RV Callista
The RV Callista is a 19.75m research and survey catamaran owned by the National Oceanography Centre Southampton, coded by the MCA as category 2 for 12 people to work up to 60nm from a safe haven. The vessel has a dry and a wet laboratory. She has twin 650hp diesel engines. She has a 10 knot service speed. She is fitted with a 4 tonne A frame and winch with a 1.3 tonne crane as well as a 1.5 tonne capstan. She is also equipped with a rib with outboard engine and a hydraulic platform. She is equipped with a range of scientific equipment such as ADCP and CTD rosette with water sampling Niskin bottle carousel. The rosette is also equipped with various sensors for dissolved oxygen, PAR, turbidity and chlorophyll. She also has a surface water flow through system and carries a range of meteorological sensors.
CTD (Conductivity Temperature and Depth) and Niskin Bottles
The CTD set up for the RV Callista measured the Temperature, Salinity, Flourometry, Turbidity and Depth with computerised closing of the six attached niskin bottles at various depths. Each Niskin bottle had a volume of 5 litres. Due to the high weight of the rosette, the deployment required a hydraulic A frame along with two ropes for stabilisation of the rosette. Samples were taken using the niskin bottles at the base of the profile, the surface and at points of interest within the profile.
Close Net Plankton Collection
The closing plankton net allowed specific depth plankton trawls by using a weight to initiate the closing of the net at specific depth regions. Utilising the ADCP backscatter to determine regions of interest the net was lowered into the trawl zone and raised to the desired stopping point. A weight then initiated the closing of the net by causing the release of the cables holding the net mouth. This caused the weight of the net to be held by a cable around a choke point, closing the mouth and preventing further sampling. The net was then hosed off at the surface to collect any samples caught in the net material.
ADCP (Acoustic Doppler Current Profiler)
The ADCP was run along a series of transects to determine current strenght and direction but also imaged the backscatter for use as an indicator of plankton growth, with increased localised backscatter potentially indicating a colony of planktonic growth.
