13. The Temperate Rainforest Lakes of Chile and Canada
269
Pacific Ocean (Thomasson, 1963). Annual precipitation averages from
1500 to 3000mm, and most of the rivers and streams show marked
seasonal hygrographs with high flows in winter and low flows in summer.
A similar pattern occurs in BC coastal lakes and rivers which experience
annual precipitation>2000mm with most occurring during the wet, winter
period (November to March) . The BC lakes are generally fast-flushing,
<3.5 y (Stockner, 1981), while the Chilean lakes show a longer water
residence time, >lOy (Table 13.1).
Catchment Basin
The soils on the Chilean lake catchments are predominately volcanic and
the original Valdivian rainforests are a diverse assemblage of nonconiferous evergreens represented by various combinations of Nothofagus
dombeyi, N. nitida, Aextoxicon, Laurelia, Drimys, Weinmannia, Podocarpus, Fitzroya, and so on (Alaback, 1991). Human disturbance has
altered from 5 to 60% of this original rainforest vegetation during the last
200 years (Campos, 1984; Campos et aI., 1988). The catchments now
Table 13.1. Some salient Iimnological variables from Chilean (Araucanian)
and Canadian (British Columbia south coastal) rainforest lakes . (Values are
annual means)
Area (knr')
Mean depth ~m)
Volume (km)
Residence (yr)
Secchi (m)
Compensation Depth (m)
Temp. summer (max . "C)
winter (max. "C)
Growing Season (mo)
Total P (ug -L-1)
Nitrate (ug· L-1)
Tot. N (ug-L-1)
Na (rng -L-1)
Ca (mg-L-1)
Mg (mg-L-1)
TDS (rng-L-1)
pH
CHL a (ug-L-1)
Prim . prod . (gC*m- 2*yr- 1 )
Zooplankton biomass (ug -L- 1)
Bacteria range (no. mL -1 x 10 6 )
Auto. picoplankton range (no. mL-1 X 10
3
)
Chilean
(n = 12)
209.3
139.4
31.5
10.4
13.2
36.5
22.5
10.0
8
4.8
18.2
78.6
3.2
3.6
1.3
63.0
7.4
0.7
89.4
18.8
0.08-1.3
11-132
British Columbian
(n = 8)
17.9
66.2
3.2
3.0
7.8
10.9
15.9
5.4
7
2.6
14.2
220.0
1.2
4.4
0.8
32.9
1
6.9
1.3
32.4
10.2
0.06-1.2
9-60
1 Untreated lakes (n = 5) (G. Central, Hobiton, Kennedy (2yrs), Long lakes)
269
Pacific Ocean (Thomasson, 1963). Annual precipitation averages from
1500 to 3000mm, and most of the rivers and streams show marked
seasonal hygrographs with high flows in winter and low flows in summer.
A similar pattern occurs in BC coastal lakes and rivers which experience
annual precipitation>2000mm with most occurring during the wet, winter
period (November to March) . The BC lakes are generally fast-flushing,
<3.5 y (Stockner, 1981), while the Chilean lakes show a longer water
residence time, >lOy (Table 13.1).
Catchment Basin
The soils on the Chilean lake catchments are predominately volcanic and
the original Valdivian rainforests are a diverse assemblage of nonconiferous evergreens represented by various combinations of Nothofagus
dombeyi, N. nitida, Aextoxicon, Laurelia, Drimys, Weinmannia, Podocarpus, Fitzroya, and so on (Alaback, 1991). Human disturbance has
altered from 5 to 60% of this original rainforest vegetation during the last
200 years (Campos, 1984; Campos et aI., 1988). The catchments now
Table 13.1. Some salient Iimnological variables from Chilean (Araucanian)
and Canadian (British Columbia south coastal) rainforest lakes . (Values are
annual means)
Area (knr')
Mean depth ~m)
Volume (km)
Residence (yr)
Secchi (m)
Compensation Depth (m)
Temp. summer (max . "C)
winter (max. "C)
Growing Season (mo)
Total P (ug -L-1)
Nitrate (ug· L-1)
Tot. N (ug-L-1)
Na (rng -L-1)
Ca (mg-L-1)
Mg (mg-L-1)
TDS (rng-L-1)
pH
CHL a (ug-L-1)
Prim . prod . (gC*m- 2*yr- 1 )
Zooplankton biomass (ug -L- 1)
Bacteria range (no. mL -1 x 10 6 )
Auto. picoplankton range (no. mL-1 X 10
3
)
Chilean
(n = 12)
209.3
139.4
31.5
10.4
13.2
36.5
22.5
10.0
8
4.8
18.2
78.6
3.2
3.6
1.3
63.0
7.4
0.7
89.4
18.8
0.08-1.3
11-132
British Columbian
(n = 8)
17.9
66.2
3.2
3.0
7.8
10.9
15.9
5.4
7
2.6
14.2
220.0
1.2
4.4
0.8
32.9
1
6.9
1.3
32.4
10.2
0.06-1.2
9-60
1 Untreated lakes (n = 5) (G. Central, Hobiton, Kennedy (2yrs), Long lakes)