Intercalibration effortIntercalibration – The process, procedures, andactivities used to ensure that the severallaboratories engaged in a monitoring programcan produce compatible data. When compatibledata outputs are achieved and this situation ismaintained, the laboratories can be said to beintercalibrated (Taylor, 1987).

Intercalibration therefore is an active processbetween laboratories that includes all steps fromsampling to analyses, with the goal of achievingthe same accurate results regardless of themethod or lab.

(1) Develop and test the US GEOTRACES sampling systems andprocedures for dissolved and particulate TEIs. This equipmentwill be a community resource for use in all future USGEOTRACES cruises;

(2) Using these systems, conduct a thorough intercalibration forall the key GEOTRACES TEIs, and as many others as possible,in the dissolved and particulate phases through theparticipation of the worldwide TEI community;

(3) Establish GEOTRACES Baseline Stations in the western NorthAtlantic (BATS) and eastern North Pacific (SAFe) as part of theIntercalibration Cruises; and

(4) Fully document the intercalibration results and create “USGEOTRACES User Manuals and Procedures” for future USsponsoredGEOTRACES cruises.

AIMS

BATS cruise: Leg 1 6-21st June 2008

(1) Epoxy powder-coated clean rosette with 24 12 L GOFlo sampling bottles capable of being

triggered 3 at a time while on the up-cast into uncontaminated water

(2) CTD with oxygen probe, fluorometer, and transmissometer(3) 8000 m Kevlar/polyester conducting cable for deploying the clean CTD/rosette

(4) Dynacon traction winch with composite sheaves and line monitoring, plus a composite block/sheave to behung on the J frame

(5) UNOLS-approved trace metal-clean sampling van for processing the clean water and particle samples

(6) Shipping van for the rosette and winch; also has a removable winch and CTD control room

(7) Flatbed trailer to store and ship the 2 vans and all the associated equipment.

Problems:• Level winder did not work well• Deploying-tight wire angle-new A-Frame submitted• Bottles close to the clean lab floor

Filling a variety of sample bottles from the Baseline profile using a capsule filter (left) and 47 mm membrane filters. The capsule filter was a 0.45 μm Teflon Osmonics capsule. The 47 mm filters were 0.45 μm Supor and 0.4 μm Nuclepore filters.

Comparison with other samplers:

MITESS (Boyle)

Vanes (Wu)

CLIVAR rosette

No difference between samplers for Fe, Zn and Al was observed onboard ship.

Vane samplers and CLIVAR rosette were used to collect a full water prolife for dissolved trace elements comparison with the GEOTRACES rosette for lab based laboratories.

Tanks & Bottling for intercalibration

Bottling the GEOTRACES (below)

The filtration cartridges (upper left)and one of the pair of tankswith the valves (lower left).

Particulate sampling with in-situ McLane pumps

Battery powered, 400-600L in 2 hours

Deploy 8 pumps at one depth on “rosette” - 3x per station /depth

Particulate Sampling

Particulate MULVFS sampling

Plugged into the deck

1000L- 2000L in 2 hrs

Can have up to 5 on a wire but only goes to 1000 m

Where we are at to date

• Inter calibration meeting 2-3rd April (report will be out soon)

• Next cruise (5th – 29th May SAFe site and coastal site)

• Workshop-Jan-Feb 2010-finalise results and begin work on decimating results and writing GEPTRACES user manuals

• Overall for most elements sampling is excellent

Cruise 2 –only one leg

• New –Speciation and Aerosols• Surface tank samples for dissolved TM• Focus on filtration-filter type• Digestion procedures for particulate trace metals-blanks• Sample storage-freezing vs drying• Nutrients-more labs involved for long wave liquid core guide• Hg-sparging and headspace• Nd-dissolved more samples + sending known std to all labs• Th-Pa-Be- Particulate 231Pa (230Th) requires samples >100 l in

upper 1000 m-working on blanks, spike intercalibration and equilibration

Elemental Co-ordinators• Dissolved Trace Elements – Ken Bruland, Bruland@ucsc.edu• Particulate Trace elements – Rob Sherrell, Sherrell@rutgers.edu• Si isotopes - Mark Brzezinski, brzezins@lifesci.ucsb.edu• N (and O) isotopes– Karen Casciotti, kcasciotti@whoi.edu• P (O isotopes) – Albert Colman, colman@umbi.umd.edu• Hg – Carl Lamborg, clamborg@whoi.edu• Metal stable isotopes – Ed Boyle, eaboyle@mit.edu• Nd and Hf – Tina van de Flierdt, tina@ldeo.columbia.edu• Os - Bernhard Peucker-Ehrenbrink, behrenbrink@whoi.edu• Th - Ken Buesseler, kbuesseler@whoi.edu• Ra – Billy Moore, moore@geol.sc.edu• Pb-, 210Po – Mark Baskaran, ag4231@wayne.edu• Aerosols - Bill Landing, wlanding@fsu.edu• Speciation - Jim Moffett, moffett@usc.edu• 130Th, 231Pa ,10Be- Bob Anderson, boba@ldeo.columbia.edu• Pu,137Cs - Tim Kenna, tkenna@ldeo.columbia.edu