Geoscience Reference
In-Depth Information
(a)
300
NH
2
O
HO
OH
HYDROXYANTHRANILIC ACID
CH
3
200
N
H
O
SKATOLE
100
OH
HN
2
HN
N
H
TRYPTOPHAN
INDOLE
0
300
350
400
Emission Wavelength (nm)
(b)
OH
800
H
OH
H
2
N
O
OH
600
TYROSINE
NH
2
(
R
)
HO
OH
OH
H
N
400
NORADRENALINE
(
R
)
HO
OH
ADRENALIN
OH
OH
200
CATECHOL
DOPAMINE
HO
NH
2
HO
0
300
350
400
Emission Wavelength (nm)
Figure 8.6. Fluorescence properties and structures of
(a)
tryptophan and
(b)
tyrosine compared with
their respective degradation products. (Modified from Determann et al.,
1998
.)
(Jørgensen et al., 2011.) and to also apply for CDOM absorption (Nelson et al.,
2010
).
Earlier experimental work also supports these findings. Rochelle-Newall and Fisher (
2002
)
and Stedmon and Markager (
2005b
) have shown how humic-like fluorescence is not evi-
dently produced by phytoplankton directly, but by microbial activity on otherwise color-
less DOM. In contrast, amino acid-like fluorescence appeared to be produced during the
