Figure 4. Summary of the gas exchange rate estimates of Emerson et al. (1991), determined using depletion of dissolved Radon in the surface mixed layer, compared with average rates calculated from the gas exchange relations of Liss et al. (1986) and Wanninkhof (1992). The data are indistinguishable from the Liss et al. (1986) formulation, and significantly lower than predicted by Wanninkhof (1992).