A rock dredge is a large bag made of metal chain links attached to a simple heavy frame that keeps the bag expanded. The dredge is lowered off the back of a ship to the seafloor and dragged along to collect large pieces of rock. Rock dredge is a frame and heavy chain...

A similar seafloor mapping technique to multibeam sonar is the use of airborne laser bathymetry, or Light Detection and Ranging (lidar), which use low-flying aircraft to scan pulsed laser beams across the seafloor and generate a swath of depth soundings. Example of...

The 3D visualisation software we use is Fledermaus - a powerful, interactive 4D (space and time) data visualisation software developed by QPS. Fledermaus software is used for a variety of ocean mapping applications, such as multibeam depth editing, environmental...

Deep-sea underwater cameras may take either video or still images with high-resolution digital cameras. There are a huge range of underwater cameras for every purpose but they all have several things in common. They all need a waterproof housing, such as a heavy metal...

Sidescan sonar uses sound energy reflected off the seabed to reveal the detailed texture or roughness of the seafloor. Unlike echosounders which only measure depth, a sidescan sonar records an image of the seabed by measuring the strength of returned echoes. A...

Sediment grabs come in all shapes and sizes, but they all do much the same thing, to collect a sample of sediment from the seabed. These samples are used to analyse the properties of the sediment itself or to discover the marine life living on the seafloor. Smith...

Singlebeam echosounders have been used routinely for many years to collect depth data from the world’s oceans. This acoustic technique relies on a vessel-mounted transducer to generate a single acoustic pulse directed towards the seabed underneath the vessel. Example...

A conductivity-temperature-depth profiler, or CTD, is an instrument lowered into the sea from a ship and used to measure the physical characteristics of the ocean and also to collect water samples. Preparing CTD on RV Southern Surveyor Around the outside of the...