Metadata Report for BODC Series Reference Number 1681257

• 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

Public domain data

These data have no specific confidentiality restrictions for users. However, users must acknowledge data sources as it is not ethical to publish data without proper attribution. Any publication or other output resulting from usage of the data should include an acknowledgment.

The recommended acknowledgment is

"This study uses data from the data source/organisation/programme, provided by the British Oceanographic Data Centre and funded by the funding body."

Narrative Documents

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.

Pigments for Belgica, Charles Darwin and Poseidon cruises

Document History

Converted from CDROM documentation

Content of data series

Data Originator

Dr Stuart Gibb, Plymouth Marine Laboratory, UK.

Sampling strategy and methodology

Cruises: Belgica BG9714B, BG9815C, BG9919B and BG9919C, Charles Darwin CD110A, CD110B, CD114A and CD114B and Poseidon PS237_1.

Water samples were either collected from water bottles deployed on a CTD rosette or taken from a continuous surface seawater supply.

1-2 litres of water were filtered through a 25mm GF/F filter, flash frozen and stored in liquid nitrogen until analysed either on board or back in the laboratory.

Pigment concentrations were determined by reverse phase HPLC following the protocols described in Barlow et al. (1993a). Frozen filters were extracted in 90% acetone, sonicated and centrifuged to remove debris. An aliquot (300 µl) of clarified extract was mixed with an equal volume of 1M ammonium acetate and 100 µl of this mixture was injected into a Shimazdu HPLC system incorporating a 3 micron C18 Pecosphere column (3.3 x 0.45 cm, Perkin Elmer) heated to 30 °C.

Pigments were separated by a linear binary gradient changing from 0% B to 100% B over 10 minutes, followed by an isocratic hold at 100% B for 7.5 minutes, at a flow rate of 1 ml per minute. Solvent A consisted of 80:20 (v/v) MeOH : ammonium acetate. Solvent B contained 60:40 (v/v) MeOH : acetone.

Chlorophylls and carotenoids were detected by absorbance at 440nm and phaeopigments by fluorescence detection at 405nm excitation, 670nm emission. Data collection and integration was performed with the Philips PU6000 chromatography software. Diavynyl chlorophyll-a was determined on some samples using a C8 column as described by Barlow et al. (1996).

Pigments were identified and calibrated by comparison with retention times of pigments isolated from well-documented microalgal species in the Plymouth Culture Collection and with standards obtained from the Water Quality Institute, Denmark. Peak identity was further confirmed on selected samples by on-line diode array visible spectroscopy. Chlorophyll-a and chlorophyll-b were calibrated using authentic standards (Sigma Chemical Co.) in acetone and quantified spectrophotometrically using the extinction coefficients of Jeffrey and Humphrey (1975). Diavynyl chlorophyll-a standard was obtained from R. Bidigare, University of Hawaii. Phaeopigment concentrations were estimated from peak areas and calibrations performed by simultaneous absorbance (667nm) and fluorescence detection of phaeopigments extracted from copepod and mussel faeces as detailed by Barlow et al. (1993b).

All pigments were supplied in units of ng/l. Chlorophyll-a values were converted to mg/m³ by dividing by 1000 to unify units for this parameter in the database.

Comments on data quality

The HPLC analyst reported that for BG9919 fucoxanthin may contain phaeophorbides and the chlorophyll-a data loaded were the sum of chlorophyll-a and chlorophyll-a allomer.

References

Barlow, R.G., Mantoura, R.F.C., Gough, M.A. and Fileman, T.W., 1993a. Pigment signatures of the phytoplankton composition in the north-east Atlantic during the 1990 spring bloom. Deep Sea Res. II, 40, 459-477.

Barlow, R.G., Mantoura, R.F.C., Gough, M.A. and Fileman, T.W., 1993b. Phaeopigment distribution during the 1990 spring bloom in the north-east Atlantic. Deep Sea Res. I, 40, 2229-2242.

