Metadata Report for BODC Series Reference Number 1837707

• Metadata Summary

• Problem Reports

• Data Access Policy

• Narrative Documents

• Project Information

• Data Activity or Cruise Information

• Fixed Station Information

• BODC Quality Flags

• SeaDataNet Quality Flags

Metadata Summary

Problem Reports

No Problem Report Found in the Database

CTD data from cruise JR16006 Quality Report

Screening and Quality Control

During BODC quality control, data were screened using in house visualisation software. The data were screened and any obvious outliers and spikes were looked at in closer detail and flagged if necessary.

TVLTDR01 and POPTDR01

There were a number of spikes in both TVLTDR01 and POPTDR01 for a large number of series. After comparing these spikes to other parameters, the spikes looked improbable and so were flagged 'M' during BODC screening.

OXYOCPVL and DOXYSC01

The originator has advised that the data from the primary oxygen sensor are dubious and so OXYOCPVL and DOXYSC01 have been flagged 'L' during BODC processing. The parameters were later dropped from the file as the originator advised that the secondary sensor data should be used instead.

Data Access Policy

Open Data supplied by Natural Environment Research Council (NERC)

You must always use the following attribution statement to acknowledge the source of the information: "Contains data supplied by Natural Environment Research Council."

Narrative Documents

Sea-Bird Dissolved Oxygen Sensor SBE 43 and SBE 43F

The SBE 43 is a dissolved oxygen sensor designed for marine applications. It incorporates a high-performance Clark polarographic membrane with a pump that continuously plumbs water through it, preventing algal growth and the development of anoxic conditions when the sensor is taking measurements.

Two configurations are available: SBE 43 produces a voltage output and can be incorporated with any Sea-Bird CTD that accepts input from a 0-5 volt auxiliary sensor, while the SBE 43F produces a frequency output and can be integrated with an SBE 52-MP (Moored Profiler CTD) or used for OEM applications. The specifications below are common to both.

Specifications

Further details can be found in the manufacturer's specification sheet.

Instrument Description for JR16006 CTD

CTD Unit and Auxiliary Sensors

The CTD unit comprised a Sea-Bird Electronics (SBE) 9plus underwater unit, an SBE 11 plus deck unit, a 24-way SBE 32 carousel and 24 20 L TMF Water Samplers; all of which were mounted on a stainless steel 24-way CTD frame. Attached to the CTD were two SBE 3P temperature sensors, two SBE 4C conductivity sensors, one Paroscientific Digiquartz pressure sensor, two SBE 43 dissolved oxygen sensor, one QCP2350 PAR sensor, one one CTG Aquatracka MKIII fluorometer, one WetLabs C-Star transmissometer, one Tritech Altimeter, one SBE35 temperature sensor and two RDI LADCPs.

* The secondary oxygen sensor was installed from cast 14 (Series Reference Number 1905480, ORIG_STN 78) onwards.

Sea-Bird Electronics SBE 911 and SBE 917 series CTD profilers

The SBE 911 and SBE 917 series of conductivity-temperature-depth (CTD) units are used to collect hydrographic profiles, including temperature, conductivity and pressure as standard. Each profiler consists of an underwater unit and deck unit or SEARAM. Auxiliary sensors, such as fluorometers, dissolved oxygen sensors and transmissometers, and carousel water samplers are commonly added to the underwater unit.

Underwater unit

The CTD underwater unit (SBE 9 or SBE 9 plus) comprises a protective cage (usually with a carousel water sampler), including a main pressure housing containing power supplies, acquisition electronics, telemetry circuitry, and a suite of modular sensors. The original SBE 9 incorporated Sea-Bird's standard modular SBE 3 temperature sensor and SBE 4 conductivity sensor, and a Paroscientific Digiquartz pressure sensor. The conductivity cell was connected to a pump-fed plastic tubing circuit that could include auxiliary sensors. Each SBE 9 unit was custom built to individual specification. The SBE 9 was replaced in 1997 by an off-the-shelf version, termed the SBE 9 plus, that incorporated the SBE 3 plus (or SBE 3P) temperature sensor, SBE 4C conductivity sensor and a Paroscientific Digiquartz pressure sensor. Sensors could be connected to a pump-fed plastic tubing circuit or stand-alone.

