Timmermans, van der Wagt, de Baar, in prep.
80 µm
Fragilariopsis kerguelensisin natural Antarctic seawater
Nutrients Stoichiometryof Fragilariopsis kerguelensis
Ratio Southern Ocean IncubationsFe-deplete Fe-deplete Fe-replete
Si : N 7.7 2.5
N : P ~ 5 + 1 ~ 5 + 1 ~12 + 2
heavily silicified Frag.kerguelensis has higher Si/N ratio
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0 2 4 6 8 10 12
Actinocyclus sp.
µ (
d-1)
Fe dissolved (x 10 -9 M)
Km Fediss: 0.98 x 10-9 Mµmax: 0.34 . d-1
Klaas Timmermans et al., in prep.
Actinocyclus sp.
Elemental composition in relation to Fediss
mol per liter cell volume
Actinocyclus sp.
Fediss Si N P Si : N N:P (x10-9 M)0.25 18.25 0.69 1.48 27 0.470.45 17.25 0.75 1.50 23 0.500.65 9.88 0.56 1.38 18 0.411.05 5.69 0.59 0.78 10 0.761.85 4.02 0.52 0.52 8 1.003.45 3.66 0.53 0.63 7 0.8510.45 2.36 0.61 0.33 4 1.86
Klaas Timmermans et al., in prep.
Timmermans et al. (2001), MEPS 287 - 297.
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
0.55
0 10 20 30 40 50
60 µmol photons.m-2.s-1
15µmol photons.m-2.s-1and
Fe’ (x 10-12 M)
µ (
d-1)
open symbols60 mol fotons m-2 sec-1
filled symbols15 mol fotons m-2 sec-1
Light and Fe co-limitation
single cells 4 - 6 µm diameter (small)
Chaetoceros brevis
0
0.1
0.2
0.3
0.4
0.5
0.6
0 2 4 6 8 10
µ (
d-1)
Fe dissolved (x 10 -9 M)
20 h light: 4 h dark
12 h light : 12 h dark
Chaetoceros dichaetaC. dichaetaKmFediss:1.12 x 10-9 M
Timmermans et al. (2001), MEPS 287 - 297.
does notgrow at all
Chain-forminglarge cells
C. dichaeta
C. brevis
single cells 4 - 6 µm diameter (small)
chain-forming cells, individual cells 80 µm long, 30 µm width (large)
Timmermans et al. Limnol & Oceanogr. 46: 699 - 703.
Open Southern Ocean HNLC species
Large versus smallat optimal light levels
0
0.1
0.2
0.3
0.4
0.5
0.6
0 2 4 6 8 10
µ (
d-1)
Fe dissolved ( x 10 -9 M)
C. brevis in its pristine Antarctic seawater“a wonderful start”
growth rates not affected by Fe additions
Timmermans et al. Limnol & Oceanogr. 46: 699 - 703.
-0.1
0
0.1
0.2
0.3
0.4
0.5
2 4 6 8 10 12 14
µ (
d-1)
DFOB (M) addition
x 10-9
C. brevis, it works…. a limitation response
Timmermans et al. Limnol & Oceanogr. 46: 699 - 703.
effect of Fe: restoration of µ
increasing DFOB
decreasing Fe’
Add DFOB siderophore to tie down the iron
-0.1
0
0.1
0.2
0.3
0.4
0.5
2 4 6 8 10 12 14
µ (
d-1)
DFOB (M) addition
x 10-9
C. brevis, it works…. a limitation response
Timmermans et al. Limnol & Oceanogr. 46: 699 - 703.
effect of Fe: restoration of µ
increasing DFOB
decreasing Fe’
10-14
10-13
10-12
10-11
10-10
10-9
10-8
-0.1
0.0
0.1
0.2
0.3
0.4
0.5
0.6 C. brevis
Fe dissolved (M )10
-1410
-1310
-1210
-1110
-1010
-910
-8-0.1
0.0
0.1
0.2
0.3
0.4
0.5
0.6 C.dichaeta
In the Southern Ocean:Large C. dichaeta is mostly Fe-limited except after Fe supply
Small C. brevis is never Fe-limited but grazer-controlled
ambient dissolved Fe
Km C.brevis0.59 x 10-12 M
Km C.dichaeta:1.12 x 10-9 M
Timmermans et al. Limnol & Oceanogr. 46: 699 - 703.
