Metadata Report for BODC Series Reference Number 1347167

• 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

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

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.

RRS Discovery Cruise D341 Discrete inorganic nutrient (nitrate, silicate and phosphate) concentrations from CTD bottles

Cruise Details

Content Of Data Series

^aPlease note: A number of samples were duplicate/triplicate analyses made from the same CTD OTE niskin bottle. Replicate analyses were averaged during BODC data processing (see BODC processing notes).

Originator's Data Acquisition and Processing

Sampling Strategy

A total of 73 CTD casts were undertaken on the cruise, 67 of which used the stainless steel frame, 2 used a trace metal free titanium frame, and 4 used a lightweight aluminium frame adapted to recover pressurised water samples from depth. Samples taken using the aluminium frame are not part of this dataset.
Casts were conducted for a variety of purposes, though the majority formed part of two high spatial resolution surveys to acquire near synoptic physical and biological parameters of a small part of the study site. Casts that formed part of the surveys were invariably to 1000 metres. Both surveys were reduced in scope due to adverse weather.
The aim of the first CTD survey was to map the spatial distribution of both physical and biological features around the PAP (Porcupine Abyssal Plain) site. The survey area was 100km2 centred on the PAP site with station spacing of 20km. Please refer to cruise report for a map and further details.

Instrumentation and Methodology

The stainless steel frame configuration was as follows:

Sea-Bird 9/11 plus CTD System carrying 2 pairs of SBE 3p Temperature and 4c Conductivity sensors with a Digiquartz pressure sensor.
24 by 20L Ocean Test Equipment External Spring Water Samplers
Sea-Bird 43 Oxygen Sensor
Chelsea MKIII Aquatracka Fluorometer
Chelsea MKII Alphatracka 25cm path Transmissometer
Wetlabs BBRTD backscatter detector
Teledyne Benthos Altimeter
OED LADCP Pressure Case Battery Pack
RD Instruments Workhorse 300 KHz Lowered ADCP (downward-looking master configuration)

The pressure sensor is located 15cm from the bottom of the water samplers, and 132 cm from the top of the water samplers. This frame was used for the majority of casts.

The titanium frame configuration was as follows:

Sea-Bird 9/11 plus CTD System carrying a single pair of SBE 3p Temperature and 4c Conductivity sensors and a Digiquartz pressure sensor.
24 by 10L Ocean Test Equipment External Spring Water Samplers
Sea-Bird 43 Oxygen Sensor
Chelsea MKIII Aquatracka Fluorometer
Chelsea MKII Alphatracka 25cm path Transmissometer
Wetlabs BBRTD backscatter detector
Teledyne Benthos Altimeter

The pressure sensor is located 30cm from the bottom of the water samplers, and 119 cm from the top of the water samplers. This frame was used twice, once for trace metal sampling to a depth of 4000m and once to collect water for a bioluminescence experiment.

The nutrients were analysed following techniques described in Kirkwood, D. (1996) "Nutrients: Practical notes on their determination in seawater."

Data Processing

No information on the originator's data processing in the cruise report, and no further details supplied by the originators.

BODC Data Processing

Data Processing

Data arrived at BODC in a Microsoft Excel spreadsheet containing all the samples taken during the cruise. The spreadsheet was initially converted into a Comma Separated Values format file (.csv) and appropriate BODC parameter codes were assigned. The following table shows how the variables supplied were mapped to BODC parameter codes.

In total, 50 sets of duplicate and triplicate analyses from the same CTD bottle were averaged. Additionally, the measurements for replicate bottle 19 on cast 16501 were loaded in preference to the first set of measurements which were flagged 'bad' by the data originator, and included negative nitrate values. The overall result was a .csv file containing only one phosphate, nitrate and silicate measurement per CTD OTE bottle sampled.

In the originator's spreadsheet, the flags on the nutrient values were confirmed by Mark Stinchcombe (NOCS) to be:

2 = good
3 = suspect
4 = bad
9 = absent data

These originator's flags were replaced by BODC bottle flags, such that absent data are flagged 'N', bad or suspect data are flagged 'L' and there are no flags applied to good data.

In the originator's spreadsheet, casts numbered 16514, 16515, 16516, 16518, 16622, 16623, 16624, 16625 and 16626 all had bottles labeled with letters instead of numbers. The data originators were emailed for clarification as to which bottle numbers the letters referred to here. They were unable to provide it, and the CTD log sheets for these casts could not resolve this issue either, so these records were omitted from the .csv file which was eventually uploaded to an SQL table.

A further problem with this dataset was identified after examining the originator's spreadsheet for some of the CTD casts taken during 'CTD Survey1', and the corresponding CTD log sheets. According to the spreadsheet, bottles number 1 to 11 inclusive had been sampled on each cast. The log sheets revealed that in total, 22 bottles were fired on each of these casts, with 2 bottles being fired at each depth. Bottle number 1 was fired at the deepest point of the cast, and bottle 22 was fired at the shallowest point. It seemed unlikely that only the first 11 bottles would have been sampled, as this would only represent the deepest section of the cast, with duplicates being taken for 5 depths, whilst all bottles fired in the upper section of the cast were then ignored. Jennifer Riley and Mark Stinchcombe (both NOC) were emailed for clarification, but were unable to help. However, Richard Sanders (Cruise PSO) stated that bottles 22, 20, 18,16,14,12,10,8,6,4 and 2 were actually sampled during the survey casts. This represents one bottle at every depth sampled throughout the cast. He also explained that due to a very last minute personnel change before the cruise, there was no one available to do the nutrient data on D341 apart from him, and as he was also the PSO, it was difficult to find time to give this dataset as much attention as usual.
Initially, it was considered appropriate to change the bottle numbers in the originator's spreadsheet where necessary to reflect the sampling regime described by Richard Sanders. He confirmed that nitrate values would increase with depth, which further clarified which bottles were actually sampled.
However- after examining the originator's spreadsheet further, it was decided not to bank data from the following casts: 16531, 16529, 16528, 16526, 16524, 16523, 16532, 16533, 16535, 16536, 16537, 16539, 16548, 16546, 16544, 16543, 16542, 16541
The reasons for this are that all the bottle numbers in the originator's spreadsheet are wrong for these casts, and it is not possible to assign new ones with complete confidence, even with guidance from Richard Sanders. For the more straightforward casts, it would appear, based on nitrate values, that bottles 22,20,18,16,14,12,10,8,6,4, and 2 were probably sampled, but for other casts, this sampling order has apparently been reversed based on nitrate values. For some casts, there are samples apparently taken from the same bottle which have different nitrate values. The sampling regime, according to the CTD log sheets is not always to fire 2 bottles at each depth which adds a further layer of confusion to assigning bottle numbers. Although for some of the casts listed above, it would be possible to make a fair guess at what the real bottle numbers should be, based on the trend of the nitrate values, this is not completely reliable and there would always be reasonable doubt as to the actual depth that these samples were taken from. Measurements from these casts will therefore be omitted from table BOTDATA.

The data were loaded from the .csv file into an Oracle database where measurements were linked to corresponding depths through the CTD rosette bottle number.

Data Quality Report

None

Problem Report

None

BODC Quality Control Flags

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

D341 Discovery Research Cruise Data Access Conditions

The following restrictions apply to the D341 Discovery research cruise organized by the National Oceanography Centre Southampton - Ocean Biogeochemistry and Ecosystems research group under the NERC Oceans 2025 research programme.

• All data are restricted for a period of three years from the date of collection.

• Under certain circumstances, the restriction period may be extended for some datasets, eg. where data form a PhD studentship.

• During these three years, BODC will not transfer them to third parties without the explicit agreement of the data originator.

• Three years after collection, the data should be available to the public.

The data may not be used for commercial purposes without a licence agreement with NERC, which may be arranged through BODC. Charges at commercial rates may be levied.

