Salinity Anomalies in Coastal and Near-Shelf Waters

Electrical conductivity/Absolute Salinity relationships in the open ocean vary from place to place because the relative chemical composition of major constituents in "sea salt" changes from place to place. Techniques to account for these changes, especially as they arise from the remineralization of organic matter in the open ocean, are now part of the TEOS-10 seawater standard, incorporated into a "salinity anomaly". However, in coastal regions, relative chemical composition can also change due to the inflow of river salts, and local biogeochemical processes. Numerical modelling of river salt/seawater mixtures is used to make some estimates of salinity anomalies on shelves, which can be larger than 0.1 g/kg. Actual measurements of the salinity anomaly in the Salish Sea and in the North-East Pacific along Line-P are roughly in line with these predictions, but also provide some surprises - processes other than remineralization and river inflow may also be affecting seawater composition.