commentary to richard lampitt: ‘linking surface ocean and the deep sea’ susanne neuer
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Commentary to Richard Lampitt:Commentary to Richard Lampitt:
‘‘Linking Surface Ocean Linking Surface Ocean and the Deep Sea’and the Deep Sea’
Susanne NeuerSusanne Neuer
Differences in the biological Differences in the biological carbon pump within the carbon pump within the same biogeographical same biogeographical provinceprovince
A case study from the A case study from the subtropical North Atlantic subtropical North Atlantic GyreGyre
NAST(E)NAST(W)
The North Atlantic The North Atlantic Subtropical GyralSubtropical GyralProvince (NAST)Province (NAST)
East:ESTOC (European Station for Time-Series, Canary Islands)
West:
BATS (Bermuda Atlantic Time-Series)Data sets used for this study have been obtained Data sets used for this study have been obtained
simultaneously during 1996-1998.simultaneously during 1996-1998.
0.2
0.4
0.6
0.8
1.0
Pri
ma
ry P
rod
uc
tio
n
( g
m-2 d
-1 )
0.0
0.2
0.4
Su
rfa
ce
ch
loro
ph
yll
( m
g m
-3 )
A
B
1996 1997 1998
Jan Apr Jul O ct Jan Apr Jul O ct Jan Apr Jul O ct
0
20
40
60
E-P
OC
(m
g m
-2d
-1)
E S TO C M TE S TO C S TB A TS
Seasonality of surface chlorophyll, integrated primary productionand export production at ESTOC and BATS
Chl a
PP
Epoc
Neuer et al.2002
Yearly integrated PP, E POC and
ER (EPoc /PP) for ESTOC and BATS
PP
mol C m-2 yr-1
E POC
mol C m-2 yr-1
ER
BATS ESTOC BATS ESTOCa BATS ESTOCb
1996 16.3 11.9 1.4 0.24 / 0.16 0.086 0.017
1997 13.3 12.0 1.3 0.16 / 0.16 0.098 0.013
1998 13.9 11.7 0.7 -- / 0.20 0.050 0.017
AVG 14.5 11.9 1.1 0.2 0.08 0.016aShallow moored/surface tethered trap. Surface tethered trap value of 1996 and 1997
composite of both years b Mean of moored and surface tethered traps.
Neuer et al.2002
ESTOCBATS
200
100
0
Mix
ed L
ayer
Dep
th (
m)
0
200
400 Nitrate-N
(µmo
l m-2 )
1996 1997 1998
Mixed layer depth and Nitrate-N input at ESTOC and BATS
ESTOC: 0.06 - 0.2 mmol N/m2/yr
BATS: 0.01 - 0.5 mmol N/m2/yrNeuer et al.2002
BATS ESTOC
New Production
(mol N m-2yr-1)
0.63 0.04
Convection 0.37 0.00
Vertical diffusion 0.10 0.02
Vertical advection 0.12 0.02
Horizontal advection 0.04 0.00
Horizontal diffusion 0.00 0.00
Vertical velocity( m yr-1 )
-31 -30
Nutrient budgets at BATS and ESTOC diagnosed from an eddy-resolving 0.1 degree resolution simulation of the North Atlantic (after McGillicuddy et al. in press)
Snapshots of temperature and new production in a 0.1 degree resolution simulation of the North Atlantic
(McGillicuddy et al., GBC, in press)
ConclusionsConclusions
ESTOC (NAST-E) has comparable ESTOC (NAST-E) has comparable surface chlorophyll and primary surface chlorophyll and primary production than BATS (NAST-W), production than BATS (NAST-W), but new (export) production is but new (export) production is significantly lower.significantly lower.
ConclusionsConclusions
Lower input of new nutrients does Lower input of new nutrients does not necessarily result in lower PP not necessarily result in lower PP per se but influences the removal per se but influences the removal efficiency (export ratio) of efficiency (export ratio) of biologically produced carbon into biologically produced carbon into the ocean’s interior.the ocean’s interior.
ConclusionsConclusions
Primary production and surface Primary production and surface chlorophyll alone are insufficient chlorophyll alone are insufficient to constrain the amount of carbon to constrain the amount of carbon export in the subtropical ocean.export in the subtropical ocean.
ReferencesReferences
Neuer, S., R. Davenport, T. Freudenthal, G. WeferNeuer, S., R. Davenport, T. Freudenthal, G. Wefer , O. Llinás, , O. Llinás, M-J. Rueda, D. K. Steinberg andM-J. Rueda, D. K. Steinberg and D.D. Karl. 2002. Differences in Karl. 2002. Differences in the biological carbon pump at three subtropical ocean sites. the biological carbon pump at three subtropical ocean sites. Geophys. Res. LettGeophys. Res. Lett., 29, 32-1 to 32-4.., 29, 32-1 to 32-4.
McGillicuddy, D.J., Anderson, L.A., Doney, S.C., and M.E. McGillicuddy, D.J., Anderson, L.A., Doney, S.C., and M.E. Maltrud. Eddy-driven sources and sinks of nutrients in the Maltrud. Eddy-driven sources and sinks of nutrients in the upper ocean: results from a 0.1 degree resolution model of the upper ocean: results from a 0.1 degree resolution model of the North Atlantic. In press, North Atlantic. In press, Global Biogeochemical CyclesGlobal Biogeochemical Cycles..
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