Lake Kivu pp 13-29 | Cite as

Stratification, Mixing and Transport Processes in Lake Kivu

Part of the Aquatic Ecology Series book series (AQEC, volume 5)


This chapter summarizes the knowledge on mixing and transport processes in Lake Kivu. Seasonal mixing, which varies in intensity from year to year, influences the top ∼65 m. Below, the lake is permanently stratified, with density increasing stepwise from ∼998 kg m−3 at the surface to ∼1,002 kg m−3 at the maximum depth of 485 m. The permanently stratified deep water is divided into two distinctly different zones by a main gradient layer. This gradient is maintained by a strong inflow of relatively fresh and cool water entering at ∼250 m depth which is the most important of several subaquatic springs affecting the density stratification. The springs drive a slow upwelling of the whole water column with a depth-dependent rate of 0.15–0.9 m year−1. This upwelling is the main driver of internal nutrient recycling and upward transport of dissolved gases. Diffusive transport in the deep water is dominated by double-diffusive convection, which manifests in a spectacular staircase of more than 300 steps and mixed layers. Double diffusion allows heat to be removed from the deep zone faster than dissolved substances, supporting the stable stratification and the accumulation of nutrients and gases over hundreds of years. The stratification in the lake seems to be near steady-state conditions, except for a warming trend of ∼0.01°C year−1.


Diffusive Transport Deep Zone Vertical Transport Temperate Lake Density Stratification 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



Fieldwork was supported by the Swiss National Science Foundation (SNSF) under grant 200021–122183 (Lake Kivu – turbulence and double diffusion in permanent stratification) and by SNSF and the Swiss Agency for Development and Cooperation under grant IZ70Z0_123923 (Lake Kivu: Learning from the past for managing its future).


