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Dissolved Mn in the Southern Ocean
Entry ID: Dissolved_Mn_Antarctic_Middag_IPY35_NL_1


Summary
Abstract: Sampling and Analytical Methodology:
Samples were taken using 24 internally Teflon-coated PVC 12 litre GO-FLO Samplers (General Oceanics Inc.) mounted on an all-titanium frame (De Baar et al., 2008). This frame was connected to a 17.7 mm diameter Kevlar hydrowire with seven independent internal signal/conductor cables (Cousin Trestec S.A.) and controlled from onboard. Each GO-FLO sampler had a special ultraclean all-teflon PTFE valve (Cole Parmer; PN A-06392-31) installed. Samples for trace metal analysis were collected from the GO-FLO bottles in a class 100 clean room environment. The water was filtered over a 0.2 ?m filter cartridge (Sartrobran-300, Sartorius) under pressure (1.5 atm) of (in-line prefiltered) nitrogen gas exerted via a special connector instead of the regular air bleeding valve at the top of each GO-FLO sampler. Sub-samples for Mn were taken in cleaned LDPE sample bottles (125 mL) from each GO-FLO bottle. All sample bottles were rinsed five times with the sample seawater.
Analyses of dissolved Manganese (Mn) were performed on shipboard with the method developed by Doi et al. (2004) with some slight modifications in the preparation and brands of the chemicals used. Furthermore, samples were buffered in-line with an ammonium borate sample buffer (see text below). Samples were acidified with 12 M ultraclean HCl (Baseline® Hydrochloric Acid, Seastar Chemicals Inc.) to a pH of 1.8 and stored inside double plastic bags in plastic crates. At the home institute, in a flow injection system, the samples were buffered in-line to a pH of 8.5 ± 0.2 with ammonium borate sample buffer. This buffer was produced by dissolving 30.9 grams of boric acid (Suprapure, Merck) in 1 L MQ water and adjusting the pH to 9.4 with ammonium hydroxide (Suprapure, Merck).
Dissolved Mn in the buffered sample was preconcentrated for 200 seconds on a Toyopearl AFChelate 650M (TesoHaas, Germany) column. Hereafter the column was rinsed for 60 seconds with MQ water to remove interfering salts. The Mn was subsequently eluted from the column for 200 seconds with a solution of 0.1M three times quartz distilled formic acid (reagent grade, Merck) containing 0.1 M hydrogen peroxide (Suprapure, Merck) and 12 mM ammonium hydroxide (Suprapure, Merck). The pH of this carrier solution was adjusted to 2.9 ± 0.05. The eluate with the dissolved Mn passed a second column of immobilized 8-hydroxyquinoline (Landing et al., 1986) to remove interfering iron ions in the carrier solution (Doi et al., 2004). Hereafter the carrier mixed subsequently with 0.7 M ammonium hydroxide (Suprapure Merck) and a luminol solution. The latter luminol solution was made by diluting 600 ?l luminol stock solution and 10 ?l TETA (triethylenetetramine, Merck) in 1 L MQ. The luminol stock solution was made by diluting 270 mg luminol (3-aminophtalhydrazide, Aldrich) and 500 mg potassium carbonate in 15 ml MQ. The resulting mixture of carrier solution, ammonium hydroxide and luminol solution had a pH of 10.2 ± 0.05 and entered a 3 meter length mixing coil placed in a water bath of 25°C. Hereafter the chemiluminescence was detected with a Hamamatsu HC135 Photon counter. Concentrations of dissolved Mn were calculated in nanomol?L-1 (nM) from the photon emission peak height (see below).
The system was calibrated using standard additions from a 5000 nM Mn stock solution (Fluka) to filtered acidified seawater of low Mn concentration that was collected in Antarctic Ocean. A five-points calibration line (0, 0.15, 0.36, 0.73 and 1.46 nM standard additions) and blank determination were made daily. The three lowest points (0, 0.15 and 0.36 nM) of the calibration line were measured in triplicate and the two highest points (0.73 and 1.46 nM) in duplicate to add more weight to the lower part of the calibration line. The blank was determined by measuring column-cleaned seawater. Latter was obtained by passing seawater over a Toyopearl AFChelate 650M and an 8-hydroxyquinoline column which retained the dissolved Mn. The average blank value was 20 pM. The limit of detection defined as three times the standard deviation of the blank was < 0.01 nM. The flow injection system was rinsed every day with a 0.5 M HCl solution.


