Metadata Report for BODC Series Reference Number 2080884

• 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

Turner Designs 10AU Field Fluorometer

The Turner Designs 10AU is designed for continuous-flow monitoring or discrete sample analyses of fluorescent species. A variety of optical kits with appropriate filters and lamps are available for a wide range of applications. Individual filters and lamps are also available for customised applications.

Standard optical kits include those for chlorophyll-a (extracted and/or in vivo), phycocyanin, phycoerythrin, CDOM, ammonium, rhodamine and fluorescein dye tracing, crude oil, refined oil, histamine and optical brighteners.

The instrument's light source is a 4 watt lamp and the detector is a photomultiplier tube with a standard detection range of 300-650 nm. A red-sensitive version with a detetion range of 185-970 nm is also available.

Specifications

Further details can be found in the manufacturer's specification sheet.

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.

D376 Discrete Chlorophyll-a Sampling Document

Originator's Protocol for Data Acquisition and Analysis

CTD sampling

Water samples were taken from 21 of the 61 CTD stations visited during the cruise for the analysis of chlorophyll-a. These data allow for an independent check of the CTD fluorometer's output. The decision of where to fire the CTD rosette bottles took into account the position of the chlorophyll maximum, as observed from the output of the fluorometer during the downcast. The number of water bottles sampled depended on the water depth at the station - samples from throughout the water column were typically drawn on shallow water casts, whereas only bottles fired in shallow waters were targeted on deep water stations.

Samples were collected from the CTD water bottles into 1 litre pre-washed HDPE bottles. 500 ml subsamples (or 250 ml on high biomass stations) were taken from these and filtered through 0.7 µm glass fibre filters using a vacuum pump. Filter papers were carefully removed with tweezers, placed in centrifuge tubes, capped and wrapped in foil, before being stored in the ship's -80 °C freezer for analysis back in the laboratory.

Analysis involved the extraction of chlorophyll from the filters using 90% HPLC grade acetone at a constant temperature of 4 °C (over a 24 hour period). Fluorescence of each sample was determined using a Turner 10Au Field and Laboratory Fluorometer fitted with the optional optical kit for extractive chlorophyll measurement. Standards were run prior to analysing the samples. Fluoresence of each water sample was measured before and after the addition of 1 ml of 10 % hydrochloric acid, which enabled phaeopigment concentrations to be established. Chlorophyll-a concentrations were ultimately calculated from fluorescence following the protocols established by Strickson and Parsons (1972). The D376 cruise report (linked below) provides details of this calculation.

Underway sampling

Samples were also taken from the vessel's underway non-toxic water supply, approximately every four hours. These samples were used to compare with the output of the underway fluorometer. The sampling strategy and analytical procedures for the underway samples were very similar to the CTD sampling, with a volume of 500 ml typically filtered and subsequent storage in the ship's freezer. However, the analysis for these samples actually took place whilst still at sea.

The originator notes a degree of uncertainty regarding the volumes filtered for the underway samples collected prior to 16th June 2012. There is a possibility that 250 ml bottles may have been used before this date. The calculation used to determine chlorophyll-a concentration makes the assumption that the intended 500 ml was filtered throughout the cruise. Users are advised to take note of this potential issue when using the data.

BODC Data Processing Procedures

The chlorophyll data were supplied to BODC in Microsoft Excel format. Values were extracted from this (together with the associated cruise underway chlorophyll sampling log) and loaded into BODC's ocean database under the ORACLE Relational Database Management System. Data that were considered unrealistic were flagged suspect.

Content of data series

Quality Report

Chlorophyll data from CTD cast 2 has been marked as suspicious from the Originator. The profile looked upside down which could be due to a mix up in the samples but this could not be verified and as a result data from this cast have been flagged.

References Cited

Inall, M. E. et al.,(2012). 'Cruise D376 Swansea to Southampton FASTNEt Cruise to the Celtic Sea Shelf Edge'. Internal Report No 277, Scottish Association for Marine Science.

Strikland, J.D.H and Parsons, T.R.,(1972). 'A Practical Handbook of Seawater Analysis'. Fisheries Research Board of Canada.

Project Information

Fluxes Across Sloping Topography of the North East Atlantic (FASTNEt)

Background

The FASTNEt consortium was funded to deliver NERC's Ocean Shelf Edge Exchange Programme. Commencing in October 2011, this four year study aims to couple established observational techniques, such as moorings and CTDs, with the very latest in autonomous sampling initiatives - including use of Autosub Long Range and gliders. With the aid of novel model techniques, these observations will be utilised to construct a new paradigm of Ocean/Shelf exchange.

Shelf edge regions mark the gateway between the world's deep oceans and shallower coastal seas, linking terrestrial, atmospheric and oceanic carbon pools and influencing biogeochemical fluxes. Shelf edge processes can influence near-shore productivity (and fisheries) and ultimately affect global climate.

FASTNEt brings together researchers from multiple UK organisations. Further collaboration has been established with five Project Partners: the UK Met Office, Marine Scotland Science, Agri-Food and Biosciences Institute, Marine Institute Ireland and Scripps Institution of Oceanography.

Scientific Objectives

• To determine the seasonality of physical gradients and exchange across the shelf edge by deploying new observational technologies (gliders, Autosub Long Range) and established techniques (long term moorings, drifters)
• To quantify key exchange mechanisms and to collect new data targeted at testing and improving high resolution models of the shelf edge, by carrying out detailed process studies in contrasting regions of the shelf edge of the NE Atlantic margin
• To develop a new parameterisation of shelf edge exchange processes suitable for regional-scale models, using improved resolution numerical, and new empirical models constrained by the observations
• To test the new parameterisations in a regional model in the context of making an assessment of inter-annual variability of ocean-shelf exchange.

Fieldwork

Three survey sites on the UK shelf edge have been selected for FASTNEt. These are a) the Celtic Sea shelf edge, b) Malin shelf and c) North Scotland shelf. Fieldwork is centred around two research cruises. The first, to the Celtic Sea, on RRS Discovery in June 2012. The second cruise visits the Malin shelf on RRS James Cook, during summer 2013. In addition to these dedicated cruises, opportunist cruise activity to the North Scotland shelf has been agreed with project partner Marine Scotland Science. Autonomous technologies will complement observations made during the cruises and provide knowledge of seasonal and inter-annual variability in exchange processes.

Instrumentation

Types of instruments/measurements:

• Gliders
• Autosub Long Range
• Drifter buoys
• Scanfish
• Microstructure profilers
• Moored CTD/CT loggers and ADCPs
• Shipboard measurements: CTD, underway, nutrients (and other discrete sampling), LADCP, ADCP.

Contacts

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: