Extended Data Fig. 7: CTD-derived temperature-salinity dependence.

a, Temperature-Salinity plot with depth colour-coded from CTD profiles along the calving front. Subglacial discharge modified waters are found above about 100 m depth. Subglacial discharge mixing lines have slopes of \([{T}_{d}-{T}_{0}]/[{S}_{d}-{S}_{0}]\) with subscripts d and 0 denoting the deepest waters and surface waters respectively. Submarine melt mixing lines have slopes of \([{T}_{d}\,-\,(\,-\,90\,^\circ {\rm{C}})]/[{S}_{d}-0]\), with T=−90 °C the effective temperature of submarine melt that accounts for latent heat that is extracted from the ocean. b, Water density dependence on temperature and salinity between 150–280 m. Calculated density anomaly from 1,000 kg/m³ for 0 bar reference pressure. Density is only weakly dependent on temperature but strongly on salinity below 150 m depth, where we measure IGWs. This means that the water density is salinity-dominated in our case. Salinity scales linearly with temperature \({S}=\,0.5{psu}/\,^\circ {\rm{C}}* {T}+32.6{psu}\).