Crossing the Tropic of Capricorn for New Years Eve

A prominent example was recorded in the Angola Basin at a water depth of about 5500 m. Well stratified sedimentary strata of more than 70 m are penetrated by reflection free pipe-like structures likely presenting rising gas or fluids. As part of the bathymetry working group, we also have the regular routine of two underway CTD casts per day at 10:00 and 16:00, to break up the day with some outdoor, non-computer orientated activity. But also, and more importantly, the underway CTD casts are done to obtain accurate measurements of the speed of sound in the water column. We have deployed other sound velocity profilers this cruise to check and calibrate the new multibeam replacement equipment that was installed on the ship’s hull. For calibrating the multibeam echosounder, the ship runs a patch test pattern and the data is then analyzed for roll, pitch, or yaw errors in the newly mounted sonar head. Knowledge of the seafloor topography and sediments is necessary for a wide variety of disciplines.

It is crucial for certain working groups to know the characteristics, i.e., soft sediments, rough terrain, etc. when deploying instruments that either penetrate or land softly to the seafloor. The bathymetry working group works with scientists in analyzing deployment positions, calculating ship tracks, and creating maps for reports, etc.