There is full agreement on these facts: Sea water is slightly alkaline in its reaction towards suitable indicators, and the quantitative measure of this alkalinity may be expressed in terms of the amount of strong acid necessary to bring its reaction to some standard specified "endpoint."...
Rakestraw, Norris W.. 1949. "The conception of alkalinity of excess base of sea water." Journal of Marine Research 8, (1). https://elischolar.library.yale.edu/journal_of_marine_research/699