Metadata Report for BODC Series Reference Number 1988235

• 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

Thermo Scientific Accela High Performance Liquid Chromatograph

The Accela high performance liquid chromatography system provides fast separations at pressures of up to 18,130 psi and at flow rates of 1 to 5000 µL/min. The system consists of an analytical pump, an autosampler, an optional PDA detector or UV/Vis detector and a solvent platform.

There is a choice of three analytical pumps to use with the system (the Accela Pump, Accela 600 Pump and Accela 1250 Pump) with each pump having a built-in degassing unit which is remotely controlled from the data system computer via USB. The autosampler automates sample injections and sample preparation and includes a built-in column oven, with a temperature range of 5 to 95°C, and a sample temperature control (0 to 60°C). Within the autosampler there is the capacity for 200 samples across five sample trays. There is a choice to use a PDA detector which in combination with the 5 or 1 cm LightPipe flowcell, provides the highest level of sensitivity available in photodiode array detection for HPLC. The second detector that can be used is a UV/Vis detector which can monitor two wavelength channels. Both detectors have a dual-lamp optical bench that covers the UV-visible spectrum from 190 to 800 nm. The solvent platform is located on top of the system stack and holds four 1 L solvent reservoir bottles and one 1 L wash bottle.

Please see the manufacturer's user's guide and product sheet for further details.

Non-toxic (underway) sea water supply

A source of uncontaminated near-surface (commonly 3 to 7 m) seawater pumped continuously to shipboard laboratories on research vessels. There is typically a temperature sensor near the intake (known as the hull temperature) to provide measurements that are as close as possible to the ambient water temperature. The flow from the supply is typically directed through continuously logged sensors such as a thermosalinograph and a fluorometer. Water samples are often collected from the non-toxic supply. The system is also referred to as the underway supply.

AMT26 (JR16001) pigment composition by HPLC analysis from Underway and CTD bottles

Originator's Protocol for Data Acquisition and Analysis

Samples were collected from the ship's underway system approximately twice a day and from the predawn, 10:00 and noon CTD casts. The seawater was sampled into 9.5L polypropylene carboys covered in black plastic to keep out light.

Some samples collected from the non-toxic supply were used for an experimental dataset as part of an ESA project. For these samples, 6-8L of water was filtered through a 1 micron pore size cartridge filter then processed using the same methods as the rest of the HPLC samples.

Samples (1-8L) were vacuum filtered onto GF/F filters, flash frozen in liquid nitrogen and stored at -80°C. Pigments were extracted from the sample filters into 2 mL 90% acetone using an ultrasonic probe (35 s; 50W). Extracts were clarified and analysed by reversed phase HPLC using a Thermo Accela Series HPLC system with chilled autosampler (4°C) and photodiode array detector. The HPLC was calibrated using a suite of standards purchased from DHI (Denmark). Pigments were identified based on retention time and spectral match using photo-diode array, following the methods in Zapata et al. (2000).

See the cruise report for more information.

Instrumentation Description

Thermo Accela Series HPLC system

BODC Data Processing

Data were submitted to BODC in Microsoft Excel spreadsheet format and saved to the archive with reference PML180053. The file was provided to BODC with cruise, CTD number, CTD bottle number, station, sequential day of year, depth, time, latitude and longitude as metadata. Sample metadata were checked against information held in the database - there were no discrepancies.

The following parameters were provided in the file but only the parameters that were not derived from the summation of other parameters in the dataset were loaded into the database. The absent data value was recorded as the effective limit of detection (LOD). The effective limits of detection, calculated for a filter volume of 8L are given in the table below.

The data were reformatted and marked up with BODC parameter codes. The data were provided in µg/L units that were converted to ng/L for all parameters but chlorophyll-a. Data were loaded into BODC's samples database under Oracle Relational Database Management System using established BODC data banking procedures.

The originator variables were mapped to appropriate BODC parameter codes as follows:

Data Quality Report

Quality assurance procedures for pigment analysis at PML were put in place for samples collected after 1st May 2011. The whole dataset conforms to the quality assurance criteria set out in Aiken et al. (2009).

The pigment profile of AMT26 frequently contained an unknown component with an absorption maximum at 418 nm, that coeluted with [Chl c3]. The unknown component, when present, affected the quantification of [Chl c3], and where this is relevant the data have been flagged using BODC flag 'L'.

Data were also flagged by BODC where they were at or below the Effective LOD as '<'.

References

Zapata, M., Rodriguez, F., Garrido, J.L., (2000). Separation of chlorophylls and carotenoids from marine phytoplankton: a new HPLC method using a reversed phase C8 column and pyridine-containing mobile phases. Marine Ecology Progress Series, 195, 29-45.

Aiken et al., (2009) Phytoplankton pigments and functional types in the Atlantic Ocean: A decadal assessment, 1995-2005. Deep Sea Research II: Topical Studies in Oceanography, 56, 899-917.

Project Information

No Project Information held for the Series

Data Activity or Cruise Information

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: