SurfaceFe

Data Object Fe - Surface

contact PIs:

name	title
Dr Andrew R Bowie	Principal Investigator
Dr Russell D. Frew	Co-Principal Investigator
Dr Doug Mackie	Contact

Dataset description

SOIREE Surface Fe Data

Comments preserved from the original file:
SOIREE Surface Fe underway data

Author: Andrew R. Bowie (University of Plymouth and Plymouth Marine Laboratory)
Dept. of Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA, United Kingdom
Tel. +44 1752 233128, Fax +44 1752 233035, E-mail abowie@plymouth.ac.uk

SOIREE Fe data used in the preparation of the manuscript:
Bowie et al. (2001), The Fate of Added Iron during a Mesoscale Fertilisation Experiment in the Southern Ocean

This data was prepared by Andrew Bowie, whom the ownership rests with.
The data is for use for SOIREE participants only for research purposes.
Before using this data in any presentation or printed publication, please
contact the author and include full acknowledgements. All enquiries regarding
the sampling, analysis and data preparation can be directed to the address above.

Notes
1. Dissolved iron (DFe) underway data (nM)
2. All surface Fe analyses were performed using a flow injection - chemiluminescence
   (FI-CL) technique based on the luminol reaction using dissolved oxygen as the oxidant
   (Bowie et al., 1998)
3. All underway samples taken torpedo fish towed at 0.5-1 m below the surface
4. The detection limit of the FI-CL method was 0.04 nM
5. The analytical blank varied between 0.09 and 0.24 nM over 13 d with a mean standard deviation of 0.013 nM
6. Contamination (suspected to be from the ship itself) resulted in a practical limit
   of detection for the underway mapping of 0.10-0.20 nM, which was monitored daily
7. Out-of-patch locations determined by absence of SF6 signal.
   Nevertheless, continuous tracking between high Fe within patch and
   almost two orders lower Fe out of patch may lead to memory effect contamination of the
   low values for out of patch. Therefore rejections of 61 suspect out of patch "contaminated" samples
8. A '<' symbol indicates that the concentration was below the practical limit of detection
9. The timing of samples collected from the underway system were adjusted for lag time delays
   due to surface water pumping and analysis (4.0-6.5 min)
10. Decimal time is given as days in February 1999 (GMT), with 1 February 1999 0:00 = 1.0000
11. Latitudes and longitudes are taken from the DAS on RV Tangaroa (no Lagrangian correction)
12. Each worksheet corresponds to one mapping session

References:
Bowie, A.R., Achterberg, E.P., Mantoura, R.F.C., Worsfold, P.J., 1998.
Determination of sub-nanomolar levels of iron in seawater using flow injection
with chemiluminescence detection. Analytica Chimica Acta 361, 189-200.

Bowie, A.R., Maldonado, M.T., Frew, R.D., Croot P.L., Achterberg, E.A., Mantoura,
R.F.C., Worsfold, P.J., Law, C.S., Boyd P.W., The Fate of Added Iron during a
Mesoscale Fertilisation Experiment in the Southern Ocean, Deep-Sea Research II (2001),
SOIREE special issue, in the press.

Note
Values in brackets ('[ ]') were suspected to be contaminated

Data from original Pre-release Site Survey Notes columns below

date time Notes 19990208 0021 Ship moving slowly 19990208 0202 nd 19990208 0330 nd 19990208 0414 nd 19990208 0500 Ship moving slowly 19990208 0530 nd 19990208 0907 nd 19990208 0955 nd 19990208 1000 nd 19990209 1235 Below LOD 19990209 1243 Below LOD 19990209 1308 nd Mean 0.08 Std. Dev. 0.03 n 10 2 rejections

Acquisition description

See SOIREE Preliminary Voyage Report

Underway Fe Mapping
(Andrew R. Bowie, UoP / PML, UK)

Objectives
(i)To map the ambient concentration and investigate surface water changes in Fe2+,
dissolved (diss-Fe, <0.2mm) and total dissolvable (TD-Fe) iron during the experiment

(ii)To study the vertical distribution of Fe INside and OUTside the fertilised 16
patch via laboratory based analysis of sub-samples taken from daily Go-Flo casts

(iii)To perform an intercalibration exercise between FI-CL (AB) and solvent extraction
GFAAS (RF) technologies from identical samples taken from Go-Flo casts

(iv)To study the surface water distribution of Fe and other trace metals along a latitudinal
transect of the west coast of New Zealand

Analytical and Sampling Methodologies
Shipboard determinations were performed using a semi-automated flow injection chemiluminescence
(FI-CL) analyser. The technique enabled real-time analysis of Fe2+, diss-Fe and TD-Fe fractions
at the sub-nanomolar concentration level. The system is based on the oxidation of luminol, which
is catalysed by Fe2+ ions, emitting blue light. A reduction step was performed to determine the
Fe(II+III) fraction and in-line matrix elimination / sample preconcentration was achieved using
a 8-hydroxyquinoline micro-column. Surface samples were taken from a torpedo-style fish deployed
at 1-2 m and pumped directly into container designed for trace metal work. Vertical profiling
samples were collected from 5L and 30L trace metal Go-Flo sampling bottles deployed on Kevlar rope.

Preliminary Results
The FI-CL system performed with only minor problems throughout the one-month cruise period.
A minimum of 50 samples were analysed during each mapping period for Fe2+, diss-Fe and / or
TD-Fe fractions. Ambient surface water diss-Fe levels (0.08 nM) were raised to ca. 2 nM on
the first infusion, to 1 nM during infusions 2 and 3 and to 2nM on infusion 4. Rapid loss of
diss-Fe INside the patch to near ambient levels was noted after the first 3 infusions; this
was due to the conversion of the added iron sulphate heptahydrate to colloidal and particulate
phases. However, >1 nM diss-Fe persisted INside the patch for the 5 days following the 4th
infusion. Furthermore, significant concentrations of Fe2+ species existed INside the patch on
days 12 and 13 of the experiment. Maximum surface water TD-Fe levels (>5 nM) were measured on
day 8, following the 4th infusion.

Processing description

Field Names List

Parameter	Description	Units
date	date	YYYYMMDD
time	time	HHMM
UncorrPosE	Eastward position of shiptrack	kilometers
UncorrPosN	Northward position of shiptrack	kilometers
DriftE	Eastward drift calculated from ADCP	kilometers
DriftN	Northward drift calculated from ADCP	kilometers
CorrPosE	Corrected ship-track (Eastward component)	kilometers
CorrPosN	Corrected ship track (Northward component)	kilometers
lon	longitude, negative denotes West	decimal degrees
lat	latitude, negative denotes South	decimal degrees
Dfe	Dissolved Iron	nM
Year	Year of data	YYYY
Map	Map number of mapping session	integer
SDY	Day of the year	text
SOIREEDay	Day of SOIREE Experiment (Day 1=10Feb1999)	integer
DayDate	Day/Date of Data	DD-Mon
TimeDecimal	Days in February 1999 (GMT) with 1 February 1999 0:00 = 1.0000	decimal days
Yr	Year of data	YY

Platforms List

R/V Tangaroa 61TG_3052

Instruments List

Undulator:
On SOIREE, the undulator did not undulate.
As a result, it was towed at a constant depth of 1-2 meters

This document is created from the content of the BCO-DMO metadata database. 2010-03-18 00:56:35

info app: /home/bco/dbase-v2 v.100108 CLC
Data URL: http://data.bco-dmo.org/jg/serv/BCO/Fe_Synthesis/SOIREE/61TG_3052/SurfaceFe.