Barlow, R.G., Cummings, D.G., Mantoura, R.F.C. and Fileman, T.W., 1996. Pigment chemotaxonomic distributions of phytoplankton during summer in the western Mediterranean. Deep Sea Res. II, in press.

Jeffrey, S.W. and Humphrey, G.F., 1975. New spectrophotometric equations for determining chlorophylls a, b, c1 and c2 in higher plants, algae and natural phytoplankton. Biochem. Physiol. Pflan., 167, 191-194.

Lorenzen, C.J., 1967. Determination of chlorophyll and phaeopigments: spectrophotometric equations. Limnology and Oceanography, 12.

Tahey, T.M., Duineveld, G.C.A., Berghuis, E.M. and Helder, W., 1994. Relation between sediment-water fluxes of oxygen and silicate and faunal abundance at continental shelf, slope and deep-water stations in the North West Mediterranean. Marine Ecology Progress Series, 104, 119-130.

Thomsen. L., Graf, G., Martens, V. and Steen, E., 1994. An instrument for sampling water from the bottom nepheloid layer. Contin. Shelf Res., 14, 871-882.

Thomsen, L. and Graf, G., 1995. Benthic boundary layer characteristics of the continental margin of the western Barents Sea. Oceanologica Acta, 17/6, 597-607.

Wright, S.W., Jeffrey, S.W., Mantoura, R.F.C., Llewellyn, C.A., Bjornland, T., Repeta, D. and Welschmeyer, N., 1991. Improved HPLC method for the analysis of chlorophylls and carotenoids from marine phytoplankton. Marine Ecology Progress Series, 77, 183-196.

Yentsch, C.S. and Menzel, D.W., 1963. A method for the determination of phytoplankton chlorophyll and phaeophytin by fluoresence. Deep-Sea Res., 10, 221-231.

Project Information

Ocean Margin EXchange (OMEX) II - II

Introduction

OMEX was a European multidisciplinary oceanographic research project that studied and quantified the exchange processes of carbon and associated elements between the continental shelf of western Europe and the open Atlantic Ocean. The project ran in two phases known as OMEX I (1993-1996) and OMEX II - II (1997-2000), with a bridging phase OMEX II - I (1996-1997). The project was supported by the European Union under the second and third phases of its MArine Science and Technology Programme (MAST) through contracts MAS2-CT93-0069 and MAS3-CT97-0076. It was led by Professor Roland Wollast from Université Libre de Bruxelles, Belgium and involved more than 100 scientists from 10 European countries.

Scientific Objectives

The aim of the Ocean Margin EXchange (OMEX) project was to gain a better understanding of the physical, chemical and biological processes occurring at the ocean margins in order to quantify fluxes of energy and matter (carbon, nutrients and other trace elements) across this boundary. The research culminated in the development of quantitative budgets for the areas studied using an approach based on both field measurements and modeling.

OMEX II - II (1997-2000)

The second phase of OMEX concentrated exclusively on the Iberian Margin, although RV Belgica did make some measurements on La Chapelle Bank whilst on passage to Zeebrugge. This is a narrow-shelf environment, which contrasts sharply with the broad shelf adjacent to the Goban Spur. This phase of the project was also strongly multidisciplinary in approach, covering physics, chemistry, biology and geology.

There were a total of 33 OMEX II - II research cruises, plus 23 CPR tows, most of which were instrumented. Some of these cruises took place before the official project start date of June 1997.

Data Availability

Field data collected during OMEX II - II have been published by BODC as a CD-ROM product, entitled:

• OMEX II Project Data Set (three discs)

Further descriptions of this product and order forms may be found on the BODC web site.

The data are also held in BODC's databases and subsets may be obtained by request from BODC.

Data Activity or Cruise Information

Data Activity

BODC Sample Metadata Report for BG9919B_CTD_49A

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: BG9919B_CTD_49A

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