Royal Netherlands Institute for Sea Research

CTD systems

Requests to utilise equipment can be addressed to:
Erica Koning  +31 (0) 222 369 441 | if no answer: Thomas de Greef +31 (0) 222 369 375

CTD systems are used to collect water samples at depth in the water column, while simultaneously measuring various profiles such as oxygen, conductivity, temperature and depth. The sampling bottles can be closed at the required water depths from the ship. Several types of sampling bottles are available.

Rosette frame with 24 sampling bottles

12l or 25l. Standard sampling bottles are 12l volume; the large volume CTD contains 25l sampling bottles.

General purpose high accuracy CTD-operations includingwatersampling and the use of the following additional sensors: fluorometer, DO-sensor, transmissiometer and PAR.

Specifications
The system consists of a SBE9plus underwaterunit, a SBE11plusV2deckunit, a SBE32 caroussel, a SBE3plus thermometer, a SBE4 conductivity sensor, a SBE5T underwaterpump, a SBE43 dissolved oxygen sensor, a Chelsea Aquatracka MKIII fluorometer, a WetlabsC-Star transmissiometer (25 cm, deep, red), a Satlantic logaritmicPAR-sensor for underwater PAR  and a Satlantic lineair PAR-sensor for deck reference.

For watersampling 24 watersamplers manufactured by Ocean Test Equipment are available. These 12-liter samplers are equipped with external stainless steel springs.

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 board RV Pelagia a Seapath 2000 shipmotion sensor provides high accuracy position-, date- and time-data in NMEA-0183  RMC-format. On the logging computer Seasoft for Windows is installed (Seasave V7.20 and SBE Data Processing V7.20).

Remarks
The CTD frame is made from stainless steel and consists of 2 parts: a core-part that contains all the electronic modules and an outer part containing the samplingbottles.

For CTD-operations during heavy seas a smaller outer frame without sampling-bottles is available. 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. For more product info see here.

Ultra Clean CTD system

The Ultra Clean system includes a sampling container (2 types: PTFE and PP). Needs a metal-free cable.

Clean Container

High accuracy and Ultra Clean CTD-operations including the use of following additional sensors:  fluorometer, DO-sensor, transmissiometer and PAR. The UCC-system enables large scale research on trace-elements (e.g. iron, aluminium and manganese) and isotopes. 

Specifications

The system consists of 2 major modules:
A box-shaped titanium CTD frame with 24 PVDF sampling bottles with modified butterfly valves.
A clean air container for contamination-free (sub)sampling

For deployment of this CTD-system a winch with an iron free CTD-cable with a SWL of at least 2.5 ton is needed.

To avoid contamination the frame of the UCC-system is made of titanium. All electronic pressure housings and other parts are made of titanium or clean plastics like Teflon, PETP or POM. The frame can be parked and secured ‘seasave’ inside the clean air container. Prior to a cast the frame is prepared inside this container and transported to the CTD-launching spot using a custom made aluminium pallet and an extended forklift. After the cast the frame can be returned to the clear air container within minutes thereby avoiding contamination of the equipment with grease, rust or smoke particles from the ship. Once the container is closed the air treatment system starts to clean the air using HEPA-filters. Frame, bottles and electronics can be rinsed with fresh water. All the UCC-equipment, procedures and test results are described in a paper published in Marine Chemistry (pdf-version is available upon request, contact sven.ober@nioz.nl). A poster about the UCC-system is available for a first impression.

The electronic system consists of a SBE9plus underwaterunit, a SBE11plusV2 deckunit, a NIOZ-developed multivalve bottle-controller, 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 Ultra Clean water sampling 24 sampling bottles made of PVDF are used. These bottles with a volume of 27 liters have modified butterfly valves on both ends enabling a near-perfect flow of water through the bottle when going through the water column. The samplers are controlled with a hydraulic system. For bottom-detection 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).

Remark: detailed information about the sensors (e.g. accuracy) and other system modules is available here. Extra sensors such as a secondary pumped CT-set or a SBE35 reference-thermometer are available upon request. 

Large volume sampler (1000 l) 

General purpose high accuracy CTD-operations including large volume watersampling and the use of the following additional sensors:  fluorometer, DO sensor, PAR and transmissometer. 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.

Specifications

The system consists of a SBE9plus underwaterunit, a SBE11plusV2deckunit, a SBE32 caroussel, a SBE3plus thermometer, a SBE4 conductivity sensor, a SBE5T underwaterpump, a SBE43 dissolved oxygen sensor, a Chelsea Aquatracka MKIII fluorometer, a WetlabsC-Star transmissometer (25 cm, deep, red), a Satlantic logaritmicPAR-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 computerSeasoft for Windows is installed (Seasave V7.20 and SBE  Data Processing V7.20).

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.gaccuracy) 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. Mote detailed information is available here.