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Primary production (14C) and phosphate availability in the south Pacific ocean
T. MOUTIN, P. RIMMELINLaboratoire d ’Océanographie et de Biogéochimie
Centre d ’Océanologie de Marseille
Surface
Ocean
CO2
CO2
CO2
DOC
Export production
Nutrients(N, P, Si, Fe)
POC
h
Moutin, 2000 (Océanis)
Biological pump : carbon transfert to the ocean interior by biological processCO2 : mineral carbon including carbonatesPOC : Particulate Organic CarbonDOC : Dissolved Organic Carbon
Scientific objectives :
To obtain reference measurements of primary production. To study phosphate availabilty, and its influence on planktonic community structure and on associated carbon fluxes.
CO2
P
h
POC
Primary production (JGOFS 14C method, 24-h of incubation duration)
Primary production
De
pth
(m)
0 2 4 6 80
25
50
75
100
125
150
0 2 4 6 80
25
50
75
100
125
150
East Mediterranean Sea(30°0E 34°0N)
PP = 183 mgC m-2 day-1
West Mediterranean Sea(6°1E 39°1N)
PP = 415 mgC m-2 day-1
Net absorption (mgC m-3)
LightDark
MINOS 96
PROSOPE 99
OLIPAC 94
POMME 01
Données SeaWIFS
« Against » biological diversity, a « simple » method to compare phytoplankton productivity in the ocean
Phytoplankton Productivity : Bangor, March 18th-22nd 2002
Net carbon absorption as a function of the incubation time (ti) beginning from sunrise
March 17, 2001
AN(ti) (mgC m-3) versus ti
0
10
20
30
40
0 6 12 18 24
5 m (50%)
mars-97
0
10
20
30
40
0 6 12 18 24
5 m (50%)
mars-97
AN(ti)/AN(24*) versus ti
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 6 12 18 24
apr-01
D=115
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 6 12 18 24
D=275
oct-01
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 6 12 18 24
D=72
march 01
AN(ti)/AN(24*) versus ti
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 6 12 18 24
apr-01
D=115
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 6 12 18 24
D=275
oct-01
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 6 12 18 24
D=72
march 01
Eastern North Atlantic
0
10
20
30
40
0 6 12 18 24
5 m (50 %)
April 25, 2001
0
10
20
30
40
0 6 12 18 24
5 m (50 %)
April 25, 2001
0
10
20
30
40
0 6 12 18 24
D=275
5 m (50 %)
October 2, 2001
0
10
20
30
40
0 6 12 18 24
D=275
5 m (50 %)
0
10
20
30
40
0 6 12 18 24
D=275
5 m (50 %)
0
10
20
30
40
0 6 12 18 24
D=275
5 m (50 %)
October 2, 2001
Secondary objective concerning primary production : to validate the model established in the Mediterranean Sea for daily primary production rates (dawn-to-dawn) calculation.
Phytoplankton Productivity : Bangor, March 18th-22nd 2002
POMME cruises in the Eastern North Atlantic Ocean
PO4
Conceptual scheme showing competitive absorbtion of phosphate by bacteria and phytoplankton and possible implications on the carbon cycle in a simple trophic chain model
(Moutin 2000 from Thingstad et al., 1997 and Thingstad 1998).
Heterotrophicflagellates
surface
ocean
Micro-zooplankton
Heterotrophicbacteria
Pico-phytoplankton
New Production
Regenerate production
Phosphate flux
DOC export POC export
DOC
Carbon flux
Nano-microphytoplankton
Meso-zooplankton
Si
------ +++++
PO4
HeterotrophicBacteria
Pico-phytoplankton
Nano-microphytoplankton
Carbon and phosphate uptakes 33P and 14C methods (Incubation duration << 24 h)
Biomass (Particulate Phosphate, Chlorophylle a (who?), Bacterial Biomass ?)
Phosphate availabilty -Characteritics of the phosphacline (Concentration vs depth measurements by the classic and/or the MAGIC method (if PO4<100 nM))-Turnover times measurements (=>Indirectly estimated orthophosphate concentration)-Dissolved Organic Phosphate concentration (labile DOP at surface only)
Size fractionation (0.2, 0.6, 2 µm)
Planktonic production (C & P)To study phosphate availabilty, and its influence on planktonic community structure.
One profile each day number 2 for « three days » stationsNeeds :
Radio-isotopes container CTD one hour before dawn2.5 liters per depth (max 12 depth)in situ
Primary production (JGOFS 14C method 24-h)
Planktonik production (C & P)
One profile each « one day » stationNeeds :
3 meters of working lab outside of the RA containerCTD two hours before solar noon4.5 liters per depth (max 9 depths)Deck incubators
ALOHA
SRP
N-limitationAbsence de
TrichodesmiumPrésence de
Trichodesmium
D. KarlJGOFS Conference ”Ocean Biogeochemistry: A New Paradigm”.13-17 April 2000. Bergen
D. Karl et al., Nature 1997.
Time
P-limitation
?
BIOSOPE
Image composite Seawifs
0
5
10
15
20
25
Printemps Ete Automne Hiver
PP
(n
M)
ALOHA
CHENAL
0
5
10
15
20
25
30
35
Printemps Ete Automne Hiver
SN
P (
mm
ol
m-2
)
ALOHA
CHENAL
Comparison between ALOHA and Chenal des Loyauté Station (DIAPALIS Cruises)Van Den Broeck et al., MEPS, in press.
