Use of natural-series radionuclides to understand particle dynamics and carbon flux in the NW Mediterranean Sea J.-C. Miquel 1 , B. Gasser 1 , S.W. Fowler 1,2 1 IAEA Environment Laboratories, Monaco 2 School of Marine and Atmospheric Sciences, Stony Brook , USA IAEA Symposium 2011
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Use of natural-series radionuclides to understand particle
dynamics and carbon flux in the NW Mediterranean Sea
J.-C. Miquel1, B. Gasser1, S.W. Fowler1,2
1 IAEA Environment Laboratories, Monaco 2School of Marine and Atmospheric Sciences, Stony Brook , USA
IAEA Symposium 2011
Outline DYFAMED site, a unique field lab in the Mediterranean
230Th, a tracer to calibrate trap data
234Th, a tracer for particle export
210Po, a tracer for organic carbon flux
210Po and 234Th in particles and biota
DYFAMED site
DYFAMED site
Unique open sea station in the Mediterranean Sea with a 20yrs time series (hydrodynamic, bio-optics, biogeochemical and biological observations)
Since Jan 2010, Dyfamed is integrated in a large Med network called MOOSE
- Northern current and associated geostrophic front: relatively well isolated from land masses
- Hydrological cycle: winter convection and summer stratification
- Biological cycle: spring plankton bloom
- Atmospheric inputs are important, in particular Saharan dust
biweekly means (1988-2005)
1000 m depth 200 m depth
Flux seasonality
0
100
200
300
Mass F
lux (
mg
m2 d
-1)
0
4
8
12
16
20
PO
C F
lux (
mg
m2 d
-1)
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
0
75
150
225
Sam
ple
d d
ays
0
100
200
300
Mass F
lux (
mg
m2 d
-1)
0
4
8
12
16
20
PO
C F
lux (
mg
m2 d
-1)
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
0
75
150
225
Sam
ple
d d
ays
(Miquel et al., PiO in review)
Phytoplankton and POC flux
-200
-150
-100
-50
0
de
pth
(m
)
0
100
200
300
400
500
600
700
800
900
1000
1100
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Total Chl-a (ng l-1)
Monthly means (1990-2006)
0
3
6
9
12
15
18
P O
C F
l u x
( m
g m
- 2 d
- 1 )
J A N F E B M A R A P R M A Y J U N J U L A U G S E P O C T N O V D E C
Biweekly means (1988-2005)
(Marty et al., DB 2010)
Zooplankton and POC flux
0
3
6
9
12
15
18
P O
C F
l u x
( m
g m
- 2 d
- 1 )
J A N F E B M A R A P R M A Y J U N J U L A U G S E P O C T N O V D E C
Biweekly means (1988-2005)
(Gasser, 1995)
Zooplankton fecal pellets and POC flux
0
3
6
9
12
15
18
P O
C F
l u x
( m
g m
- 2 d
- 1 )
J A N F E B M A R A P R M A Y J U N J U L A U G S E P O C T N O V D E C
Biweekly means (1988-2005)
FP
flu
x (
mg
C m
-2 d
-1)
(Carroll et al., 1998)
Ocean carbon cycle, The biological pump
238U 234Th
210Po 210Pb
230Th
230Th, a tracer to calibrate trap data
230Thlitho,232Thlitho
234Udissolved 230Thdissolved 230Thparticulate
Sinking particles
230Th, a tracer to calibrate trap data
230Thlitho,232Thlitho
234Udissolved 230Thdissolved 230Thparticulate
230Th, a tracer to calibrate trap data
Calculation of trap collection efficiency using 230Th
Calculation of trap collection efficiency using 230Th