Please help, I am confused. Assuming that the Marcets Principle of constant proportions hold, i am to use the salinity data to estimate the concentration SO4 2- in the top 10 m of the of the water column at this station at the time these data were collected. The answer is in units of mmol/kg, and to the closest 0.001 mmol/kg. Refer to Table 4.1 in Pilson (2013) for major ion concentrations at S = 35.00.Here is the table 4.1 and the data set of depth and salinity.

Thank you!

Table 4.1 Concentrations of the major constituents in surface seawater At salinity (PSS 1978): S= 35.00%o, t = 20 C = = mg kg-s-1 g kg- mmol kg mM + Na K+ Mg2+ Ca 2+ Sr2+ CI soz HCO3 CO} CO2 Br B(OH)3 B(OH) F Totals Alkalinity Everything else Water 308.1 11.40 36.68 11.76 0.223 552.93 77.49 3.217 0.317 0.017 1.923 0.591 0.186 0.037 1004.87 10.782 0.399 1.284 0.4115 0.0078 19.353 2.712 0.1126 0.0111 0.0006 0.0673 0.0207 0.0065 0.00130 35.170 469.00 10.21 52.82 10.27 0.090 545.87 28.235 1.845 0.184 0.013 0.842 0.334 0.082 0.068 1119.87 2.300 480.61 10.46 54.13 10.52 0.092 559.39 28.935 1.891 0.189 0.0133 0.863 0.342 0.0839 0.070 1147.60 2.37 -0.03 ~964.80 ~53,554 54,880 water depth temperature salinity dissolved 02 phosphate silicate nitrate nitrite DEPTH [m] CTDTMP [deg CTDSAL (pss-CTDOXY [um PHSPHT [um SILCAT [umol NITRAT (umo NITRIT (umol 10 28.832 35.540001 192.1 0.01 0.9 0 0.01 11 28.841 35.549 194.6 0.01 1 0 0.01 25 28.793 35.793999 191.6 0.01 1 0 0.01 27 28.758 35.870998 193.7 0.01 1 0 0.01 48 27.915 36.383999 193.1 0.04 1 0 0.01 51 27.864 36.389 191.5 0.05 1 0 0.01 75 27.696 36.398998 191.5 0.05 1 0 0.01 99 27.433 36.429001 193.1 0.05 1 0 0.06 100 27.413 36.433998 190.8 0.07 1 0 0.06 150 16.597 35.773998 153.3 0.9 5.1 12.7 0.04 150 15.228 35.589001 156.2 0.96 5.6 13.7 0.03 151 15.178 35.580002 156.1 0.97 5.7 13.8 0.04 Table 4.1 Concentrations of the major constituents in surface seawater At salinity (PSS 1978): S= 35.00%o, t = 20 C = = mg kg-s-1 g kg- mmol kg mM + Na K+ Mg2+ Ca 2+ Sr2+ CI soz HCO3 CO} CO2 Br B(OH)3 B(OH) F Totals Alkalinity Everything else Water 308.1 11.40 36.68 11.76 0.223 552.93 77.49 3.217 0.317 0.017 1.923 0.591 0.186 0.037 1004.87 10.782 0.399 1.284 0.4115 0.0078 19.353 2.712 0.1126 0.0111 0.0006 0.0673 0.0207 0.0065 0.00130 35.170 469.00 10.21 52.82 10.27 0.090 545.87 28.235 1.845 0.184 0.013 0.842 0.334 0.082 0.068 1119.87 2.300 480.61 10.46 54.13 10.52 0.092 559.39 28.935 1.891 0.189 0.0133 0.863 0.342 0.0839 0.070 1147.60 2.37 -0.03 ~964.80 ~53,554 54,880 water depth temperature salinity dissolved 02 phosphate silicate nitrate nitrite DEPTH [m] CTDTMP [deg CTDSAL (pss-CTDOXY [um PHSPHT [um SILCAT [umol NITRAT (umo NITRIT (umol 10 28.832 35.540001 192.1 0.01 0.9 0 0.01 11 28.841 35.549 194.6 0.01 1 0 0.01 25 28.793 35.793999 191.6 0.01 1 0 0.01 27 28.758 35.870998 193.7 0.01 1 0 0.01 48 27.915 36.383999 193.1 0.04 1 0 0.01 51 27.864 36.389 191.5 0.05 1 0 0.01 75 27.696 36.398998 191.5 0.05 1 0 0.01 99 27.433 36.429001 193.1 0.05 1 0 0.06 100 27.413 36.433998 190.8 0.07 1 0 0.06 150 16.597 35.773998 153.3 0.9 5.1 12.7 0.04 150 15.228 35.589001 156.2 0.96 5.6 13.7 0.03 151 15.178 35.580002 156.1 0.97 5.7 13.8 0.04