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www.biogeosciences-discuss.net/6/197/2009/
doi:10.5194/bgd-6-197-2009
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under the Creative Commons Attribution 3.0 License.
Factors governing the pH in a heterotrophic, turbid, tidal estuary
1Netherlands Institute of Ecology (NIOO-KNAW), Centre for Estuarine and Marine Ecology, P.O. Box 140, 4400 AC Yerseke, The Netherlands
2Laboratory of Analytical and Environmental Chemistry, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussel, Belgium
Abstract. A method to quantify the influence of kinetically modelled 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.
Discussion Paper (PDF, 2347 KB) Interactive Discussion (Closed, 11 Comments) Final Revised Paper (BG)
Citation: Hofmann, A. F., Meysman, F. J. R., Soetaert, K., and Middelburg, J. J.: Factors governing the pH in a heterotrophic, turbid, tidal estuary, Biogeosciences Discuss., 6, 197-240, doi:10.5194/bgd-6-197-2009, 2009. Bibtex EndNote Reference Manager XML
