Factors governing the pH in a heterotrophic, turbid, tidal estuary
Hofmann, A.F.; Meysman, F.J.R.; Soetaert, K.; Middelburg, J.J. (2009). Factors governing the pH in a heterotrophic, turbid, tidal estuary. Biogeosci. Discuss. 6: 197-240. dx.doi.org/10.5194/bgd-6-197-2009
In: Biogeosciences Discussions. Copernicus Publications: Göttingen. ISSN 1810-6285
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| Authors | | Top |
- Hofmann, A.F.
- Meysman, F.J.R.
- Soetaert, K.
- Middelburg, J.J.
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| Abstract |
A method to quantify the influence of kinetically modeled biogeochemical processes on the pH of an ecosystem with time variable acid-base dissociation constants is presented and applied to the heterotrophic, turbid Scheldt estuary (SW Netherlands, N Belgium). Nitrification is identified as the main process governing the pH profile of this estuary, while CO2 degassing and advective-dispersive transport "buffer" the effect of nitrification. CO2 degassing accounts for the largest proton turnover per year in the whole estuary. There is a clear inverse correlation between oxygen turnover and proton turnover. The main driver of long-term changes in the mean estuarine pH from 2001 to 2004 is a changing freshwater flow which influences the pH "directly" via [?CO2] and [TA] and to a significant amount also "indirectly" via [?NH4+] and the nitrification rates in the estuary. |
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