Dissolved aluminium distribution along 40ºS D357 & JC068

Dissolved aluminium

distribution along 40ºS

D357 & JC068Post-cruise meeting 10th – 11th September 2012

Jessica Klar, Christian Schlosser, Maxi Castrillejo Iridoy, Eric AchterbergNational Oceanography Centre of Southampton

2

Ocean

Crust

Atmospheric dust transport

PO4, Fe

Al

CO2

Biological Carbon Pump

Aluminium geochemical cycle

• Free Al3+

• Al-hydroxide complexesAluminium speciation in aqueous samples

Aluminium is highly particle reactive

Methods• 0.2 µm filtered seawater samples• Flow Injection Analysis Lumogallion fluorescence

Resing, J A & Measures, C I 1994. Fluorometric determination of Al in seawater by Flow-Injection-Analysis with in-line preconcentration. Analytical Chemistry, 66, 4105-4111.

• Toyopearl AF-Chelate-650MBrown, M T & Bruland, K W 2008. An improved flow-injection analysis method for the determination of dissolved aluminum in seawater. Limnology and Oceanography-Methods, 6, 87-95.

• Quality controlo Internal standardso SAFe

LOD LOQ Typical precisionD357 0.23 nM 0.78 nM ~ 8 % at 2 nM dAl

~ 2 % for > 7 nM dAlJC068 0.21 nM 0.69 nM ~ 6 % at 2 nM dAl

~ 3 % for > 5 nM dAl

Internal Standard

0 5 10 15 20 25 30 35 400.0

0.5

1.0

1.5

2.0

2.5

3.0 Reference SW A

Reference SW B

Reference SW C

Al (

nM)

Ref A: 0.36 ± 0.17 nM dAl (46 %)Ref B: 0.37 ± 0.19 nM dAl (51 %)Ref C: 2.30 ± 0.27 nM dAl (12 %)

SAFE S 12

0 1 2 3 41.50

1.55

1.60

1.65

1.70

1.75

1.80

1.85

1.90

1_4h

1_19c

consensus

dAl (

nM)

1_4h: 1.83 ± 0.13 nM dAl 1_19c: 1.86 ± 0.18 nM dAl Consensus: 1.74 ± 0.09 nM dAl

JC068

-60 -50 -40 -30 -20 -10 0 10 20 300.00

2.00

4.00

6.00

8.00

10.00

12.00

0

5

10

15

20

25

30

35

40

dAlSili-catesalinity

dAl (

nM)

salin

ity

Courtesy of Christian Schlosser

dAl (nM)

9

D357

D357

JC068

JC068 + D357

AAIW

NADW

River Plata Al source

AADW

NADW

AABW

AAIW

GEOTRACESGD-23 18.7 ± 0.8 nM GS-57 28 ± 3 nM

14

D361

Summary

• Extremely low dust depositions• AAIW transports low dAl waters. Water formation

with low dust depositions• NADW shows higher dAl concentrations• Higher dAl concentrations approaching River

Plata• No higher dAl in the proximity of MAR or

sediments

Publication planning• D357 + JC068 dAl in ONE paper• Need aerosol data• Master student for Total dissolvable Al analysis• Publication deadline?