submersible

CytoSub can be used for real in situ analyses, for instance directly probing the deep chlorophyll maximum found at the bottom of the mixed layer in the open ocean. On research vessels this is done using the ships winch. The instrument can be lowered separately or mounted as part of a larger instrument frame. In comparison to such shipoperated profiling, bottom-up profilers are better suited for precision measurements for instance to locate thin layers. They consist of an anchored bottom station from which a slightly buoyant instrument package is reeled upwards while taking (semi-)continuous measurements. A CytoSub can be mounted in such a package. The CytoSub is small enough (Ø322 x H500 mm) to be placed in various types of frames or vehicles. Autonomous Underwater Vehicles (AUV) are another emerging platform for analytical instruments to observe the marine environment over wide spatial scales. An example is the AutoSub in which a CytoSub flow cytometer was tested, cruising through a coccolithophore bloom SE of the Isles of Scilly. The coccolithophore cells of Emiliana huxleyi, although largely outnumbered by other smaller species, dominate the water leaving back scattered light as seen by the satellite. The CytoSub data allowed the quantification of the coccolithophore cells numbers and their light scattering properties relative to the other cells and particles.