Environmental Engineering Reference
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Okefenokee (acid adapted)
Corkscrew (neutral adapted)
100
100
A
B
Polysaccharide
Lignin
96
99
92
98
88
97
84
96
80
95
pH 3.8 pH 8.0
pH 3.8 pH 8.0
FIGURE 14.7 Percentage of remaining polysaccharide (A) and lignin (B) compounds after
degradation by microbes from a naturally acidic swamp (Okefenokee Swamp, pH 3.4-4.2)
and a neutral swamp (Corkscrew Swamp, pH 6-8) after incubation at different pH levels
(modified from Benner et al., 1989).
wetlands (i.e., once a wetland sediment becomes acidic, microbial activity
keeps it so and carbon continues to accumulate). Rates of microbial de-
composition of leaves are also lower in acidified streams (Fig. 14.8), which
may increase carbon accumulation and alter the associated food webs.
Algal populations are influenced by acidification. Filamentous green al-
gae characteristically bloom in the littoral zones of acidified lakes. When
100
pH 5.0 vs pH 6.4
pH 4.5 vs pH 5.7
90
80
70
60
50
40
30
20
10
0
0
2
4
6
8
10
12
14
16
Time (weeks)
FIGURE 14.8 Microbial activity on leaves placed in acid and neutral streams as measured
by the rate of thymidine incorporation into nucleic acids in two acidified streams compared
to two nearby neutral streams (modified from Palumbo et al., 1989).
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