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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
IntroductionASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
Metamorphic
Courtesy of J. Hartmann
Siliciclastic and unconsolidated
sed.
IntroductionASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
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
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
0
5000
10000
15000
20000pCO2 (ppm) High W (Dec. 2013)
Falling W (June 2014)
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)
Falling W (June 2014)
0 20 40 60 80 100Turbidity (mg L -1)
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
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)
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
Mainstem High W
Tributaries High W
Mainstem Falling W
Tributaries Falling W
Kasai
Savannahinfluenced
Deposition
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)
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
Mainstem High W
Tributaries High W
Mainstem Falling W
Tributaries Falling W
Increase inresidence time
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)
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
Mainstem High W
Tributaries High W
Mainstem Falling W
Tributaries Falling W
0
1
2
3
4
5
0 200 400 600 800 1000 1200 1400 1600← Downstream Distance from Kinshasa (km) Upstream →
Particulate organic carbon (POC) (mg L -1)
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
Mainstem High W
Tributaries High W
Mainstem Falling W
Tributaries Falling W
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
Mainstem High W
Tributaries High W
Mainstem Falling W
Tributaries Falling W
0
10
20
30
40
50
60
70
80
0 200 400 600 800 1000 1200 1400 1600← Downstream Distance from Kinshasa (km) Upstream →
Dissolved organic carbon (DOC) (mg L -1)
« Cuvette Centrale »(Wetland)
Savannah
0
10
20
30
40
50
60
70
80
0 200 400 600 800 1000 1200 1400 1600← Downstream Distance from Kinshasa (km) Upstream →
Dissolved organic carbon (DOC) (mg L -1)
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
Mainstem High W
Tributaries High W
Mainstem Falling W
Tributaries Falling W
-40
-38
-36
-34
-32
-30
-28
-26
-24
-22
0 200 400 600 800 1000 1200 1400 1600← Downstream Distance from Kinshasa (km) Upstream →
δ13C-POC (‰)
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
Mainstem High W
Tributaries High W
Mainstem Falling W
Tributaries Falling W
C3 plants
contribution of methanotrophic
bacteria ?
-40
-38
-36
-34
-32
-30
-28
-26
-24
-22
0 200 400 600 800 1000 1200 1400 1600← Downstream Distance from Kinshasa (km) Upstream →
δ13C-POC (‰)
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
Mainstem High W
Tributaries High W
Mainstem Falling W
Tributaries 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)
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
contribution of methanotrophic
bacteria ?
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
-40
-38
-36
-34
-32
-30
-28
-26
-24
-22
0 200 400 600 800 1000 1200 1400 1600← Downstream Distance from Kinshasa (km) Upstream →
δ13C-DOC (‰)
C3 plants
Mainstem High W
Tributaries High W
Mainstem Falling W
Tributaries Falling W
0
1
2
3
4
5
6
7
8
9
0 200 400 600 800 1000 1200 1400 1600← Downstream Distance from Kinshasa (km) Upstream →
Chlorophyll-a (µg L -1)
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
Mainstem High W
Tributaries High W
Mainstem Falling W
Tributaries Falling W
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
0
1
2
3
4
5
6
7
8
9
0 200 400 600 800 1000 1200 1400 1600← Downstream Distance from Kinshasa (km) Upstream →
Chlorophyll-a (µg L -1)
Mainstem High W
Tributaries High W
Mainstem Falling W
Tributaries Falling W
0
1
2
3
4
5
6
7
8
9
0 200 400 600 800 1000 1200 1400 1600← Downstream Distance from Kinshasa (km) Upstream →
Chlorophyll-a (µg L -1)
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
Mainstem High W
Tributaries High W
Mainstem Falling W
Tributaries Falling W
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
0 200 400 600 800 1000 1200 1400 1600← Downstream Distance from Kinshasa (km) Upstream →
pCO2 (ppm)
Mainstem High W
Tributaries High W
Mainstem Falling W
Tributaries Falling W
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
« Cuvette Centrale »(Wetland)
Savannah
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
0 200 400 600 800 1000 1200 1400 1600← Downstream Distance from Kinshasa (km) Upstream →
pCO2 (ppm)
Mainstem High W
Tributaries High W
Mainstem Falling W
Tributaries Falling W
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
0 200 400 600 800 1000 1200 1400 1600← Downstream Distance from Kinshasa (km) Upstream →
pCO2 (ppm)
Mainstem High W
Tributaries High W
Tributaries Falling W
Tributaries Falling W
Mainstem High W
Tributaries High W
Mainstem Falling W
Tributaries Falling W
0
10000
20000
30000
40000
50000
60000
0 200 400 600 800 1000 1200 1400 1600← Downstream Distance from Kinshasa (km) Upstream →
CH4 (nmol L -1)
Mainstem High W
Tributaries High W
Mainstem Falling W
Tributaries Falling W
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
0 200 400 600 800 1000 1200 1400 1600← Downstream Distance from Kinshasa (km) Upstream →
CH4 (nmol L -1)
Mainstem High W
Tributaries High W
Mainstem Falling W
Tributaries Falling W
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
« Cuvette Centrale »(Wetland)
Savannah
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
0 200 400 600 800 1000 1200 1400 1600← Downstream Distance from Kinshasa (km) Upstream →
CH4 (nmol L -1)
Mainstem High W
Tributaries High W
Mainstem Falling W
Tributaries Falling W
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
« Cuvette Centrale »(Wetland)
Savannah
0
5
10
15
20
25
30
0 200 400 600 800 1000 1200 1400 1600← Downstream Distance from Kinshasa (km) Upstream →
N2O (nmol L -1)
Mainstem High W
Tributaries High W
Mainstem Falling W
Tributaries Falling W
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
Denitrification
0
5
10
15
20
25
30
0 200 400 600 800 1000 1200 1400 1600← Downstream Distance from Kinshasa (km) Upstream →
N2O (nmol L -1)
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
Mainstem High W
Tributaries High W
Mainstem Falling W
Tributaries Falling W
Denitrification
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
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 ?
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
N2O
(n
mo
l L
-1)
CH
4 (
nm
ol L
-1)
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
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)
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
Steeper→ short residence time→ smaller flood areas→ high exchange + air
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 (
%)
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
Steeper→ short residence time→ smaller flood areas→ high exchange + air
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
pC
O2 (
pp
m)
pC
O2 (
pp
m)
ResultsASLO 2015 Science MeetingGrenada, 22-27 Feb. 2015http://www.co2.ulg.ac.be/
Steeper→ short residence time→ smaller flood areas→ high exchange + air
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
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)