Vulnerability of the ocean biological pump Corinne Le Qur University of East Anglia and British Anta

1
Vulnerability of the ocean biological
pumpCorinne Le QuéréUniversity of East Anglia
and British Antarctic Survey
2
oceanic carbon cycle
numbers in PgC/yr
atmosphere
CO2
90
chemical reactions
45
34
ocean
3
biological activity
atmosphere
surface
100 m
mixed layer depth
4
biological activity
atmosphere
100 m
real surface
5
Ecosystem composition
6

• what controls export?

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what they do
pico-autotrophs
N2-fixers
phyto-plankton
calcifiers
DMS-producers
mixed
silicifiers
8
what they do
pico-autotrophs
N2-fixers
these bloom
phyto-plankton
calcifiers
DMS-producers
mixed
silicifiers
9
what they do
pico-autotrophs
N2-fixers
these form shells
phyto-plankton
calcifiers
DMS-producers
mixed
silicifiers
10
what they do
pico-autotrophs
N2-fixers
these respond to pH
phyto-plankton
calcifiers
DMS-producers
mixed
silicifiers
11
what they do
pico-autotrophs
N2-fixers
these float
phyto-plankton
calcifiers
DMS-producers
mixed
silicifiers
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what they need
pico-autotrophs
N2-fixers
phyto-plankton
calcifiers
DMS-producers
mixed
silicifiers
13
what they do
14
what they do
pico-heterotrophs
bacteria
these control blooms
proto
zoo-plankton
meso
macro
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what they do
pico-heterotrophs
bacteria
these produce big feacal pellets
proto
zoo-plankton
meso
macro
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what they need
pico-heterotrophs
bacteria
proto
zoo-plankton
meso
macro
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time scale
phytoplankton turnover time 1 week
bacterial respiration 1 day
zooplankton turnover time
1-many weeks
sinking rate 50 m/day
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time scale
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HOT SPOTS
Respiration 34 PgC/y
pico-heterotrophs
bacteria
pico-autotrophs
N2-fixers
phyto-plankton
calcifiers
DMS-producers
mixed
silicifiers
proto
zoo-plankton
meso
macro
20
HOT SPOTS
pH RESPONSE
Respiration 34 PgC/y
pico-heterotrophs
bacteria
pico-autotrophs
N2-fixers
phyto-plankton
reduced ballast
DMS-producers
mixed
silicifiers
proto
zoo-plankton
meso
macro
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HOT SPOTS
RESPONSE TO STRATIFICATION
Respiration 34 PgC/y
pico-heterotrophs
bacteria
pico-autotrophs
N2-fixers
phyto-plankton
calcifiers
DMS-producers
mixed
silicifiers
?
proto
zoo-plankton
meso
macro
22
oceanic carbon cycle
numbers in PgC/yr
atmosphere
CO2
90
chemical reactions
45
34
ocean
23
CO2 sink (PgC/y)
4
0
10
Export (PgC/y)
14
in one decade
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• what controls export?

the ecosystem composition and the physical
transport
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• what controls export in models?

the ecosystem composition the physical
transport
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models
air-sea fluxes
PO4
Phyto
DOC
Zoo
POC
export
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(slide adapted from J. Sarmiento)
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• observations?

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Global changes in Atmospheric Potential Oxygen
models only
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Global changes in Atmospheric Potential Oxygen
Slide not available because the data is not
published. APO data shows at least 2x more
variability than the models.
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Interannual chla variability (mgChl/m3)
NPZD
Observations (SeaWiFS)
DGOM
PISCES-T
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Interannual chla variability (percent)
NPZD
Observations (SeaWiFS)
DGOM
PISCES-T
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model projection of climate change in 2060
temperature
mixed layer depth
ice cover
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Impact of climate change on the CO2 sink in 2060
(mol/m2/y)
(Preliminary result from E. T. Buitenhuis)
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• what comes now?

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evolution of model results
truth (what is the vulnerability of the marine
biological pump?)
illusion
time
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evolution of model results
truth (what is the vulnerability of the marine
biological pump?)
illusion
chaos
time
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evolution of model results
truth (what is the vulnerability of the marine
biological pump?)
relief
illusion
chaos
time
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thanks to Erik T. Buitenhuis and Olivier Aumont
for providing model codes and results