Paradigm Shift
• Old Paradigm (Sunda, Swift, Huntsman, 1991)
– coastal diatom require more Fe than oceanic diatom
• New Paradigm– O.K. but third class of large oceanic
diatoms having high Fe requirement– these large guys are driving export
Emiliania huxleyi
excretes external CaCO3 platelets
Concerted photosynthesis & calcification
Buitenhuis, Timmermans and de Baar, Limnol.Oceanogr., in press
• Zn-carbonic anhydrase permits fast use of [HCO3-]
• Calcification provides the necessary proton to make CO2
Growth on [HCO3-] at 3 different [Zn2+]
Buitenhuis, Timmermans and de Baar, Limnol.Oceanogr., in press
Growth on [Zn2+] at constant [HCO3
-]
Buitenhuis, Timmermans and de Baar, Limnol.Oceanogr., in press
Suitable Equation for co-limitation ?
• A) Multiply two Monod equations– two nutrients act independently on growth rate
• B) Minimum nutrient governs growth rate– compare [N] with KN to select one of two Monod
– most suitable for independent nutrients
• C) Affinity for [HCO3-] depends on [Zn2+]
– most suitable concept for Zn-carbonic anhydrase
Buitenhuis, Timmermans and de Baar, Limnol.Oceanogr., in press
Which would provide the best fit ??
Multiply two Monod equations
filled circles are data; open circles are intersect with 3-D model plane
best fit: mean residual on = 0.018 day-1
Minimum nutrient governs growth rate
filled circles are data; open circles are intersect with 3-D model plane
best fit: mean residual on = 0.02 day-1
Affinity for [HCO3-] depends on [Zn2+]
filled circles are data; open circles are intersect with 3-D model plane
best fit: mean residual on = 0.02 day-1
Best concept but fitnot any better
5. Iron Resources and Oceanic Nutrients;Advancement of Global Environment Simulations• Existing ecosystem model Southern Ocean
– two plankton groups diatoms and nanoplankton– limitation by light and four nutrients N, P, Fe, Si– successful for Polar Front and for SOIREE– (Lancelot et al 2000; Hannon et al 2001)
• Advance to generic global model– five bloom-forming groups: diatoms, calcifiers,
Phaeocystis, N2-fixers, pico-nano-plankton– limitation by light and four nutrients N, P, Fe, Si– embedding in Ocean Biogeochemical Climate
Models
Control of the carbon cycling in the upper ocean
intermediate and deep waters
N, P, SiFe
light pCO2 air
ice heat
Air/seaCO2 flux
upwelling
C Production
Mineralisation
export
Planktonic system
HighTrophicLevels
TCO2
wind atm
z=0
UML
zUMLPOC
C:N:P:Si:FePIC
Christiane Lancelot, Nice 2003 lecture
WML
STR
EUPHOTIC
Uwind
ice
Tair
GSR
Ice-ocean CLIO-model
Alk Sal
pCO2air
nutrient uptakecalcification / dissolution
SWAMCO-4[Sea WAter Microbial
COmmunity]
CO2
- carbonate system- air-sea CO2 flux)
PAR0
PAR
Chl.a Twater
1D-CLIO
Structure of the coupled biological-chemical-physical 1D model
Christiane Lancelot, Nice 2003 lecture
