The vertical distribution of the upwelled CSUW along the Campeche shore was illustrated in Fig. \ref{825336}. It complemented the results of Fig. \ref{163888}, showing the behavior of the upwelled water in the vertical as it flows towards the southwest. It penetrated the study region off Isla Arena, then it was kept away from the sampling region from Isla Piedra to the south of Lerma (between 20-21°N, 91°W) and got closer to the shore around Champoton until the rest of the region. This colder and fresher water could not reach the shore in the northern region due to a bathymetric step that disappears after passing Champoton, which prevents the approach of this water towards the coast. The upwelled water occupied the whole water column on the northern region (off Isla Arena) but passing Champoton it was restricted to a thin layer close to the ocean floor.