Environmental Engineering Reference
In-Depth Information
FIGURE 2.5
Responses of primary
productivity to (a) iron additions in
the Southern Ocean (
Boyd et al. 2000
),
(b) nitrogen and phosphorus additions
in a lake (Peter Lake, MI;
Carpenter
et al. 2005
), (c) nitrogen and phospho-
rus additions to Hawaiian forests
growing on substrate (islands) of dif-
ferent ages (ky
1.4
(a)
(b)
120
Lake N/P
addition
Southern ocean
Fe addition
1.2
100
1
80
0.8
60
0.6
40
0.4
thousands of years)
(
Vitousek 2004
), and (d) additions of
iron alone and combined with nitro-
gen and/or phosphorus for water iso-
lated from Lake Erie (
North et al.
2007
), where letters (A, B, C) over bars
indicate statistically different groups.
5
20
0.2
0
0
Outside
Inside
No nutrients Plus N&P
(c)
4
3
2
1
0
C
N
0.3 ky
P
NP
C
N
P
NP
C
N
P
NP
20 ky
4100 ky
(d)
7
6
C
5
4
B
3
B
2
A
A
A
1
0
Control
Fe
Fe&N
Fe&P
Fe&P&N
P&N
