Hydrobiologia

, Volume 284, Issue 1, pp 59–68 | Cite as

Benthic boundary mixing and resuspension induced by internal seiches

  • M. Gloor
  • A. Wüest
  • M. Münnich
Article

Abstract

The effect of internal seiches on horizontal hypolimnetic bottom currents and on the stationary well-mixed benthic boundary layer (BBL) induced by these currents was studied for 2 weeks in a small prealpine lake using thermistor strings, an acoustic current meter and a CTD (C: conductivity, T: temperature, D: depth) equipped with a transmissometer. 150 profiles of temperature, conductivity and transmissivity taken during two days clearly indicate the existence of a well-mixed BBL 2 to 7 m thick. This is the result of intense mixing in the zone of high shear above the sediment associated with seiching motion. The concentration of suspended or resuspended particles, mainly of organic nature, within the BBL, was 2 to 4 times greater than that measured directly above the BBL. Resuspension is thought to be associated rather with high-frequency burst-like currents with measured speeds ranging up to 7 cm s−1 than with the average bottom current speed of about 2 cm s−1.

Key words

boundary mixing nepheloid layer resuspension internal seiches vertical modes particles 

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References

  1. Baker, E. T. & J. W. Lavelle, 1984. The effect of particle size on the Light attenuation coefficient of natural suspensions. J. Geophys. Res. 89: 8197–8203.Google Scholar
  2. Bloesch, J. & U. Uehlinger, 1986. Horizontal sedimentation differences in a eutrophic Swiss lake. Limnol. Oceanogr. 31: 1094–1109.Google Scholar
  3. Dewey, R. K. & W. R. Crawford, 1988. Bottom stress estimates from vertical dissipation rate profiles on the continental shelf. J. Phys. Oceanogr. 18: 1167–1177.Google Scholar
  4. Elliott, A. J., 1984. Measurements of the turbulence in an abyssal boundary layer. J. Phys. Oceanogr. 14: 1778–1786.Google Scholar
  5. Imboden, D. M. & A. Wüest, 1994. Mixing mechanisms in Lakes. (to be published in ‘Lakes’ (ed.), Springer).Google Scholar
  6. Johnson, C. A., M. Ulrich, L. Sigg & D. M. Imboden, 1991. A mathematical model of the manganese cycle in a seasonally anoxic lake. Limnol. Oceanogr, 36: 1415–1426.Google Scholar
  7. Jørgenssen, B. B. & D. J. Des Marais, 1990. The diffusive boundary layers of sediments: Oxygen microgradients over a microbial mat. Limnol. Oceanogr. 35: 1343–1355.Google Scholar
  8. LaZerte, B. D., 1980. The dominating higher order vertical modes of the internal seiche in a small lake. Limnol. Oceanogr. 25: 846–854.Google Scholar
  9. Lemmin, U. & D. M. Imboden, 1987. Dynamics of bottom currents in a small lake. Limnol. Oceanogr. 32: 62–75.Google Scholar
  10. Miller, M. C., I. N. McCave & P. D. Komar, 1977. Threshold of sediment motion under unidirectional currents. Sedimentology 24: 507–527.Google Scholar
  11. Münnich, M., A. Wüest & D. M. Imboden, 1993. Observations of the second vertical mode of the internal seiche in an alpine lake. Limnol. Oceanogr. 37: 1705–1719.Google Scholar
  12. Pak, H. & J. R. Zaneveld, 1983. Temporal variations of beam attenuation coefficient on the continental rise off Nova Scotia. J. Geophys. Res. 88: 4427–4432.Google Scholar
  13. Sandilands, R. G. & A. Mudroch, 1983. Nepheloid Layer in Lake Ontario. J. Great Lakes, 9: 190–200.Google Scholar
  14. Shields, A. 1936. Anwendung der Aehnlichkeitsmechanik und der Turbulenzforschung auf die Geschiebebewegung. Mitt. preuss. Versuchsanst. Wasserbau Schiffbau, Berlin 26: 1–26.Google Scholar
  15. Thorpe, S. A., 1988. The dynamics of the boundary layers of the deep ocean. Sci. Prog., 72: 189–206.Google Scholar
  16. Vanoni, V. A., 1964. Measurements of critical shear stress for entraining fine sediments in a boundary layer. Report No. KH-R-7, W. M. Keck Laboratory Caltech, Pasadena, California.Google Scholar
  17. Wehrli, B., G. Friedl & A. Manceau, 1993. Reaction rates and products of manganese oxidation at the sediment-water interface. In Huang, C. P., C. O'Melia & J. J. Morgan (eds), Aquatic Chemistry. ACS Advances in Chemistry, Washington DC, Series 244 (in press).Google Scholar
  18. Wiegand, R. C. & V. Chamberlain, 1987. Internal waves of the second vertical mode in a stratified lake. Limnol. Oceanogr. 32: 29–42.Google Scholar
  19. Yalin, M. S, 1977. Mechanics of sediment transport. Pergamon Press.Google Scholar

Copyright information

© Kluwer Academic Publishers 1994

Authors and Affiliations

  • M. Gloor
    • 1
  • A. Wüest
    • 1
  • M. Münnich
    • 1
  1. 1.Environmental PhysicsInstitute for Aquatic Sciences and Water Pollution ControlDübendorfSwitzerland

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