Prsentation PowerPoint

1
Physical / Chemical Drivers of the Ocean in a
High CO2 World
Laurent Bopp IPSL / LSCE, Gif s/ Yvette,
France
2
Introduction
Food Web / Fisheries
Climate
Atmospheric Components CO2, DMS, CH4, N2O,
Atmosphere
Biosphere Soils
Ocean
Circulation, Temperature, Light, Dust,
Marine Biogeochemistry
Sediment
3
6
Introduction
4
Temperature Change (C)
2
Coupled Models response to increased Atmospheric
pCO2
0
9
(IS92a, IPCC 2001)
6
3
Precipitation Change ()
0
5
Max. Atlantic Over. ()
-5
-15
1850 1900 1950 2000 2050 2100
4
Introduction
Drivers of Marine Biogeochemistry
Atmospheric pCO2 Temperature Circulation (Advect
ion Mixing) Light Supply Dust
Deposition Rivers Input
5
Tools Ocean-Atmosphere General Circulation
Models
IPSL Coupled Model
6
Tools Biogeochemical Models for the Global
Ocean
Geochemical Models to ..
Simple Ecosystem Models
PO43-
Diatoms
NH4
Si
PO43-
Phyto
PO43-
Nano-phyto
NO3-
Iron
MicroZoo
Zoo
Dissolved
D.O.M
Meso Zoo
P.O.M
Particles
Particles
Small Ones
Big Ones
Euphotic Layer (100-150m)
7
Outline
1. Increased Atmospheric pCO2
Atmospheric pCO2 Temperature Circulation (Advect
ion Mixing) Light Supply Dust
Deposition Rivers Input
Carbon Cycle O2 Cycle Nutrients Cycle Marine
Productivity Ecosystem Structure
8
Outline
1. Increased Atmospheric pCO2
2. Oceanic Circulation (Advection / Mixing)
Atmospheric pCO2 Temperature Circulation (Advect
ion Mixing) Light Supply Dust
Deposition Rivers Input
Carbon Cycle O2 Cycle Nutrients Cycle Marine
Productivity Ecosystem Structure
9
Outline
1. Increased Atmospheric pCO2
2. Oceanic Circulation (Advection / Mixing)
3. Atmospheric Dust Deposition
Atmospheric pCO2 Temperature Circulation (Advect
ion Mixing) Light Supply Dust
Deposition Rivers Input
Carbon Cycle O2 Cycle Nutrients Cycle Marine
Productivity Ecosystem Structure
10
Changes in pH Acidification
11
Changes in pH Marine Production / Ecosystem
Many studies have revealed/estimated the impact
on marine ecosystems
12
Changes in Ocean Physics Stratification
13
Changes in Ocean Physics Stratification
Sarmiento et al. in press
Mechanisms of Changes
D Mixed Layer
D SSS
D SST
80N
80N
1000
100
40N
40N
10
0
0
0
-10
40S
40S
-100
80S
80S
(m)
(psu)
(C)
Changes in Winds increase in Southern Ocean but

14
Changes in Ocean Physics Stratification
Implications for the Carbon Cycle
Implications for the Oxygen Cycle
Implications for Marine Productivity Ecosystem
15
Changes in Ocean Physics Carbon Cycle
IPCC, 2001
Climate Change Impact
Climate Change reduces ocean CO2 sink (from
6 to 25 in 2050)
16
Changes in Ocean Physics Carbon Cycle
Mechanisms
17
Changes in Ocean Physics Carbon Cycle
Climatic Effect on CO2 sink at 4xCO2
(HAMOCC3-OPA-LMD)
gC m-2 yr-1
Decrease sink
Increase sink
Stratification prevents anthropogenic CO2
penetration
Main Effect
18
Changes in Ocean Physics Oxygen Cycle
Recent data have shown O2 decreases in most
regions of the ocean in the past 40 years
(Emerson et al. 2001, Ono et al. 2001, Wanatabe
et al. 2001, Matear et al. 2000, )
19
Changes in Ocean Physics Oxygen Cycle
Focus on the Equatorial Pacific
Dissolved O2 at 100 m (mmol/l)
Anoxic / Suboxic Zone increases by 30 in 2100
20
Changes in Ocean Physics Oxygen Cycle
Mechanisms of Changes (3S, Equatorial Pacific)
0 m
SEC
Temperature Currents
300 m
0 m
Changes in T U (2090-1990)
300 m
South Equatorial Current shallower and weaker
No more warm oxygenated water to the
sub-surface
21
Changes in Ocean Physics Marine Productivity
22
Changes in Ocean Physics Marine Productivity
30 gC m-2 an -1
Simulation NPZD-IPSL, 2100-1990
- 30 gC m-2 an -1
Decreases globally (-5/10) BUT increases at
high latitudes (20/30)
23

Changes in Ocean Physics Marine Productivity
(NPZD-IPSL)
Ocean Stratification increases
Surface nutrient ? -5 to 10
Oligotrophic Gyres Area increases

1xCO2
2xCO2-1xCO2
24
Changes in Ocean Physics Marine Productivity
Less Nutrient But Longer Growing Season
IPSL NCAR Princeton MPIM Hadley CSIRO
80N
80N
40N
40N
0
0
40S
40S
80S
80S
(m)
(days)
Sarmiento et al. in press
25
Changes in Ocean Physics Marine Ecosystem
26
Changes in Dust Deposition
27
Changes in Dust Deposition Marine Productivity
Dust Deposition and
annual-mean Chlorophyll (M. Werner I. Tegen)
(PISCES model, O. Aumont)
5
1
(mg/m3)
0
(see talk by O. Aumont)
28
Conclusions
In a high CO2 world, the ocean will be
More acidic More stratified More oligotrophic,
but better light conditions Less oxygenated
29
(No Transcript)
30
Oceanic Carbon Cycle Coupling climate and
carbon
Climate (OPA-LMD)
Emissions
pCO2
Carbon models (HAMOCC3,SLAVE)
31
Ocean Carbon Cycle Coupling carbon and climate

• Comparison to Cox et al. 2000

IPSL 700 ppm 770 ppm
Hadley 700 ppm 950 ppm
Climatic Effect
32
Diatoms Abundance with Global Warming (using
the PISCES model)
Diatoms replaced by NanoPhyto at mid/high
Latitudes
1
0.2
0.02
-0.02
-0.2
-1
Changes in Diatoms Abundance (2090-1990)