查看文章

Salinities, δD and δ¹⁸O values of water samples collected bimonthly from two stations in San Francisco Bay estuary during 1991–1993, and along a salinity transect in March of 1992, indicate a linear mixing relation between the isotopic compositions of the waters and their salinities. The salinities and stable isotope compositions of samples from two locations in San Francisco Bay vary in response to changes in freshwater inflow. The data from these locations indicate simple mixtures of Pacific Ocean water (salinity ≈33, δ¹⁸O ≈ 0 to −1‰, δD ≈ 0 to −10‰) and Sacramento-San Joaquin River water (salinity ≈ 0, δ¹⁸O = −10 to −12‰, δD = −75 to −85‰). Preliminary water balance estimates, using isotopic differences between local and upland runoff, suggest that local runoff (including waste water) comprises less than 20% of total freshwater entering the bay. The average δ¹⁸O values of mussel shells (Mytilus …