modeling black carbon in the environment
DESCRIPTION
Nguyen B, Lehmann J, Hockaday WC, Joseph S, Masiello CA (2010) Temperature sensitivity of black carbon decomposition and oxidation. Environ Sci Tech DOI: 10.1021/es903016y. - PowerPoint PPT PresentationTRANSCRIPT
Modeling black carbon in the environmentBente Foereid, Johannes Lehmann, Julie Major
Crop and Soil Sciences, Cornell University
Lab data for decomposition
y=1.452ln(x)-2.4599r2=0.7094
Temperature (oC)
0 20 40 60
Tem
pera
ture
mod
ifier
-1
0
1
2
3
4
5
0-15 cm
0
500
1000
1500
2000
2500
standardstable pool decomposition rateerosion ratemoisture modifiertemperature modifier
15-30 cm
Time since BC application (years)
0 20 40 60 80 100
BC
in s
oil l
ayer
(g m
-1)
0.0
0.1
0.2
0.3
Conclusions•Erosion is poorly quantified, but probably the largest flux of BC out of a given area •A two pool model can adequately describe BC decomposition dynamics•Decomposition rate of the slowest carbon pool is unimportant on time-scales < 100 y•Downwards movement is small as a mass flux, but not the only downward flux of BC
Major et al., 2010 Glob Change Biol 16:1366-1379
Nguyen et al., 2010 Environ Sci Tech 44, 3324–3331Whitman , 2010 M.Sc. thesis, Cornell University
Time (years)
0 500 1000 1500 2000B
C in
0-3
0 cm
soi
l (gm
-2)
0
100
200
300
400
500
standarderosion rateslow pool decomposition ratetemperature sensitivity
•Black carbon (BC) is produced in fires and is assumed to be stable in the environment•“Biochar” is BC intentionally produced for soil amendment•BC has not yet been explicitly introduced into carbon turnover models•Here we make a simple model accounting for loss of BC by decomposition and horizontal as well as vertical movement out of the area
Stable
Stable
Labile
Labile
CO2
Leaching
Erosion Erosion
Decomposition
15 cm
30 cm
Added black carbon
CO2
CO2
0-15 cm
400
600
800
1000
1200
1400
1600
1800
2000
2200
2400
2600
15-30 cm
Time since BC application (days)
0 200 400 600
Bla
ck c
arbo
n in
laye
r (g
m-2
)
0
5
10
15
20
25
30
SimulatedMeasured
RMSD=0.24
Time since BC application (days)
100 200 300 400 500 600 700 800
CO
2 pr
oduc
tion
from
BC
(g C
O2-
C m
-2da
y-1)
0.0
0.1
0.2
0.3
0.4
0.5
0.6
MeasuredSimulated
Field data for leaching
Results
Predicted and measured CO2 production. Data from Major et al. 2010 Predicted and
measure BC in top- and sub-soil. Data from Major et al. 2010
Effect of changing parameter values, erosion rate ± 50%, slow pool turnover rate 500-5000 y, alternative values for temperature and moisture modifier
Major J, Lehmann J, Rondon M, Goodale C (2010a) Fate of soil-applied black carbon: downward migration, leaching and soil respiration. Glob Change Biol 16:1366-1379Major J, Lehmann J, Rondon M, Goodale C (2010a) Fate of soil-applied black carbon: downward migration, leaching and soil respiration. Glob Change Biol 16:1366-1379Major J, Lehmann J, Rondon M, Goodale C (2010a) Fate of soil-applied black carbon: downward migration, leaching and soil respiration. Glob Change Biol 16:1366-1379Major J, Lehmann J, Rondon M, Goodale C (2010a) Fate of soil-applied black carbon: downward migration, leaching and soil respiration. Glob Change Biol 16:1366-1379Major J, Lehmann J, Rondon M, Goodale C (2010a) Fate of soil-applied black carbon: downward migration, leaching and soil respiration. Glob Change Biol 16:1366-1379Nguyen B, Lehmann J, Hockaday WC, Joseph S, Masiello CA (2010) Temperature sensitivity of black carbon decomposition and oxidation. Environ Sci Tech DOI: 10.1021/es903016y
Next step – earth system model, CLM
Model structure
100 y 2000 y