Geoscience Reference
In-Depth Information
(a)
65
r = 0.48
55
45
35
25
15
5
0.8
1.0
Humification index of the water sample
0.9
0.8
1.2
1.3
(b)
1.35
1.20
1.05
0.09
r = 0.66
0.75
0.8
1.0
Humification index of the water sample
0.9
0.8
1.2
1.3
(c) 1.5
r = 0.89
1.4
1.3
1.2
1.0
0.9
0.8
1.0
Humification index of the water sample
0.9
0.8
1.2
1.3
Figure 9.2. Correlations of humification index (HIX
SYN
) for whole water (
x
-axis) with the
(a)
C/N
ratio of the sample,
(b)
humification index of the fulvic acid fraction, and (c) IR absorption at
1620 cm
-1
. The whole water HIX
SYN
is calculated as (ex 390/em 408)/(ex 355/em 373) and the fulvic
acid HIX
SYN
graphed here is calculated as (ex 400/em 418)/(ex 360/ em 378) using synchronous scans
with an 18 nm offset. (From Kalbitz et al. [
2000
] with minor modifications.)
potential to use spectroscopy on the original water sample to determine the chemical char-
acter of the humic material.
Kalbitz and Geyer (
2001
) further tested the humification index for the effect of DOC
concentration and spectrometer type (a LS 50B luminescence spectrometer by Perkin
Elmer and a SFM 25 spectrometer by BIO-TEK Instruments). They confirmed that
