Metadata Report for BODC Series Reference Number 895626

• 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

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

NAS-2E in situ Nutrient Analyser

The NAS-2E in situ Nutrient Analyser is a submersible instrument for the automated measurement of dissolved nutrient concentrations in marine and fresh waters. It employs colorimetric wet-chemistry to determine nutrient concentrations by measuring the light absorbance of a coloured dye produced by a chemical reaction. The instrument, manufactured by WS Ocean Systems Ltd., Hans, UK, is designed for deployment on moorings. Versions have been developed for nitrate+nitrite, phosphate and silicate. The use of standard wet-chemistry techniques ensure comparability with laboratory results.

References for manufacturer's standard chemical methods are:

• Nitrate and Nitrite: adapted from Armstrong, Stearns and Strickland (1967), modified by Stainton (1974)
• Silicate: adapted from Grasshoff et al. (1983) and Hydes (1984)
• Phosphate: adapted from Murphy and Riley (1962)

although these may be altered by the user.

The system utilizes a syringe pump and rotary valve to acquire and react discrete water samples. For nitrate+nitrite analysis, the samples is first passed over a copper-cadmium column to reduce nitrate to nitrite before reacting with the reagents to form the dye. Once the reaction takes place the sample is injected into the colorimeter where optical beam attenuation is measured. An integral system controller drives the syringe and valve via stepper motors and records the colorimeter readings.

The analysis routines include blank measurements for turbidity and optical fouling. An on-board calibration standard is periodically analysed to ensure the continuous integrity of the results. Programmable controls allows the operator to develop and program alternative chemical routines. All raw data are recorded as voltages representing beam transmission through the sample within the colorimeter pathlength. Following recovery of the instrument, raw data are downloaded to a PC and converted to absorbance units and nutrient concentration using manufacturer's calibration and on- board blank and standard readings.

Manufacturer's specification:

Level of detection (PL = colorimeter path length):

PAP mooring Envirotech NAS2E sensor data processing document

This document outlines the procedures undertaken to process and quality assure the NAS2E nutrient analyser data collected on moorings deployed as part of the PAP project.

Originator's processing

The raw data are downloaded from the instrument and converted to ASCII format .csv files.

Calibration

No instrument serial numbers or calibration details were supplied in any of the mooring deployment cruise reports. The data originators were contacted by BODC but were unable to provide any further information.

Quality control

The data originator's processing has quality indicators to the data for inconsistent, bad, doubtful or missing values- these were mapped to BODC flags during transfer via the table below:

BODC processing

Data are received after the data originator's processing has been completed. The data files are submitted in ASCII format as one file per instrument.

Once the submitted data files are safely archived, the data undergo reformatting and banking procedures:

• The data files are transferred into a common format, a NetCDF subset.

• Standard parameter codes are assigned that accurately describe the data (see Parameter mapping section below).

• Unit conversions are applied, if necessary, so that units are standardised (see Parameter mapping section below).

• The data are screened visually and any spikes or instrument malfunctions can be clearly labelled with quality control flags.

• Comprehensive documentation is prepared describing the collection, processing and quality of each data series.

• Detailed metadata and documents are loaded to the database and linked to each series so that the information is readily available to future users.

Parameter mapping

The following describes the parameters contained in the originator's files and their mapping to BODC parameter codes:

The remaining variables in the originator's file have not been transferred as they are either uncorrected nitrate values, or Microcat temperature, conductivity and salinity data which have been banked with BODC in a separate accession.

Data Quality

There is a ~340m difference in the depth of the instrument over the duration of the time series. There is no mention of mooring 'knock-down' in either the deployment or recovery cruise reports, and data originator Maureen Pagnani has no further information on the subject. However, other PAP recovery cruise reports (i.e. the one for D296, p. 11) mentions that high current speeds have knocked down the mooring so the sensor package descends by 160 m on occasions. Additionally, a search on Google identified the following document:
http://www.noc.soton.ac.uk/nmf/usl/gxg/CaseNotes3_RAPID_wb4_2000703.pdf
in which part of a mooring was 'knocked down' from its operational depth of 400 m to 853 m (p.21). With no more relevant information to refer to, and no particular reason to query the validity of the data gathered by the sensor, even at large depth variations from its stated deployment depth, it is suggested that a knockdown of as much as 300 m is at least plausible.

Project Information

ANIMATE- Atlantic Network on Interdisciplinary Moorings and Time-series for Europe

Scientific Rationale

The objective of the ANIMATE program is to make time series measurements from deep water observatories in the North Atlantic. ANIMATE is a European program coordinated by Prof. Uwe Send at IFM, Kiel and will establish deep ocean observing sites at three contrasting locations. The locations are CIS (Central Irminger Sea) east of Greenland, ESTOC (Estación Europea de Series Temporales del Oceano, Islas Canarias) about 100km north of the Canary Islands, and PAP (Porcupine Abyssal Plain). The measurements in the first instance are somewhat basic but nevertheless encapsulate the crucial processes that drive the biogeochemistry of any oceanic region.

At all three sites at about 15m depth (100m off the Canary Islands) there are frequent measurements of CO2 concentration, nutrients and fluorescence as a proxy for phytoplankton concentration. Throughout the top 100m there are measurements at about a dozen depths of salinity and temperature and this will enable us to characterise the complete annual cycle of the physics of the upper ocean. It is this physics which determines to a great extent the concentrations of limiting nutrients in the upper sunlit zone and the growth of phytoplankton. Phytoplankton are responsible for about half of the oceanic CO2 uptake and, as such, a better understanding of the relationship between physics, nutrients, phytoplankton growth and CO2 concentration is essential if we are to understand the processes and predict future responses of the oceans to anthropogenic CO2 release.

The ANIMATE project is funded by the EU in 2002-2004 as the 5th framework project EVR1-CT-2001-40014 and also funded in part by EU-funded projects Mersea IP and Carbo-Ocean.

References

Billett, D.S.M., Bett B.J., Reid, W.D.K., Boorman, B. and Priede, M. Long-term change in the abyssal NE Atlantic: The 'Amperima Event' revisited. Deep Sea Research II; PAP special volume (Submitted)

Hartman. S., Larkin. K. E., Lampitt, R. S, Koeve, W., Yool, A., Körtzinger, A., Hydes, D.J. (This volume) Seasonal and inter-annual biogeochemical variations at PAP (49°N, 16.5°W) 2003-2005. Deep Sea Research II; PAP special volume (Submitted)

Gooday, A et al. Long term change in foraminiferans Deep Sea Research II, PAP special volume (Submitted)

Martin, A.P., Lucas, M.I., Painter, S.C., Pidcock, R., Prandke H., Prandke,H., Stinchcombe, M.C. (2008) The supply of nutrients due to vertical turbulent mixing: a study at the Porcupine Abyssal Plain study site (49° 50'n 16° 30'w) in the northeast Atlantic. Deep Sea Research II, PAP special volume (Submitted)

Data Activity or Cruise Information

Data Activity

Moored Instrument Rig PAP1_102002

This rig was deployed as part of the Porcupine Abyssal Plain (PAP) observatory project. 'PAP1_102002' refers to the deployment of mooring number 1 in October 2002 ('102002') located at the PAP Observatory. This was the second deployment of this mooring configuration at the PAP site, under this project.

This rig was anchored by a 1200 kg weight and was kept erect by groups of sub-surface floats attached along the mooring. The instrument depths stated below are taken from the mooring recovery sheet in the cruise report for PO300_1.

Instruments deployed on the rig

Related Data Activity activities are detailed in Appendix 1

Cruise

Complete Cruise Metadata Report is available here

Fixed Station Information

Fixed Station Information

Porcupine Abyssal Plain (PAP) Observatory

The Porcupine Abyssal Plain (PAP) observatory is a site at which moorings were deployed in the Northeastern Atlantic, as part of the ANIMATE (Atlantic Network of Interdisciplinary Moorings and Time-series for Europe), MERSEA (Marine Environment and Security for the European Area), EuroSITES, Oceans2025, Fix03 and CLASS projects. The PAP site is centred at latitude 49° N and longitude 16.5° W. Moorings have occupied this region since 2002 and are typically deployed for 12 months.

Please note: Near Real Time data is only stored at BODC where delayed mode data were not recovered. All near real time data can be found at the OceanSites GDA and through IFREMER.

Data summary

Status Indicators

Related Fixed Station activities are detailed in Appendix 2

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: PAP1_102002

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

If you are interested in these series, please be aware we offer a multiple file download service. Should your credentials be insufficient for automatic download, the service also offers a referral to our Enquiries Officer who may be able to negotiate access.

Appendix 2: Porcupine Abyssal Plain (PAP)

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

If you are interested in these series, please be aware we offer a multiple file download service. Should your credentials be insufficient for automatic download, the service also offers a referral to our Enquiries Officer who may be able to negotiate access.