Karol Kulinski

Marine Chemistry and Biochemistry Department

Supervisor: Janusz Pempkowiak

Carbon cycling in the Baltic Sea

Introduction Goal Methods Conclusion

CARBOOCEAN final meetingBergen, 5-9.10.2009

Borges et al., 2006

•Global uptake by the shelf seas 0.33-0.36 Pg C yr-1

•Global emission from estuaries, salt marshes and mangroves -0.50 Pg C yr-1

•(Chen & Borges, 2009)

Coastal and marginal seas sink or source of CO2?

Introduction Goal Methods Conclusion

The Baltic Sea:

- Semi-enclosed shelf sea

- Sea surface: 385 000 km2

- Catchment area: 1 700 000

km2

- Water volume: 23 000 km3

- River run-off : 428 km3

Baltic Sea sink or source of CO2?

• 10.8 g C m-2 yr-1 (Thomas et al.,

2003)

• 36.0 g C m-2 yr-1 (Kuss et al., 2006)

• -35.4 g C m-2 yr-1 (Algesten et al.,

2006)HELCOM, 2007

Introduction Goal Methods Conclusion

Baltic Sea

North Sea

Atmosphere

Land

Sediments

Fs

Fm

Fr

Fp

Ff

Fo Fa

Fe

Fi

Box model

Fi – input from the North SeaFe – output to the North SeaFo – precipitationFa – net CO2 exchange with atmophereFf – fisheries

Fp – point sourcesFr – river run-offFm – return flux from sedimentsFs – sedimentation

∑inputs = ∑outputs

Fi + Fe + Fo + Fa + Ff + Fp + Fr + Fm + Fs =

0

Fa = Fi + Fe + Fo + Ff + Fp + Fr + Fm + Fs

Inputs – positive

Outputs - negative

Introduction Goal Methods Conclusion

HELCOM, 2007

Carbon input from rivers is quantified based on the national monitoring programmes data.

Database :Period 2003-2008Monthly means of TOC and TIC concentrationsMonthly means water volume

63 the largest rivers 85% of the total water volume from river run-off

F = C • VF- carbon fluxC – carbon concentrationV – water volume

River run-off

Introduction Goal Methods Conclusion

North Sea

Baltic Sea

Carbon exchange between the Baltic and the North Sea

x + y = 1

SalB · x + SalNS · y = SalMod

x – Baltic water contribution

y – North Sea water contribution

Introduction Goal Methods Conclusion

Hydrodynamical model CMOD

•Period: VI.2002 – V.2006

•Time resolution: 1 hour

•Horizontal resolution: 2 nm

•Vertical resolution: 1mParameters:

•Water volume

•Salinity

•Temperature

F = C • VF- carbon fluxC – carbon concentrationV – water volume

Baltic Sea DIC

Thomas & Schneider,

1999

North Sea DIC

Prowe et al., 2009

North Sea

Baltic Sea

Carbon concentrations seasonality

DOC extrapolated from the weekly measurements in the near-shore zone.

Introduction Goal Methods Conclusion

•Algesten et al., 2006•Emeis et al., 2000•Christoffersen et al., 2007•PIG, 2005•Błaszczyszyn, 1982

Organic carbon deposition to the sediments

Surface of depositional

areas and the organic

carbon accumulation

rates are adopted from:

Introduction Goal Methods Conclusion

gradientionsconcentratcarbon

tcoefficiendiffusionsediement

porosity

fluxdiffusion

x

C

D

Jx

CDJ

sed

sed

Ullman & Aller, 1982

Carbon return flux from sediments

DOC and DIC fluxes from sediments are calculated

usingFick’s First Law

Introduction Goal Methods Conclusion

Baltic Sea

North Sea

Atmosphere

Land

Sediments

Fi = 3,90

Fe = -11,63Fr =

10,90

Fs =

-3,7

8

Fm =

1,1

4

Fp = 0,04

Ff = -0,06

Fo =

0,5

7

Fa =

-1,0

8

Values are in Tg C yr-

1

River run-offIC: 62%OC: 38%

Import from the North SeaIC: 95%OC: 5%Export to the North SeaIC: 83%OC: 17%

Deposition to the sedimentsOC: 100%

Return flux from the sedimentsIC: 91%OC: 9%

Net CO2 emission to the

atmosphere

-2.8 g C m-2 yr-1 ± 2.1 g C m-2 yr-1

Introduction Goal Methods Conclusion

Thank you

Chisholm, 2000

Anthropogenic CO2 emission ~6.5 Pg C yr-1 50% of this is accumulated in the atmosphere

~28-30% ocean uptake~20-22% land uptake

(Emerson & Hedges, 2008; Sabine et al., 2004; Takahashi et al., 2002 & 2009)

Introduction Goal Methods Conclusion