Bathymetry

Bathymetry is the measurement of water depth. Today, this is done by echosounders sending out acoustic signals that reflect off the seabed and are received back, providing information on the distance to the seabed. As for now, just over 25% of the global seabed is mapped with echosounders – leaving a little less than 75% that are without direct measurement and only estimated from satellite data. 

Detailed bathymetric data is a key parameter to understand many marine processes, e.g. to identify density defined pathways of bottom currents or mass transport events (e.g. landslides), tectonic processes and habitat studies. Furthermore, bathymetric data provide spatial context for isolated point measurements like e.g. sediment cores, CTD casts.

A specific example for the usefulness of bathymetric data is the reconstructions of ice sheet histories. Ice sheets leave typical landforms on the seabed that can be detected in detailed bathymetric data. Orientation and location of these landforms provide information on past ice sheet dynamics.