As part of the Water Institute's WaterTalks lecture series, Bertram Boehrer, Helmholtz Centre for Environmental Research - UFZ, Magdeburg, Germany, will present: Extreme gas pressures in lakes: from the "killer" Lake Nyos (Cameroon) to Guadiana Pit Lake (Spain) and Lake Kivu (Rwanda and DR Congo).
This event will be offered in person on the University of Waterloo campus in DC 1302 and online via Zoom.
More information
Several lakes show extreme loads of gases in their deep water. If those gases exert a gaspressure close to absolute pressure, bubbles can form. When the volume of potentially released gases is high, the situation must be assessed for the risk of large scale ebullition. In 1986, about 1700 humans died in the carbon dioxide released from the deep lake waters of Lake Nyos.
We report, how reliable measurements of extreme gas loads can be accomplished [1]. In the case of Lake Kivu 40 billion m³ of exploitable methane could be substantiated and the idustrial exploitation for power generation has started. In Guadiana Pit Lake carbon dioxide loads of nearly 3 liters of gas per liter of lake water were detected [2]. We report about possibilities to confirm high gas loads by direct measurements of gas pressure or sound speed [3]. In the case of Guadiana Pit Lake, authorities followed the recommendation to remove the gas load artificially to avert the danger of a limnic eruption [4], while in the case of Lake Kivu prescriptions for the survey of the lake have been issued by an international expert team for the period of methane exploitation.
[1] Boehrer et.al. (2019): Reliable reference for the methane concentrations in Lake Kivu at the beginning of industrial exploitation. Hydrol. Earth Syst. Sci. 23 (11), 4707 – 4716. [2] Boehrer et.al. (2016): Quantifying, assessing and removing the extreme gas load from meromictic Guadiana pit lake, Southwest Spain. Sci. Total Environ. 563-564 , 486 – 477. [3] Boehrer et.al. (2021): Carbon Dioxide in Lake Nyos, Cameroon, estimated quantitatively from sound speed measurements. Front. Earth Sci. 9, 645011. [4] Sánchez‑España et.al. (2020): Degassing pit lakes: Technical issues and lessons learnt from the HERCO2 project in the Guadiana open pit (Herrerías mine, SW Spain). Mine Water Environ. 39 (3), 517 – 534.
Speaker bio
Dr. Bertram Boehrer finished his tertiary physics education at Heidelberg University from 1984 to 1990, earned Masters at the Institute for Environmental Physics of the Univ. of Heidelberg and the Limnological Institute Konstanz from 1989 to 1990 and his Ph.D. at the University of Western Australia, Centre for Water Research from 1991 to 1996. He did Postdoc research in UFZ-section Inland Waters from 1996 to 1998.
He has been leading the scientific committee, Workshop on Physical Processes in Natural Waters since 2016 and Co-chaired the Physical Limnology work group of International Society of Limnology (SIL). He has been a member of the Expert Advisory Board at the Lake Kivu Management Programme (Rwanda, Africa) and a member in several scientific organizations: DPG (environmental physics), AGU (Americal Geophysical Union), ASLO (Association for the Sciences of Limnology and Oceanography), DGL (German Society of Limnology), SIL International Society for Limnology), International PhD referee, etc.
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