Temperature, conductivity and pressure sensors

The conductivity, temperature, and pressure sensors supplied with Sea-Bird CTD systems have outputs in the form of variable frequencies, which are measured using high-speed parallel counters. The resulting count totals are converted to numeric representations of the original frequencies, which bear a direct relationship to temperature, conductivity or pressure. Sampling frequencies for these sensors are typically set at 24 Hz.

The temperature sensing element is a glass-coated thermistor bead, pressure-protected inside a stainless steel tube, while the conductivity sensing element is a cylindrical, flow-through, borosilicate glass cell with three internal platinum electrodes. Thermistor resistance or conductivity cell resistance, respectively, is the controlling element in an optimized Wien Bridge oscillator circuit, which produces a frequency output that can be converted to a temperature or conductivity reading. These sensors are available with depth ratings of 6800 m (aluminium housing) or 10500 m (titanium housing). The Paroscientific Digiquartz pressure sensor comprises a quartz crystal resonator that responds to pressure-induced stress, and temperature is measured for thermal compensation of the calculated pressure.

Additional sensors

Optional sensors for dissolved oxygen, pH, light transmission, fluorescence and others do not require the very high levels of resolution needed in the primary CTD channels, nor do these sensors generally offer variable frequency outputs. Accordingly, signals from the auxiliary sensors are acquired using a conventional voltage-input multiplexed A/D converter (optional). Some Sea-Bird CTDs use a strain gauge pressure sensor (Senso-Metrics) in which case their pressure output data is in the same form as that from the auxiliary sensors as described above.

Deck unit or SEARAM

Each underwater unit is connected to a power supply and data logging system: the SBE 11 (or SBE 11 plus) deck unit allows real-time interfacing between the deck and the underwater unit via a conductive wire, while the submersible SBE 17 (or SBE 17 plus) SEARAM plugs directly into the underwater unit and data are downloaded on recovery of the CTD. The combination of SBE 9 and SBE 17 or SBE 11 are termed SBE 917 or SBE 911, respectively, while the combinations of SBE 9 plus and SBE 17 plus or SBE 11 plus are termed SBE 917 plus or SBE 911 plus.

Specifications

Specifications for the SBE 9 plus underwater unit are listed below:

Further details can be found in the manufacturer's specification sheet.

SeaBird SBE35 Deep Ocean Standards Thermometer

The SBE 35 is a high precision thermometer that can be used in fixed point cells or at depths up to 6800 m. It is not affected by shock and vibration, allowing it to be used in calibration laboratories and for thermodynamic measurement of hydro turbine efficiency.

The SBE35 can be used with the SBE32 Carousel Water Sampler and with a real-time or autonomous CTD system. In this case, an SBE35 temperature measurement is collected each time a bottle is fired and the value is stored in EEPROM (Electrically Erasable Programmable Read-Only Memory), eliminating the need for reversing thermometers while providing a high accuracy temperature reading.

The SBE35 is standardized in water triple point (0.0100 °C) and gallium melting point (29.7646 °C) cells, following the methodology applied to the Standard-Grade Platinum Resistance Thermometer (SPRT). However, it does not need a resistance bridge, making it more cost-efficient than an SPRT.

Temperature is determined by applying an AC excitation to reference resistances and an ultrastable aged thermistor. Each of the resulting outputs is digitized by a 20-bit A/D converter. The AC excitation and ratiometric comparison uses a common processing channel, which removes measurement errors due to parasitic thermocouples, offset voltages, leakage currents and gain errors.

Specifications

Further details can be found in the manufacturer's specification sheet and manual.

