Metadata Report for BODC Series Reference Number 2051959

• 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

Flow Injection Chemiluminescence System

The Flow Injection Chemiluminescence (FI-CL) technique is based on a flow injection method coupled with chemiluminescence detection. A FI-CL system is composed of individual components that are typically uniquely assembled for each analysis. The model and manufacturer of each component can vary.

A typical FI-CL system consists of peristaltic pumps, multiway valves, a flow injection valve, a preconcentration column and chemiluminscence detector, such as a photon-counting head. Peristaltic pumps are used to deliver the reagent, sample, buffer and wash solutions to the system's components, and multi way valves enable the sample and wash solutions to pass sequentially through the preconcentration column. The injection valve is used to transport the sample to the detector. Cycles of loading, washing and injection may be computer controlled.

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.

Shimadzu RF-20 A fluorescence detector

A high-sensitivity fluorescence spectrometer used to identify and quantify trace-level components of liquid samples, for applications such as food, pharmaceutical and environmental analyses. The fluorescence detector uses the principle of Raman spectroscopy to excite the liquid sample with excitation light from a Xenon lamp, and breaks up the emitted fluorescence light with a fluorescence monochromator. It extracts the required fluorescence wavelengths and measures the intensity with a photomultiplier. The RF-20A is capable of ultra fast, high-sensitivity multi-component analysis using a wavelength switching by time program, and utilises a four-wavelength measurement function that detects each component at its optical wavelength. Optional additions include an Amino Acid Analysis System, a Reducing Sugar Analysis System, a Carbamate Pesticide Analysis System and a Synthetic Antibacterial Agent/Mycotoxin Screening System. The RF-20A achieves a water Raman S/N ratio of 1200, and the Xenon lamp lasts approximately 2000 hours. It also has a 10 ms response time, and a wavelength range of 0, 200 nm to 650 nm.

For more information, please see this document: https://www.bodc.ac.uk/data/documents/nodb/pdf/shimadzu_RF-20A_brochure.pdf

Total dissolved trace metals from titanium CTD bottle samples for JC150

Acquisition description:

Sampling methodology

Seawater samples were collected during cruise JC150 in the subtropical North Atlantic. The cruise took place during summer (26th June to 12th August 2017) sampling between Guadeloupe and Tenerife on-board the R.R.S. James Cook. Seven stations were occupied for high resolution vertical profiling. Seawater samples were collected according to the GEOTRACES guidelines.

A titanium rosette fitted with 24 x 10 L trace metal-clean Teflon-coated OTE (Ocean Test Equipment) bottles and a CTD profiler (Sea-bird Scientific) were deployed on a conducting Kevlar wire to collect samples from the water column. Upon recovery, the OTE bottles were transported into a class 1000 clean air van and pressurized (0.7 bar) with compressed air filtered in-line through a 0.2 µm PTFE filter capsule (Millex-FG 50, Millipore). Unfiltered samples were collected for total dissolvable iron and zinc, which is solubilized after at least 6 months of acidification to 0.024 M HCL.

Sub-samples for dFe were filtered through 0.45/0.2 µm two-step acetate membrane cartridge filters (Sartobran-300, Sartorius) into trace metal-clean 125 ml low-density polyethylene (LDPE) bottles and acidified to pH 1.7 (0.024 M) by addition of 12 M ultrapure hydrochloric acid (HCl, Romil, UpA) under a class 100 laminar flow hood (Lohan et al., 2006). Samples for sFe went through an additional in-line filtration step through 0.02 µm syringe filters (Anotop, Whatman) before acidification, whereas samples for TDFe were collected unfiltered and then acidified.

Analytical methodology

Iron

All dFe, sFe and TDFe samples were analysed in triplicate using flow injection analysis with chemiluminescence detection (Birchill et al., 2017; Obata et al., 1993; 1997) inside a class 1000 clean air laboratory either on-board the R.R.S. James Cook or subsequently at the National Oceanography Centre Southampton, UK. Each sample was spiked one hour prior to analysis with 0.013 M ultrapure H₂O₂ (Sigma-Aldrich) in a ratio of 1 µl H₂O₂ per ml sample to ensure the complete oxidation of Fe(II) to Fe(III) (Lohan et al., 2006). Each sample was buffered in-line to pH 3.5-4.0 using 0.15 M ammonium acetate (Romil, SpA) before Fe(III) was selectively pre-concentrated onto the cation exchange resin Toyopearl-AF-Chelate 650 M (Tosohaas). Following the removal of the seawater matrix from the resin using a weak 0.013 M HCl (Romil, SpA) wash, the Fe was liberated from the resin using 0.24 M HCl (Romil, SpA) and entered the reaction stream. The eluent was mixed downstream with a 0.015 mM luminol solution containing 70 µl L-1 triethylenetetramine (both Sigma-Aldrich), buffered to pH 9.4-9.6 using 1 M ammonia solution (Romil, SpA) with the chemiluminescent reaction occurring following the addition of 0.4 M H₂O₂ (Rose & Waite, 2001). The light signal at a wavelength of 425 nm was detected by a photomultiplier tube and concentrations were quantified using standard additions to low Fe seawater. The limit of detection (3x the standard deviation of the lowest standard addition) was 0.03±0.02 nM (n = 59), whilst the precision of triplicate analysis was 2.78±2.02 % (n = 1764). The accuracy of the method was established by repeat quantification of dFe in the SAFe reference samples yielding values of 0.11±0.02 nM (n = 6) and 0.94±0.04 nM (n = 17) for SAFe S and SAFe D2 respectively, which are in close agreement with the reported consensus values (S = 0.095±0.008 nM; D2 = 0.96±0.02 nM).

