Metadata Report for BODC Series Reference Number 1657939

• 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

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.

AMT17 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 for all successful CTD casts and some samples collected from the ship's non-toxic supply while on station.

Water samples (300-500 ml) from CTD bottles were filtered on 25 mm GF/F filters. At a small number of stations the 1% and 55% of surface light level samples were size-fractionated with 2 µm and 0.2 µm 25 mm polycarbonate filters. Filters were extracted in 90% acetone for 24 hrs and total chlorophyll-a measured with a TD-700 Turner Designs fluorometer following the procedure of Welschmeyer (1994) which minimises interference by chlorophyll-b. The fluorometer was calibrated with dilutions of a solution of pure chlorophyll-a (Sigma, UK) in 90% acetone, the concentration of which was determined spectrophotometrically after the cruise.

References Cited

Welschmeyer N.A., 1994. Fluorometric analysis of chlorophyll-a in the presence of chlorophyll-b and phaeopigments. Limnology and Oceanography, 39, 1985-1992.

Instrumentation Description

Not relevant to this dataset.

BODC Data Processing Procedures

Data were submitted to BODC in an Excel spreadsheet and accessioned under BODC archive SOC060480. Sample metadata were checked against information held in the database. There were a number of discrepancies between combination of depth and bottle number of the samples provided in the file and those recorded on the log sheets and in the Sea-Bird bottle log files. Resolution of these discrepancies are listed in the table below.

For the size-fractionated samples only the sum of the size-fractions were provided. There were two samples with replicate measurements provided and these were loaded as mean and standard deivation for these samples.

Parameter codes defined in BODC parameter dictionary were assigned to the variable. The units supplied in the spreadsheet were mg l^-1, however comparison with data values reported from onboard calibration in the Cruise Report and sensor range of fluorometer (from manufacturer's website) suggests this is an error and the data should be labelled mg m^-3(equivalent to µg l^-1).

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

A parameter mapping table is provided below;

Data Quality Report

There was no indication that the dataset had been quality controlled prior to submission to BODC.

Problem Report

Not relevant to this dataset.

AMT17 extracted chlorophyll-a measured fluorometrically from surface non-toxic supply samples

Data Acquisition and Analysis

These data originate from analyses on discrete samples collected every few hours from the ship's non-toxic supply.

Water samples (300-500 ml) from CTD bottles were filtered on 25 mm GFF filters. Filters were extracted in 90% acetone for 24 hrs and total chlorophyll-a measured with a TD-700 Turner Designs fluorometer following the procedure of Welschmeyer (1994) which minimises interference by chlorophyll-b. The fluorometer was calibrated with dilutions of a solution of pure chlorophyll-a (Sigma, UK) in 90% acetone, the concentration of which was determined spectrophotometrically after the cruise.

References Cited

Welschmeyer N.A., 1994. Fluorometric analysis of chlorophyll-a in the presence of chlorophyll-b and phaeopigments. Limnology and Oceanography, 39, 1985-1992.

Instrumentation Description

Not relevant to this dataset.

BODC Data Processing Procedures

Data were submitted to BODC in an Excel spreadsheet and accessioned under BODC archive SOC060480. Sample metadata (lat, lon, date and time) were loaded to the database.

Parameter codes defined in BODC parameter dictionary were assigned to the variable. The units supplied in the spreadsheet were mg l^-1, however comparison with data values reported from onboard calibration in the Cruise Report and sensor range of fluorometer (from manufacturer's website) suggests this is an error and the data should be labelled mg m^-3(equivalent to µg l^-1).

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

A parameter mapping table is provided below;

Data Quality Report

There was no indication that the dataset had been quality controlled prior to submission to BODC. No data values were flagged by BODC. Details of the calibration calculation can be found in the CTD processing notes.

Problem Report

Not relevant to this dataset.

Project Information

The Atlantic Meridional Transect - Phase 2 (2002-2006)

Who was involved in the project?

The Atlantic Meridional Transect Phase 2 was designed by and implemented by a number of UK research centres and universities. The programme was hosted by Plymouth Marine Laboratory in collaboration with the National Oceanography Centre, Southampton. The universities involved were:

• University of Liverpool
• University of Newcastle
• University of Plymouth
• University of Southampton
• University of East Anglia

What was the project about?

AMT began in 1995, with scientific aims to assess mesoscale to basin scale phytoplankton processes, the functional interpretation of bio-optical signatures and the seasonal, regional and latitudinal variations in mesozooplankton dynamics. In 2002, when the programme restarted, the scientific aims were broadened to address a suite of cross-disciplinary questions concerning ocean plankton ecology and biogeochemistry and the links to atmospheric processes.

The objectives included the determination of:

• how the structure, functional properties and trophic status of the major planktonic ecosystems vary in space and time
• how physical processes control the rates of nutrient supply to the planktonic ecosystem
• how atmosphere-ocean exchange and photo-degradation influence the formation and fate of organic matter

The data were collected with the aim of being distributed for use in the development of models to describe the interactions between the global climate system and ocean biogeochemistry.

When was the project active?

The second phase of funding allowed the project to continue for the period 2002 to 2006 and consisted of six research cruises. The first phase of the AMT programme ran from 1995 to 2000.

Brief summary of the project fieldwork/data

The fieldwork on the first three cruises was carried out along transects from the UK to the Falkland Islands in September and from the Falkland Islands to the UK in April. The last three cruises followed a cruise track between the UK and South Africa, only deviating from the traditional transect in the southern hemisphere. During this phase the research cruises sampled further into the centre of the North and South Atlantic Ocean and also along the north-west coast of Africa where upwelled nutrient rich water is known to provide a significant source of climatically important gases.

Who funded the project?

Natural Environment Research Council (NERC)

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: