| Between March and June 1988, a series of diurnal acoustic records was carried out using a 50 kHz echosounder on a transect crossing the density front of the Ligurian Sea, off Villefranche-sur-Mer (Mediterranean Sea). The depth, thickness and pattern of the sound scattering layers were studied with respect to physical (temperature, salinity and density) and biological (chlorophyll a) measurements made along the acoustic transect. Seasonal differences were observed. A surface scattering layer (SSL), from 0 to 100 m, and a main deep scattering layer (MDSL), located between 250 and 550 m, occurred permanently during the study. In spring, an intermediate scattering layer (ISL), about 50 m thick, occurred between the SSL and the MDSL. The ISL, a permanent... |