Aquatracka fluorometer

The Chelsea Instruments Aquatracka is a logarithmic response fluorometer. It uses a pulsed (5.5 Hz) xenon light source discharging between 320 and 800 nm through a blue filter with a peak transmission of 420 nm and a bandwidth at half maximum of 100 nm. A red filter with sharp cut off, 10% transmission at 664 nm and 678 nm, is used to pass chlorophyll-a fluorescence to the sample photodiode.

The instrument may be deployed either in a through-flow tank, on a CTD frame or moored with a data logging package.

Further details can be found in the manufacturer's specification sheet.

Biospherical Instruments QCP-2350 [underwater] PAR sensor

A cosine-corrected PAR quantum irradiance profiling sensor. For use in underwater applications with 24 bit ADC systems. Measures light available for photosynthesis on a flat surface. Operation is by a single channel compressed analog output voltage that is proportional to the log of incident PAR (400-700 nm) irradiance. The sensor is designed for operation in waters to depths of up to 2,000 m (standard) or 6,800 m (optional).

For more information, please see this document: https://www.bodc.ac.uk/data/documents/nodb/pdf/Biospherical_QCP2300_QCP2350_Apr2014.pdf

WETLabs C-Star transmissometer

This instrument is designed to measure beam transmittance by submersion or with an optional flow tube for pumped applications. It can be used in profiles, moorings or as part of an underway system.

Two models are available, a 25 cm pathlength, which can be built in aluminum or co-polymer, and a 10 cm pathlength with a plastic housing. Both have an analog output, but a digital model is also available.

This instrument has been updated to provide a high resolution RS232 data output, while maintaining the same design and characteristics.

Specifications

Further details are available in the manufacturer's specification sheet or user guide.

BODC Data Processing

Data Processing

The CTD data from Changing Arctic Ocean cruise JR16006 were received in both .mat and .csv format accompanied by a list of variables and units which were subsequently archived following BODC procedures. The .csv files were transferred to BODC internal format using standard BODC procedures. The variables provided in the files were mapped to BODC parameter codes as follows:

The following parameters were derived by BODC when the data were transferred to internal BODC netcdf format:

Uncalibrated and secondary channels that have not been transferred are available on request.

Screening

Post transfer analysis and crosschecks were applied according to BODC procedures. This involved the screening of data using BODC's in house visualisation software where any improbable data were flagged but not removed. During screening any data that were flagged as improbable by the originator were converted to BODC data flags. The originator highlighted that the data from the primary oxygen sensor were dubious and so these values were flagged 'L' during screening and were later dropped from the file as the originator specified that the second oxygen sensor should be used instead.

Originator Data Processing

Sampling Strategy

A total of 59 CTD casts were performed during JR16006 in the Barents Sea for the Changing Arctic Ocean programme.

Data Processing

For each CTD cast the following raw data files were generated:

• JR16006_XXX.bl (a record of bottle firing locations)
• JR16006_XXX.hdr (header file)
• JR16006_XXX.hex (raw data file)
• JR16006_XXX.con (configuration file)

where XXX is the cast number of the CTD data series.

The CTD processing was started using Seabird Data Processing version 7.26.4.23 were the following modules were run:

• Data conversion - converted raw data from engineering units to binary .cnv files and created .ros files.
• Wild edit - flagged any major spikes.
• Filter - smoothed the high frequency pressure and depth data using a low-pass filter (values of 0.15 - recommended by SeaBird).
• AlignCTD - shifted conductivities and oxygen relative to pressure to compensate for sensor time lag.
• CellTM - ran a recursive filter to remove conductivity cell thermal mass effects from measured conductivity.
• Derive - derived computation variables from the processed pressure, temperature and conductivity.
• Translate - converted the binary data to ASCII.
• BottleSum - created .bl files using a five second window centered around the bottle firing time.
• Strip - removed the first depth variable obtained at the Data Conversion stage.
• Binavg - averaged all variables to 2Hz bins and 1 second bins for LADCP processing.
• AsciiOut - reformatted the 1 second bin files for LADCP processing.

