Modeling Transport Rates in Lake Baikal: Gas Exchange and Deep Water Renewal

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• 作者：F. Peeters ; R. Kipfer ; R. Hohmann ; M. Hofer ; D. M. Imboden ; G. G. Kodenev ; and T. Khozder
• 刊名：Environmental Science & Technology
• 出版年：1997
• 出版时间：October 1997
• 年：1997
• 卷：31
• 期：10
• 页码：2973 - 2982
• 全文大小：277K
• 年卷期：v.31,no.10(October 1997)
• ISSN：1520-5851

文摘

Concentrations of molecular oxygen in Lake Baikal (EasternSiberia), the deepest lake on earth (1634 m), are above80% saturation in the whole water column suggesting fastdeep-water renewal. A model is developed to describevertical water exchange based on measured concentrationsof tritium, ³He, and the chlorofluorocarbons CFC-11(CCl₃F)and CFC-12 (CCl₂F₂). Lake Baikal consistsof three mainbasins (south, central, north) that are separated by sillsreaching up to about 300 m depth. Each basin isverticallydivided into two boxes: a surface box 300 m thick and adeep-water box below 300 m. Tracers are transported from/into the surface layer by gas exchange with the atmosphereduring ice-free periods, by precipitation, by evaporation,and by rivers. The tracer distribution in the lakedependsprimarily on the three intrabasin vertical water exchangerates. These rates are simultaneously fitted bymodelingthe four tracers from 1900 to the present. Meanresidencetimes in the south, central, and north basins are 11.2 ±0.6,10.4 ± 0.5, and 6.2 ± 0.5 yr, respectively. Applicationofthe transport model to measured oxygen concentrationsyields O₂ consumption rates in all deep-water boxes of 0.1mgL^-1yr^-1.