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The Role of Rivers in the Global The Role of Rivers in the Global Carbon Cycle: Landscape-Hydrology-Carbon Cycle: Landscape-Hydrology-
Biogeochemistry ConnectionsBiogeochemistry Connections
Ocean 582/529 Fall ‘03
I. Review of overall Rivers cycle
II. In depth analysis of components, to ….
III. … derive functional models of a geographic-specific global view
VEGETATION
SOILS (+)
ATMOSPHERIC CO2
Active SOM,NP (1-2y)
Int. SOM,NP (20-40y)
Pass, SOM,NP (1000y)
Litter
COASTALOCEAN
SHELF SEDIMENTS
~.4 aw
DOC UV Ox?
.1 cw, ~.4aw
.1 cw,~.4aw
.2
.2
MCO3
.2S&S
gigatons/ycw = conventional wisdomaw = alternate wisdomS&S = sensu Sarmiento & Sundquist(+) anthro. effect
RIVERS
GLOBAL RIVER C CYCLE
ESTUARIE
S
ANTHROPOGENICN,P, Toxics
(+:1.8+1.1)
(P Desorp)
PPR
PPT->Q
DAMSRIP
ARIAN
(1)CO2+H20+M(C,Si)O3->M+2HCO3(2) SOM->CO2
erosion, PPr
leaching
DIC (pCO2,HCO3)
POC (.5uM - 1mm)
DOC (%s < .5uM)
Q (N,P,Toxics)
.4 (+)
.2 cw .5aw(++)
.2 (~)
.1 cw, ~.4aw
COASTALOCEAN
THE RIVER CONTINUUM
0
4
8
0
102030
0
600
1,200
0
200
400
0
200
400
-10
-20
-30
0
10
20
0
0.6
1.2
DOC (mg/l)
pCO2 (uM) O2 (uM)
DON (uM)
NO3 (uM) PO4 (uM)
DIC (uM)
DIC13 (permil)
FSS (mg/l) CSS (mg/l)
0
400
800
050
100150
50,000
100,000
150,000
200,000
250,000June 2
Oct 20
Dis
cha
rge
(m
3/s
)
Time over a water year
Time (water year)
OBIDOS: “New Orleans”
Amazon
Zaire
Orinoco
Yangsei
Brahmaputra
Yenisei
Lena
Mississippi
Ganges
Mekong
0
50,000
100,000
150,000
200,000
250,000Amazon
ZaireOrinoco
Yangsei
Brahmaputra Yenisei Lena
Mississippi
Ganges Mekong
195,000
40,00035,000
28,000
19,000 18,00016,300
15,80015,600
14,800
0
2
4
6
8Amazon
Zaire
Orinoco Yangsei
Brahmaputra
Yenisei Lena Mississippi
Ganges Mekong
6.10
3.80
0.991.90
0.61
2.60 2.503.30
0.980.79
Discharge (m3/s)
Basin Area (Mkm2)
0
300
600
900
1,200
1,500Amazon
Huanghe
Brahmaputra Ganges
Yangsei
Irrawaddy
Magdalena Mississippi
Godavari Mekong
1,200
1,100
540 520 480
260220 210
170 160
Sediments (MT/y)
Top 10 Rivers
TOP 10, REST OF RIVERS
Discharge 1.3 M m3/s Sediment Transport: 31,000 MT/y
2456 78 13
10 9
23 456
78
10 19
Amazon (1) Zaire (2) Orinoco (3) Yangsei (4)Brahmaputra (5) Yenisei (6) Lena (7) Mississippi (8) Ganges (9) Mekong (10)
Amazon (1) Huanghe (2) Brahmaputra (3) Ganges (4) Yangsei (5) Irrawaddy (6) Magdalena (7) Mississippi (8) Godavari (9) Mekong (10)
Amazon
AsSE
Ocn
ErsA
AfrW
AsE
NAmENAmW NAmA
SAmE
EurW
SAmW
CAmAfrE
EurEAus
Ocn
AsE
AsSE CAmSAmE Amazon
SAmW
NAmANAmEEurENAmW
AfrWAfrEErsA
EurWAus
Discharge
Sediment Transport
1.3 M m3/s
31,000 MT/y
GEOGRAPHIC ZONES
Oce
AsE
AsSE
SA NE
SA W
SA SENA W
NA At
NA EGEA At
Eur
Afr W
Afr E
Aust
0
50
100
150
200
250
300
350
"Traditional": 200
Area-loading: 350
Calc. Yield: 800
POC Loading by Geographic Region
"Best Guess: ~500 ish"
Tg/y
Consequences for different assumptions in computation of POC yield by geographic zone, ranging from the conventional wisdom of .2 Gt/y , to an area-loading function (.35 Gt/y), and a calculated yield function (.8 Gt/y). ZonesInclude Oceania (Oce), East and Southeast Asia (AsE, AsSE), South America (North-east SA NE, western SA W, southeast SA SE), North America (West NA W, Atlantic NA ATL, East and Gulf NA EG), Europe & Artic (Atlantic EA At, Eur), Africa (West W, East Afr E) and Australia (Aust).
