Metadata Report for BODC Series Reference Number 1890527

• 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.

AMT1-6 and 11 size-fractionated extracted chlorophyll-a measured fluorometrically from CTD bottle samples

Data Acquisition and Analysis

These data originate from analyses on samples collected from CTD rosette bottles and the measurements were made concurrently with the depths sampled for the primary production (¹⁴C) incubations carried out during each cruise.

Water samples from the 5-7 main light depths were collected from CTD bottles. For AMT1 all samples were filtered through 0.2 µm filters only. For AMTs 2-6 and 11 size-fractionated chlorophyll-a concentrations were determined fluorometrically after sequential filtration of a 200 - 300 ml seawater sample through 20 µm, 2 µm and 0.2 µm polycarbonate filters. All filters were placed in 90% acetone at -20°C for pigment extraction.

Instrumentation Description

Turner Designs 10-AU fluorometer

BODC Data Processing Procedures

Data were submitted to BODC in an Excel spreadsheet with the Primary Production incubation data and were saved to the BODC archive with reference UVI020056. Sample metadata provided (CTD cast, latitude and depth) were checked against information held in the database. There were no discrepancies.

Where chl-a values were provided with no size fractioned data, the data were loaded under a separate parameter for total chl-a collected on a 0.2 µm filter, not a summation of different filter sizes.

Parameter codes defined in BODC parameter dictionary were assigned to the variable. The units supplied in the spreadsheet were mg m^-3, which match the Parameter Dictionary units so no unit conversions were necessary.

Data loaded into BODC's database without any changes applied.

A parameter mapping table is provided below;

Data Quality Report

BODC were not advised of any data quality checks made by the data originator prior to submission of the dataset.

Problem Report

Not relevant to this dataset.

AMT11 pigment composition by HPLC analysis (CTD bottles)

Data Acquisition and Analysis

For vertical profiling samples were taken from five depths down to 250 m and 1.5-3 litres were filtered through 0.2 µm glass fibre filters. Pigment samples were stored at -80 ^oC until analysis by HPLC. Pigments were extracted in acetone using ultrasonication, and centrifugation to remove debris, and analysed using the method of Barlow et al. (1997).

References Cited

Barlow R.G. , Cummings D.G. and Gibb S.W., 1997. Improved resolution of mono- and divinyl chlorophylls a and b and zeaxanthin and lutein in phytoplankton extracts using reverse phase C8 HPLC. Marine Ecology Progress Series, 161 , 303-307.

Instrumentation Description

Section not relevant.

BODC Data Processing Procedures

Data were submitted to BODC in Microsoft Excel spreadsheet format and saved to the BODC archive with reference PML030067. The file was provided to BODC with CTD cast number and depth as metadata. Sample metadata were checked against information held in the database - there were no discrepancies.

There were three samples provided with null data values for all pigments (cast 7 depth 70 m; cast 27 depth 80 m; cast 46 depth 80 m). It was unclear if these were measured null values or no data because of a lost filter and these data were not loaded to the database.

The data were provided in units of micrograms per litre. The units associated with the parameter codes in the BODC Parameter Dictionary were nanograms per litre, with the exception of chlorophyll-a which was in units of milligrams per cubic metre. All data had a unit conversion factor applied (x 1000) except the chl-a data where the units are equivalent.

Parameter codes defined in BODC parameter dictionary were assigned to the variables as shown in the table below.

Data loaded into BODC's database without any changes.

Data Quality Report

BODC were not advised by the data originator of any quality control processes applied to the data set.

Problem Report

This section is not relevant to this data set.

Project Information

The Atlantic Meridional Transect (AMT) - Phase 1 (1995-2000)

Who was involved in the project?

The Atlantic Meridional Transect (AMT) programme was designed by and implemented as a collaboration between Plymouth Marine Laboratory (PML) and Southampton Oceanography Centre (SOC). The programme was hosted by Plymouth Marine Laboratory and involved additional researchers from UK and international universities throughout its duration.

What was the project about?

When AMT began in 1995 the programme provided a platform for international scientific collaboration, including the calibration and validation of SeaWiFs measurements and products. The programme provided an exceptional opportunity for nationally and internationally driven collaborative research and provided a platform for excellent multi-disciplinary oceanographic research. As an in situ observation system, the data collected by the AMT consortium informed on changes in biodiversity and function of the Atlantic ecosystem during this period of rapid change to our climate and biosphere.

The scientific aims were to assess:

• mesoscale to basin scale phytoplankton processes
• the functional interpretation of bio-optical signatures
• the seasonal, regional and latitudinal variations in mesozooplankton dynamics

When was the project active?

The first phase of the AMT programme ran from 1995 to 2000 and consisted of a total of 12 cruises. A second phase of funding allowed the project to continue for the period 2002 to 2006 with a further 6 cruises.

Brief summary of the project fieldwork/data

The AMT programme undertook biological, chemical and physical oceanographic research during the annual return passage of the RRS James Clark Ross between the UK and the Falkland Islands or the RRS Discovery between the UK and Cape Town, a distance of up to 13,500 km. This transect crossed a range of ecosystems from sub-polar to tropical and from euphotic shelf seas and upwelling systems to oligotrophic mid-ocean gyres. The transect route was covered north-south in September/October and south-north in April/May of each year.

The measurements of hydrographic and bio-optical properties, plankton community structure and primary production completed on the first 12 transects (1995-2000) represent the most coherent set of repeated biogeochemical observations over ocean basin scales. This unique dataset has led to several important discoveries concerning the identification of oceanic provinces, validation of ocean colour algorithms, distributions of picoplankton, identifying new regional sinks of pCO2 and variability in rates of primary production and respiration.

Who funded the project?

The programme was funded by the Natural Environment Research Council (NERC) and further support was received from the National Aeronautics and Space Administration (NASA) with equipment and funding from the Sea-viewing Wild Field-of-view Sensor (SeaWiFS) project.

Data Activity or Cruise Information

Data Activity

BODC Sample Metadata Report for AMT11_CTD_AMT11-15

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: AMT11_CTD_AMT11-15

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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