Comparative marine geochemistries of lead-210 and radium-226

The 226Ra and 210Pb concentrations in the Gulf of California and eastern North Pacific seawaters appear to be governed by the extents of upwelling and by the consequential biological productivities. The residence times of 226Ra and 210Pb in the highly productive Gulf of California surface waters are calculated to be a few months and less than a month, respectively, on the basis of upwelling rates.