Marine Systems & Ocean Technology

, Volume 10, Issue 1, pp 18–25 | Cite as

Numerical study on the effect of artificial mound settled in the shallow ocean for CO2 fixation

  • Shinichiro Hirabayashi
  • Toru Sato
  • Michimasa Magi
  • Tatsuo Suzuki


An artificial mound was settled in the shallow ocean to enhance vertical mixing of nutrients and consequent primary production. It is expected that this technology contributes to the biological fixation of CO2 in the ocean. The turbulent mixing generated by the interaction between tidal currents and the mound was numerically simulated by using large eddy simulation in the cases of spring and half tides. The energy dissipation rate calculated from the numerical simulation shows a large horizontal variation when the tidal speed is large and a clear enhancement by the mound can be seen. The comparison between numerical result and the measurement implies that the location of the measurement was not included in the region of large energy dissipation. The vertical diffusivity was estimated from the numerical result to roughly quantify the vertical diffusive velocity of nutrients, which was enhanced up to 10−6–10−5 m s−1 when the tidal speed is its maximum, while it was 10−7 m s−1 when the effect of the mound is little .


Artificial mound Large eddy simulation Energy dissipation rate Vertical diffusivity Biological CO2 fixation Primary production 



The present study was supported in part by the Research Institute of Innovative Technology for the Earth (RITE).


  1. 1.
    M.C. Gregg, Scaling turbulent dissipation in the thermocline. J. Geophys. Res. 94 (1989)CrossRefGoogle Scholar
  2. 2.
    J.R. Lerwell, E.T. Montegomery, K.L. Polzin, L.C. St. Laurent, R.W. Schmitt, J.M. Toole, Evidence for enhanced mixing over rough topography in the abyssal ocean. Nature 403 (2000)Google Scholar
  3. 3.
    R.G. Lueck, T.D. Mudge, Topographically induced mixing around a shallow seamount. Science 276 (1997)CrossRefGoogle Scholar
  4. 4.
    J.A. Mackinnon, M.C. Gregg, Mixing on the late-summer New England shelf—solibores, shear, and stratification. J. Phys. Oceanogr. 33 (2003)CrossRefGoogle Scholar
  5. 5.
    J.N. Moum, Efficiency of mixing in the main thermocline. J. Geophys. Res. 101 (1996)CrossRefGoogle Scholar
  6. 6.
    T.R. Osborn, Estimates of the local rate of vertical diffusion from dissipation measurements. J. Phys. Oceanogr. 10 (1980)CrossRefGoogle Scholar
  7. 7.
    K.L. Polzin, J.M. Toole, J.R. Ledwell, R.W. Schmitt, Spatial variability of turbulent mixing in the abyssal ocean. Science 276 (1997)CrossRefGoogle Scholar
  8. 8.
    C.M. Rhie, W.L. Chow, Numerical study of the turbulent flow past an airfoil with trailing edge separation. AIAA J. 21 (1983)CrossRefGoogle Scholar
  9. 9.
    J. Smagorinsky, General circulation experiments with the primitive equations, I. The basic experiment. Mon. Weather Rev. 91 (1963)CrossRefGoogle Scholar
  10. 10.
    L. St. Laurent, C. Garrett. The role of internal tides in mixing the deep ocean. J. Phys. Oceanogr. 32 (2002)Google Scholar
  11. 11.
    L.C. St. Laurent, J.M. Toole, R.W. Schmitt, Buoyancy forcing by turbulence above rough topography in the abyssal Brazil basin. J. Phys. Oceanogr. 31 (2001)Google Scholar
  12. 12.
    J.M. Toole, R.W. Schmitt, K.L. Polzin, Near-boundary mixing above the flanks of a midlatitude seamount. J. Geophys. Res. 102 (1997)CrossRefGoogle Scholar
  13. 13.
    T. Yanagi, M. Nakajima, Change of oceanic condition by the man-made structure for upwelling. Mar. Pollut. Bull. 23 (1991)CrossRefGoogle Scholar

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© The Author(s) 2015

Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Authors and Affiliations

  • Shinichiro Hirabayashi
    • 1
  • Toru Sato
    • 1
  • Michimasa Magi
    • 2
  • Tatsuo Suzuki
    • 3
  1. 1.Department of Ocean Technology, Policy, and EnvironmentUniversity of TokyoKashiwaJapan
  2. 2.CO2 Storage Research GroupResearch Institute of Technology for the EarthKizugawaJapan
  3. 3.Artificial Sea-Mount InstituteHachioji-shiJapan

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