Bathymetric data were collected using the swath-mapping multibeam sonar system HYDROSWEEP (details see Grant & Schreiber, 1990) onboard RV SONNE to produce a detailed map of the seafloor in the DISCOL area to gain better insights into the seafloor morphology and thus to assist in the planning of sampling stations. In general, a multibeam system, like other sonar systems, emits sound waves to determine the water depth by recording the time it takes for the beam, which is reflected from the seafloor, to return to the receiver.   

Within the HYDROSWEEP system, 59 preformed beams are combined to create a swath width of about twice the water depth (here: 7 – 8 kilometers). Therefore, profiles were spaced about 6.5 kilometers apart to ensure a slight overlap between neighboring lines and thus 100% coverage of the area.

Grant, J. A. and Schreiber, R. (1990): Modern swaths sounding and sub-bottom profiling technology for research applications: The Atlas HYDROSWEEP and PARASOUND systems; Mar. Geophys. Res. 12; 9-19

Schematic display of a multibeam echosounder operation (source: GEOMAR)