Deviation of Boron Concentration From Predictions Using Salinity in Coastal Environments

Abstract

AbstractTo test whether the established B/Cl ratio (0.2414 mg·kg–1·‰–1) derived for the open ocean is applicable to coastal systems globally, we measured the B concentration and salinity of seawater samples (n = 245) collected from the coastal waters of the Yellow, East China, and East Seas. We also measured the B concentration of freshwater samples (n = 10) from six rivers discharging into these seas and analyzed along with the B concentrations of other rivers globally, obtained from literatures. Our results show that the supply of riverine B (2–6 μmol B/kg) did not discernably alter the B/Cl ratio in most estuarine systems. The impact of this riverine B input on the interconversion between total alkalinity ([HCO3–] + 2[CO32–] + [B (OH)4–] + others) and carbonate alkalinity ([HCO3–] + 2[CO32–]) is less than a few micromoles per kilogram for most estuarine and coastal systems, although exceptions in the Baltic Sea do occur.