Data Processing:
The system was calibrated using standard additions from a 5000 nM Mn stock solution (Fluka) to filtered acidified seawater of low Mn concentration that was collected in Antarctic Ocean. A five-points calibration line (0, 0.15, 0.36, 0.73 and 1.46 nM standard additions) and blank determination were made daily. The three lowest points (0, 0.15 and 0.36 nM) of the calibration line were measured in triplicate and the two highest points (0.73 and 1.46 nM) in duplicate to add more weight to the lower part of the calibration line. The blank was determined by measuring column-cleaned seawater. Latter was obtained by passing seawater over a Toyopearl AFChelate 650M and an 8-hydroxyquinoline column which retained the dissolved Mn. The average blank value was 20 pM. The limit of detection defined as three times the standard deviation of the blank was < 0.01 nM. The flow injection system was rinsed every day with a 0.5 M HCl solution.
A standard was measured in triplicate every day. This standard was a sub-sample of a 25 L volume of filtered seawater that was taken at the beginning of the cruise. This standard was analysed 40 times on different days and the relative standard deviation of the replicate analysis in triplicate was 3.2%. The relative standard deviation on the separate days was on average 1.3 %. The average concentration of Mn of this standard was 0.44 nM and the deviation from this average for a given measuring day was used as a correction factor. To verify whether this correction was decreasing the inter-daily variability in the dataset, every day a sample which was collected and measured the previous measuring day, was analysed once again. The deviation between the concentrations measured on the different days decreased from 3.5% to 2.5%, indicating the data correction procedure is beneficial.
As an independent comparison, the certification samples collected on the SAFe cruise (Johnson et al., 2007) were analysed for Mn. As an independent comparison, the certification samples collected on the American SAFe cruise (Johnson et al., 2007) were analysed in triplicate for Mn. The resulting concentrations of Mn for both SAFe Surface (S) and SAFe deep (D2) from 1000 m, agreed very nicely the community consensus value that is starting to emerge on the absolute concentrations of Mn in the SAFe samples. The dataset was scanned for obvious outliers and these have been quality flagged with the number 4. Some samples gave anomalous nutrient results for the intended depth and were assumed to have been closed at the wrong depth and quality flagged with the number 8. All other values are assumed to be correct and flagged with the number 0.

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Geographic Coverage
 N: -41.14 S: -69.39  E: 9.96  W: -65.53

 Min Depth: 0 M  Max Depth: 5293.7 M

Data Set Citation
Dataset Creator: Rob Middag
Dataset Title: Dissolved Mn Southern Ocean
Dataset Series Name: GEOTRACES IPY-NL
Dataset Release Date: 2009-01-01T00:00:00.000Z
Dataset Release Place: The Netherlands
Dataset Publisher: NIOZ
Version: 1
Data Presentation Form: digital


Temporal Coverage
Start Date: 2008-02-11
Stop Date: 2008-04-13


Location Keywords
OCEAN > ATLANTIC OCEAN > SOUTH ATLANTIC OCEAN
OCEAN > SOUTHERN OCEAN > Drake Passage
OCEAN > SOUTHERN OCEAN > Prime Meridian
GEOGRAPHIC REGION > POLAR
OCEAN > SOUTHERN OCEAN > WEDDELL SEA


Science Keywords
OCEANS >OCEAN CHEMISTRY >TRACE ELEMENTS >DISSOLVED MANGANESE    [Definition]


Platform
R/V POLARSTERN    [Information]


Instrument
FIA >FLOW INJECTION ANALYSIS


Project
IPY >INTERNATIONAL POLAR YEAR    [Information]
GEOTRACES >Biogeochemical cycles of Trace Elements/Isotopes in the Arctic and S. Oceans    [Information]