1D SWAMCO-4 results at KERFIX [1993] :
Jul93 Oct93 Jan94 Apr94 Jul942
2.5
3
3.5
4
4.5
5
SST
(°C
)
Jul93 Oct93 Jan94 Apr94 Jul94250
300
350
400
µat
m
Jul93 Oct93 Jan94 Apr94 Jul94-25
-20
-15
-10
-5
0
5
10
mm
ol m
-2 d
-1
-0.18
Jul93 Oct93 Jan94 Apr94 Jul940
10
20
30
40
50
mm
olC
m-2
d-1
2.32
1.33
Jul93 Oct93 Jan94 Apr94 Jul940
1
2
3
4
5
6
7
mm
olC
m-3
Jul93 Oct93 Jan94 Apr94 Jul940
0.5
1
1.5
µg
l-1
Jul93 Oct93 Jan94 Apr94 Jul940
0.2
0.4
0.6
DF
e µ
mol
m-3
Temperature fCO2 air-sea CO2 flux
DFe Chl.aDIA
NAN
PP
Export
moles C m-2 a-1
Prim. Prod/export Taxon succes. Iron/Chl a
moderate diatom bloom and low CO2 sink
Christiane Lancelot, Nice 2003 lecture
1D SWAMCO-4 results at KERFIX [1993] :Thermodynamic & biological control of air-sea CO2 fluxes
Jul93 Oct93 Jan94 Apr94 Jul942
2.5
3
3.5
4
4.5
5
SST
(°C
)
Jul93 Oct93 Jan94 Apr94 Jul94250
300
350
400
µat
m
Jul93 Oct93 Jan94 Apr94 Jul94-25
-20
-15
-10
-5
0
5
10
mm
ol m
-2 d
-1
-0.18
0.90
Jul93 Oct93 Jan94 Apr94 Jul940
10
20
30
40
50
mm
olC
m-2
d-1
2.32
1.33
Jul93 Oct93 Jan94 Apr94 Jul940
1
2
3
4
5
6
7
mm
olC
m-3
Jul93 Oct93 Jan94 Apr94 Jul940
0.5
1
1.5
µg
l-1
Jul93 Oct93 Jan94 Apr94 Jul940
0.2
0.4
0.6
DF
e µ
mol
m-3
Temperature fCO2
Prim. Prod/export
no biologyno biology
air-sea CO2 flux
Taxon succes. Iron/Chl a
PP
ExportNAN
DIADFe Chl.a
moles m-2 a-1
Christiane Lancelot, Nice 2003 lecture
1D SWAMCO-4 results at AESOPS [1996]:Thermodynamic & biological control of air-sea CO2 fluxes
Jul96 Oct96 Jan97 Apr97 Jul97-2
-1.5
-1
-0.5
0
0.5
1
SST
(°C
)
Jul96 Oct96 Jan97 Apr97 Jul97250
300
350
400
µat
mJul96 Oct96 Jan97 Apr97 Jul97
-25
-20
-15
-10
-5
0
5
10
mm
ol m
-2 d
-1
-0.93
0.16
Jul96 Oct96 Jan97 Apr97 Jul970
50
100
150
200
mm
olC
m-2
d-1
7.90
1.83
Jul96 Oct96 Jan97 Apr97 Jul970
10
20
30
40
50
60
70
mm
olC
m-3
Jul96 Oct96 Jan97 Apr97 Jul970
5
10
µg
l-1
Jul96 Oct96 Jan97 Apr97 Jul970
2
4
µm
ol m
-3
Temperature fCO2 air-sea CO2 flux
Prim. Prod/export Taxon succes. Iron/Chl a
moles C m-2 a-1
PP
Export
PHAEO DFe
Chl.a
Christiane Lancelot, Nice 2003 lecture
PISCES Model by Olivier Aumont:Co-limiting of 4 taxa by 3 nutrients
Fe
N Si
Example: the Diatoms
6. GEOTRACES (GEOSECS II)
Epoxy-coated stainless steel prototype frame;final type of titanium or carbon fibre, within own clean van
GoFlo withrotatingball valves
NOEXexpanding
silicone closures
driver unitpneumatics
Air tubeslink
Routine deep profiling with ultraclean CTD frame and cable:
allows GEOSECS II for trace elementsDFe (nM)
-4500
-4000
-3500
-3000
-2500
-2000
-1500
-1000
-500
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
De
pth
(m
)
34.2
34.1
34.3
NOEX
Geraldine Sarthou, Stephane Blain, Patrick Laan, Klaas Timmermans
October 2003 cruise IRONAGES-3 off West Africa
GOFlo on CTD-frame
GOFlo on single wire
True and accuratedissolved Fe values still are puzzling.
