Geoscience Reference
In-Depth Information
Table 7.1.
EEM peak locations (excitation/emission wavelength ranges)
Peak
Ex/Em (nm)
Description
A
260/380-460
Terrestrial humic-like
C
320-360/420-460
Terrestrial fulvic-like
M
290-310/370-410
Marine humic-like; microbial
N
280/370
Phytoplankton-derived; labile
T
270/340
Tryptophan; protein-like
B
270/305
Tyrosine; protein-like
Source
: Reproduced from Coble (1998).
Table 7.2.
The differences in DOM and COM fluorescence (in calibrated Raman units)
compared between river (fresh) and marine waters
Peak or peak ratio
Surface
Permeate
Retentate
% Recovery
River DOM
A
0.517
0.124
0.313
76
C
0.365
0.059
0.218
68
M
0.304
0.077
0.166
72
T
0.097
0.048
0.058
98
M/C
0.83
1.31
0.76
n/a
T/A
0.19
0.39
0.19
n/a
Marine DOM
A
0.042
0.020
0.022
99
C
0.014
0.003
0.009
86
M
0.021
0.013
0.009
103
T
0.031
0.018
0.009
85
M/C
1.51
4.33
1.01
n/a
T/A
0.73
0.90
0.40
n/a
The Retentate fluorescence was normalized by its concentration factor for comparison to the Surface
and Permeate fluorescence. Ratios of peak fluorescence are dimensionless. % Recovery is the vol-
ume-weighted mass balance of permeate fluorescence + retentate fluorescence (not normalized)
divided by the surface DOM fluorescence.
Table 7.1
, the M and T peak regions correspond to more freshly produced (autochthonous)
DOM sources (microbial and protein, respectively), while the A and C peak regions cor-
respond to more recalcitrant, terrestrial humified DOM sources (Coble,
1998
). Even if
these discrete peaks were not observable in EEM contour plots, the ratio of fluorescence in
the M peak region to the C peak region (M/C), for example, could indicate relative abun-
dance of microbial to terrestrial DOM sources. Similarly, the ratio of T/A describes the
