Factors governing the pH in a heterotrophic, turbid, tidal estuary

A method to quantify the in?uence 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, N5 Belgium). Nitri?cation is identi?ed as the main process governing the pH pro?le of
this estuary, while CO2 degassing and advective-dispersive transport "bu?er" the e?ect
of nitri?cation. 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 ?ow which in?uences the pH "directly" via [P
CO210 ] and[TA] and to a signi?cant amount also "indirectly" via [P
NH+4 ] and the nitri?cation rates
in the estuary.

Jaar van publicatie:2009

Trefwoorden:estuary