Titan: A new facility for ultraclean sampling of trace elements and isotopes in the deep oceans in the international Geotraces program
Résumé
Towards more rapid ultraclean sampling of deep ocean waters for trace elements, a novel rectangular frame was constructed of titanium, holding two rows of 12 samplers, as well as various sensors. The frame is deployed to deep ocean waters by an 8000 m length Kevlar wire with internal power and signal cables. Closing of each sampler is by seawater hydraulics via silicone tubings connecting each sampler with a central 24 position Multivalve. Upon recovery the complete frame with 24 samplers is placed inside an ultraclean laboratory van, where water is drawn via filters into bottles. Previously the clean sampling of ocean waters has been very time-consuming by attachment of individual ultraclean bottle samplers one by one to a metal-free (e.g. all-Kevlar) hydrowire. The novel Titan system is 3–4 times faster and permits routine collection of deep ocean sections while economizing required shiptime. In a test of the new system in November 2005 in the Canary Basin excellent low dissolved Fe concentrations (not, vert, similar 0.1 to not, vert, similar 0.4 nM) are consistent with values obtained of individual samplers on a simple wire, and previous values in a pilot study of 2002 in the same basin, as well as published dissolved Fe values elsewhere in the northeast Atlantic Ocean.