The originator then proceeded to process the data in Matlab as follows:

• Reading and plotting of 'raw' data - raw data as produced by SeaBird processing.
• Creation of bottle files - extracted the scan number of each bottle firing from .bl files and all variables in 5 second windows centred on the bottle firings. Averages, standard deviations, minimum and maximum values over the 5 second window were computed and saved. If present, the SBE35 data were included in the file.
• Manual removal of surface soak and out of water data post-cast
• Split data in to downcast and upcast - extracted the maximum pressure from the pressure data and split the cropped data in to downcast and upcast files.
• Manual removal of spikes and data anomalies
• Averaging of cast in 1db bins - averaged all variables to 1db bins centered around round values.
• Salinity calibration - analysed discrete salinity samples taken from the CTD Niskins using a salinometer following standard techniques.
• Oxygen calibration - applied calibration equations to the CTD data.

Calibrations

Conductivity

201 discrete salinity samples were taken from the CTD Nskin bottles which were analysed using a Guildline 8400B Autosal salinometer (SN 68533). At the start and end of each batch a standard seawater (SSW) sample was analysed to monitor the drift of the instrument. No clear drift pattern was visible and so the average of the two SSW offsets was used to correct the salinometer readings. These corrected salinometer readings were plotted against the CTD conductivity sensors and a drift in the sensors or relative to pressure was not visible. The median and standard deviation of the differences between the raw CTD conductivity and the salinometer readings were calculated, and all readings with a difference larger than 0.2 standard deviations of the median were excluded from the dataset. The median offset of each subset of selected points was then calculated and used as the correction offset.

Oxygen

Discrete samples were taken from the CTD Niskin bottles for analysis using the Winkler titration method. The following calibrations were then applied to the CTD dissolved oxygen data:

Data Quality

The primary oxygen sensor was initially the single oxygen sensor and was showing very low values from the start of the cruise. From cast 14 onwards, a secondary oxygen sensor was added which read values approximately 50% higher than the primary sensor and was much closer to the Winkler titration results. After calibration, the originator decided that the values from sensor 1 are still dubious, particularly at depths greater than 1,000 m, and that the data from sensor 2 should be used instead where possible.

Further information on the processing can be found in section 2.2 of the cruise report.

Project Information

Changing Arctic Ocean: Implications for marine biology and biogeochemistry

Changing Arctic Ocean (CAO) is a £16 million, five year (2017-2022) research programme initially funded by the Natural Environment Research Council (NERC). The aim of the CAO programme is to understand how change in the physical environment (ice and ocean) will affect the large-scale ecosystem structure and biogeochemical functioning of the Arctic Ocean, the potential major impacts and provide projections for future ecosystem services. In July 2018, additional projects were added to the programme that were jointly funded by NERC and the German Federal Ministry of Education and Research.

Background

The Arctic Ocean is responding to global climate change in ways that are not yet fully understood and in some cases, not yet identified. The impacts of change in the Arctic are global in range and international in importance. To achieve the aim, the programme has two key research challenges:

• To develop quantified understanding of the structure and functioning of Arctic ecosystems.
• To understand the sensitivity of Arctic ecosystem structure, functioning and services to multiple stressors and the development of projections of the impacts of change.

The decision to fund the CAO project was both scientific and political and is the second largest research programme funded by NERC.

The programme involves 33 organisations, the majority of which are research institutions in the UK and Germany, and over 170 scientists. The programme consists of four large projects with an additional 12 research projects added in July 2018.

Further information can be found on the Changing Arctic Ocean website.

Participants

There are 33 organisations involved in the Changing Arctic Ocean project, these are:

• Alfred Wegener Institut (AWI)
• Bangor University
• British Antarctic Survey (BAS)
• Centre for Environment, Fisheries and Aquaculture Science (CEFAS)
• Durham University
• GEOMAR
• Helmholtz-Zentrum Geesthacht Centre for Materials and Coastal Research
• Lancaster University
• Marine Biological Association (MBA)
• Max Planck Institute for the Science of Human History
• National Oceanography Centre (NOC)
• Newcastle University
• Northumbria University
• Ocean Atmosphere Systems GmbH
• Plymouth Marine Laboratory (PML)
• Scottish Association for Marine Science (SAMS)
• Scottish Universities Environmental Research Centre (SUERC)
• Université Libre de Bruxelles
• University College London (UCL)
• University of Bristol
• University of East Anglia (UEA)
• University of Edinburgh
• University of Glasgow
• University of Huddersfield
• University of Leeds
• University of Liverpool
• University of Manchester
• University of Oldenburg
• University of Oxford
• University of Southampton
• University of St Andrews
• University of Stirling
• University of Strathclyde

In addition to the core organisation, there are a number of international collaborators.

Research Details

The four large projects funded by NERC are:

• Arctic Productivity in the seasonal Ice Zone (Arctic PRIZE)
• Can we detect changes in Arctic ecosystems? (ARISE)
• The Changing Arctic Ocean Seafloor (ChAOS) - How changing sea ice conditions impact biological communities, biogeochemical processes and ecosystems
• Mechanistic understanding of the role of diatoms in the success of the Arctic Calanus complex and implications for a warmer Arctic (DIAPOD)

The additional 12 projects added in July 2018 funded jointly by NERC and the German Federal Ministry of Education and Research are:

• Advective Pathways of nutrients and key Ecological substances in the Arctic (APEAR)
• How will changing freshwater export and terrestrial permafrost thaw influence the Arctic Ocean? (CACOON)
• Chronobiology of changing Arctic Sea Ecosystems (CHASE)
• Potential benefits and risks of borealisation for fish stocks and ecosystems in a changing Arctic Ocean (Coldfish)
• Diatom Autecological Responses with Changes To Ice Cover (Diatom-ARCTIC)
• Ecosystem functions controlled by sea ice and light in a changing Arctic (Eco-Light)
• Effects of ice stressors and pollutants on the Arctic marine cryosphere (EISPAC)
• Linking Oceanography and Multi-specific, spatially-Variable Interactions of seabirds and their prey in the Arctic (LOMVIA)
• Understanding the links between pelagic microbial ecosystems and organic matter cycling in the changing Arctic (Micro-ARC)
• Microbes to Megafauna Modelling of Arctic Seas (MiMeMo)
• Primary productivity driven by escalating Arctic nutrient fluxes? (PEANUTS)
• Pathways and emissions of climate-relevant trace gases in a changing Arctic Ocean (PETRA)

Fieldwork and Data Collection

The programme consists of seven core cruises that survey areas in the Barents Sea and the Fram Strait on board the NERC research vessel RRS James Clark Ross. Measurements will include temperature, salinity, dissolved oxygen, dissolved inorganic carbon, total alkalinity, inorganic nutrients, oxygen and carbon isotopes and underway meteorological and surface ocean observations. In addition to ship based cruise datasets gliders, moorings and animal tags are part of the fieldwork. Further data are collected from model runs.

Data Activity or Cruise Information

Cruise

Complete Cruise Metadata Report is available here

Fixed Station Information

Fixed Station Information

Changing Arctic Ocean Fixed Station B22

This station is one of several sites sampled on the Barents Sea as part of the Changing Arctic Ocean programme. The station has a mean water depth 108 m at the following co-ordinates:

The position of this station relative to the other Changing Arctic Ocean sites can be seen from the figure below (in red).

Sampling History

Related Fixed Station activities are detailed in Appendix 1

BODC Quality Control Flags

The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:

SeaDataNet Quality Control Flags

The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:

Appendix 1: CAO-B22

Related series for this Fixed Station are presented in the table below. Further information can be found by following the appropriate links.

If you are interested in these series, please be aware we offer a multiple file download service. Should your credentials be insufficient for automatic download, the service also offers a referral to our Enquiries Officer who may be able to negotiate access.