3 - Supersaturation of Gases

Abstract

This chapter presents information on the computation and reporting of gas supersaturation for oceanographic and for gas bubble disease applications. Gas supersaturation levels are reported in terms of several unique parameters such as Δ P , total gas pressure (TGP), or N 2 +Ar (%). Concentrations of gases in terms of μmol/kg, mg/L, or percent saturation are not too significant in gas supersaturation work because formation of gas bubbles depends on pressure rather than concentrations. The physics of dissolved gases and the physiological basis of gas bubble disease are reviewed. Information is presented on dissolved gas analysis for gas bubble disease applications and the computation and reporting of gas supersaturation levels. Equations are presented to estimate standard gas saturation parameters from concentration units and from older reported gas supersaturation data. The importance of depth on gas supersaturation levels is developed in terms of uncompensated Δ P (Δ P uncomp ) or uncompensated TGP (%) (TGP (%) uncomp ). The impacts of (a) heating and cooling waters and (b) mixing waters of different temperatures and salinities are presented for common water treatment applications. Sample problems are included to demonstrate how the various parameters are computed.