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Large Volume CTD System
Goal	General purpose high accuracy CTD-operations including large volume watersampling and the use of the following additional sensors:  fluorometer, DO-sensor, transmissiometer and PAR. This CTD-system is developed mainly to enable efficient sampling for research that needs large volumes of sample water e.g. research on rare elements, sedimentology and microbiology.
Description	The system consists of a SBE9plus underwaterunit, a SBE11plusV2 deckunit, a SBE32 caroussel, a SBE3plus thermometer, a SBE4 conductivity sensor, a SBE5T underwaterpump, a SBE43 dissolved oxygen sensor, a Chelsea Aquatracka MKIII fluorometer, a Wetlabs C-Star transmissiometer (25 cm, deep, red), a Satlantic logaritmic PAR-sensor for underwater PAR  and a Satlantic lineair PAR-sensor for deck reference.   For large volume watersampling  24 watersamplers each with a volume of 25 liter manufactured by Ocean Test Equipment are applied. These 25-liter samplers are equipped with a internal stainless steel spring and a horizontally mounted Teflon drain assembly. Via this drain assembly flexible jerry cans can be filled easily and the horizontal orientation of the drain enables easy and efficient CFC-sampling.   For bottomdetection 2 devices are installed: A Benthos PSA-916 altimeter and a bottom switch with a weight. The SBE11+ has a NMEA interface for navigational data.  On the logging computer Seasoft for Windows is installed (Seasave V7.20 and SBE Data Processing V7.20).
Remarks	The CTD frame is made of stainless steel and consists of 2 parts: a core-part that contains all the electronic modules and an outer part containing the sampling bottles.   Due to the large dimensions of the bottles the frame is rather big. It has a hexagonal shape with an overall diameter of about 2 m and a height of 1.9 meter. The mass of the frame with 24 filled bottles is about 1500 kg. Detailed information about the sensors (e.g accuracy) and other system modules are available via the links. When necessary extra sensors such as a secondary pumped CT-set, SBE35 reference-thermometer or SIS electronic reversing pressure meters (ERPM-6000X) are available.
Contact	Sven Ober