“Physical and Anthropogenic Controls
of the Biogeochemistry of the Ji-Paraná
River Basin (Western Amazônia)”
1Ballester, M.V.R.; 1Krusche, A.V.; 1Kavaguishi, N.L.; 2Gomes, B.M.;
1Victoria, D. de C.; Montebelo, A.A.; 3Neill, C.; 3Deegan, L.; 4Richey, J.E.
and 1Victoria, R.L.1Centro de Energia Nuclear na Aagricultura – Universidade de São Paulo; 2Universidade
Federal de Rondônia; 3Marine Biological Laboratory; 4University of Washington
CD-06, ND-03 and ND-09
What are the water stores and fluxes, and the controls on water movement and What are the water stores and fluxes, and the controls on water movement and
transport of constituents on and below the surface of small uniform basins? transport of constituents on and below the surface of small uniform basins?
How does change of land use affect the sustainability of the ecosystem for different How does change of land use affect the sustainability of the ecosystem for different
soil types and topographies, and how can the larger scale models be improved to soil types and topographies, and how can the larger scale models be improved to
represent these small scale processes? represent these small scale processes?
What are the spatial and temporal patterns of surface and sub-surface water What are the spatial and temporal patterns of surface and sub-surface water
storage and flux in the soils and river corridors of the Amazon Basin, and how are storage and flux in the soils and river corridors of the Amazon Basin, and how are
they influenced by variations in climate and land use? they influenced by variations in climate and land use?
What are the characteristics of soil moisture and river flow for mesoscale basins What are the characteristics of soil moisture and river flow for mesoscale basins
and how can they be predicted?and how can they be predicted?
Land surface Hydrology and Water Biogeochemistry specific questions
How do the pathways and fluxes of organic matter, nutrients and How do the pathways and fluxes of organic matter, nutrients and
associated elements through river corridors associated elements through river corridors (riparian, floodplain, channels (riparian, floodplain, channels
and wetlands)and wetlands) change as a function of land cover? change as a function of land cover?
RATIONALE
Several LBA studies have shown that forest clearing
in the Amazon can alter the transport of sediments,
organic matter and associated nutrients to the rivers
Our previous results demonstrated that both soil properties
and land use are the main drivers of river biogeochemistry
and metabolism
Na+
Ca2+
Mg2+
K+
ECCl-
PO43-
TZ+
0 - 200
201 - 450
451 - 700
Pasture
ECEC
1
2
3
4
5
6
7
8
9
10
11
12
The pasture explained 99% (p < 0,01) of
the variability observed in most of the ions
concentrations
Cattle pasture are statistically correlated
with nutrient content
Ballester et al., 2003
River biogeochemistry drivers
0
10
20
30
40
50
60
70
0 50 100 150 200 250 300 350
Julian Day
0
50
100
150
200
250
[Na] (µM)
Q (m3.s-1)
- Differential effect of geology and soil properties - Human effects
Rio Urupá
JIP em Cacoal
River ions concentrations are control by different mechanism
Spatially integrated analysis of Ji-Paraná basin
(RO).
OBJECTIVE
Evaluate physical and anthropogenic controls
on river biogeochemistry at the mesoscale
level
Ji-Paraná
Study area
Is the 3rd most deforest State in the
Braziliam Amazon (INPE, 2003)
Is responsible for ~10% of the Braziliam
Amazon deforestation, around 20.000
km2 year-1 are cleaned in RO
Classe
Pasto
Flor esta
Água
Ur baniz ação
Cer r ado
Cult ur as Anuais
Rebr ot a
Solos expostos
Nuvens
Out r os
Legenda
Land use/cover (1999)
habitantes
2527 - 8233
8234 - 21862
21863 - 47382
47383 - 106800
106801 - 334661
estradas
habitantes
0
1 - 15434
15435 - 36542
36543 - 95356
95357 - 334741
estradas
habitantes
0
1 - 23156
23157 - 48759
48760 - 97799
97800 - 287534
estradas
habitantes
0
1 - 34751
34752 - 67030
67031 - 133882
estradas
habitantes
0
27016
84048
estradas
2000
19961991
19801970
In 30 years: the population grew 12x,
there is an increase in cattle pastures
and a loss of about 24% natural
forest
Legend
Soil unit (area)
Alfisol (12.6%)
Entisol (16.2%)
Eptisol (1.8%)
Oxisol (46.1%)
Ultisol (23.1%)
Water (0.3%)
estradas
20001999
199819971996
199519941993
199219911990
Legenda: = 5.000 cabeças
estradas
20001999
199819971996
199519941993
199219911990
Legenda: = 5.000 cabeças
Ordem
1
2
3
4
5
6
7
Field work at 38 sites during both Wet
(January) and Dry (June) seasons
Spatially oriented (GIS physical template)
0
500
1000
1500
2000
2500
3000
3500
4000
4500
D F A J A O D F A J A
Dis
charge (
m3.s
-1)
2000 2001
Drainage area: 75. 400 km2
Q = 700m3.s-1,
To answer our research on land use change and soil properties as
drivers of water chemistry in the Ji-Paraná River Basin, we:
Impact SBases
Low 0.26 - 0.79
Medium 0.39 – 0.52
High 0.57 – 0.91
Very high 0.76 – 0.96
Each site represents a different mixture of cover type and soil properties
Legend
Soil unit (area)
Alfisol (12.6%)
Entisol (16.2%)
Eptisol (1.8%)
Oxisol (46.1%)
Ultisol (23.1%)
Water (0.3%)
Impact (% of pasture area) Area %
Low - 0 –15% 37
Medium 15 - 30% 16
High 30 - 50% 16
Very high 50 - 75% 32
To quantify the effects of these two drivers, we performed a
multiple linear regression analysis, relating basin characteristics
and RBGC
Data Analysis
Independent variables
Saturation of bases and percentage of
pastures
River water:
Electrical conductivity (EC) Na+,
Ca2+, Mg2+, K+, Cl- , DOC, TSS, DIC
and PO43- concentrations
Dependent variables
Pasture
ECEC
1
2
3
4
5
6
7
8
9
10
11
12
Pasture
ECEC
1
2
3
4
5
6
7
8
9
10
11
12
RESULTS
Pasture
ECEC
1
2
3
4
5
6
7
8
9
10
11
12
Pasture
ECEC
1
2
3
4
5
6
7
8
9
10
11
12
y = 6.1355e2.3397x
R2 = 0.5611
0
10
20
30
40
50
60
70
80
0 0.2 0.4 0.6 0.8 1 1.2
Base saturationPa
stur
e ar
ea (
%)
~90% of the pasture areas were in
eutrophic soils in 1999
Pasture areas are related to more fertile soils (higher
ECEC and BS) and this relation is statically significant
(p<0.01)
Higher values of all ions were associated with areas dominated by
pasture
Spatial patterns
Lower reaches, forests dominate the landscape, and the concentrations
drop.
Highest concentrations found in the central part of the basin, where
pasture areas and soil fertility are at a maximum
TZ+
0 - 200
201 - 450
451 - 700
Pasture
ECEC
1
2
3
4
5
6
7
8
9
10
11
12
TZ+ values for the
waters of the Ji-
Paraná river
Higher DOC concentrations were related to higher values of
TSS
During the dry season this pattern was not observed.
TSS, in turn, were originated in pasture areas.
17 Fevereiro - Floresta
0
10
20
30
40
50
60
70
9:3
7
9:4
7
9:5
7
10:0
7
10:1
7
10:3
8
10:4
8
10:5
8
11:0
8
11:3
3
12:1
3
12:5
3
13:3
3
Horas
Flu
xo
(m
g.s-1)
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Descarg
a (L
.s -1)
Fluxo COD Descarga
17 Fevereiro - Pastagem
0
500
1000
1500
2000
2500
9:4
1
9:5
1
10:0
1
10:1
1
10:2
1
10:3
1
10:4
1
10:5
1
11:1
6
11:5
6
12:3
6
13:1
6
Horas
Flu
xo
(m
g.s
-1)
0
20
40
60
80
100
120
140
Descarg
a (L
.s-1)
Fluxo COD Descarga
Gouveia Neto et al., CD 36.13
Forest: higher infiltration
deeper into the soils and
canopy interaction
Pasture: soil is compacted,
there is less infiltration and
higher surface run off
promoting the leaching of
soil superficial layers caring
more DOC to the stream
The pasture stream showed higher “peaks ” of DOC fluxes when compared to the forest stream
DOC during the wet season as a function of land use
impactImpact Area % Min DOC MAX DOC
Low 37 4 313
Medium 16 170 399
High 16 183 367
Very high 32 296 423
Electric Conductivity
0
20
40
60
80
100
120
140
Wet Dry
Na +
WET DRY50
60
70
80
90
100
110
120
130
140
150K +
WET DRY36
38
40
42
44
46
48
50
52
54
56
58
60
62
64
66
Mg 2+
WET DRY30
35
40
45
50
55
60
65
70
75
80
Wet x Dry season
DOC
WET DRY120
140
160
180
200
220
240
260
280
300
320
340
360
Ca 2+
WET DRY30
40
50
60
70
80
90
100
110
120
TSS
WET DRY8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
Wet x Dry season
Wet x Dry season and Pasture x Soils
R2 Pasture Soil Base Saturation
Na+ 0,74 58 38
Cl- 0,54 67 13
K+ 0,72 68 25
Mg2+ 0,87 19 81
Ca2+ 0,8 14 80
DOC 0,82 44 56
Statistically significant for p < 0.01
The percentage of the basin
area covered by pasture was
consistently the best
predictor for all parameters
during the wet season.
Concluding remarks
Conversion of forest into pastures is
changing river biogeochemical composition
However, the degree of effect of each of these end members varies along a
wide range and regional (and local) patterns remains still to be investigated