inorganic and organic carbon spatial variability during ... · inorganic and organic carbon spatial...

Inorganic and organic carbon spatial variabilityin the Congo River

during high waters (December 2013) and low waters ( June 2014)

A.V. Borges 1, S. Bouillon 2, C. Teodoru 2, J.-P. Descy 3, T. Lambert 1

& F. Darchambeau 1

1University of Liège, Belgium2KULeuven, Belgium

3University of Namur, Belgium

ASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/

IntroductionASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/

Wetland

GLC 2000

HumidForest

Savannah

Savannah


Metamorphic

Courtesy of J. Hartmann

Siliciclastic and unconsolidated

sed.


Courtesy of J. Hartmann

Kisangani

Kinshasa

1700 km

Cruises & MethodsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/

164 stations29 variables

> 23,000 continuous measurementspCO2, cond, temp, pH, O 2, TSM, cDOM

ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/

0

20

40

60

80

100Conductivity (µS cm-1)High W (Dec. 2013)

Falling W (June 2014)

3

4

5

6

7

8

15 16 17 18 19 20 21 22 23 24 25← Dowstream Longitude ( °E) Upstream →

pH

Cuvette Centrale (Wetland) Black-water tributaries


0

5000

10000

15000

20000pCO2 (ppm) High W (Dec. 2013)


0

20

40

60

80

100

120

15 16 17 18 19 20 21 22 23 24 25← Dowstream Longitude ( °E) Upstream →

%O2 (%)

Cuvette Centrale (Wetland) Black-water tributaries

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

0 20 40 60 80 100 120

pCO

2(p

pm)

%O2 (%)

High W (Dec. 2013)


0 20 40 60 80 100Turbidity (mg L -1)


Black waters

White waters

0

20

40

60

80

100

120

0 200 400 600 800 1000 1200 1400 1600← Downstream Distance from Kinshasa (km) Upstream →

TSM (mg L -1)


Mainstem High W

Tributaries High W

Mainstem Falling W

Tributaries Falling W

Kasai

Savannahinfluenced

Deposition

0

20

40

60

80

100

120


TSM (mg L -1)


Mainstem High W

Tributaries High W

Mainstem Falling W


Increase inresidence time

0

20

40

60

80

100

120


TSM (mg L -1)


Mainstem High W

Tributaries High W

Mainstem Falling W


0

1

2

3

4

5


Particulate organic carbon (POC) (mg L -1)


Mainstem High W

Tributaries High W

Mainstem Falling W



Mainstem High W

Tributaries High W

Mainstem Falling W


0

10

20

30

40

50

60

70

80


Dissolved organic carbon (DOC) (mg L -1)

« Cuvette Centrale »(Wetland)

Savannah

0

10

20

30

40

50

60

70

80


Dissolved organic carbon (DOC) (mg L -1)


Mainstem High W

Tributaries High W

Mainstem Falling W


-40

-38

-36

-34

-32

-30

-28

-26

-24

-22


δ13C-POC (‰)


Mainstem High W

Tributaries High W

Mainstem Falling W


C3 plants

contribution of methanotrophic

bacteria ?

-40

-38

-36

-34

-32

-30

-28

-26

-24

-22

10 100 1000 10000 100000

δ13

C-P

OC

(‰

)

CH4 (nmol L -1)


contribution of methanotrophic

bacteria ?


-40

-38

-36

-34

-32

-30

-28

-26

-24

-22


δ13C-DOC (‰)

C3 plants

Mainstem High W

Tributaries High W

Mainstem Falling W


0

1

2

3

4

5

6

7

8

9


Chlorophyll-a (µg L -1)


Mainstem High W

Tributaries High W

Mainstem Falling W



0

1

2

3

4

5

6

7

8

9



Mainstem High W

Tributaries High W

Mainstem Falling W


0

1

2

3

4

5

6

7

8

9




Mainstem High W

Tributaries High W

Mainstem Falling W


0

2000

4000

6000

8000

10000

12000

14000

16000

18000


pCO2 (ppm)

Mainstem High W

Tributaries High W

Mainstem Falling W




Savannah


0

2000

4000

6000

8000

10000

12000

14000

16000

18000


pCO2 (ppm)

Mainstem High W

Tributaries High W

Mainstem Falling W



0

2000

4000

6000

8000

10000

12000

14000

16000

18000


pCO2 (ppm)

Mainstem High W

Tributaries High W



Mainstem High W

Tributaries High W

Mainstem Falling W


0

10000

20000

30000

40000

50000

60000


CH4 (nmol L -1)

Mainstem High W

Tributaries High W

Mainstem Falling W



0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000


CH4 (nmol L -1)

Mainstem High W

Tributaries High W

Mainstem Falling W




Savannah

0

5

10

15

20

25

30


N2O (nmol L -1)

Mainstem High W

Tributaries High W

Mainstem Falling W



Denitrification

0

5

10

15

20

25

30


N2O (nmol L -1)


Mainstem High W

Tributaries High W

Mainstem Falling W


Denitrification


10 100 1000 10000 100000CH4 (nmol L -1)

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

0.0 20.0 40.0 60.0 80.0

pCO

2(p

pm)

DOC (mg L -1)

Limitation of bacterial growth ?Low pH ?Low O 2 ?Low P ?


N2O

(n

mo

l L

-1)

CH

4 (

nm

ol L

-1)


A.V. Borges, F. Darchambeau, C.R. Teodoru, T.R. Mar wick, F. Tamooh, N. Geeraert, F.O. Omengo, F. Guéri n, T. Lambert, C. Morana, E. Okuku & S. Bouillon, submi tted

CH

4 (

nm

ol L

-1)

CH

4 (

nm

ol L

-1)


Steeper→ short residence time→ smaller flood areas→ high exchange + air


Borges, Darchambeau, Teodoru, Marwick, Tamooh, Geer aert, Omengo, Guérin, Lambert, Morana, Okuku & Bouillon, unpublished AFRIVAL et al. data-base + GLC 2000

%O

2 (

%)

%O

2 (

%)





pC

O2 (

pp

m)

pC

O2 (

pp

m)





AnnouncementsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/

023 Biogeochemistry and ecology of African inland w atersWednesday 17:00 - Andalucia 2 (Floor 1)

Bouillon et al. Biogeochemistry of Congo (Abstract ID:27067) O

Darchambeau et al. Plankton in the Congo (Abstract ID:26104) P

AcknowledgmentsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/

Funded byEuropean Research Council (ERC)

Fonds National de la Recherche Scientifique (FNRS)

inorganic and organic carbon spatial variability during ... · inorganic and organic carbon spatial...

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