The data may NOT be passed on to third parties for any reason whatsoever. Interested parties should be referred to BODC.

References

(1) Kirkwood, D (1996) Nutrients: Practical notes on their determination in sea water. ICES techniques in marine environmental sciences. No. 17, 25pp.

Project Information

Oceans 2025 - The NERC Marine Centres' Strategic Research Programme 2007-2012

Who funds the programme?

The Natural Environment Research Council (NERC) funds the Oceans 2025 programme, which was originally planned in the context of NERC's 2002-2007 strategy and later realigned to NERC's subsequent strategy (Next Generation Science for Planet Earth; NERC 2007).

Who is involved in the programme?

The Oceans 2025 programme was designed by and is to be implemented through seven leading UK marine centres. The marine centres work together in coordination and are also supported by cooperation and input from government bodies, universities and other partners. The seven marine centres are:

• National Oceanography Centre, Southampton (NOCS)
• Plymouth Marine Laboratory (PML)
• Marine Biological Association (MBA)
• Sir Alister Hardy Foundation for Marine Science (SAHFOS)
• Proudman Oceanographic Laboratory (POL)
• Scottish Association for Marine Science (SAMS)
• Sea Mammal Research Unit (SMRU)

Oceans2025 provides funding to three national marine facilities, which provide services to the wider UK marine community, in addition to the Oceans 2025 community. These facilities are:

• British Oceanographic Data Centre (BODC), hosted at POL
• Permanent Service for Mean Sea Level (PSMSL), hosted at POL
• Culture Collection of Algae and Protozoa (CCAP), hosted at SAMS

The NERC-run Strategic Ocean Funding Initiative (SOFI) provides additional support to the programme by funding additional research projects and studentships that closely complement the Oceans 2025 programme, primarily through universities.

What is the programme about?

Oceans 2025 sets out to address some key challenges that face the UK as a result of a changing marine environment. The research funded through the programme sets out to increase understanding of the size, nature and impacts of these changes, with the aim to:

• improve knowledge of how the seas behave, not just now but in the future;
• help assess what that might mean for the Earth system and for society;
• assist in developing sustainable solutions for the management of marine resources for future generations;
• enhance the research capabilities and facilities available for UK marine science.

In order to address these aims there are nine science themes supported by the Oceans 2025 programme:

• Climate, circulation and sea level (Theme 1)
• Marine biogeochemical cycles (Theme 2)
• Shelf and coastal processes (Theme 3)
• Biodiversity and ecosystem functioning (Theme 4)
• Continental margins and deep ocean (Theme 5)
• Sustainable marine resources (Theme 6)
• Technology development (Theme 8)
• Next generation ocean prediction (Theme 9)
• Integration of sustained observations in the marine environment (Theme 10)

In the original programme proposal there was a theme on health and human impacts (Theme 7). The elements of this Theme have subsequently been included in Themes 3 and 9.

When is the programme active?

The programme started in April 2007 with funding for 5 years.

Brief summary of the programme fieldwork/data

Programme fieldwork and data collection are to be achieved through:

• physical, biological and chemical parameters sampling throughout the North and South Atlantic during collaborative research cruises aboard NERC's research vessels RRS Discovery, RRS James Cook and RRS James Clark Ross;
• the Continuous Plankton Recorder being deployed by SAHFOS in the North Atlantic and North Pacific on 'ships of opportunity';
• physical parameters measured and relayed in near real-time by fixed moorings and ARGO floats;
• coastal and shelf sea observatory data (Liverpool Bay Coastal Observatory (LBCO) and Western Channel Observatory (WCO)) using the RV Prince Madog and RV Quest.

The data is to be fed into models for validation and future projections. Greater detail can be found in the Theme documents.

Data Activity or Cruise Information

Data Activity

BODC Sample Metadata Report for D341_CTD_16629

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.

Related Data Activity activities are detailed in Appendix 1

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:

Appendix 1: D341_CTD_16629

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

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