Environmental Engineering Reference
In-Depth Information
Autochthonous Fulvic Acids (C-like and M-like)
Two fluorescent components can be autochthonously produced from algae or phy-
toplankton biomass under photorespiration or microbial respiration (or assimila-
tion) in natural waters (Fig.
3
h-l; Table
2
) (Mostofa et al.
2009a
,
b
; Coble
1996
,
2007
; Parlanti et al.
2000
; Stedmon et al.
2007a
; Zhang et al.
2009a
; Balcarczyk
et al.
2009
; Murphy et al.
2008
; Aoki et al.
2008
). The first component can exhibit
either two or three fluorescence peaks, at Ex/Em
=
330-370/434-480 nm and
290-300/430-448 nm in the peak C-region as well as 250-270/434-480 nm in
the peak A-region (Fig.
3
h-j; Tables
1
,
2
). The EEM images of the first autoch-
thonous fluorescent component are similar to those of the allochthonous fulvic
acid (C-like). Therefore, this component can be denoted as autochthonous ful-
vic acid (C-like). The early stage of autochthonous fulvic acid (C-like) when it
originates from algae can exhibit three fluorescence peaks, which are subse-
quently altered into two peaks (Mostofa KMG et al., unpublished data). The
EEM spectra shows that the fluorescence intensity of autochthonous fulvic acid
Peak A
Peak C
Peak A
Peak C
(i)
(j)
(h)
Peak A
Peak M
(k)
(l)
Ex wavele ngth (nm)
Fig. 3
Continued
The fluorescent components of autochthonous fulvic acid (C-like) under microbial respiration or
assimilation of lake algae (
h
), autochthonous fulvic acid (C-like) under photorespiration or assimilation
of lake algae (
i
) in natural waters, Tributary of NenJiang River, China (
j
) as well as autochthonous
fulvic acid (M-like) in microbial respiration of lake algae (
k
) and in surface waters of Lake Hongfeng,
China (
l
) identified using PARAFAC modeling on the EEM spectra of their respective samples.
Data
source
Mostofa KMG et al., (unpublished data).
