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An estimate of CO 2 flux in Lake Nyos, Cameroon
Author(s) -
Nojiri Yukihiro,
Kusakabe Minoru,
Tietze Klaus,
Hirabayashi Junichi,
Sato Hiroaki,
Sano Yuji,
Shinohara Hiroshi,
Njine Thomas,
Tanyileke Greg
Publication year - 1993
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1993.38.4.0739
Subject(s) - hypolimnion , flux (metallurgy) , saturation (graph theory) , atmosphere (unit) , sedimentary rock , geology , total dissolved solids , hydrology (agriculture) , chemical composition , limnology , environmental science , mineralogy , geochemistry , oceanography , chemistry , meteorology , nutrient , eutrophication , physics , mathematics , geotechnical engineering , organic chemistry , combinatorics , environmental engineering
An outburst of lethal gas from Lake Nyos, Cameroon, killed more than 1,700 people on 21 August 1986. The surveys carried out so far indicate that a considerable portion of the CO 2 dissolved in the lake was released to the atmosphere and asphyxiated the people. We revisited the lake in December 1988. The conductivity‐temperature‐depth profiler (CTD) measurements and chemical analysis of the lake water revealed that temperature, total dissolved solids (TDS), and CO 2 content of the bottom water increased in parallel fashion, especially in the bottom layer, during the preceding 25 months. The result supports the view that CO, is being supplied to the lake bottom in the form of warm, CO 2 ‐charged, mineralized water. From the increments of temperature and CO 2 , during the period, fluxes of heat and CO 2 , were estimated to be 0.43 MW and 1.0 Mmol yr −1 . The CO 2 flux is large enough to saturate the lake’s hypolimnion within ∼30 yr. In the 1988 survey, the very bottom layer of the lake was estimated to be close to saturation with CO 2 . Using the CO 2 ‐TDS‐Si relationship and temperature dependence of the solubility of amorphous silica, we estimated the chemical composition of the warm, mineralized water; these estimates suggest the existence of a CO 2 ‐saturated fluid below the sedimentary cover.