  1. Bergonzini L (1998) Bilans hydriques des lacs (Kivu, Tanganyika, Rukwa et Nyassa) du Rift Est-Africain. Annales – Sciences Géologiques. Musée Royale de L’Afrique Centrale, Tervuren, BelgiumGoogle Scholar
  2. Branchu P, Bergonzini L, Pons-Branchu E, Viollier E, Dittrich M, Massault M, Ghaleb B (2010) Lake Malawi sediment and pore water chemistry: proposition of a conceptual model for stratification intensification since the end of the Little Ice Age. Global Planet Change 72:321–330. doi: 10.1016/j.gloplacha.2010.01.008 CrossRefGoogle Scholar
  3. Bultot F (1971) Atlas climatique du bassin Congolais, vol 2: Les composantes du bilan d’eau. Publications de l’Institut National pour l’Étude Agronomique du Congo. RD CongoGoogle Scholar
  4. Corman JR, McIntyre PB, Kuboja B, Mbemba W, Fink D, Wheeler CW, Gans C, Michel E, Flecker AS (2010) Upwelling couples chemical and biological dynamics across the littoral and pelagic zones of Lake Tanganyika, East Africa. Limnol Oceanogr 55:214–224. doi: 10.4319/lo.2010.55.1.0214 CrossRefGoogle Scholar
  5. Degens ET, Von Herzen RP, Wong H-K, Deuser WG, Jannasch HW (1973) Lake Kivu: structure, chemistry and biology of an East African rift lake. Geol Rundsch 62:245–277. doi: 10.1007/BF01826830 CrossRefGoogle Scholar
  6. Durisch-Kaiser E, Schmid M, Peeters F, Kipfer R, Dinkel C, Diem T, Schubert CJ, Wehrli B (2010) What prevents out-gassing of methane to the atmosphere in Lake Tanganyika? J Geophys Res Biogeosci G02022. doi: 10.1029/2010JG001323
  7. Expert Working Group on Lake Kivu Gas Extraction (2009) Management prescriptions for the development of Lake Kivu gas resources. Report prepared for the Ministry of Infrastructure of the Republic of Rwanda and the Ministry of Hydrocarbons of the Democratic Republic of the Congo, 17 June 2009, 38ppGoogle Scholar
  8. Goldman CR, Jassby A, Powell T (1989) Interannual fluctuations in primary production: meteorological forcing at two subalpine lakes. Limnol Oceanogr 34:310–323CrossRefGoogle Scholar
  9. Griffiths RW (1979) The transport of multiple components through thermohaline diffusive interfaces. Deep Sea Res 26A:383–397. doi: 10.1016/0198-0149(79)90052-9 Google Scholar
  10. Hirslund F (2012) An additional challenge of Lake Kivu in Central Africa – upward movement of the chemoclines. J Limnol 71:45–60. doi: 10.4081/jlimnol.2012.e4 Google Scholar
  11. Kelley DE, Fernando HJS, Gargett AE, Tanny J, Özsoy E (2003) The diffusive regime of double-diffusive convection. Prog Oceanogr 56:461–481. doi: 10.1016/S0079-6611(03)00026-0 CrossRefGoogle Scholar
  12. Lahmeyer and Osae (1998) Bathymetric survey of Lake Kivu. Final report. Republic of Rwanda, Ministry of Public Work, Directory of Energy and Hydrocarbons, KigaliGoogle Scholar
  13. Lewis WM (1987) Tropical limnology. Annu Rev Ecol Syst 18:159–184. doi: 10.1146/ CrossRefGoogle Scholar
  14. Lorke A, Tietze K, Halbwachs M, Wüest A (2004) Response of Lake Kivu stratification to lava inflow and climate warming. Limnol Oceanogr 49:778–783. doi: 10.4319/lo.2004.49.3.0778 CrossRefGoogle Scholar
  15. Muvundja FA, Pasche N, Bugenyi FWB, Isumbisho M, Müller B, Namugize J-N, Rinta P, Schmid M, Stierli R, Wüest A (2009) Balancing nutrient inputs to Lake Kivu. J Great Lakes Res 35:406–418. doi: 10.1016/j.jglr.2009.06.002 CrossRefGoogle Scholar
  16. Newman FC (1976) Temperature steps in Lake Kivu: a bottom heated saline lake. J Phys Oceanogr 6:157–163. doi:10.1175/1520-0485(1976)006<0157:TSILKA>2.0.CO;2CrossRefGoogle Scholar
  17. Pasche N, Dinkel C, Müller B, Schmid M, Wüest A, Wehrli B (2009) Physical and biogeochemical limits to internal nutrient loading of meromictic Lake Kivu. Limnol Oceanogr 54:1863–1873. doi: 10.4319/lo.2009.54.6.1863 CrossRefGoogle Scholar
  18. Pasche N, Alunga G, Mills K, Muvundja F, Ryves DB, Schurter M, Wehrli B, Schmid M (2010) Abrupt onset of carbonate deposition in Lake Kivu during the 1960s: response to recent environmental changes. J Paleolimnol 44:931–946. doi: 10.1007/s10933-010-9465-x CrossRefGoogle Scholar
  19. Rinta P (2009) Modelling nitrogen and phosphorus inputs to Lake Kivu, Central Africa. MSc Thesis, University of Turku, FinlandGoogle Scholar
  20. Schmid M, Lorke A, Dinkel C, Tanyileke G, Wüest A (2004a) Double-diffusive convection in Lake Nyos, Cameroon. Deep Sea Res I 51:1097–1111. doi: 10.1016/j.dsr.2004.02.010 CrossRefGoogle Scholar
  21. Schmid M, Tietze K, Halbwachs M, Lorke A, McGinnis D, Wüest A (2004b) How hazardous is the gas accumulation in Lake Kivu? Arguments for a risk assessment in light of the Nyiragongo Volcano eruption of 2002. Acta Vulcanol 14/15:115–121Google Scholar
  22. Schmid M, Halbwachs M, Wehrli B, Wüest A (2005) Weak mixing in Lake Kivu: new insights indicate increasing risk of uncontrolled gas eruption. Geochem Geophys Geosyst 6:Q07009. doi: 10.1029/2004GC000892 CrossRefGoogle Scholar
  23. Schmid M, Busbridge M, Wüest A (2010) Double-diffusive convection in Lake Kivu. Limnol Oceanogr 55:225–238. doi: 10.4319/lo.2010.55.1.0225 CrossRefGoogle Scholar
  24. Tassi F, Vaselli O, Tedesco D, Montegrossi G, Darrah T, Cuoco E, Mapendano MY, Poreda R, Delgado Huertas A (2009) Water and gas chemistry at Lake Kivu (DRC): Geochemical evidence of vertical and horizontal heterogeneities in a multibasin structure. Geochem Geophys Geosyst 10:Q02005. doi: 10.1029/2008GC002191 CrossRefGoogle Scholar
  25. Tietze K (1978) Geophysikalische Untersuchung des Kivusees und seiner ungewöhnlichen Methangaslagerstätte – Schichtung, Dynamik und Gasgehalt des Seewassers. PhD Thesis, Christian-Albrechts-Universität KielGoogle Scholar
  26. Turner JS (1973) Buoyancy effects in fluids, Cambridge Monographs on Mechanics and Applied Mathematics. Cambridge University Press, CambridgeCrossRefGoogle Scholar
  27. Verburg P, Hecky RE (2009) The physics of the warming of Lake Tanganyika by climate change. Limnol Oceanogr 54:2418–2430. doi: 10.4319/lo.2009.54.6_part_2.2418 CrossRefGoogle Scholar
  28. Vollmer MK (2005) Deep-water warming trend in Lake Malawi, East Africa. Limnol Oceanogr 50:727–732. doi: 10.4319/lo.2005.50.2.0727 CrossRefGoogle Scholar
  29. von Rohden C, Boehrer B, Ilmberger J (2010) Evidence for double diffusion in temperate meromictic lakes. Hydrol Earth Syst Sci 14:667–674CrossRefGoogle Scholar
  30. Wüest A, Lorke A (2003) Small-scale hydrodynamics in lakes. Annu Rev Fluid Mech 35:373–412. doi:10.1146/annurev.fluid.35.101101.161220CrossRefGoogle Scholar
  31. Wüest A, Piepke G, Halfman JD (1996) Combined effects of dissolved solids and temperature on the density stratification of Lake Malawi. In: Johnson TC, Odada EO (eds) The limnology, climatology and paleoclimatology of the East African Lakes. Gordon and Breach, AmsterdamGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2012

Authors and Affiliations

  1. 1.Eawag: Swiss Federal Institute of Aquatic Science and TechnologyKastanienbaumSwitzerland
  2. 2.ETH Zurich, Institute of Biogeochemistry and Pollutant DynamicsZurichSwitzerland

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