Quality
Data Processing:
The system was calibrated using standard additions from a 5000 nM Mn stock solution (Fluka) to filtered acidified seawater of low Mn concentration that was collected in Antarctic Ocean. A five-points calibration line (0, 0.15, 0.36, 0.73 and 1.46 nM standard additions) and blank determination were made daily. The three lowest points (0, 0.15 and 0.36 nM) of the calibration line were measured in triplicate and the two highest points (0.73 and 1.46 nM) in duplicate to add more weight to the lower part of the calibration line. The blank was determined by measuring column-cleaned seawater. Latter was obtained by passing seawater over a Toyopearl AFChelate 650M and an 8-hydroxyquinoline column which retained the dissolved Mn. The average blank value was 20 pM. The limit of detection defined as three times the standard deviation of the blank was < 0.01 nM. The flow injection system was rinsed every day with a 0.5 M HCl solution.
A standard was measured in triplicate every day. This standard was a sub-sample of a 25 L volume of filtered seawater that was taken at the beginning of the cruise. This standard was analysed 40 times on different days and the relative standard deviation of the replicate analysis in triplicate was 3.2%. The relative standard deviation on the separate days was on average 1.3 %. The average concentration of Mn of this standard was 0.44 nM and the deviation from this average for a given measuring day was used as a correction factor. To verify whether this correction was decreasing the inter-daily variability in the dataset, every day a sample which was collected and measured the previous measuring day, was analysed once again. The deviation between the concentrations measured on the different days decreased from 3.5% to 2.5%, indicating the data correction procedure is beneficial.
As an independent comparison, the certification samples collected on the SAFe cruise (Johnson et al., 2007) were analysed for Mn. As an independent comparison, the certification samples collected on the American SAFe cruise (Johnson et al., 2007) were analysed in triplicate for Mn. The resulting concentrations of Mn for both SAFe Surface (S) and SAFe deep (D2) from 1000 m, agreed very nicely the community consensus value that is starting to emerge on the absolute concentrations of Mn in the SAFe samples. The dataset was scanned for obvious outliers and these have been quality flagged with the number 4. Some samples gave anomalous nutrient results for the intended depth and were assumed to have been closed at the wrong depth and quality flagged with the number 8. All other values are assumed to be correct and flagged with the number 0.


Access Constraints
No constraints


Use Constraints
Please contact Rob Middag at NIOZ for citation details.


Keywords
GEOTRACES
IPY-NL


Data Set Progress
ACTIVE


Data Center
Netherlands National Polar Data Centre, Royal Netherlands Institute for Sea Research, Netherlands Organization for Scientific Research, Netherlands    [Information]
Data Center URL: http://www.nioz.nl/dmg

Data Center Personnel
Name: IRA VAN DEN BROEK
Phone: +31 222 369 420
Fax: +31 222 319 674
Email: ira.van.den.broek at nioz.nl
Contact Address:
P.O. Box 59
City: Den Burg
Postal Code: 1790 AB
Country: The Netherlands



Data Center Personnel
Name: TACO F. DE BRUIN
Phone: +31-222-369 479
Fax: +31-222-319674
Email: bruin at nioz.nl
Contact Address:
P.O. Box 59
City: Den Burg
Postal Code: 1790 AB
Country: The Netherlands



Distribution
Distribution_Media: internet


Personnel
ROB MIDDAG
Role: INVESTIGATOR
Role: METADATA AUTHOR
Role: TECHNICAL CONTACT
Phone: +31222369464
Fax: +31222319674
Email: rob.middag at nioz.nl
Contact Address:
P.O. Box 59
City: Den Burg
Postal Code: 1790 AB
Country: The Netherlands


PATRICK LAAN
Role: TECHNICAL CONTACT
Phone: +31222369464
Fax: +31222319674
Email: Patrick.laan at nioz.nl
Contact Address:
P.O. Box 59
City: Den Burg
Postal Code: 1790 AB
Country: The Netherlands


Extended Metadata Properties
(Click to view more)

Creation and Review Dates
DIF Creation Date: 2009-07-17
Last DIF Revision Date: 2018-08-29



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