Vulnerability of the ocean
biological pump
Corinne Le Quéré
University of East Anglia and British Antarctic Survey
oceanic carbon cycle
numbers in
PgC/yr
atmosphere
90
CO2
chemical reactions
CO2 + H2O + CO2-3
biological activity
45
34
2HCO-3
33
11
physical transport
ocean
11
atmosphere
biological activity
surface
100 m
mixed layer depth
atmosphere
biological activity
100 m
real surface
bacteria
Ecosystem composition
pico-heterotrophs
Respiration
34 PgC/y
pico-autotrophs
N2-fixers
phytoplankton
calcifiers
DMS-producers
Primary
Production
45 PgC/y
mixed
silicifiers
zooplankton
proto
Export
meso
11 PgC/y
macro
what controls export?
what they do
pico-autotrophs
N2-fixers
phytoplankton
calcifiers
DMS-producers
mixed
silicifiers
Primary
Production
45 PgC/y
what they do
pico-autotrophs
N2-fixers
phytoplankton
calcifiers
DMS-producers
mixed
silicifiers
these bloom
what they do
pico-autotrophs
N2-fixers
phytoplankton
calcifiers
DMS-producers
mixed
silicifiers
these form shells
what they do
pico-autotrophs
N2-fixers
phytoplankton
calcifiers
DMS-producers
mixed
silicifiers
these respond
to pH
what they do
pico-autotrophs
N2-fixers
phytoplankton
calcifiers
DMS-producers
mixed
silicifiers
these float
what they need
pico-autotrophs
N2-fixers
phytoplankton
calcifiers
DMS-producers
mixed
silicifiers
Fe
P
N
Fe
P
N
Fe
P
Fe
P
N
N
Fe
P
N
Fe
P
N
Si
what they do
bacteria
pico-heterotrophs
Respiration
34 PgC/y
zooplankton
proto
meso
macro
what they do
bacteria
pico-heterotrophs
these control
blooms
zooplankton
proto
meso
macro
what they do
bacteria
pico-heterotrophs
these produce
big feacal
pellets
zooplankton
proto
meso
macro
what they need
bacteria
pico-heterotrophs
zooplankton
proto
meso
macro
F
O
O
D
F
O
O
D
F O O D
F
O
O
D
time scale
phytoplankton
turnover time:
1 week
sinking rate:
50 m/day
bacterial
respiration:
1 day
zooplankton
turnover time:
1-many
weeks
time scale
a few days
a few +1 days
HOT SPOTS:
bacteria
TEMPERATURE RESPONSE
Respiration
pico-heterotrophs
Q10=3.0
34 PgC/y
pico-autotrophs
Primary
Production
N2-fixers
phytoplankton
calcifiers
DMS-producers
mixed
Q10=1.9
45 PgC/y
silicifiers
zooplankton
proto
meso
macro
Q10=2.2 Export
11 PgC/y
HOT SPOTS:
bacteria
pH RESPONSE
pico-heterotrophs
Respiration
34 PgC/y
pico-autotrophs
N2-fixers
phytoplankton
reduced ballast
DMS-producers
mixed
Primary
Production
45 PgC/y
silicifiers
zooplankton
proto
meso
macro
Export
11 PgC/y
HOT SPOTS:
bacteria
RESPONSE TO STRATIFICATION
Respiration
pico-heterotrophs
34 PgC/y
pico-autotrophs
N2-fixers
phytoplankton
calcifiers
DMS-producers
mixed
Primary
Production
45 PgC/y
silicifiers
zooplankton
proto
meso
macro
Export
?
11 PgC/y
oceanic carbon cycle
numbers in
PgC/yr
atmosphere
90
CO2
chemical reactions
CO2 + H2O + CO2-3
biological activity
45
34
2HCO-3
33
11
physical transport
ocean
11
CO2 sink (PgC/y)
0
4
Export (PgC/y)
10
14
in one decade
what controls export?
the ecosystem composition
and
the physical transport
what controls export in models?
the ecosystem composition
=
the physical transport
models
air-sea fluxes
PO4
Phyto
DOC
Zoo
POC
export
CLIMATE RESPONSE OF OCEANIC UPTAKE
Time Span
Sarmiento
Matear and
et al. (1998) Hirst (1999)
1990-2065
1850-2100
Joos et al.
(1999)
1765-2100
Warming Effect
-11%
-12%
-13%
Anthropogenic Effect
-22%
-10%
-3%
Biological Pump
+24%
+8%
+6%
TOTAL
-9%
-14%
-10%
(slide adapted from J. Sarmiento)
observations?
MIT
MPI
Observations (station average)
Observation (Inversion)
Global changes in Atmospheric
Potential Oxygen
1980
2.0
1985
1990
1.5
14
10 mol yr
-1
1.0
0.5
0.0
-0.5
-1.0
-1.5
-2.0
IPSL
MIT
MPI
Observations (station average)
Observation (Inversion)
models only
1995
2000
MIT
MPI
Observations (station average)
Observation (Inversion)
Global changes in Atmospheric
Potential Oxygen
1980
2.0
1985
1990
1995
2000
1.5
14
10 mol yr
-1
1.0
0.5
0.0
-0.5
-1.0
-1.5
-2.0
IPSL
MIT
MPI
Observations (station average)
Observation (Inversion)
Slide not available because the data is not published.
APO data shows at least 2x more variability than the
models.
Interannual chla variability (mgChl/m3)
Observations (SeaWiFS)
NPZD
PO
4
DOC
Zoo
POC
export
PISCES-T
DGOM
Fe
PO
4
Calcifie
rs
Interannual chla variability (percent)
Observations (SeaWiFS)
PISCES-T
NPZD
DGOM
model projection of climate change in 2060
temperature
mixed layer depth
ice cover
Impact of climate change on the CO2 sink in 2060 (mol/m2/y)
F
e
P
O
4
Calci
fiers
(Preliminary result from E. T. Buitenhuis)
what comes now?
evolution of model results
truth
(what is the
vulnerability
of the
marine
biological
pump?)
illusion
time
evolution of model results
truth
(what is the
vulnerability
of the
marine
biological
pump?)
illusion
chaos
time
evolution of model results
ocean
biogeochemistry
models
truth
(what is the
vulnerability
of the
marine
biological
pump?)
illusion
relief
chaos
time
thanks to Erik T. Buitenhuis and Olivier Aumont
for providing model codes and results