Transcript Diapositiva 1 - Mediterranean Oceanic Data Base (MODB)

The 45th International Liège Colloquium
Liège, Belgium 13th – 17th May 2013
Primary production and the carbonate system in the
Mediterranean Sea
Cossarini G., Lazzari P., Solidoro C.
OGS – National Institute of Oceanography and
Experimental Geophysics
Trieste (Italy)
Introduction: understanding Ocean Acidification calls for
the resolution of the carbonate system and its variability
Carbonate system: DIC (CT)
and Alkalinity (AT)
Few data on
carbonate chemistry
are available for the
Mediterranean Sea
Intense gradients
from west to east
Touratier and Goyet, 2012
Introduction: Mediterranean Sea circulation and
boundaries
Anti estuarine circulation at Gibraltar
Surface circulation
Siokou-Frangou et al., 2010
Rhone
Po
Ebro
Dardanelles
Nile
Alkalinity profile at
Gibraltar
Huertas et al., 2009
Input from rivers:
Alk 0.92 1012 mol/y
DIC 11.23 1012 gC/y
Meybeck and Ragu, 1995;
Ludwig et al., 2009
Input from Dardanelles:
Alk 1.15 1012 mol/y
DIC 12.6 1012 gC/y
Chopin-Montegut, 1993
Introduction: spatial variability of trophic conditions
Integrated vertical net primary production
Controlling mechanism: extinction factor coefficient (k)
Declining DCM moving eastward
NWM
TYR
ALB
SWE
ION
LEV
Longitudinal and
latitudinal transects of
chlorophyll a
Lazzari et al., 2012
• Aim: evaluate scales of variability of carbonate system
(DIC and alkalinity) in the Mediterranean Sea and quantify
the contribution of physical & biological processes
1. 3D physical-biogeochemical model: OPATM-BFM
2. Reconstruction of alkalinity and DIC spatial patterns & validation
3. Decomposition of physical and biological contributions on spatial
and temporal variability
4. Air-sea CO2 exchanges
Method: 3D coupled OPATM-BFM-carbonate model
BFM – Biogeochemical Flux Model
Carbonate system
OCMIP II model
Schneider et al.1999
Wanninkhof,1992
OCMIP II model
Orr et al., 1999
DIC=[CO2]+[HCO3-]+[CO32-]
consumption:photosynthesys
production: respiration by phyoplankton,
zooplankton and bacterial functional type groups
Alkalinity:
Production: denitrification
phytoplankton uptake of NO3- and PO43mineralization and realise of NH4+
Consuption: phytoplankton uptake of NH4+
nitrification
mineralization and realise of PO43Atmopheric pCO2=360-390ppm
Physical and biogeochemical setup and validation
Beranger et al., 2010; Lazzari et al. 2012 & poster Lazzari et al
Wolf-Gladrow et
Nutrients
Consumption/production al., 2007
www.bfm-community.eu
Results: Alkalinity – spatial patterns and validation
1
2
3
1
4
6
mmol/kg
2
3
5
4
5
6
Taylor Diagram: B0, B400, B1000: Boum 2008
cruise at 0, 400 and 1000 m; M0,M400, M1000:
Meteor51 cruise at 0, 400 and 1000 m; Sm0,
Sm400, So0, So400 Sesame dataset at 0 and 400
m, March and October cruises; P0: Prosope cruise,
Dyf0, Dyf400, Dyf1000: Dyfamed site at 0, 400 and
1000 m.
Results: DIC – spatial pattern and validation
1
2
3
1
4
6
mmol/kg
2
3
5
4
5
6
Taylor Diagram: B0, B400, B1000: Boum 2008
cruise at 0, 400 and 1000 m; M0,M400, M1000:
Meteor51 cruise at 0, 400 and 1000 m; Sm0, Sm400,
So0, So400 Sesame cruises at 0 and 400 m, March
and October cruises; P0: Prosope cruise, Dyf0,
Dyf400, Dyf1000: Dyfamed site at 0,400 and 1000m.
Results: spatial variability DIC along W-E transect
and its temporal variability
NWM
TYR
ALB
SWM
ION
LEV
Annual average
DIC concentration
Amplitude of the
seasonal cycle
 DpH = 0.1-0.2
Latitudinal transect
Longitudinal transect
Results: biological and physical contributions on DIC
NWM
TYR
ALB
SWM
ION
LEV
Decomposition of physical and biological
part of the amplitude of the seasonal
cycle
variability of
biological fluxes
[mmol/m3/d]
variability of
physical fluxes:
[mmol/m3/d]
flux at air-sea
interface, advection
and diffusion
Results: biological and physical contributions on DIC
NWM
TYR
ALB
SWM
ION
LEV
Decomposition of physical and biological
annual average fluxes
Biological carbon pump
Photosynthesis - respiration
physical process
Upwelling transport and
diffusion of the adsorbed
atmospheric CO2
Results: biological and physical contributions on DIC
NWM
TYR
ALB
SWM
ION
LEV
Decomposition of physical and biological
effects: average annual signal
Biological carbon pump
Photosynthesis - Respiration
Seasonal cycle of
phytoplankton
production and
community
respiration
mmol/m3/d
mmol/m3/d
Results: CO2 flux at air-sea interface
OPATM-BFM:
sink of 1.6 x 1012 mol/y
(-0.65 mol/m2/y)
Other estimates:
0.35-1.85 x 1012 mol/y
Copin-Montegut, 1993
2.1 x 1012mol/y
Huertas et al., 2009
Sink
molC/m2/y
source
From D’Ortenzio et al., 2009
Results: CO2 flux at air-sea interface
OPATM-BFM:
sink of 1.6 x 1012 mol/y
(-0.65 mol/m2/y)
Sink
molC/m2/y
source
Switching off the biology from the system
-20% of atmospheric CO2 sink
 quantification (€) of the role of biology
(ecosystem service) in carbon cycle
Conclusions:
•Mediterranean sea has strong spatial variability of carbonate
system (model can help in reconstructioning patterns)
•Physical processes impact the spatial and temporal
variability
•Biology has lower effect on seasonal scale but impacts on
longer time scale
• CO2 flux affected by biological pump (~20%) at the
present atmospheric pCO2 conditions
THANK YOU
Reseach founded by
http://medsea-project.eu/
http://www.ritmare.it/