Figure 3.

Attribution of monthly CO₂ fugacity changes across physical and biological drivers at each site. (a–c) measured monthly changes in $fC{O}_2^{sw}$ ($d_{obs}fC{O}_2^{sw}$, grey boxes) and expected changes in $fC{O}_2^{sw}$ due to the variability of temperature ($d_{T}fC{O}_2^{sw}$, yellow line with circles), salinity ($d_{S}fC{O}_2^{sw}$, magenta line with squares) and air-sea fluxes ($d_{air-sea}fC{O}_2^{sw}$, blue line with triangles); (e–g) estimated changes in $fC{O}_2^{sw}$ due to the combined effect of dynamics and biological processes ($d_{dyn-bio}fC{O}_2^{sw}$, grey boxes) and separately due to primary productivity ($d_{bio}fC{O}_2^{sw}$, green line with dots), advection ($d_{adv}fC{O}_2^{sw}$, orange line with triangles), entrainment ($d_{entr}fC{O}_2^{sw}$, brown line with squares) and diffusion ($d_{dif}fC{O}_2^{sw}$, fuchsia line with stars)(see Eqs 2 and 3 in Methods).