Metadata Report for BODC Series Reference Number 2094702

• 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

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.

Dissolved and Particulate Trace Metals for RV Sea Vigil cruises and TWEED campaign.

Document History

Converted from CDROM documentation.

Content of data series

Data Originator

Professor Dennis Burton, School of Ocean and Earth Sciences, Southampton Oceanography Centre, UK.

Sampling strategy and methodology

RV Sea Vigil cruises SV30B, SV32A, SV32B and SV34B.
Tweed campaign TWEED01, TWEED04, TWEED07, TWEED09 and TWEED12.

Samples were collected into 500 ml low density polyethylene bottles deployed on a specially designed sampler (unit described in Balls and Laslett (1991)). Water samples were filtered in-line through 47 mm diameter 0.4 µm pore-sized polycarbonate filter membranes, using ca. 0.7 bar overpressure. The filtrates were collected in 250 ml low density polyethylene bottles and acidified to approximately pH 2 to stabilise the total dissolved metals. Bottles were stored in resealable polyethylene bags until analysis. Filtration and acidification were undertaken in a Class 100 laminar flow hood. All critical equipment used for sample collection and manipulation had been degreased and acid cleaned prior to use.

Dissolved Aluminium Analysis

Dissolved aluminium was determined following complexation by lumogallion and fluorometric determination of the Al complex (Hydes and Liss, 1976; Heron and Burton, 1987). The precision of the Al measurements was determined as 5% or better using laboratory-made standards.

Alan Tappin, who undertook most of the analytical work, reported that he believed the aluminium in estuarine waters to be underestimated by the lumogallion technique. This was based on comparison of lumogallion results with graphite furnace atomic absorption spectrophotometry. The discrepancy was attributed to the presence of aluminium in colloidal complexes that failed to react with the lumogallion reagent.

The data were supplied in units of µg/l. These were converted to nM at BODC by multiplying by 1000 and dividing by an atomic weight of 26.98.

Dissolved Trace Metal Analysis

The total dissolved metals (except Al) were separated from the estuarine water matrix following dithiocarbamate complexation and extraction of the chelated metals into chloroform. The metals were back-extracted into 5% (v/v) HNO₃ (metal concentration factor ca. 52) and the concentrations determined by graphite furnace atomic absorption spectrophotometry. The method described here is a modified version of that given in Tappin et al. (1995), taking into account the replacement of the freon solvent with chloroform.

The accuracy and intra-batch precision were assessed by analysing aliquots of the SLEW-2 standard reference estuarine water for dissolved metals. This standard was analysed with every batch of determinations. Accuracy and intra-batch precision was <10% for each metal.

The data were supplied in units of µg/l. These were converted to nM at BODC by multiplying by 1000 and dividing by the atomic weight. The atomic weights used were 26.98 for Al, 112.4 for cadmium, 63.55 for copper, 55.85 for iron, 207.2 for lead, 54.94 for manganese, 58.69 for nickel and 65.37 for zinc.

Particulate Trace Metal Analysis

Filter membranes containing the retained suspended particulate matter were frozen (-20°C) in the dark prior to analysis. For the analysis the membranes were defrosted and dried to constant weight, at room temperature, in a laminar flow hood. Each was re-weighed and the mass of particulate matter determined.

Filters, with retained particles, were digested in covered Teflon beakers at room temperature for 24 hours, using 10 ml 10% (v/v) HCl (Aristar grade, diluted with MilliQ water). If the weight of the particulate matter on the filter exceeded 0.2 g then a sub-sample of approximately 0.1 g of dried particulate matter was lifted from the filter using a Teflon-coated spatula and digested in the manner described above.

Following the digestion, the suspensions in the Teflon beakers were filtered through 47 mm, 0.45 µm cellulose acetate filter membranes housed within polycarbonate filter holders. The digested filter membranes and beakers were then rinsed with 2x5 ml aliquots of 10% HCl, which were also filtered.

The leachates were transferred to 25 ml polyethylene volumetric flasks and made up to the mark with 10% HCl. Metal concentrations in the leachates were determined by ICP-MS. All critical equipment used for sample collection and manipulation had been degreased and acid cleaned prior to use. The method follows that given in, for example, Tappin et al. (1995).

The method represents a partial leaching technique; therefore accuracy cannot be determined. The precision of the method has been assessed at <10% for all metals (except for barium, silver and strontium for which the precision has not been estimated; nevertheless the value should be similar to the other metals) using standard reference materials for marine sediment.

The data were supplied as particle composition analyses in units of g/g, in other words parts per million by weight. The data values for major elements (Al, Fe and Mn) were scaled by a factor of 0.0001 to the database units of per cent.

Data expressed in terms of particulate metal content per unit volume of water were computed from the data in ppm by multiplying by the SPM concentration included in the data set then dividing by the atomic weight. These are stored for convenience as an additional data set in units of nM. The atomic weights used were 26.98 for Al, 112.4 for cadmium, 63.55 for copper, 55.85 for iron, 207.2 for lead, 54.94 for manganese, 58.69 for nickel, 65.37 for zinc, 107.9 for silver, 137.3 for barium and 87.6 for strontium.

References

Achterberg, E. P. and van den Berg, C.M.G., 1994. Automated voltammetric system for shipboard determination of metal speciation in sea water. Anal. Chim. Acta 284, 463-471.

Colombo, C and van den Berg, C.M.G., 1997. Simultaneous determination of several trace metals in seawater using cathodic stripping voltammetry with mixed ligands. Anal. Chim. Acta 337, 29-40.

Heron, S.J. and Burton, J.D., 1987. Evaluation of a Spectrofluorimetric Method for Aluminium by Lumogallion. Final Report on Department of Environment Contract No. PECD 7/7/173. Department of Oceanography, University of Southampton. January 1987, 22 pp.

Hydes, D.J. and Liss, P.S., 1976. A fluorimetric method for the determination of low concentrations of dissolved aluminium in natural waters. Analyst 101, 922 931.

Morley, N.H., Statham P.J. and Fay, C., 1988. Design and use of a clean shipboard handling system for seawater samples. In: Advances in Underwater Technology, Ocean Science and Offshore Engineering, Volume 16 (Oceanology '88), Graham and Trotman, London, 283-290.

Nimmo, M., van den Berg, C.M.G. and Brown, J., 1989. The chemical speciation of dissolved nickel, copper, vanadium and iron in Liverpool Bay, Irish Sea. Coastal Shelf Res. 29, 57-74.

Pihlar, B., Valenta, P. and Nurnberg, H.W., 1981. New high-performance analytical procedure for the voltammetric determination of nickel in routine analysis of waters, biological materials and food. Fres. Z. Anal. Chem. 307, 337-346.

Tappin, A.D., Millward, G.E., Burton, J.D., Statham, P.J. and Morris, A.W., 1995. Trace metals in the central and southern North Sea. Estuarine, Coastal and Shelf Science 41, 275-323.

Project Information

LOIS River-Atmosphere-Coast Study (LOIS - RACS)

Introduction

The Land-Ocean Interaction Study (LOIS) was a NERC research programme designed to study processes in the coastal zone. The Rivers, Atmosphere and Coasts Study (RACS) was a major component of LOIS that looked at land-sea interactions in the coastal zone and the major exchanges (physical, chemical and biological) between rivers and estuaries and the atmosphere. The study focused on the east coast of the UK from the Wash to the Tweed.

RACS included several sub-components

• BIOTA - A study of salt marshes of the Humber and Wash
• RACS (A) - An atmospheric chemistry study looking at air mass changes from the Wash into East Anglia
• RACS (C) - A study of the estuaries, coasts and coastal waters between Great Yarmouth and Berwick upon Tweed.
  1. The coastal oceangraphic survey
  2. The Humber estuarine study
  3. The Tweed estuarine study
  4. The Holderness experiment
• RACS (R) - A study of rivers that drain into the North Sea

RACS (A) was coordinated by the University of East Anglia and RACS (C) by the Plymouth Marine Laboratory.

RACS (A)

The bulk of the RACS (A) data set was collected during two field campaigns in the winter (October/November) of 1994 and the summer (May/June) of 1995. During these campaigns data were collected continuously from the University of East Anglia Atmospheric Observatory at Weybourne on the north Norfolk coast. An instrumented vessel was stationed offshore to provide a second sampling site to allow changes in a given air mass to be monitored. The Imperial College Jetstream research aircraft made one flight during each campaign to provide a link between the two surface stations. The Jetstream made four additional flights in 1996 and 1997.

RACS (C)

The coastal oceanographic survey

The coastal oceanographic data set was collected during a series of 17 RRS Challenger cruise legs. Most cruises covered two survey grids. One from Great Yarmouth to the Humber designed around the distribution of the sandbanks and a second simple zig-zag grid from the Humber to Berwick on Tweed. A large number of anchor stations, usually over one or two tidal cycles, were worked in the area of the Humber mouth or the Holderness coast.

The Humber estuarine study

The Humber estuarine data set was collected during a series of 33 campaigns on the Environment Agency vessels Sea Vigil and Water Guardian in the Humber, Trent and Ouse river systems at approximately monthly intervals between June 1993 and December 1996. Each campaign consisted of two or three one-day cruises. The tracks covered the estuary from the tidal limits of both Trent and Ouse to Spurn Point. Instrumental and sample data are available from a series of fixed stations that were sampled during every campaign.

The Tweed estuarine study

The Tweed estuarine data set was collected during a series of 13 campaigns using RV Tamaris in association with a rigid inflatable vessel at approximately monthly intervals between July 1996 and July 1997. Each campaign covered the tidal reaches of the River Tweed.

The Holderness experiment

The Holderness Experiment was designed to monitor the process of sediment transport along the Holderness coastline. It consisted of three moored instrument deployments during the winters of 1993-1994, 1994-1995 and 1995-1996. Mooring platforms were deployed at eight stations along two lines off the Holderness coast. A northerly and a southerly line of four stations each were used (N1 - N4 and S1 to S4) with the lowest numbers being inshore. Both lines were approximately perpendicular to the coast, although the S4 station lay to the south of the S line, off Spurn Head.

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: