Alkalinity and pH in the southern Chesapeake Bay and the James River estuary1

The ranges of alkalinity and pH in the southern Chesapeake Bay and the James River estuary were 2.25 meq·liter−1 at 32‰ to <0.85 at salinities below 6‰ and 7.5– 8.3 during the sampling period. Alkalinity is linearly related to salinity in southern Chesapeake Bay. In the James River estuary, the relationship is more complicated as a result of the mixing of various sources of water or the removal of alkalinity. pH values increase with salinity. The variations in pH may be caused by the salinity‐dependence of the apparent dissociation constants of carbonic acid.