SPO
Ica
Jut Jur
JapPur
Neg Mad
Tro
Tap Xin
Par
0
10,000
20,000
30,000
40,000
50,000
par = sum "parana"Tap, Xin approxTocantins not incl
AMAZON TRIBUTARIES
FLUVIAL SYSTEMS BOX MODEL
SOILS
RIVERS
STREAMS
ATMOSPHERE
DAMS CoastalZone
FLOODPLAINS
RIPARIAN
Soils
Rivers
Streams
Atmosphere
DamsCoastal Zone
FloodplainsRiparian
PATHWAYS OF ATMOSPHERIC CO2 THROUGH FLUVIAL SYSTEMS
Richey, J.E. (in press). Ch. 15. Field et al (eds) A SCOPE/GCP Rapid Assessment Project. Island Press.
Conventional Wisdom
- 0.6
0.6 River← Atm
POC → sea
DOC → sea
DIC → sea
Δ Net Atm
Cont Sed
Outgassing
-2.0 -1.0 0.0 1.0 2.0 Gt C/y
- 1.1
1.3
CW + Continent Sediment
↓ ↓
- 1.6
1.8
2.5x
2x
?
CW+CS+(POC,DOC)
↓
2.5x
2x
CW+CS+OC+OG
↑
- 0.2
2.6
?
Transient
- 0.3
1.3
STRUCTURE OF LAND-FLUVIAL SYSTEMS
River Routing and Sediment Transport NetworkGas Exchange
FloodplainErosion
Deposition
Estuary/Delta
Reservoirs Free-Flowing
Land Surface Processes (Grid)
Surface Water
River Routing
mineral soil
Water and dissolved
Fresh OM Particulate
Riparian/FloodplainUpland
SCALINGAmazon Floodplain from Aircraft: ‘eye’
Amazon Floodplain from Landsat TM: 30 m
Xingu (Amazon trib) from AVHRR: 1 km
Taiwan: AVHRR to Global 1-degree (~100 km)
“HYDROLOGY” IN A REGIONAL NPP MODEL (e.g., CASA)
Water Stress Scalar Formulation:We(t) = 0.5 [1 + ET(t) / PET(t)] From hydrology model
NPP(t) = emax * Te (t) * We (t) * FPAR (t) * PAR(t)
FPARGlobal CASAcalibration Sn Albedo
Surf. Temperature Sn, Temp., Rain,Ln, Soils, Roots
INTERANNUAL NPP MODEL (CASA Potter et al)
Tg C 8-km-1 mo-1
-1.0 -0.5 0 0.5 1.0
INIT 82 83 84 85 86 87 88 89 90
0 25 50 75 100
0
125
250
375
500
col
row
-1000000-500000 0 500000 1000000
6 N
20 S
La
titu
de
1983 1985 1987 1990
g C m-2 yr-1
-500 -250 0 250 500
RIVERS & FLOODPLAINS (> 100 m in width)
$
$
$
$$
$
$
$$
$
$
$
$$$
PB-1
PB-2
JaruJIP-3
COM-1
COM-2
JIP-1
Rolim
UrupáJIP-2
JIP-4
JIP-5Preto
Machadinho
Streams (< 100 m) STREAMS & RIPARIAN (< 100 m)
15
0
5
10
20
25
30
J F M A M J J A S O N D
CO
2 E
vas
ion
(T
g C
mo
-1)
T (>100m)
S (<100 m)MF
MC
: 1.2 ± . 3 Mg C ha-1 y-1 (basin ~ .5 Gt y-1)
CO2 EVASION: FROM WATER → ATMOSPHERE
Low-ElevationHigh-Elevation
DIC - UDOC -FPOC -CPOC
14C
14C: Downstream Translocation
Space & Time
Soil CO2
SoilDOC
Litter-fall
Macro-phytes
0%
10%
20%
30%
40%
Plankton
Sources & Implicit Dynamics?
