Customisation of rapid visual reconnaissance technology for use within the deep sea-sediment profile imagery

The utility of a rapid visual reconnaissance technique for benthic surveying of shallow soft bottom sediments has already been well demonstrated in the case of sediment profile imagery (SPI). This technique provides quantitative and qualitative data on the sediment water interface which call be used to make inferences about sediment health. Its rapidity in terms of areal coverage and subsequent image analysis and reporting means that SPI has obvious advantages over traditional time consuming benthic survey techniques when a rapid response to changes in environmental quality is required. While SPI has mostly been used to provide rapid synoptic views of sediment health in shallow waters, its use in the deep-sea has received less attention. This paper describes the challenge of adapting sediment profile imagery for use down to abyssal depths as part of the EU-funded MAST III project ALIPOR. Principal considerations were to counter the effects of pressure and cold, minimise sample number-deployment time ratio, facilitate ease of operation and allow ready access to generated images. Sediment profile imagery functions like an inverted periscope which, on penetrating the deposit, yields undisturbed images of the sediment/water interface. The device is built around a Kodak DCS 410 (1524/spl times/1012 pixel CCD array) with a Nikon N-90s camera. The basic SPI design is modified so that routine servicing and maintenance can be performed without removing the main pressure housing containing camera and batteries.