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Kalff 2002
Kalff 2002
Fig. 16-2 (Kalff 2002)
Wetzel 2001
Payne (1986)
Payne (1986)
Depth (m)
Chemical stratification in Lake Tanganyika and Malawi (Hecky et al. 1996)
Depth (m)
Chemical stratification in Lake Victoria 1961 – 1990 (Hecky et al. 1996)
Concentration-depth profile of chlorophyll a in Lake Victoria 1961 -1990
(from Hecky 1993)
Lake Nyos
Attempts to tame a killer lake
Betsy Bodamer
General Info
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Volcanic Crater Lake
Formed ~400+ years ago
Surface area = 1.58 km2
Max depth = 210 m
Chemocline ≈50 m
Volume = 179,400,000
m3
• rainfall = 2.5 m/yr
• Inflow
– 0-50 m: rainfall & streams
– 50-210 m: soda springs
• CO2 rich water
• Outflow
– Natural dam/spillway
The 1986 Disaster
• ~80 million m3 of CO2 released
from Lake Nyos
• Killed ~1800 people and
thousands of animals.
• Cause = rapid overturn
• Volcanic or limnetic? Or both?
Degassing Lake Nyos
• 2001: full fledge
degassing column was
successfully
assembled, installed
and primed.
– continuous
– 50 m fountain
• Spray = 90% CO2 and
10% water.
• 50,000 STP m3/day
Trends across
latitude in some
important
characteristics of
freshwater
systems
[Lewis 1987]