Update on the U.S. North Atlantic Cruise (GA03)

The North Atlantic cruise sailed from Lisbon on 15 October 2010.  The cruise was terminated after completing one-third of the planned stations due to mechanical problems with the ship. Virtually all planned sampling had been completed successfully up to the termination of the cruise, testimony to the excellent preparations on the part of the cruise organizers and shipboard personnel.

US GEOTRACES has been offered time aboard the R/V Atlantis to complete the North Atlantic section in November 2011.  The cruise will depart from the Cape Verde Islands on 31 October and resume science operations by reoccupying the final station of the aborted cruise as an intercalibration exercise.  The cruise will then continue along the track originally planned, ending in Woods Hole in early December.

Investigators involved in the North Atlantic cruise held a cruise planning meeting at Old Dominion University (Norfolk, Virginia) last week (7-9 March 2011) to organize staffing and logistics of the cruise aboard the Atlantis. 

Review of preliminary results from the terminated cruise revealed some surprises, leading to a modification of sampling plans for the remaining stations.  For example, evidence for near-bottom sources or sinks of various trace elements and isotopes was found at several stations, but particularly at the base of the continental slope off NW Africa.  In addition, variability of the concentrations of selected trace elements in the thermocline was found to be greater than expected.  It was felt that greater depth resolution of sampling would be needed to constrain these features.  Consequently, samples for trace elements will be collected at 36 depths aboard the Atlantis for stations with water depths exceeding ca. 4000 m rather than at 24 depths, as was done previously.