Metadata Report for BODC Series Reference Number 2135659

• 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

Hitachi U-1800 Spectrophotometer

The Hitachi U-1800 Spectrophotometer works in the ultra-violet and visible wavelength ranges and with its ratio-beam design the U-1800 can be used for time dependent measurements of absorption.

Features of the U-1800 include a Good Laboratory Practise (GLP) routine for QC applications and a validation function. A scanning mode allows multiple wavelength measurements to be made. The U-1800 is capable of DNA/RNA measurements as the instrument can automatically make measurements at two different wavelengths and calculate their ratio. The U-1800 has full UV capabilities down to 190 nm.

A wide range of accessories are available for the U-1800 including a 4 cell changer for rapid sample selection, and an RS-232 interface and optional PC solutions software. This package provides photometry, wavelength and time scan functions allowing enzyme kinetic data to be acquired. Data can be readily exported to a spreadsheet for further processing.

Further details can be found in the manufacturer's manual.

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.

D366 Transparent Exopolymer Particles (TEP), Dissolved Organic Carbon (DOC) and Total Dissolved Nitrogen (TDN) measurements from CTD rosette bottle samples

Originator's Protocol for Data Acquisition and Analysis

TEP

Seawater was taken from 56 CTD casts. Four to six depths were chosen from each CTD cast. TEP were collected by filtering the seawater through 0.45 µm pore-size polycarbonate filters (25 mm diameter) at constant 200 mBar vacuum. Three replicates were filtered for one seawater sample. The particles retained on the filters were stained with 500 µL of 0.02% aqueous Alcian Blue in 0.06% acetic acid (pH = 2.5). The dye was pre-filtered with 0.2 µm pore-size polycarbonate filters before use. After being stained, filters were rinsed once with Milli-Q water, and then put into 15 mL neutral centrifuge tubes and stored in freezer at -20 °C.

TEP was analysed using a colorimetric technique after the cruise. The particles were detected by staining with Alcian Blue, a cationic copper phthalocyanine dye that combined with carboxyl (-COO-) and half-ester sulphate (-OSO3 -) reactive groups of acidic polysaccharides. The amount of Alcian Blue adsorbed onto the filter was directly related to the weight of the polysaccharide retained on the filter. The filters were soaked in 6 mL of 80% sulphuric acid for 2 h to dissolve the adsorbed Alcian Blue. The absorbance of the solution at 787 nm (absorption maximum) was be measured using an U-1800 spectrophotometer (Hitachi).

DOC

Seawater samples were taken from every depth of 57 CTD casts. Water taken from the surface to 300 m (or shallower depending on seafloor depth) was filtered using pre-combusted (450 °C, 4 h) GF/F filters (Fisher) to remove the particulate carbon and most organisms in the seawater. Samples were filled into pre-combusted glass ampoules and acidified to pH<2 with 40 µL 50% HCl immediately after collection. The ampoules were sealed and stored in fridge (4 °C).

DOC samples were analysed using the high temperature combustion technique. The principle of this technique was to combust the dissolved organic carbon compounds in the samples into CO2 and measure the amount of generated CO2. Filtered and acidified seawater samples were sparged with oxygen to remove dissolved inorganic carbon from the water and then injected into a combustion column. The non-purgeable organic carbon in the sample was combusted at 680 °C and converted to CO2, which was detected by a non-dispersive infrared detector (NDIR). A Shimadzu TOC-TDN instrument was used (TOC V CPN).

TDN

No details of the TDN sampling or analyses were provided in the cruise report. The TDN data were provided in pairs with the DOC data and it has been assumed that the TDN values were obtained from the same protocol using the Shimadzu DOC-TDN instrument.

BODC Data Processing Procedures

Data were submitted after the cruise and archived under BODC's accession number USO130146. The data were provided in a file with sample metadata (station, cast number, date, time, latitude, longitude, rosette bottle number and depth). The data were matched to the metadata in the database based on cast/rosette bottle combinations. There were no discrepancies. Where replicate data were provided for a depth the mean value and standard deviation of the replicates were calculated for loading to the database.

No unit conversion was necessary as the data were provided in equivalent units to the assigned BODC parameter code. The data were loaded to the database using established BODC procedures.

A parameter mapping table is provided below;

Data Quality Report

The data were supplied with WOCE flags applied for all data points. These were converted to the BODC data quality flags duirng loading to the database.

Problem Report

Not relevant to this data set.

Project Information

UKOARP Theme B: Ocean acidification impacts on sea surface biology, biogeochemistry and climate

The overall aim of this theme is to obtain a quantitative understanding of the impact of ocean acidification (OA) on the surface ocean biology and ecosystem and on the role of the surface ocean within the overall Earth System.

The aims of the theme are:

• To ascertain the impact of OA on planktonic organisms (in terms of physiological impacts, morphology, population abundances and community composition).
• To quantify the impacts of OA on biogeochemical processes affecting the ocean carbon cycle (both directly and indirectly, such as via availability of bio-limiting nutrients).
• To quantify the impacts of OA on the air-sea flux of climate active gases (DMS and N₂O in particular).

The main consortium activities will consist of in-situ measurements on three dedicated cruises, as well as on-deck bioassay experiments probing the response of the in-situ community to elevated CO₂. Most of the planned work will be carried out on the three cruises to locations with strong gradients in seawater carbon chemistry and pH; the Arctic Ocean, around the British Isles and the Southern Ocean.

Weblink: http://www.oceanacidification.org.uk/research_programme/surface_ocean.aspx

Data Activity or Cruise Information

Data Activity

BODC Sample Metadata Report for D366_CTD_D366072

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.

Related Data Activity activities are detailed in Appendix 1

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:

Appendix 1: D366_CTD_D366072

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

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