Figure 1

Vertical profiles of environmental parameters in the bay of Douarnenez (left column) and the bay of Brest (right column). (a, b) Light intensity: each point corresponds to the mean of PAR values at a given hour and layer, and the vertical bars are the standard deviation. Grey shaded area indicates nighttime. (c, d) Temperature, (e, f) salinity, (g, h) chlorophyll-a concentration, and (i, j) current velocity and direction; positive values indicate eastward currents. Horizontal black and white bars indicate nighttime and daytime, respectively. Horizontal white line in c is the thermocline depth. Vertical white lines correspond to times of sunset and sunrise (see “Methods” section).