Zinc

Following collection, all sub-samples were acidified (0.024 M HCl; Romil SpA) and then analysed onboard ship for DZn concentration using flow-injection analysis with fluorimetric detection, as first described by Nowicki et al. (1994). 20 mL of seawater was buffered in-line (pH 4.5) and then DZn pre-concentrated for 200 seconds onto a cation exchange resin (Toyopearl AF650 Chelate). The major seawater cations were rinsed from the resin with weak NH₄OAc before the DZn liberated from the resin with HCl and then mixed with p-tosyl-8-aminoquinoline (pTAQ, Sigma-Aldrich), which forms a stable fluorescent complex with Zn(II). The fluorescent reaction was measured by a Shimadzu RF-20A fluorimeter. Dissolved Zn was determined using two separate calibration curves, depending on ambient concentrations as Zn concentrations ranged from 30 pM to 4.5 nM at depth. Calibration standards were made using low Zn seawater collected from the towed 'fish'. Each sub-sample was run in triplicate with each complete analytical cycle taking 18 minutes. The analysis produced excellent analytical figures of merit with detection limits 10-30 pM and excellent agreement with SAFe and GEOTRACES reference samples.

Aluminum

All dAl samples were analysed in triplicate using flow injection analysis with fluroimetric detection (Resing & Measures, 1994; Brown & Bruland, 2008) inside a class 1000 clean air laboratory at the National Oceanography Centre Southampton, UK. Briefly, the sample was buffered in-line to pH 6 with 0.8 M ammonium acetate before being loaded onto a chelating iminodiacetic acid (Toyopearl AF-Chelate 650 M) preconcentration column. The column was rinsed using 0.01 M ammonium acetate to remove the seawater matrix cations before Al was eluted from the column with 0.1 M HCl (SpA, Romil). The HCl eluent entered the reaction stream where it mixed with a 4.8 mM lumogallion solution and 5% solution of Brij-35. The emission of the fluorescent complex was detected by a Shimadzu RF-10Axl fluorimeter with excitation and emission wavelengths set to 489 and 559 nm, respectively.

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. DOI: 10.1002/2017GL073881

Lohan M.C., Aguilar-Islas A.M., Bruland K.W. (2006) Direct determination of iron in acidified (pH 1.7) seawater samples by flow injection analysis with catalytic spectrophotometric detection: Application and intercomparison, Limnol. Oceanogr. Methods, 4, doi:10.4319/lom.2006.4.164

Nowicki J.L., Johnson K.S., Coale K., Elrod V.A., and Lieberman S.H. (1994) Determination of Zinc in Seawater Using Flow Injection Analysis with Fluorometric Detection. Analytical Chemistry 66. 2732-2738. 10.1021/ac00089a021.

Obata H.O., Karatani, H. and Nakayama E. (1993) Automated Determination of Iron in seawater by chelating resin concentration and chemiluminescence detection. Analytical Chemistry 65. 1524-1528. 10.1021/ac00059a007.

Rose A.L. and Waite T. (2002) Chemiluminescence of Luminol in the Presence of Iron(II) and Oxygen: Oxidation Mechanism and Implications for Its Analytical Use. Analytical chemistry. 73. 5909-20. 10.1021/ac015547q.

Obata H., Karatani, H., Matsui M. and Nakayama E. (1997) Fundamental studies for chemical speciation of iron in seawater with an improved analytical method. Marine Chemistry. 56. 97-106. 10.1016/S0304-4203(96)00082-5.

BODC Data Processing Procedures

Data received were loaded into the BODC database using established BODC data banking procedures. A parameter mapping table is provided below:

Project Information

Zinc, iron and phosphorous co-limitation in the Ocean: ZIPLOc

ZIPLOc is an 3 year project that aims to measure how zinc and phosphorous control biological activity in the North Atlantic subtropical gyre using novel measurement techniques. The observations made will be further explored using the latest modelling techniques over decadal timescales and in other basins.

The research aims to make an improvement in our overall understanding of how subtropical gyre ecosystems respond to ongoing climate change.

The project is led by the University of Liverpool, Earth, Ocean and Ecological Sciences and is a collaboration with the University of Southampton, School of Ocean and Earth Science. The project received funding from the Natural Environmental Research Council and runs between January 2017 and February 2020.

Data Activity or Cruise Information

Data Activity

BODC Sample Metadata Report for JC150_UCCTD_CTD019T

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: