Metadata Report for BODC Series Reference Number 2081052

• Metadata Summary

• Problem Reports

• Data Access Policy

• Data 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

Data Access Policy

Virginia Institute of Marine Science (VIMS) Data Licence Agreement

When using this data please use the following acknowledgment:

'This study uses data from Walker Smith, provided by the British Oceanographic Data Centre and funded by the Virginia Institute of Marine Science.'

Data Policy

British Oceanographic Data Centre (BODC) Data Licence Agreement

It is BODC's policy to encourage the use of our data holdings for science, education and industry, as well as the wider public. Data are made available, in line with the Natural Environment Research Council (NERC) Data Policy, under a licence agreement.

• BODC grants the licensee a non-exclusive and non-transferable licence to retrieve and use data sets and products in accordance with this licence.
• The use of unrestricted data sets for academic purposes is free of charge unless otherwise stipulated.
• The use or reproduction of data for commercial purposes might require additional permission from the data source and may incur a charge.
• The ownership of the data remains the property of NERC or the originating source providing the data to NERC.
• Users should not give any data or products to third parties without prior consent from BODC.
• Regardless of whether the data are quality controlled or not, BODC and the data source do not accept any liability for the correctness and/or appropriate interpretation of the data. Correct and appropriate data interpretation is solely the responsibility of data users.
• Users must acknowledge data sources as it is not ethical to publish data without proper attribution. Any publication or other output resulting from usage of the data should include an acknowledgment.
  The acknowledgment should be:
  

  'This study uses data from Walker Smith, provided by the British Oceanographic Data Centre and funded by the Virginia Institute of Marine Science.'

• BODC reserves the right to inform the data source of who has accessed what and when.
• Users are requested to inform BODC (enquiries@bodc.ac.uk) of any problems encountered with data as this feedback may result in an enhancement in the quality of the data we hold.
• BODC reserves the right to terminate this licence at any time if the above conditions are not observed.

Optional co-authorship clause

• Users must respect specified restrictions on the use or reproduction of data. In some circumstances, due acknowledgment is considered to be co-authorship on any publication or other output. This may be dependent on the usage of the data supplied, so should be the result of a negotiation between the data source and the data user.

Narrative Documents

Carlo-Erba EA-1108 elemental analyser

An elemental analyser. It simultaneously determines the total carbon, hydrogen, nitrogen and sulphur in a small solid or liquid sample. A sample is put into a tin capsule which is placed in the combustion tube. Here, the sample is in oxygen rich gas stream which causes flash combustion of the tin capsule and in turn the sample is rapidly combusted. The resulting gases are separated on a packed gas chromatography column and quantified using a thermal conductivity detector. The instrument was originally manufactured by Carlo-Erba, which has since been replaced by Thermo Scientific (part of Thermo Fisher Scientific). This model is no longer in production. It is also possible to determine oxygen with a modification to the systems configuration. Analysis times: CHN in 7 min, S in 5 min and O in 6 min. Range: 10 ppm to 100%.

Currently no specifications sheet available.

Niskin Bottle

The Niskin bottle is a device used by oceanographers to collect subsurface seawater samples. It is a plastic bottle with caps and rubber seals at each end and is deployed with the caps held open, allowing free-flushing of the bottle as it moves through the water column.

Standard Niskin

The standard version of the bottle includes a plastic-coated metal spring or elastic cord running through the interior of the bottle that joins the two caps, and the caps are held open against the spring by plastic lanyards. When the bottle reaches the desired depth the lanyards are released by a pressure-actuated switch, command signal or messenger weight and the caps are forced shut and sealed, trapping the seawater sample.

Lever Action Niskin

The Lever Action Niskin Bottle differs from the standard version, in that the caps are held open during deployment by externally mounted stainless steel springs rather than an internal spring or cord. Lever Action Niskins are recommended for applications where a completely clear sample chamber is critical or for use in deep cold water.

Clean Sampling

A modified version of the standard Niskin bottle has been developed for clean sampling. This is teflon-coated and uses a latex cord to close the caps rather than a metal spring. The clean version of the Levered Action Niskin bottle is also teflon-coated and uses epoxy covered springs in place of the stainless steel springs. These bottles are specifically designed to minimise metal contamination when sampling trace metals.

Deployment

Bottles may be deployed singly clamped to a wire or in groups of up to 48 on a rosette. Standard bottles and Lever Action bottles have a capacity between 1.7 and 30 L. Reversing thermometers may be attached to a spring-loaded disk that rotates through 180° on bottle closure.

Particulate Organic Carbon (POC) and Particulate Organic Nitrogen (PON) data from water samples collected during GENTOO cruise JR20120120

Originator's Protocol for Data Acquisition and Analysis

Samples were collected from both the underway supply and CTD Niskin bottles at various depths but most commonly 5, 10, 20, 40, 50 60, 80, 100, 150 and 200m. The samples were collected in 1000 mL amber polycarbonate bottles and filtered through pre-combusted GF/F filters at pressures of 7 - 10 in Hg. Filters were rinsed with 0.01N HCl before removal from the filtration frits. Blanks were created using 0.2µm gravity filtered seawater from the underway system and 0.01N HCl through a pre-combusted GF/F filter. Both the sample filters and blanks were folded in half, placed in pre-combusted cuvettes and covered with pre-combusted aluminium foil. The cuvettes were stored in a 60°C drying oven and transported back to the Virginia Institute of Marine Science for analysis. Back at the laboratory, the filters were combusted using an elemental analyzer using acetanilide as a standard following Gardner et al (2000).

References Cited

Gardner W.D., Richardson M.J. and Smith W.O., 2000. Seasonal patterns of water column particulate organic carbon and fluxes in the Ross Sea, Antarctica. Deep-Sea Research II, 47, 3423-3449.

Instrumentation Description

Carlo-Erba 1108 elemental analyzer

BODC Data Processing Procedures

The spreadsheet consists of two sheets containing calculations data and blanks data. The calculations sheet contains all variables used in the calculation of POC (µmol L^-1) and PON (µmol L^-1) including: nitrogen weight (mg), carbon weight (mg), blank-corrected nitrogen weight (mg), blank-corrected carbon weight (mg), volume filtered, nitrogen concentration (mg L^-1), carbon concentration (mg L^-1) and C:N ratio. Station, depth and sample ID are also included. The blanks sheet included the station, sample ID, nitrogen weight (mg) and carbon weight (mg). Only POC and PON are loaded to the BODC database but the remaining parameters are available on request.

The data were reformatted and assigned BODC parameter codes which were in equivalent units to the data and so unit conversions were not necessary. Data were loaded in BODC's database using established BODC data banking procedures. A parameter mapping table is provided below:

Data Quality Report

The originator did not advise BODC of any data quality issues however during BODC quality control the data supplier was contacted to query a POC concentration that was negative. After discussing this with the data supplier, the value was marked as suspect. No further flagging was applied during BODC quality control.

Project Information

Gliders: Excellent New Tools for Observing the Ocean (GENTOO)

Funding

Funding was provided by NERC through the 11^th round of the Antarctic Funding Initiative (AFI), an annual competition-based award which is supported logistically by the British Antarctic Survey (BAS). The award had a total value of £1,070,531 which was split between different researchers at various international institutions in the form of grants, fellowships and training grant records.

Project dates - 06 September 2010 to 31 March 2015

Background

Research has shown that surface waters surrounding Antarctica play an important role in driving the global oceanic circulation as they are subjected to ideal physical conditions to become denser and sink at specific locations. The mapping of these locations and the identification of the properties of these water cells have been relying on expensive and season-dependent shipborne observations in impractical polar seas. This study aims at revealing the potential of Seagliders, which are autonomous, inexpensive and sustainable underwater vehicles able to carry out certain physical, biological and chemical measurements of the water column all year round. Seagliders were deployed in the Weddell Sea, as the recent collapse of the Larsen Ice Shelf has raised questions on whether dense water may now be spilling off the continental shelf on the eastern side of the Antarctic Peninsula. Changes in location of deep water formation may affect local oceanic currents and consequently the global circulation and the Earth's climate; reliable mapping and description of the Antarctic waters are therefore key to generate accurate climate and circulation models and predictions. Possible changes in the ocean currents also affect the organisms living in the waters near Antarctica. In particular, krill lay eggs around the Antarctic Peninsula and rely on ocean currents to transport them to South Georgia. It is important to determine whether changes in the local circulation may impact krill's ecosystem, as animals such as whales, seals and penguins feed on them and they support a multi-million pound krill fishing industry. In light of the decreasing availability of resources for an increasing human population, the possibility of krill's immunity to temperature and circulation changes may result in a popular food resource for people in the future.

Objectives

The main objectives of the GENTOO project depend on a critical evaluation of the ability to measure current velocity and krill biomass from a glider.

1) To quantify and understand the possible new source of dense water overflow and its variability; to determine the outflow's potential as an early indicator of Antarctic climate change; to assess the impact of changing dense overflows on the locations and strengths of the surface currents and frontal jets; to provide valuable constraints for climate models that describe how changes in ocean circulation feedback on and regulate climate change in polar latitudes.

2) To determine the krill biomass distribution and (temporal and spatial) variability to the east of the Antarctic Peninsula and its likely impact on the circumpolar krill ecosystem; to assess the impact of any variations in the location of the frontal jets (from objective 1) on the krill biomass distribution; to alleviate a severe regional lack of field data on krill, a key species in the Antarctic food web.

Participants

• University of East Anglia, United Kingdom (Lead Research Organisation)
• NOAA - National Oceanic and Atmospheric Administration, United States
• Bjerknes Centre for Climate Research, Norway
• AWI - Alfred Wegener Institute for Polar and Marine Research, Germany
• VIMS - Virginia Institute of Marine Science, United States

• Prof. Karen Heywood, University of East Anglia, Environmental Science (Principal Investigator)
• Dr. Sophie Fielding, NERC British Antarctic Survey, Science Programmes
• Prof. Gwyn Griffiths, National Oceanography Centre, Science and Technology
• Dr. Stuart Dalziel, University of Cambridge, Applied Mathematics and Theoretical Physics
• Dr. Eugene Murphy, NERC British Antarctic Survey, Science Programmes
• Dr. Andrew Thompson, California Institute of Technology, Environmental Science and Engineering.

Methodology

During cruise RRS James Clark Ross 255A three Seagliders were deployed, and a hydrographic survey was undertaken together with nets and underway biological, chemical and physical measurements. The data gathered was analysed to meet the objectives listed above. Please read the 'Instrumentation' section below, and visit the GENTOO website for more information on the methodology and outcomes of the various research studies.

Fieldwork

• RRS James Clark Ross 255A - 20 January 2012 to 03 February 2012. Port of arrival and departure is Stanley, Falkland Islands (Malvinas). Study area - Drake Passage, Weddell Sea, Powell Basin. Principal Scientist - Dr. Karen Heywood, University of East Anglia. This was the glider deployment cruise and the primary data gathering exercise.
• RRS James Clark Ross 255B - 07 February 2012 to 22 March 2012. Port of arrival and departure is Stanley, Falkland Islands (Malvinas). This was the glider recovery cruise; other projects not linked to GENTOO shared the voyage.

Instrumentation

• Seagliders - three in total, each equipped with a Seabird CT sail (i.e. free-flushed temperature and conductivity sensors), Aandera oxygen optode and a WETLabs ECO Triplet. (Biddle et al. 2015)
• SeaBird (SBE) CTD-11plus rosette equipped with 24 12-litre Niskin bottles. Sensors installed are SBE 43 Oxygen sensor, LI-COR Biospherical PAR Sensor, Chelsea Aqua 3 Fluorometer, WET Labs C-Star Transmissometer, and Altimeter sensor.
• 300 kHz WorkHorse (WH) Lowered Acoustic Doppler Current Profiler (LADCP)
• 75 kHz RD Instruments Ocean SUrveyor (OS75) Vessel-Mounted Acoustic Doppler Current Profiler (ADCP)
• Surface drifters: 20 Clearsat-15 Minidrogue drifters with a GPS navigation option and 20 Clearsat-15 SVP Minidrigue drifters with Argos data telemetry, both purchased from Clearwater Instrumentation, Inc.
• Three AOEX-SBE Argo floats profilers produced by Webb Research Corporation USA.
• RMT8 Nets Macrozooplankton
• Guildline Autosal salinometer
• Winkler O₂ titrator
• Simrad EK60 Echo Sounder
• Underway - navigation, surface and meteorology.

Contacts

References

Biddle, L.C., Kaiser J., Heywood K.J., Thompson A.F., and Jenkins A., 2015. Ocean glider observations of iceberg-enhanced biological production in the northwestern Weddell Sea, Geophys. Res. Lett. (42), 459-465.

Data Activity or Cruise Information

Data Activity

BODC Sample Metadata Report for JR20120120_CTD_CTD_005

Please note:the supplied parameters may not have been sampled from all the bottle firings described in the table above. Cross-match the Sample Reference Number above against the SAMPRFNM value in the data file to identify the relevant metadata.

Cruise

Complete Cruise Metadata Report is available here

Fixed Station Information

No Fixed Station Information held for the Series

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: