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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).
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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 • 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 • CO2rich 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]