Certified standard is urgently needed
- outliers not shown- IOC station
de Baar and de Jong(2001) Chapter in:Biogeochemistry of Iron
in Seawater
Atlantic Fe distribution in Hamburg model
Modelers are ready to go, but lack of good Fe data for validation
Six and Maier-Reimer, European Ironages project modeling
Dust storm on 25Dust storm on 25thth Sept 2000 off Western Sept 2000 off WesternAfrica observed by SeaWiFS satelliteAfrica observed by SeaWiFS satellite
IRONAGES-1 Cruise, IRONAGES-1 Cruise, Sep 29Sep 29thth–Oct 23–Oct 23rdrd 2000 2000
IRONAGES standard: collection
-10o
-20o
-30o
-40o
50o
40o
30o
20o
10o
0o
0o-20o 20o-40o-60o
Start
Finish
AtlanticAtlanticOceanOcean
<0.25 0.26- 0.50 0.51- 0.75 0.76- 1.00 >1.00
Dissolved Fe (nM)(UoP data)
Longitude (Longitude (ooE)E)
Lat
itu
de
(L
atit
ud
e (oo
N)
N)
“IRONAGES”standard
collected here
(Provided by the SeaWiFSproject NASA/Goddard Space
Flight Center, and ORBIMAGE)
Analytical challenge - how to collect, preserve and distribute sea water samples for the preparation of a low level iron in sea water CRM?Paul Worsfold, Nice 2003 lecture
IRONAGES standard: sampling
• 1000 l HDPE cubic tank• Filled to 700 l over 8 h• South Atlantic Ocean, 6.0oS 5.6oW• Acidified to ~pH 2 using 700 ml Q-HCl• Homogenised by gentle shaking of
tank
R.V. PolarsternR.V. Polarstern
Towed fishTowed fish
HDPE tankHDPE tank
Towed fishTowed fish
Paul Worsfold, Nice 2003 lecture
IRONAGES standard: bottling• Transfer from tank to clean
laboratory using Teflon FEP line and peristaltic pump
• 200 x 1 l LDPE bottles filled in two batches - 160 UoP & 40 NIOZ
• Trials underway for:– homogeneity– time-series stability– sample storage
• Other bottles sent to 25 worldwide iron laboratories
Paul Worsfold, Nice 2003 lecture
IRONAGES standard: participants/methods
Analytical methods used duringAnalytical methods used duringthe IRONAGES exercisethe IRONAGES exercise
Laboratories participating in the “Ironcal”Laboratories participating in the “Ironcal”workshop, San Antonio, January 2000workshop, San Antonio, January 2000
SolventSolventextractionextraction
GFAASGFAAS
FI-CLFI-CL(O(O22, FeII), FeII)
FI-CLFI-CL(H(H22OO22, FeIII), FeIII)
FI-FI-spectrophotometryspectrophotometry
CSV (1N2N)CSV (1N2N)
CSV (SA)CSV (SA)
CSV (TAC)CSV (TAC)
SpectrophotometrySpectrophotometry(long pathlength)(long pathlength)
Isotope dilutionIsotope dilutionICP-MS ICP-MS
Solid phaseSolid phaseextractionextraction
ICP-MSICP-MS
Total: 25Total: 25
AustraliaAustralia
BelgiumBelgium
BermudaBermuda
CanadaCanada
FranceFrance
GermanyGermany
JapanJapan
NetherlandsNetherlands
New ZealandNew Zealand
SwitzerlandSwitzerlandUnitedUnited
KingdomKingdom
UnitedUnitedStatesStates Total: 29Total: 29
Paul Worsfold, Nice 2003 lecture
Laboratory data versus analytical method
Jim Moffett, independent chair
0.0
0.4
0.8
1.2
1.6
Analytical method
Fe
co
nce
ntr
ati
on
(n
M)
Data courtesy of Andrew Bowie (University of Tasmania, Australia)
FI-C
L -
Fe(II)
FI-C
L -
Fe(III)
ID-IC
P-
MS
SP
E - IC
P-M
S
SE - G
FA
AS
CS
V (D
HN
)
FI - S
PEC
Overa
ll mean
Mean
s fo
r e
ach
tech
niq
ue
Paul Worsfold, Nice 2003 lecture
Towards GEOTRACES (GEOSECS II)
• Imbalance of ocean sciences– plenty modeling of the virtual ocean
• armchair oceanography: cheap and easy
– not much real data in real ocean – accuracy, certification, calibration is
underfunded
• need for certified standards• nitrate, phosphate, silicate • essential metals Fe, Mn, Zn, Co, Cd
Summary
• Co-limitation is the rule• Single limiting factor is exceptional• Southern Ocean nice and simple
– only light and Fe as two co-limitations– only two taxa: diatoms and Phaeocystis
• Oligotrophic central gyres– surface waters uncharted for all nutrients– NO3, PO4, SiO4 in nanomoles or picomoles ?– Fe, Mn, Zn, Co, Cu ?– seasonality of these nutrients ?
• New concepts beyond Liebig (1840 !) and M&M (1913 !) are needed– dynamics beyond steady state– co-limitations beyond single factor
The EndWith many thanks for support by
Scientific Committee for Oceanic Research SCOREuropean Union Programs MERLIM, CARUSO, IRONAGES
National Science Agencies (NWO, NERC, DFG, CNRS)Our universities and institutes
Koninklijk Nederlands Instituut voor Onderzoek der ZeeRoyal Netherlands Institute for Sea Research
Europese UnieEuropean Union