Metadata Report for BODC Series Reference Number 2121639

• 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

Plymouth University Flow Injection Chemiluminescence system with Hamamatsu H8259 photon counting head

An analytical system manufactured by Plymouth University and used by Birchill et al. (2017) to determine concentrations of chemical species in a sample based on the luminescence of the species of interest. The system is normally uniquely assembled for each analysis, and comprises pumps, injection and autosampler valves, preconcentration columns and a Hamamatsu H8259 photon counting head for chemiluminescence detection. The H8259 device includes a side-on photomultiplier tube with a diameter of 28 mm, a high-speed photon counting circuit, and a high-voltage power supply circuit. Depending on the product type number used, the photon counting head device has a spectral response range of 185 nm to 680 nm, 850 nm or 900 nm, and a low dark count in UV to visible or near IR range.

For more information, please see this document: https://www.bodc.ac.uk/data/documents/nodb/pdf/hamamatsu_h8259

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.

Cruise DY018 soluble, dissolved iron and total dissolvable iron from CTD and tow fish

Originator's Protocol for Data Acquisition and Analysis

Soluble iron (< 0.02 µm), dissolved iron (< 0.2 µm) and total dissolvable iron (unfiltered) concentrations were collected during the Shelf Sea Biogeochemistry programme (November 2014), from the Celtic Sea (50° N 8° W) to investigate the autumnal distriubtion of iron in the Celtic Sea as part of a wider seasonal study. The samples were collected during RRS Discovery cruise DY018, as part of the UK Shelf Sea Biogeochemistry research programme. Discrete samples were collected from CTD casts carried out with the titanium CTD. Samples were withdrawn from several depths, spanning the entire water column. The dataset contains depth profiles of the concentration of iron fractions provided in units of nmol L^-1. Samples collected following trace metal protocols (Cutter et al., 2010) in acid clean LDPE bottles and acidifed to 0.024 M HCl (Romil, UpA) following collection. Soluble and dissolved iron sample stored for > 2 months before analysis, total dissolvable samples stored for > 6 months before analysis. The different iron fractions were analysed by flow injection with chemiluminesence detection (Obata et al 1993, Floor et al 2015). Full details available in Birchill et al 2017.

References Cited

Birchill, A. J., Milne, A., Woodward, E. M. S., Harris, C., Annett, A., Rusiecka, D., Achterberg, E. P., GledhilL, M., Ussher, S. J., Worsfold, P. J., Geibert, W. and Lohan, M. C., 2017. Seasonal iron depletion in temperate shelf seas. Geophysical Research Letters, 44(17), 8987?8996.

Cutter, G. , Andersson, P. , Codispoti, L. , Croot, P. , François, R., Lohan, M. C. , Obata, H. and Rutgers v. d. Loeff, M., 2010. Sampling and Sample-handling Protocols for GEOTRACES Cruises.

Floor, G. H., Clough, R., Lohan, M. C., Ussher, S. J., Worsfold, P. J. and Quétel C. R., 2015 Combined uncertainty estimation for the determination of the dissolved iron amount content in seawater using flow injection with chemiluminescence detection. Limnology and Oceanography: Methods, 13(12), 673-686.

Obata, H., Karatani, H. and Nakayama E., 1993. Automated determination of iron in seawater by chelating resin concentration and chemiluminescence detection. Analytical Chemistry, 65(11), 1524-1528.

BODC Data Processing Procedures

Data were provided in an Excel spreadsheet and archived at BODC. The file contained the water sample data from an UltraClean CTD (UCCTD) bottles. Data received were loaded into the BODC database using established BODC data banking procedures. The data were loaded into BODC's database without any changes. The originator variables were mapped to appropriate BODC parameter codes as follows:

The originator variables were mapped to appropriate BODC parameter codes as follows:

Data Quality Report

Flag 'S' was provided by originator to indicate that the used analytical system was not optimised for higher concentrations and the use of such value need to be done with care in any calculations.

Project Information

Shelf Sea Biogeochemistry (SSB) Programme Work Package 3: Supply of iron from shelf sediments to the ocean

Work Package 3 is a £0.78 million component of the Natural Environment Research Council (NERC) Shelf Sea Biogeochemistry (SSB) research programme, running from 2013 to 2017. It is jointly funded by NERC and the Department for Environment, Food and Rural Affairs (DEFRA). The goal of this project is to quantify iron (Fe) fluxes from the north-west European shelf seas to the adjacent North Atlantic Ocean.

Background

Low iron (Fe) concentrations control productivity, phytoplankton community structure and carbon cycling in 25 % of the open ocean. Iron concentrations are tightly coupled to Fe supply, and Fe fluxes from shelf seas to the open ocean are poorly constrained, although estimates indicate they could be 2-10 times higher than atmospheric inputs and thus potentially a major contributor to the oceanic Fe cycle.

The goal of Work Package 3 will be realised during cruises in the Celtic Sea as part of the Shelf Sea Biogeochemistry Research Programme (SSB), which will provide the physical and chemical context for our study. The data collection will utilise trace metal clean sampling techniques, with associated physical diffusion and advection measurements, to determine the supply of dissolved, colloidal and particulate forms of Fe from sediments and their subsequent fate in shelf sea waters and during export to the North Atlantic Ocean. Data analyses will use Fe isotopes, physical-chemical Fe species characterisation and geochemical tracers to quantify the Fe supply, attenuation and export processes.

Further details are available on the SSB website.

Participants

6 different organisations are directly involved in research for SSB Work Package 3. These institutions are

• Centre for Environment, Fisheries and Aquaculture Science (Cefas)
• National Oceanography Centre (NOC)
• Plymouth University
• University of Edinburgh
• University of Oxford
• University of Southampton

Objectives

This Work Package aims to:

• Study the processes whereby iron is released from shelf sediments into overlying waters, and how these mechanisms can be influenced by organic matter from decaying plant material

• Provide new information on processes influencing release of iron to shelf waters to allow improved modelling of the size of this source, and of the key processes involved. For example, organic carbon inputs are expected to be associated with iron releases from the sediments, and using models will help extrapolate into the future and how the system will respond to climate change.

• Link the processes impacting iron in shelf waters with physical models and radionuclide estimates of the movement of water off shelf to give new estimates of the size of this source to the ocean. This information will have implications for shelf break and ocean productivity.

• Help interpret existing collected data (sediment profile images) on organic carbon within sediments and the status of the seabed through specific studies of sediment iron geochemistry. Specific studies of sediment iron geochemistry will help better interpret presently collected data (sediment profile images) on organic carbon within sediments and status of the seabed.

Fieldwork and data collection

Data for Work Package 3 will be gathered on all process cruises. These are listed in the table below. The study area is the marine shelf (and shelf-edge) of the Celtic Sea. Work will be carried out on board the NERC research vessels RRS Discovery and RRS James Cook.

Activities will include iron and radium measurements, glider work, coring, CTDs, stand alone pumps (SAPS), incubations with sediments and sea water.

Data Activity or Cruise Information

Data Activity

No Document Information Held for the Series

Related Data Activity activities are detailed in Appendix 1

Cruise

Complete Cruise Metadata Report is available here

Fixed Station Information

Fixed Station Information

Western Channel Observatory station E1

The Western Channel Observatory (WCO) is situated in the Western English Channel and comprises of sustained long-term observations at a number of stations.

Station E1 is located south-west of Plymouth at 50°2.00'N, 4°22.00'W.

More information can be found on the Western Channel Observatory website.

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: DY018_UCCTD_261

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: Western Channel Observatory E1

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.