EYP 2005EYP 2005

““Lab on a ship – Obtaining high quality analytical data in adynamic environment”

Professor Paul Worsfold

Biogeochemistry & Environmental Analytical Chemistry(BEACh) Group

School of Earth, Ocean and Environmental Sciences

University of Plymouth

Plymouth, England

email pworsfold@plymouth.ac.uk

““Challenges in the determination ofChallenges in the determination ofnutrient species in natural watersnutrient species in natural waters””

• Environmental Analytical Chemistry and Biogeochemistry•New measurement technologies and methods; high temporal andspatial resolution data; interaction of chemistry with biology, ecology& ecotoxicology and with land use, hydrology, physicaloceanography, GIS & modelling; emerging legislation; physico-chemical speciation (including colloids), data quality.

• Major nutrients (N and P species) in Freshwater / Terrestrial systems•Flow injection with solid state detection, instrument design, in situdeployment, estuarine transects, eutrophication, catchmentmanagement (Water Framework Directive), colloids (FFF), CRMs.

• Minor nutrients (Iron species) in Marine systems•Flow injection with chemiluminescence detection, picomolardetection limits, selectivity and contamination, Atlantic transects,Southern Ocean (SOIREE) fertilization and iron budget, iron redoxspeciation, size fractionation, siderophore identification,intercomparison exercises.

Environmental Analytical ChemistryEnvironmental Analytical Chemistry

Understandingenvironmental

processes

High qualityanalytical chemistry

data

LIMITING FACTORHypothesisgenerating

Data archivingand datamining

Other chemical,biological, physical andsocio-economic factors

Hypothesistesting

Legislation

Novel techniquesand methods

High temporaland spatialresolution

Detection limit

Qualityassurance

Speciation

Environmental monitoring objectivesEnvironmental monitoring objectives•• The aim is to obtain high quality analytical data in orderThe aim is to obtain high quality analytical data in order

to:to:•• Elucidate environmental processes and biogeochemicalElucidate environmental processes and biogeochemical

cyclescycles•• Study chemical fluxes, pathways and fatesStudy chemical fluxes, pathways and fates•• Test and generate environmental hypothesesTest and generate environmental hypotheses•• Monitor compliance with legislation, e.g. WFDMonitor compliance with legislation, e.g. WFD•• Provide archival data and baseline surveys, e.g. EIAProvide archival data and baseline surveys, e.g. EIA•• BUT sampling is expensive and time consumingBUT sampling is expensive and time consuming•• AND sample integrity may be lostAND sample integrity may be lost THEREFORE we need THEREFORE we need in situin situ monitoring monitoring

River Frome PORiver Frome PO44-P storage-P storage

01234

0 20 40 60 80Day

PO4 -P

(uM

)

0.00.51.01.52.0

0 20 40 60 80Day

PO4 -P

(uM

)

01234

0 20 40 60 80Day

PO4 -P

(uM

)01234

0 20 40 60 80Day

PO4 -P

(uM

)

01234

0 20 40 60 80Day

PO4 -P

(uM

)

01234

0 20 40 60 80Day

PO4 -P

(uM

)

Fridge ControlFridge Control Fridge ChloroformFridge Chloroform Freezer ChloroformFreezer Chloroform

FridgeFridge FreezerFreezer Deep FreezerDeep Freezer

Water Research 35 (2001)3670

In situ environmental monitoringIn situ environmental monitoring•• The aim is to provide high quality data with excellentThe aim is to provide high quality data with excellent

temporal and spatial resolution for process studies andtemporal and spatial resolution for process studies andmapping. For this we require:mapping. For this we require:

•• Rugged, portable, automated instrumentationRugged, portable, automated instrumentation•• Contamination free environment (includes reagents,Contamination free environment (includes reagents,

containers, sampling apparatus, shipcontainers, sampling apparatus, ship))•• Sensitive and selective detectionSensitive and selective detection•• Removal of matrix interferences e.g. sea saltsRemoval of matrix interferences e.g. sea salts•• System stability (reagents, standards, pumps, detector,)System stability (reagents, standards, pumps, detector,)•• On-board filtration and prevention of On-board filtration and prevention of biofoulingbiofouling•• Remote calibration, validation and maintenanceRemote calibration, validation and maintenance•• FLOW INJECTION and CONTINUOUS FLOW techniquesFLOW INJECTION and CONTINUOUS FLOW techniques

meets these requirements.meets these requirements.

High qualityanalytical chemistry

data

LIMITING FACTOR

High Quality data forN & P (also Si, C)

LIMITING FACTOR

Macronutrients in natural watersMacronutrients in natural waters

Understandingenvironmental

processes

Hypothesisgenerating

Data archivingand datamining

Other chemical,biological, physical andsocio-economic factors

Hypothesistesting

Legislation

Novel techniquesand methods

High temporaland spatialresolution

Detection limit

Qualityassurance

Speciation

UnderstandingEutrophication

WFD

Excessive nutrientloads causeeutrophication.

FI, Ecotox,ISEs

Diurnal, seasonalcycles. estuarine

transects

uM – nM

CRMs,intercomparisons,

stability

Inorganic/organic

E.A. database.Predictivemodels

pH, DO, chl. a, turbidity,river flow, rainfall, land use,human & animal populations.

Inorganic/organicspeciation & N/P ratioare the critical factors.

Water Framework DirectiveWater Framework Directive• Defines the need to establish

monitoring programmes todetermine water status.

• Provides management based onriver basins (catchments).

• Nutrients are key chemicalparameters because eutrophicationis a major water quality issue.

Challenges in monitoring macronutrientsChallenges in monitoring macronutrients• High temporal resolution, e.g. transient events, diurnal

cycles• Long term deployment, e.g. seasonal trends• Good spatial resolution, e.g. catchment management,

estuarine modelling• Acceptable accuracy, precision and detection limit• Speciation capability for N and P• Sediment-water, atmosphere-water and water column

processes• Need to measure other physico-chemical parameters

and hydrographic data

Flow injection analysisFlow injection analysisPump

Injection valve

Mixing coil Detector

WasteData output

Time (s)

Resp

on

se

Sample

Carrier stream

•On-line physical sample treatment•On-line chemical sample treatment•Speed, flexibility and low cost•Automated & reproducible samplepresentation• Easily automated, rugged and portable•Automatic on-board calibration•Enclosed environment (reducedcontamination)•Compatible with most detection systems

Http://Http://www.fia.unf.eduwww.fia.unf.edu (Stuart Chalk)(Stuart Chalk)Http://Http://www.flowinjection.comwww.flowinjection.com ((EloElo Hansen) Hansen)

Focused LED (6000 mcd)

Photodiode, Peak Response at 560nm

Path length20 x 1.5 mm

Inlet

Outlet

Microscopicallydeburred andpolished toprevent bubbletrapping

Submersible nitrate manifoldSubmersible nitrate manifold

Ammonium chloride(10 g l-1)

Mixed colourreagent

0.32

0.16

Flow cell

1 m reaction coil

ml min -1Packed reduction column

260 ul sample injected via 5 um filter

20 mm path: LOD 2.8 ug L-1 N

Linear range 5 - 100

10 mm path: LOD 85 ug L-1 N Linear range 100 - 2500

ACA 361 (1998) 63

CRM for nutrients in seawaterCRM for nutrients in seawaterNitrate z scores

-8

-6

-4

-2

0

2

4

6

2b 2a 23a

3b 5a 7b 3a 29b

14a

5b 14b

15b

29a

21a

10b

26b

25b

21b

25a

11a

16a

19b

26a

9a 11b

18a

6b 1b 7a 12b

19a

1a 9b 16b

31b

18b

6a 12a

30a

30b

32b

4b 31a

32a

4a 27a

27b

15a

FI a

SF

A a

SF

A b

FI b 8b 23

b24

b8a 17

a10

a17

b24

a

Laboratory

z sc

ore

s

NOAA TechnicalMemorandum 143

MOOS-1 nowavailable from NRCin Canada as astable seawater CRMfor nutrients.

30 participatingexpert laboratoriesof which Plymouthwas the only non-North Americanrepresentative.

North Sea Submersed DeploymentNorth Sea Submersed Deployment

0

10

20

30

40

50

Nitr

ate-

N(m

g/L

x10

0). T

urbi

dity

(pp

m)

29.15

29.55

29.95

30.35

30.75

Salin

ity (

1/PS

U x

100

0)

1145 19451345 1545 1745

Time (BST)

Submersible Sensor Turbidity Salinity AutoAnalyzer

High Tide: 1230 Low Tide: 1930

PTFE tubing0.75mm i.d.Perspex cylinder

PTFE support screenMembrane filterPTFE spacer

PerspexblockPlan view

8 l min-1

Side view

5-10 ml min-1

Tangential filtration unit for turbid watersTangential filtration unit for turbid waters

Dual channel sampling from turbid waters

Analyst 125 (2000) 51

Portable gas pressurised FI manifold for PPortable gas pressurised FI manifold for P

S, sample inlet; PP, peristaltic pump; TFF, 0.2 µm tangential flow filter; FS, differential flowsplitter; PG, propellant gas and regulator; MC, mixing coil; FC, flow cell; V0, 2-way valve; V1,V2 and V3, miniature solenoid valves; R1, ammonium molybdate reagent; R2, tin(II) chloridereagent; Std, standard; W, waste; 0.5 mm id PTFE tubing for liquid flow and gas delivery

Talanta 58 (2002) 1043

Manifold for dissolved phosphorus speciationManifold for dissolved phosphorus speciation

Acid Peroxydisulphate

690

Sample(600 ul)1.3

1.0

0.5

0.4

ml min-1

Water

Ammonium Molybdate

Tin(II) Chloride

.

UV photoreactor

Debubblers

Mixing Coils

Talanta 45 (1997) 47

P speciation manifold;Lamp off gives DRP; lamp on gives DRP + DOP (+ condensed P)

Novel features of gas pressurised manifoldNovel features of gas pressurised manifold

Rapid segmentation of thereagent and sample streams

Multi-reflection photometricflow cell

ACA 499 (2003) 81

High throughput phosphorus mappingHigh throughput phosphorus mappingTalanta 58 (2002) 1043

•Port Phillip Bay•225 analyses per hour.•542 analyses over 150 km.

0

10

20

30

40

50

60

Time

0

5

10

15

20

25

Yarra river salinity gradient trials

Organic P release from sedimentOrganic P release from sediment

0

10

20

30

40

50

60

70

70 90 110 130 150 170 190Time elapsed (hr)

P co

ncen

trat

ion

(µg

L

P)

Inorganic P Organic P

5 ‰10 ‰

15 ‰

20 ‰

Water Research 38 (2004)688

Release of filterableorganic phosphorus(FOP) and filterablereactive phosphorus(FRP) from aerobicriver sediment as afunction of increasingsalinity.Elapsed time refers tototal time of theexperiment andincludes equilibrationtime prior to seawateradditions.Mean control concs. forFRP/FOP over 4-dayexperiment were 17.5 ±4.6 and 17.0 ± 4.8 µg L-1

P respectively (±2s,n=16).

Concentration data volume corrected and error bars ± 2s (n = 3).

Data output

Computer

Data acquisition

Control

Standard

Sample

Gas diffusion cell

BTBWater

635nm

Waste

All 0.7 ml min-1

50 cmreaction

coil

NaOH

Integrating in situ chemistry & ecotoxicologyIntegrating in situ chemistry & ecotoxicologyACA 314 (1995) 33

96 hour exposure tests

Heart rate monitor

PhagocytosisAssay

cell viability and health

Neutral RedAssay

cell viability and health

Stress?

Sub-lethal Exposures

FI Ammonia gas diffusionmanifold (minimal reagents)

LED sensors to monitorcardiac activity inorganisms, e.g. crayfishand swan mussels

Integrated chemical / ecotoxicology monitorIntegrated chemical / ecotoxicology monitor

Physical probeslogger

Ammonia

CAPMON Computer

Computer

Computer

Reservoir

PumpOverflow

Holding tank

Test organisms - crayfish (Pacifastacus leniusculus)

Sample

Ecotoxicology 8 (1999) 225

0.1 1.0 5.0 15 30Ammonia (mg l-1)

Heart rate (bpm)

Control40

80

120

160

Colloids in environmental matricesColloids in environmental matrices

Traditional membrane filtration techniques use filter pore sizes of 0.2 or 0.45 µmto operationally define the ‘dissolved’ and ‘particulate’ fractions, therefore boththe dissolved and particulate fraction will include colloidal material

0.2

0.001 µm 0.01 µm 0.1 µm 1 µm 10 µm 100 µm

COLLOIDS

Colloidal NOM, Humic colloids

Amorphous iron and manganese oxides

Clay minerals

Bacteria

0.45

Algae

Colloidal material (0.001 – 1 µm) in soil leachate and agricultural drainagewaters is an important mechanism for the transport of contaminants

Flow Field Flow Fractionation (Flow Field Flow Fractionation (FlFFFFlFFF))Crossflow

Frit

SpacerMembrane

FritChannel Flow

Frit

Crossflow

Membrane

Channel floww

Frit

l l

Field-flow fractionation (FFF) is anemerging family of techniques usedto obtain information on particle sizeor relative molecular mass (RMM)distributions in complex matricessuch as environmental andbiological samples.

Flow FFF (FlFFF) is the most widelyused version of the technique and isapplicable to macromolecules,particles and colloids ranging from0.001 µm (approximately 1,000molecular mass) up to at least 50 µmin diameter. w = 50 – 250 um.

Trends in Analytical Chemistry 22 (2003)615

Soil solutions Soil solutions –– Centrifugation vs. Filtration Centrifugation vs. FiltrationAnalysis by Sedimentation FFFAnalysis by Sedimentation FFF

Time basedcentrifugation to give<0.45 and <0.2 um cut-off(axis in um).

Membrane filtration togive <0.45 and <0.2 umcut-off (axis in time(s)).

Clayey Lilydale soil solution settled to give <1.0 um fraction prior tocentrifugation and filtration. Membrane filtration recovered 79% lessmaterial than centrifugation for the <0.45 µm and 73% less for the <0.2µm fractions

(A)

0

10000

20000

30000

40000

50000

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

Diameter (µm)

Rel

ativ

e m

ass

<1 µm<0.45 µm centrifuged

<0.2 µm centrifuged

(B)

0

1

2

3

4

5

6

0 1000 2000 3000

Time (s)

Ab

sorb

ance

(ar

bit

rary

u

nit

s)

<1 µm

<0.45 µm filtered

<0.2 µm filtered

(B)

0

1

2

3

4

5

6

0 1000 2000 3000

Time (s)

Ab

sorb

ance

(ar

bit

rary

u

nit

s)

<1 µm

<0.45 µm filtered

<0.2 µm filtered

High qualityanalytical chemistry

data

LIMITING FACTOR

High quality data foriron species.

LIMITING FACTOR

Hypothesistesting

Legislation

Micronutrients in natural watersMicronutrients in natural waters

Understandingenvironmental

processes

Hypothesisgenerating

Data archivingand datamining

Other chemical,biological, physical andsocio-economic factors

Novel techniquesand methods

High temporaland spatialresolution

Detection limit

Qualityassurance

Speciation

Understandingiron

fertilization

Hypothesistesting

LegislationUNEP/ICES

Iron is a ratelimiting nutrientin HNLC regions

FI-CL,preconcentration

Surface transectsand depth profiles

nM - pM

CRMs,intercomparisons,

contamination

Redox, colloidal

Fe biogeochemistryClimate modelling

DO, DOC, chl. a, turbidity,salinity, temperature,macronutrients, depth

Fe(II) is an importantspecies in surface

waters

Iron biogeochemistry & analytical challengesIron biogeochemistry & analytical challenges

• Major component of Earth’s crust (and research vessels!)• Highly reactive trace element• Dissolved Fe in seawater at very low concentrations (sub-nM)• Complex biogeochemistry, e.g. redox speciation, organic

complexation (siderophores, porphyrins), colloids• Speciation studies (e.g. Fe(II)/Fe(III) at even lower concns.

(pM)• Essential trace micro-nutrient for phytoplankton• Bio-limiting in HNLC (High nutrient, low chlorophyll) regions,

implications for global carbon cycles

Fe biogeochemical cycleFe biogeochemical cycle

Fedesorption

volcanic Fe

aeolian

dry deposition wet deposition

continentalshelf anaerobic

sediments

deep ocean

upwelling

sinking

hydrothermalvents

aggregation

assimilation

grazing trophicrecycling

riverineFe2+

Fe3+

FeLx

FeLy

O 2

sedimentation

light

L = iron bindingligands such ashydroxamate andcatacholatesiderophoreswith high stabilityconstants

Historical open ocean Fe concentrationsHistorical open ocean Fe concentrationsYYYeeeaaarrr Concentration (nM)

100 - 800

0.2 - 2.0

25,000 1924500 - 1400 1931

193560 1954

19890.6 1996

Profile of Fe in North Pacific (fromJ.H. Martin et al., Deep Sea Research,1989, 36: 649)

-4000

-3000

-2000

-1000

0

0.0 0.2 0.4 0.6 0.8 1.0

Fe (nmol kg-1)

Dep

th (

m)

2003 0.3Decreases in reportedconcentrations due to improvementsin analytical protocols rather thanenvironmental change.

In general laboratory:1. Immerse 50 1 L LDPE bottles in 5% detergent bath (e.g. Decon, Merck) for a week.2. Rinse 3x with DI water thoroughly until there is no trace of detergent.3. Rinse 3x with UHP (ultra-high purity; e.g. Milli-Q) water.4. Immerse in 6 M analytical grade HCl bath (2 weeks, e.g. Aristar, Merck BDH).5. Rinse 3x with UHP water.6. Immerse in 3 M analytical grade HNO3 bath (2 weeks, e.g. Aristar, Merck BDH).7. Rinse 3x with UHP water.

In clean air (class-100) laboratory:8. Fill with UHP water and acidify to pH 2 with 1 ml ultra-pure Q-HCl (9 M)

per 1 l UHP sample (ultra-pure Q-acids are sub-boiling quartz distilled reagents).9. Double bag, seal and store inside large plastic bag within plastic box until use.

10. Sample collection: empty acidified UHP water, rinse 3x with UHP,rinse 3x with seawater sample, fill and acidify sample (if necessary). Double bag, seal and store for analysis.

Protocols for washing sample bottlesProtocols for washing sample bottlesACA 442 (2001) 1

Shipboard FI-CLShipboard FI-CL•• Flow injection with chemiluminescence detection (FI-CL)Flow injection with chemiluminescence detection (FI-CL)•• Wide dynamic range and sub-Wide dynamic range and sub-nanomolarnanomolar detection limits detection limits•• Robust, low power, low cost, automated instrumentationRobust, low power, low cost, automated instrumentation•• Selectivity and preconcentration via solid phase chelatingSelectivity and preconcentration via solid phase chelating

micro-columnsmicro-columns•• Sample treatment on-line, e.g. digestion, reduction,Sample treatment on-line, e.g. digestion, reduction,

chelationchelation•• Low blanks due to closed environment & in-line reagentLow blanks due to closed environment & in-line reagent

clean-upclean-up•• Excellent temporal and spatial resolutionExcellent temporal and spatial resolution•• Immediate results and potential for in situ measurementsImmediate results and potential for in situ measurements

Analytical Chemistry 66 (1994)916A

Luminol reactionLuminol reaction

+ h

-hydroxy hydroperoxide intermediateαluminol

O

2NH

NH2

NH2

2NH

NH

NH

O

O

N

NO- OOH

CO

O-

-O

OC

O

OC

O

OC

H

H

3-aminophthalateexcited state 3-aminophthalate dianion

υ

Base (pH 10.5)

O2 + Fe(II)

FI-CL manifold for ironFI-CL manifold for iron

Waste

Chartrecorder

Spiralflow cell PMT

Light-tighthousing

Injectionvalve

8-HQ column

'T'-piece

Mixingloop

Reagents pump

ml / min

Sample pump

Wash pump

Autosampler

HCleluent

UHP water

Acid wash

Buffer

Luminolreagent

REAGENT &SAMPLE BOX

‘Y’

1.6

1.6

1.6

1.6

0.2

C

8-HQ

V

V

V

HVsupply

Amp

PC controlunit

Fe(II+III) analysisafter S(IV) reduction

ACA 361 (1998) 189

LOD 40 pM; Range 0.04 – 10 nM; Analytical cycle 3 min;NASS-4 2..01 +/- 0.12 nM cf. certificate of 1.88 +/- 0.29 nM

Matrix elimination / preconcentrationMatrix elimination / preconcentration

Quartz wool

10mm8-HQ

2.4mm i.d.PTFE 0.75mm i.d.

PTFE

0.089mm i.d.Tygon

8-hydroxyquinoline immobilisedon Toyopearl gel (TSK-8HQ)

Interferences• sea-salt matrix (alkaline-earth metals, halide ions)• selectively preconcentrate Fe ions from seawater– 8-HQ chelating resin microcolumn• highly selective for transition metal cations• redox selectivity using pH buffering control• use in-line before detection mechanism• active groups immobilised on solid support beads

Underway sampling for trace metalsUnderway sampling for trace metals

Container Lab

RRS James Clark RossRRS James Clark Ross

Kevlar cable

Torpedo fish

FI-CLOn-line

filter

Go-Flo bottles (5-30 L)Vertical profilingSuspended on Kevlar wire

Towed torpedo fishUnderway surface seawaterOn-line uncontaminatedsupply for filtration andanalysis

AMT-3 latitudinal surface transectAMT-3 latitudinal surface transect

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

-60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60

Latitude (S-N)

Sh

ip T

D-F

e (n

M)

Celticshelf

Saharandusts

Equatorialregion

Frontalsystem

Falkland’sshelf

Averageerror

.

FIC SWApp

NEAOGSAOG NEq/SUp

Eq NWAUpAtlantic Province:Atlantic Province:

Deep Sea Research 1, 49 (2002) 605

Cruise TrackCruise Track

64oS

40oS

48oS

56oS

140oE

170oE

SouthernOcean

SSouthern outhern OOcean cean IIron ron REREleaselease EExperimentxperiment

Aim: To raise the background level of iron ina coherent patch of seawater and interpretany iron-mediated effects by conducting asuite of biological, chemical and physicalexperiments INside and OUTside thefertilised patch

Release site: 61oS, 141oE HNLC region (ca. 0.25 µg Chl-a l-1) ca. 10 tonnes FeSO4 added over 13 d Inert tracer SF6 used to map patch

First Southern Ocean unenclosed ironenrichment experiment

RV Tangaroa, NIWA (NZ) Previous Equatorial Pacific

experiments

http://tracer.env.uea.ac.uk/soiree

Nature 407 (2000)695

Southern OceanSouthern Ocean

Redox speciation (Redox speciation (Fe(IIFe(II) stable in seawater!)) stable in seawater!)[F

e] (n

M)

012345678

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Days since beginning of experiment

D-Fe (nM)D-Fe (nM)Fe(II) (nM)Fe(II) (nM)InfusionInfusion

61.061.0oo SS

60.560.5oo SS

141141oo EE 143143oo EE142142oo EE140140oo EE

Distance (km)

0 20 40 60 80 100

61.061.0oo SS

60.560.5oo SS

141141oo EE 143143oo EE

Distance (km)

0 20 40 60 80 1000 20 40 60 80

SeaWiFSsatellite imageof bloom

Iron speciation in the Southern OceanIron speciation in the Southern Ocean

0

10

20

30

40

50

21:00 22:00 23:00 00:00 01:00 02:00 03:00 04:00 05:00

8HQ

reac

tive

-Fe(

II) (

pm

ol l

-1),

% F

e(II)

/ F

e(II+

III)

0

50

100

150

200

250

300

Dis

solv

ed F

e(II+

III)

(pm

ol l

-1)

Fe(II) (±1s)

% Fe(II) / dissolved Fe(II+III)

Dissolved Fe(II+III)

Environmental Science & Technology 36 (2002)4600

Approx. 5 - 10% of the dissolved iron is present as Fe(II).Hypothesis: bacterial and/or photochemical reduction.

?

SOIREE Iron BudgetSOIREE Iron Budget

19 pM

Dissolved FeParticulate Fe(inorganic & detrital)

SOIREE Feenriched patch(141oE, 61oS)

OUTpatch IN

patch

Upper mixedlayer 65 m

Atmospheric flux

Sinking biogenic Fe(from sediment

trap data,mostly diatom aggregates)

Patch area 56 to 200 km2

Upwelling

0.004 pM d-1 185 pM d-1

?

Sinking non-

biogenic Fe

72 pM d-1

Biogenic Fe

Diffusive flux(pre-infusion)

Eddy diffusion(post-infusion)

Four Fe infusions over 13 d (ferrous sulphate solution)

Horizontaldispersion

180 pM d-1

1073 pM 1110 pM

negligible0.1 pM d-1 0.85 pM d-1 0.72 pM d-1

58 pM

11.9 7.3

11.9 3.3

Producers Micro-zooplankton

Meso-zooplankton

?

Sinking mesozooplankton biogenic Fe

(predicted from biogenic budget)

0.79 pM d-1

6.5

25.2 pM

Deep Sea Res. II 48 (2001)2703

SPE-LCMS for SPE-LCMS for detndetn. of . of siderophoressiderophores in seawater in seawater

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30Time (min)

0

20

40

60

80

100

20

40

60

80

100

Rel

ativ

e A

bund

ance

NL: 6.31E7

NL: 1.38E6

a

b

FeRA

FeFO

FeFC

a) Total ion chromatogramfor a seawater sample after1400 × preconcentration onan ENV+ SPE cartridge.b) Extracted masschromatograms for thethree spiked iron(III)hydroxamate siderophores rhodotoluate (FeRA),ferrioxamine (FeFO) andferrichrome (FeFC).

LODs (nM):FeRA 26, FeFO 0.23, FeFC 0.40.

Stationary phase: 100 × 2.1 mm 3 µm polystyrene divinyl benzene. Mobile phase: (A) 95 H2O: 5 MeOH: 0.1 formic acid, (B) 100 MeOH: 0.1 formic acid.Gradient elution 100% A – 100 % B; 20 min, then 100 % B; 10 min.

Analytical Chemistry 75 (2003) 2647

Siderophore extractions from incubated seawaterSiderophore extractions from incubated seawater

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30Time (min)

0

20

40

60

80

1000

20

40

60

80

100

Rel

ativ

e A

bund

ance

NL: 5.88E7

NL: 2.29E6

600 610 620 630 640 650 660 670 680 690 700m/z

13

0246810

Rel

ativ

e A

bund

ance

627.4

629.4NL:2.59E5

m/z600 610 620 630 640 650 660 670 680 690 700

100

020406080

685.4

687.4

NL:2.04E6

a

b

c d

A

B

•Ferrioxamines areexcreted by species ofActinomycetes, a group ofbacteria foundubiquitously in seawaterand marine sediments.• A = FeFO, B = unknownsiderophore•Siderophores identifiedby substitution of Fe withgallium (Mr = 69 and 71,ratio 3:2) and monitoringshift in mass/charge ofparent ion

Dust storm on 25Dust storm on 25thth Sept 2000 off Western Sept 2000 off WesternAfrica observed by SeaWiFS satelliteAfrica observed by SeaWiFS satellite

AnreiseAnreise dFe intercomparison, dFe intercomparison, Sep 29 Sep 29thth––Oct 23Oct 23rdrd 2000 2000

IRONAGES standard: collectionIRONAGES standard: collection

-10o

-20o

-30o

-40o

50o

40o

30o

20o

10o

0o

0o-20o 20o-40o-60o

Start

Finish

AtlanticAtlanticOceanOcean

<0.25 0.26- 0.50 0.51- 0.75 0.76- 1.00 >1.00

Dissolved Fe (nM)(UoP data)

Longitude (Longitude (ooEE))

Lat

itu

de

(L

atit

ud

e (oo

NN))

“IRONAGES”standard

collected here

(Provided by the SeaWiFSproject NASA/Goddard Space

Flight Center, and ORBIMAGE)

Towards a certified referencematerial for low level iron inseawater

IRONAGES standard: samplingIRONAGES standard: samplingR.V. R.V. PolarsternPolarstern

HDPE tankHDPE tank

Towed fishTowed fish

• 1000 l HDPE cubic tank• Filled to 700 l over 8 h• South Atlantic Ocean, 6.0oS 5.6oW• Acidified to ~pH 2 using 700 ml Q-HCl• Homogenised by gentle shaking of

tank• Transfer from tank to clean laboratory

using Teflon FEP line and peristalticpump

• 200 x 1 l LDPE bottles filled

Summary of intercomparison dataSummary of intercomparison data

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

SE-GFAAS

ID-ICPMS

FI-DPD

FI-CL Fe(II)

Overall average

Fe c

once

ntra

tion

(nM

)

FI-CL Fe(III)

CSV DHN

SPE-ICPMS

Method

averages

ConclusionsConclusions• Determination of nutrient species in natural waters is a

key aspect of understanding environmental processes.• Analytical techniques and methods with appropriate

selectivity and detection limits are often the limitingfactor.

• In situ methods are required to provide the necessarytemporal and spatial resolution.

• Emerging legislation is also a driver for new analyticaltechnologies.

• Flow injection and continuous flow techniques canprovide suitable solutions to the above challenges.

AcknowledgementsAcknowledgementsBEAChBEACh group group:: Malcolm Nimmo, Miranda Keith-Roach, Charly Braungardt,Richard Sandford, Alan Tappin.ResearchersResearchers:: Simon Ussher, Laura Gimbert, Utra Mankasingh, MohammedOrif, Nduka Omaka, Angie Milne, Cathryn Money, Ed Mawji, Marie Seguret,Rebecca Nimmo Smith, Stephanie Handley, Andy Cartwright.CollaboratorsCollaborators:: Eric Achterberg and Martha Gledhill (SOC), Tamara Galloway,Mike Depledge (EA), Phil Haygarth (IGER), Ian McKelvie and Ron Beckett(Monash, Australia), Grady Hanrahan (CSU-LA), Andy Bowie (UTas, Australia),John Wood, Tony David (Daviron Instruments Ltd), Christophe Quetel (IRMM,Geel, Belgium), Chiang Mai University, Thailand, MBA and PML, CEH Dorset,CEH Wallingford.Erasmus linksErasmus links: : Oviedo, Vienna, Bologna, Valencia.Recent VisitorsRecent Visitors:: German Guttierrez, Orawan Tue-Ngeun, Dezhong Dan, DavidStiles, Mohammad Yaqoob, Yolanda Moliner-Martinez, Alexandra Exenberger.Recent SponsorsRecent Sponsors:: NERC, EU (MAST & SOCRATES), RSC/EPSRC, CEH, Defra,British Council, MBA, Saudi, Thai, Nigerian and Pakistan Govt. Agencies,HiPACT, EA.