Metadata Report for BODC Series Reference Number 1197579

• 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

RRS Discovery (D371) AMT21 FRRF Data Quality Report

Data Quality Report

Values marked -999 in the originator's data files have been converted to the appropriate absent data values using the flag 'N'.

Functional Absorption cross-section (light and dark)

Values outside the expected range of values (0-1600 A²Q^-1)for these parameters have been flagged as suspect.

Photochemical efficiency {Fv/Fm}

Values outside the expected range of values (0-1) for these parameters have been flagged as suspect.

In-vivo fluorescence (chlorophyll)

Values outside the expected range of values (0-5) for these parameters have been flagged as suspect.

Data Access Policy

Open Data

These data have no specific confidentiality restrictions for users. However, 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.

If the Information Provider does not provide a specific attribution statement, or if you are using Information from several Information Providers and multiple attributions are not practical in your product or application, you may consider using the following:

"Contains public sector information licensed under the Open Government Licence v1.0."

Narrative Documents

Chelsea Technologies Group FASTtracka MKI FRRF

The FASTtracka is a Fast Repetition Rate Fluorometer (FRRF) designed to measure the variable fluorescence of marine phytoplankton. It can be deployed on its own or integrated in moorings, profiling systems or in towed applications.

The operation mode comprises a rapid series of high frequency flashes (200 kHz), which enable the measurement of the absorption cross section of photosystem II (PSII), the rate of electron transport and the level of photochemical quenching. A 16 MHz clock microcontroller monitors the digital acquisition of the stimulated fluorescence and the excitation flashes, while simultaneously measuring Photosynthetic Active Radiation (PAR). These concurrent measurements allow for estimates of phytoplankton primary productivity to be made.

A comparison of ambient-irradiated and dark adapted phytoplankton samples is possible due to the optical head dual (light and dark) chamber design. All measurements are stored on an internal memory card with a 24 MB capacity and are downloaded through an RS232 connector.

Additional specifications include a maximum depth rating of 500 m and a chlorophyll-a sensitivity of 0.1 to 30 µg l^-1.

Further information can be found in the manufacturer's specification sheet or the user guide.

RRS Discovery (D371) AMT21 FRRF Sensor Profiles Instrumentation

GE Druck PDCR/PTX 1830/1840 series presssure sensors

Basic Information

The PDCR 1830/1840 transducer (mV output) and PTX 1830/1840 transmitter (4-20 mA output) are fully submersible sensors for the measurement of hydrostatic liquid levels. IP68 rated for indefinite immersion in 700 mH2O.The Druck micromachined silicon element is sealed within an all-titanium pressure module assembly isolated from the media assembly. This is contained in a welded titanium body, terminated in an injection moulded cable assembly which features a Kevlar strain cord.

Pressure measurement

Performance Specification

Additional Options

More information can be found in the manufacturer's specification sheet.

RRS Discovery (D371) AMT21 Bio-Optics - Fast Repetition Rate Fluorometer (FRRF) profiles

Data Acquisition and Analysis

These data originate from analysis of profiles collected from the FRRF sensor deployed on the optics rig on RRS Discovery (D371) between 29th September and 14th November 2011. The optics rig was deployed from a crane on the starboard aft quarter of the ship (which was not the sunward side of the ship as often as hoped) using 350 m of 10 mm wire on the deck winch. Profiles were made at or within 1 hour of solar noon. The instruments were turned on then lowered into the water and kept at the surface for three minutes. The rig was then lowered at a fairly fast rate of (0.5 m/s) down to 200 m depth. The upcast is the important part of the deployment and this was carried out at 0.2 m/s. Upon recovery, data from the instruments was downloaded using hyperterminal.

The FRRF data were processed using Sam Laney's (WHOI) Matlab code. This requires the FRRF to be characterised using 0.2 µm filtered water, at each of the gain settings (0, 1, 4, 16, 64, 256) for both the light and dark chambers, in a black bucket.

The primary outputs of the FRRF data stream are the maximum fluorescence (Fm) and the ratio of the variable to maximum fluorescence (Fv/Fm). The final FRRF data product will consists of the phytoplankton physiological parameters binned to 2 m depth resolution.

BODC Data Processing Procedures

Data were submitted to BODC in 31 binned .csv files, which were then archived using the BODC accession protocols. The files were provided to BODC with the following metadata: cruise, date, Julian Day, latitude and longitude. The light/dark Photosynthetically Active Range (PAR) irradiance channels were not loaded as these channels have been loaded to the database with the UV and AC9 profiles. Light/dark chamber turnover time for electron flow (tau) and light/dark chamber gain settings were not loaded to the database and are available upon request. The data was processed using the BODC transfer protocol and then screened.

Parameter codes defined in BODC parameter dictionary were assigned to the variables as shown in the table below. No unit conversions were necessary as all the parameters were provided in the same units as in the BODC Parameter Dictionary.

Project Information

Oceans 2025 Theme 10, Sustained Observation Activity 1: The Atlantic Meridional Transect (AMT)

The Atlantic Meridional Transect has been operational since 1995 and through the Oceans 2025 programme secures funding for a further five cruises during the period 2007-2012. The AMT programme began in 1995 utilising the passage of the RRS James Clark Ross between the UK and the Falkland Islands southwards in September and northwards in April each year. Prior to Oceans 2025 the AMT programme has completed 18 cruises following this transect in the Atlantic Ocean. This sustained observing system aims to provide basin-scale understanding of the distribution of planktonic communities, their nutrient turnover and biogenic export in the context of hydrographic and biogeochemical provinces of the North and South Atlantic Oceans.

The Atlantic Meridional Transect Programme is an open ocean in situ observing system that will:

• give early warning of any fundamental change in Atlantic ecosystem functionng
• improve forecasts of the future ocean state and associated socio-economic impacts
• provide a "contextual" logistical and scientific infrastructure for independently-funded national and international open ocean biogeochemical and ecological research.

The specific objectives are:

• To collect hydrographic, chemical, ecological and optical data on transects between the UK and the Falkland Islands
• To quantify the nature and causes of ecological and biogeochemical variability in planktonic ecosystems
• To assess the effects of variability in planktonic ecosystems on biogenic export and on air-sea exchange of radiatively active gases

The measurements taken and experiments carried out on the AMT cruises will be closely linked to Themes 2 and 5. The planned cruise track also allows for the AMT data to be used in providing spatial context to the Sustained Observation Activities at the Porcupine Abyssal Plain Ocean Observatory (SO2) and the Western Channel Observatory (SO10).

More detailed information on this Work Package is available at pages 6 - 9 of the official Oceans 2025 Theme 10 document: Oceans 2025 Theme 10

Weblink: http://www.oceans2025.org/

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: