Double diffusion and methane in Lake Kivu – "Interfacing" environmental science and engineering
Event details
| Date | 12.03.2012 |
| Hour | 12:15 › 13:15 |
| Speaker | Prof. Alfred Johny Wüest |
| Location | |
| Category | Conferences - Seminars |
Double-diffusive upward-directed fluxes play a fascinating role in the accumulation of ~60 km3 of methane dissolved in the 485 m deep and permanently stratified Lake Kivu. Driven by a geothermal flux of ~50 mW m-2 and stratified by salt and carbon-dioxide (from deep subaquatic springs), double-diffusive conditions (density-ratio ~2 to ~10) have evolved: As a result, a spectacular staircase of ~350 sharp interfaces (down to ~2 mm) and well-mixed layers have formed probably over centuries or even millennia.
Due to very strong stratification and weak wind forcing, turbulence is negligible and restricted to the convectively-driven double-diffusive layers. As a result, the upward directed fluxes from the subaquatic springs are small for the dissolved constituents: Therefore, not only salt and carbon-dioxide have accumulated in the deep-water but also methane. It has reached harvestable concentrations and is now a resource with a value of ~20 billion dollars.
The links from double-diffusion to methane accumulation and its harvesting is a wonderful example for opportunities in combining environmental science and engineering.
Due to very strong stratification and weak wind forcing, turbulence is negligible and restricted to the convectively-driven double-diffusive layers. As a result, the upward directed fluxes from the subaquatic springs are small for the dissolved constituents: Therefore, not only salt and carbon-dioxide have accumulated in the deep-water but also methane. It has reached harvestable concentrations and is now a resource with a value of ~20 billion dollars.
The links from double-diffusion to methane accumulation and its harvesting is a wonderful example for opportunities in combining environmental science and engineering.
Links
Practical information
- General public
- Free
- This event is internal
Organizer
- Décanat ENAC
Contact
- Christina Treier