Environmental Engineering Reference
In-Depth Information
(C-like) at the peak C-region is relatively high, or similar to the intensity at the
peak A-region (Fig.
3
h-j; Table
2
) (Mostofa et al.
2009b
; Stedmon and Markager
2005a
; Balcarczyk et al.
2009
). In contrast, the fluorescence intensity of alloch-
thonous fulvic acid (C-like) is higher at peak A-region than at peak C-region
(Figs.
2
a,
3
a). The autochthonous fulvic acid (C-like) showed fluorescence
peaks at Ex/Em
=
340-350/460 nm in the peak C-region and at 260/460 nm in
the peak A-region in mainstream and tributaries of NenJiang River, China; at
335-340/442-464 nm and 260/442-464 nm in surface waters of Lake Hongfeng,
China; at ~360/~460 nm (peak A-region not mentioned) in streams; at 340-
350/460, 340/448-454 and 260-270/448-454 nm upon photo-assimilation
of algae in Milli-Q and river water; at 340/448-455, 290-300/430-448, and
260-448 nm upon microbial respiration (or assimilation) in Milli-Q and river
water; at 365/453 and 270/453 nm upon microbial respiration (or assimilation)
of phytoplankton in isotonic water (0.5 ‰ salinity); at 355/445 and 280/435 nm
when originateng from algae under both light and dark incubation (12 h each);
at 350/400-450 and 275/400-450 nm in bay waters (Brazil); at 370/466 and
<260/466 nm in the deep waters of Okhotsk Sea and the North Pacific Ocean; at
340/420 and 260/420 nm in the Southern ocean; at 355/434 and 260/434 nm in
north Pacific and Atlantic oceans; and at 330-350/420-480 and 250-260/420-
480 nm in marine waters (Table
2
) (Mostofa et al.
2009b
; Coble
1996
,
2007
;
Parlanti et al.
2000
; Stedmon et al.
2007a
; Zhang et al.
2009a
; Wedborg et al.
2007
; Luciani et al.
2008
; Zhao et al.
2009
; Chen et al.
2010
; Yamashita et al.
2010
; Balcarczyk et al.
2009
; Murphy et al.
2008
).
On the other hand, the second fluorescent component of algal or phytoplank-
ton origin can exhibit one strong fluorescence peak in the peak C-region and one
minor peak (not often shown) in the peak A-region. The peak in the C-region is
located at shorter wavelengths compared to the first component of autochthonous
fulvic acid (C-like) (Fig.
3
k, l) (Mostofa et al.
2009b
; Coble
1996
,
2007
; Parlanti
et al.
2000
; Stedmon et al.
2003
,
2007a
; Stedmon and Markager
2005a
,
2005b
;
Zhang et al.
2009a
; Balcarczyk et al.
2009
; Murphy et al.
2008
; Yamashita et al.
2008
; Yamashita and Jaffé
2008
; Wang et al.
2007
). Considering the EEM images
of the second fluorescent component, which are similar to those of allochthonous
fulvic acid (M-like) (Fig.
3
c) and of marine humic acid denoted as M (Coble
1996
), such component can be denoted as autochthonous fulvic acid (M-like). The
autochthonous fulvic acid (M-like) of algae or phytoplankton origin usually exhib-
its two fluorescence peaks at Ex/Em
=
290-330/358-434 nm in the peak C-region
and at 225-360/358-416 nm in the peak A-region (Table
2
). The autochthonous
fulvic acid (M-like) is often detected in several studies in field and experimen-
tal observations, at Ex/Em
=
295-300/396-422 nm in the peak C-region and at
235-240/396-422 nm in the peak A-region in surface waters (0-25 m) of Lake
Hongfeng, China; at 315/372 nm in the waters of Lake Taihu; at 322/407 nm in
the waters of Lake Taihue; at 300/406 and 240/405 nm upon microbial respira-
tion (or assimilation) of algae in river water; at 290-310/400-410 nm upon micro-
bial assimilation of marine algae in Milli-Q water; at 295/398 nm upon microbial
production in a mesocosm experiment; at 320-325/388-428 nm in estuaries;