Central Amazon Basin (1.77 million km2)
Methane Emission CO2 Evasion Tg C y-1 Tg C y-1
7.6 + 2.3 210 + 60
Lowland Amazon Basin (5.19 million km2)Methane Emission 25 + 8 Tg C y-1
Greenhouse gas potential ~ 0.5 Pg C y-1
as CO2
CH4 and CO2 Emissions
IMPORTANCE OF EPISODIC EVENTS
ENSO-Orchestrated Sediment Accumulation on Bolivian Amazon floodplains (Aalto et al. Nature 2003) [& utility of SRTM]
NORTH AMERICA: “ambiguous, but provocative”
Increase in the export of alkalinity from North America’s largest river (Raymond & Cole, Science, 2003)
Long-term decline in carbon dioxide super-saturation in rivers across the contiguous United States. (Jones et al, Geophys Res Lett in press)
RECENT GBC Publications on Trace Gas Sources & Sinks in Peatlands, Tundra, Rice paddies, Savannas; as f(water table depth, flow regimes…)
Torben Christensen “….a good understanding of local controls … does not necessarily explain large scale gradients…..”
Progress, but not there yet…….
NAGA Version 2 (1-km)Physical Template, Dynamic Modeling, Drivers
BIOPHYSICAL DATA LAYERS
(REGIONAL) HYDROLOGY ←→BGC: Q= ΣR = P – ET + ΔSM
HYDROLOGY MODEL “FIELDS”
Soil Moisture→ Discharge→ Trace Gas Biogeochemistry
Rn
LAI
T
UNCERTAINTIES IN POC LOADING BY GEOGRAPHIC REGION
Oce
AsE
AsSE
SA NE
SA W
SA SENA W
NA At
NA EGEA At
Eur
Afr W
Afr E
Aust
0
50
100
150
200
250
300
350
"Traditional": 200
Area-loading: 350Calc. Yield: 800
"Best Guess: ~500 ish"
Tg/y
Average OC concentration of Fly-Strickland river samples ~ 3.75% (June ’03)
IMPORTANCE OF EPISODIC EVENTS
ENSO-Orchestrated Sediment Accumulation on Bolivian Amazon floodplains (Aalto et al. Nature 2003) [& utility of SRTM]
physical forcing via remote sensing
(solar radiation, FPAR, rainfall, temperature)
terrestrial NPP
and biomass turnover
via CASA ecosystem model
hydrology
via VIC model
soil biogeochemistry
via ROMBUS model
aquatic biogeochemistry
via ROMBUS model
geographical properties via GIS
(vegetation, soil, topography, river network, etc.)
DOC, DIC
CO2
evasion
heterotrophicrespiration
DOC
POCDIC
CO2
fixation
water flux
carbon flux
autotrophicrespiration
ROMBUS (River basin Organic Matter and Biogeochemistry Synthesis Model)
HMW DOC(1-30 kDa)
LMW DOC(<1 kDa)
CH4
Mineral-Associated OM(FPOM) (0.1 µm - 63 µm)
HMW FPOC(1-30 kDa)
LMW FPOC(<1 kDa)
Detrital Particulate Organic Matter (>2mm)
Production via Terrestrial Biosphere Model
Living Organic Carbon
CPOC
CO2CO2, CH4
Black C (soot and charcoal)
DOM (>0.1 µm)
CPOM (63 um - 2 mm)DIC
VHMW DOC(>30 kDa)
VHMW FPOC(>30 kDa)
Structural C(insoluble)
Metabolic C(soluble)
LMW DON(200-1000Da)
VLMW DON(<200Da)
NH4
LMW FPON(200-1000Da)
VLMW FPON(<200Da)
Detrital Particulate Organic Matter (>2 mm)
Structural N(insoluble)
Metabolic N(soluble)
Production via Terrestrial Biosphere Model
Living Organic Nitrogen
CPON
Sorbed NH4
CPOM (63 um - 2 mm)
NO3
N2, NOx
NH3
Mineral-Associated OM (FPOM)
(0.1 µm - 63 µm)VHMW DON
(>30 kDa)VHMW FPON
(>30 kDa)
DOM (>0.1 µm)
Carbon Nitrogen
Biotic fluxes
Abiotic fluxes
NESTED AND COUPLED MODELS; e.g.
FLOODS OF THE MEKONG (2000)