Calculation of molecular and ionic diffusion coefficients in sea water or in pore water of a sediment column. Various investigators have developed models (formulas) to predict diffusion coefficients when the solute in question is present in small vanishingly concentrations. While one might first presume that such formulas are of limited value in moderately strong electrolyte solutions such as marine waters - instuition fails in this case. In fact, infinite dilution coefficients play an integral role in the theories for stronger solutions, and they are reasonably accurate approximations for all but the major ions. (Boudreau, 1997)

Enter:Parameter |
Unit |
Range |
User-input |

Temperature | °C | 0-40 | |

Salinity | PSU (ppt) | 0.5-43 | |

Pressure | atm (1 atm at surface) | 0-1200 |

Diffusion coefficients are in C. CANDI units [cm^{2} a^{-1}] and in SI-Units [m^{2} s^{-1}]:

Parameter |
Result [cm^{2} a^{-1}] |
SI-Result [m^{2} s^{-1}] |

H_{2}O |
||

O_{2} |
||

CO_{2} |
||

NH_{3} |
||

H_{2}S |
||

H_{3}PO4 |
||

B(OH)_{3} |
||

HCO_{3}^{-} |
||

CO_{3}^{2-} |
||

NH_{4}^{+} |
||

HS^{-} |
||

NO_{3}^{-} |
||

H_{2}PO_{4}^{-} |
||

HPO_{4}^{2-} |
||

PO_{4}^{3-} |
||

B(OH)_{4}^{-} |
||

H^{+} |
||

OH^{-} |
||

Ca^{2+} |
||

Mg^{2+} |
||

Fe^{2+} |
||

Mn^{2+} |
||

SO_{4}^{2-} |
||

H_{4}SiO_{4} |
||

CH_{4} |
||

Na^{+} |
||

Cl^{-} |

Boudreau, B., 1997, Diagenetic Models and thier implementation, Springer, Berlin.

© Copyright R. Luff (DG2HL) 1997-2000.