Table T4. Budgets for Norg below 1.45 mcd horizon based on pore water ammonium.
Parameters used in calculations
Site 1234
Site 1235



Average porosity, 0.65 0.65
Diffusivity, Ds, (m2/day)* 5.0 x 10–5 5.0 x 10–5
Sediment accumulation rate, ws, m/day 2.15 x 10–6 1.9 x 10–6
Pore fluid burial rate, wpw, m/day 1.33 x 10–6 1.9 x 10–6
Peclet number = Ds x /[(1 + K) x w]†, ‡ 0.42 0.23
(found by fitting the profiles) 0.065 0.02
Calculated fluxes
JA2JA1 0.019 0.015
JD2JD1 0.006 0.003
Total ammonium production flux, PN 0.025 0.018
Total Norg flux at 1.45 mcd** 0.131 0.097
Fraction buried below zone of active diagenesis††
81% ± 10%
82% ± 10%

Notes: Fluxes are in mmol/m2 x d. * = Ds = Dm/[1 – ln(2)] (Boudreau, 1997; Li and Gregory, 1974); Dm = molecular diffusivity. † = K = 1.3, ammonium partition coefficient (Berner, 1980), dimensionless. ‡ = = 1/e-folding distance for ammonium profiles. ** = TNorg flux = PN + TNorg at the bottom of active diagenesis zone; TNorg = TN x 0.8, since adsorbed ammonium is 20% of TN. †† = The uncertainty is based on assumed porosity uncertainty of 5%.