fapesp s research program for global climate change ... · camrex nsf •fapesp •nasa •cnpq lba...
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PIs: Maria Victoria R. Ballester; Reynaldo L. Victoria; Alex V. Krusche & Jefrey E. Richey –Co- Is: Humberto R. da Rocha (IAG-USP); Hilandia da C. Brandão (INPA, AM); Maria E.C. Sales & José F.B.R da Silva (MPEG); Ivan B.T. de Lima (EMBRAPA
Pantanal); Cleber I. Salimon (UFAC); Alan C. da Cunha (UFAM); Beatriz M. Gomes (UNIR); Kelli C.A. Munhoz (UEMG); Christopher Neill & Linda Deegan (MBL, EUA); Mark S. Johnson (UBC, Canada)
FAPESP’s Research Program for Global Climate Change
(PFPMCG) annual workshop
São Paulo, February 18 -19, 2016
NSFCamrex• FAPESP• NASA• CNPq
LBA FAPESP: Belmont Forum e SPECPFPMCG
1981 - 1998 1999 – 2007 2008 – Current
• Rivers and freshwater ecosystems release high levels of CO2 to
the atmosphere
• Globally these waters process, transport and sequester 2.7 Pg C
yr-1 (a)
• Similar value to the estimated for terrestrial ecosystems carbon
sequestration from human activities (2.8 Pg C yr-1 (b))
(a) Battin et al., 2009; Tranvik et al., 2009, (b) Canadell et al., 2007;
Fluvial processing plays a key role on carbon (and associate nutrients) transport and re-
cycling not only in the watersheds but also in the oceans that receive their waters.
Raymond, 2005)
develop tools to comprehensively describe Amazonian fluvial
biogeochemistry and the role of rivers in the regional C cycle to predict
their responses to climate change
Long term data collection : 20 extensive sampling (Rede Beija-Rio), distributed in
the Amazon basin
+
Intensive campaigns employing several measurement methods and laboratory
experiments at least once at each stage of the hydrograph, at several spatial scales
Produce scientific data on Amazonian fluvial systems to feed
a carbon base basin wide model to predict their responses to
global climate change and regional land use change
Evading to the atmosphere ~0,5 Gt C yr-1
13 x more C than discharged to the ocean:
TOC: 0,036 and DIC: 0,035 Gt.yr-1
Higher than the amount released by regional deforestation at it’s
peak (0,38 GtC yr-1, ~25.000 km2. yr-1)
We have demonstrated that the rivers of the Amazon play an important role in the regional carbon cycle
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C (‰)
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CP
OC
FP
OC
DO
C
contemporaryC4 grasses
contemporarylowland
C3 plantsatmosphere
carbonate rocks,solid earth CO2
CO
2
Legend
Mountain
Mixed
Lowland
1991
2003
old
er
carbonate weathering bycontemporary plant CO2
55 % of terrestrial lignin is
degraded by in channel bacteria
What is these CO2 main source?
In channel
respiration of young
labile organic matter
(~5 year)
CO2 evasion main C export pathway:
289 Gg C yr−1
~2,4 x the amount of C exported as dissolved inorganic carbon
(121 Gg C y−1) and 1,6 x as dissolved organic carbon (185 Gg C
y−1)Ji-Paraná River Basin
~92% of the Amazon river network are small rivers,
usually supersaturated with CO2
• surface small rivers area: 0,3± 0,05 millions of km2,
• Potential evasion to the atmosphere:170 ± 42 Tg C
y−1 as CO2
• Relevant role in the regional carbon cycle
Rasera et al., 2008
The most striking finding of our current integrated network approach is that, regardless of
any scale or basin characteristic, the distribution of biogenic species show the same
seasonal patterns, tightly connected to the hydrograph
5 year time series of CO2 fluxes in Amazon rivers, spanning
the whole hydrograph and encompassing representative rivers
of the region
Group I- drain low lands,
highly weathered, high
levels of DOM, low DIC
and pH
While these river can be separated into 3 groups according to their water characteristics:
Solimões
Group III- drain the Brazilian shield, low sediments
and OM, inter medium DIC levels, pH ~ neutral
Group II- High sediment transport from the Andes,
high DIC concentrations and pH ~ neutral
Negro, Cristalino and Caxiuanã Teles Pires, Javaés
CO2 Fluxes seasonal cycles
High viariability for both low and high water: -0,8 a
15,3 mmol CO2 m-2 s-1
0
1000
2000
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9000
Ris
ing
Hig
h
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ng
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ing
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h
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h
Falli
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Low
2006 2007 2008 2009 2010
pC
O2
(at
m)
Solimões
Caxiuanã
Negro
Araguaia
Javaés
Teles Pires
Cristalino
ATM
• CO2 Fluxes always higher at high water
• Key to develop adequate models to
describe C cycle: a seasonal pattern link to
the hydrograph can simplify scaling
• Wide spatial and temporal variability
• Hydrograph differential effect
• We estimate an emission of 0.49(±0.09) Tg CH4 yr -1 from large
rivers Or 44 – 65% of the global tropical river CH4 emissions and
22 – 28% of the global river emission
• These values are to 31–84% higher than the previous estimate
(Bastviken et al., 2011)
Two mechanism of emission, diffusion and ebullition + Methane oxidation
MOX
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E.G.: Higher levels of MOX at high
water in black and white water rivers
and minimal in clear water at low
water
Abundance of genetic markers for MOX bacteria (pmoA) were positively correlated
with enhanced signals of oxidation: independent support for the detected MOX
patterns.
varied according to hydrologic regime and general tributaries geochemical
characteristics.
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• MOX in large Amazonian rivers can consume from
0.45 to 2.07 Tg CH4 yr-1 or up to 7% of the estimated
global soil sink.
• Climate change and changes in hydrology (e.g.
construction of dams) can alter this balance,
influencing CH4 emissions to atmosphere.
(MOX): diffusive CH4 flux can be reduced by ~ 28 –
96 %
• Current CO2 flux: 0.8 Pg C yr-1 for upstream rivers from Óbidos (~70 % of the amazon basin)
• This value is 60 % higher than our previous measurements
• Fluxes are highly correlate to the hydrograph, moreover climate changes can lead to a significant change in ecosystem metabolism
12,636,7
215,4 239,9
504,7
14 44
108,9 54,3
221,3
0
100
200
300
400
500
600
700
800
Main stem Floodplain Main tributaries Samll rivers Total
2015 2002
Main tributaries: ~2 x Small rivers: ~4.4 x
similar fluxes
Total: ~2.3 x