Metadata Report for BODC Series Reference Number 1270821

• 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

Public domain 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.

The recommended acknowledgment is

"This study uses data from the data source/organisation/programme, provided by the British Oceanographic Data Centre and funded by the funding body."

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.

Dissolved inorganic nutrient data series for cruise Mitra MT0499

Document History

Converted from CDROM documentation.

Data Originator

Jo Suijlen, National Institute for Coastal and Marine Management, RIKZ, The Netherlands.

Content of data series

CTD= CTD-Rosette sampling

Sampling strategy and methodology

Water samples for nutrient analysis were collected from 6 depths in the water column on every CTD cast using the CTD-rosette water sampler. Samples were filtered through Whatman GF/C filters immediately after sampling, and stored in polyethylene bottles prior to analysis. Nutrients were analysed with a Continuous Flow Analyzer System using standard colorometric autoanalysis methods.

In addition, measurements of dissolved inorganic nutrients (ammonium, nitrite, nitrate, silicate, phosphate) were made during the cruise by the Centre d' Océanologie de Marseille (C. Grenz and co-workers) on bottom water collected with the rosette sampler. These data were collected in the context of sediment flux studies and the analytical method was similar to that used for sediment cores interstitial water analysis (GF/F filtration and autoanalysis). Further details regarding these data are available from the data documentation mt0499sed.Dissolved inorganic nutrients were also measured by the Dunstaffnage Marine Laboratory (K. Jones and co-workers) on samples collected with an Interfacial Sampler. Further information is available from the data documentation mt0499ifs.

Sample analysis was performed under the supervision of Principal Chemical Analyst Wim Schreurs from the RIKZ laboratory, Middelburg, The Netherlands.

BODC processing

In order to standardise parameter units with that held in the BODC Parameter Dictionary, all nutrient concentrations were converted from mg N, mg P and mg Si per litre to µmol l^-1 by multiplying their original values by 1000 and dividing by their respective atomic weights (14.01 for N, 30.97 for P and 28.09 for Si). The data were then loaded into a database under the ORACLE Relational Database Management System without further modification.

Comments on data quality

None to report.

Project Information

PROcesses of Vertical Exchange in Shelf Seas (PROVESS)

Introduction

PROVESS was an interdisciplinary study of the vertical fluxes of properties through the water column and the surface and bottom boundary layers. The project was funded by the European Community MAST-III programme (MAS3-CT97- 0159) and ran from March 1998 to May 2001.

Scientific Rationale

PROVESS was based on the integration of experimental, theoretical and modelling studies with the aim of improving understanding and quantification of vertical exchange processes in the water column, in particular in the surface and benthic boundary layers and across the> pycnocline. PROVESS also explored mechanisms of physical-biological coupling in which vertical exchanges and turbulence significantly affect the environmental conditions experienced by the biota with particular reference to aggregation, flocculation, sedimentation and trophic interactions.

Fieldwork

The experimental phase of the project was carried out at two contrasting sites in the North Sea: the northern North Sea site (NNS) and the southern North Sea site (SNS).

The two sites had the following characteristics:

At both locations measurements were concentrated at a central position with additional measurements being made to estimate horizontal gradients. Moored instruments (including current meters, temperature and pressure sensors, fluorometers, transmissometers, nutrient analysers and meteorological sensors) were deployed between 7 September and 5 November 1998 at the NNS and between 29 March and 25 May 1999 at the SNS. Each experiment was supported by intensive measurement series made from oceanographic ships and involving turbulence dissipation profiler CTD, particle size profilers, optical profilers, benthic sampling and water bottle sampling.

Details of the cruises were as follows:

Data Activity or Cruise Information

Data Activity

BODC Sample Metadata Report for MT0499_CTD_CTD134

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.

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: