SPI allows researchers to quickly and easily take pictures of the top layers of the seafloor. A camera is mounted to a prism that is pushed 15 to 20 centimeters (~6-8 inches) deep into the sediment. A mirror on the prism reflects a perfect cross-sectional image up to a camera. This technique minimizes disturbance and is therefore an effective method of studying biodiversity as well as biological (for example, animal burrows) and physical (for example, sediment layering) features. A series of photographs can be taken to produce a time-lapse movie that provides scientists with information about how organisms behave and how the structure of the sediment changes over time.
A photograph of a sediment profile imager, highlighting the key components. (John Costello, Aqua-Fact International Services Ltd [1].)