Geoscience Reference
In-Depth Information
1.41
(a)
r
2
= 0.81
p
< 0.001
1.36
1.31
1.26
y
= 0.0031x + 1.24
1.21
0
5
10
15
20
25
30
35
40
45
Continuous cropland in riparian zone (%)
1.41
(b)
r
2
= 0.69
p
< 0.001
1.36
1.31
1.26
y
= -0.0132x + 1.36
1.21
0
1
2345678
Wetland in riparian zone SQRT %)
Figure 3.8. Relationships between indices of DOM character and landcover. The best predictors
for fluorescence index
(a,b)
. (Reprinted from Wilson and Xenopoulos,
2009
, by permission from
Macmillan Publishers Ltd:
Nature Geoscience
.)
be utilized to provide information about environmental conditions and the biogeochemical
transformations that are taking place, which is very informative in studies examining nutri-
ent cycling in hyporheic and riparian ecosystems (Fellman et al.,
2010
).
Protein-like fluorescence has been linked to biological labile DOM in a range of fresh-
water ecosystems. For example, a study in
Lakes of Southern Quebec
by Cammack et al.
(
2004
) correlated protein-like fluorescence with bacterial production, bacterial respiration,
and community respiration. Laboratory incubation experiments from a diverse range of
freshwater DOM sources have also found strong relationships between protein-like fluo-
rescence and biodegradable DOM (Fellman et al.,
2009b
; Hood et al.,
2009
). Protein-like
fluorescence can also be used with respect to examining in stream uptake of DOM as
Fellman et al. (
2009c
) demonstrated that protein-like fluorescence decreased downstream
during soil leachate addition experiments in forested headwater streams in Alaska (USA).
In this leachate addition experiment, humic-like fluorescence did not change and protein-