Lowest orthohosphate turnover time measured
CHENAL
ALOHA : 2 d CHENAL : 4 h
0
2
4
6
8
10
12
14
16
Printemps Ete Automne Hiver
SR
P (
mm
ol m
-2) ALOHA
CHENAL
Collaborations :
-Frede Thingstad :-to study the phosphate cycle in the upper photic zone of oligotrophic ocean.
-France Van Wambeke : -to study bacterial production vs primary production and the role of heterotrophic bacteria in the DOP pool utilization.
-Dave Karl : (in discussion)-to compare phosphate availabilities in the South and the North Pacific gyres (ALOHA station).
0.2-0.6µm0.6-2µm>2µm
Stations
Particulate phosphate (nM)
0
4
8
12
16
20
24B
Chl a (µg l-1)
0.0
0.1
0.2
0.2-0.6µm
0.6-2µm
>2µm
A
Vmax/Ks (l nmol-1 h-1)
0.0
0.1
0.2
0.3
0.4
0.5
1 2 3 4 5 6 7
affinity (l nmol-1 h-1)
0.0
0.1
0.2
0.3
0.4
0.5D
Vmax (h-1)
0.0
0.5
1.0
1.5
2.0
2.5C
E
Figure 2 Size fractionation of biomass and studies of kinetics parameters for P-uptake along a west-east transect in the Mediterranean Sea (5°W-22°E). A: chlorophyll a, B: particulate phosphate; C: maximum uptake rate of phosphate; D: phosphate affinity and E: Michaelis-Menten parameters, Vmax divided by Ks. Each parameter is shown by size fractions (between 0.2 and 0.6 µm; between 0.6 and 2µm, and above 2 µm).
Gibraltar Ionnian Sea
Moutin, Thingstad, Van Wambeke, Marie, Slawyk, Raimbault & Claustre, 2002 (Limnol. Oceanogr.)
« Expected » results !PROSOPE Cruise
HIVER PRINTEMPS ETE AUTOMNE396 3,9 1,6 Mer Méditerranée370 2,4 0,9 Golfe du LionD1S9 D1S17 D1S20
9,02,1 Alboran
D1S2
1,71,5 OccidentaleD1S5
1,20,5 Orientale
D1S4
230 1,3 217 Océan Atlantique38 0,4 Golfe de Gascogne*
D1S3 D1S4 D1S1 Panache de la Gironde
8225 Upwelling au large du Maroc
D3S1
1182 152 168382 55 110 Nord Est (POMME)D2S3 D2S4 D2S4
504 107 10,8 4,0 68 Océan Pacifique175 37 2,4 0,3 2 Tropical Sud OuestD5S1 D5S1 D3S2 D5S1 D5S1 Chenal des loyauté
Temps de recyclage du phosphate (moyenne et écart-type en heure) dansles eaux de surface des océans (0-20 m), D5S1 signifie 5 profondeurs (D)et 1 station (S) échantillonnées (Sont inclues les valeurs obtenues par C.Labry* et N. Van de Broeck).
2.5 h
1 day
Turnover times
1 week
1 month
-12 5
-10 5
-8 5
-6 5
-4 5
-2 5
-5D
epth
(m
)
O ct-0 1 D ec -0 1 Jan -0 2 A p r-0 2 M ay -0 2 A ug -0 2
Sp r in g S u m m e r F a ll W in te r
0 .4
0 .8
1 .2
1 .6
2 .0
2 .4
2 .8
3 .2
3 .6
0
1
2
3
4
1 2 3 4 5 6 M IO
Stations
Pi (
nM
) d
édu
ites
de
T
Proposition d ’une méthode indirecte simple (Radio isotopique 33P) pour évaluer indirectement la concentration en orthophosphate (L.D. < 0.02 nM).
0.1
1.0
10.0
100.0
1000.0
0.1 1.0 10.0 100.0 1000.0
SRP (nM)
[PO
4]
( nM
)
ENAO Apr 2001
ENAO Sep 2001
1:1
Pi (
nM
) d
édu
ites
de
T
SRP (nM)
Mer Méditerranée
{Océan Atllantique Nord Est
Moutin, Thingstad, Van Wambeke, Marie, Slawyk, Raimbault & Claustre, 2002 (Limnol. Oceanogr.)
y = 0,005xMAGIC *25
y = 0,002xMAGIC *10
y = 0,0002xClassique
0
0,05
0,1
0,15
0,2
0,25
0,3
0 10 20 30 40 50
Concentration PO4 (nM)
Abs
orba
nce
(cuv
e 10
cm
)Nécessite l ’achat d ’unecentrifugeuse grand volume
2 nM
0,8 nM
20 nM
Limite de détectionet sensibilité attendue
Container Radio-isotopes IFREMER
0
5
0.2-0.6 0.6-2 >2 µm
0.00
0.05
0.2-0.6 0.6-2 >2 µm
0
400
0.2-0.6 0.6-2 >2 µm
0
4
0.2-0.6 0.6-2 >2 µm
0.0
8.0
0.2-0.6 0.6-2 >2 µm
0.00
0.08
0.2-0.6 0.6-2 >2 µm
Chlorophylle a µg l-1
Absorption de phosphate nM h-1
Phosphate particulaire nM
Station "UPWELLING" au large du Maroc Station "M IO" en mer Ionienne
Mission PROSOPE
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