The track of Polarstern Cruise ANTXXI/3-"EIFEX"- leaving from Cape Town on 21st January 2004 and arriving back in Cape Town on 25th March 2004. The purpose of this cruise was to conduct an iron fertilisation experiment in the ACC. The reason for using an eddy was that the water fertilised with iron sulphate would be trapped and relatively easy to follow. The first eddy (Eddy 1) selected on the basis of altimeter data was at about 50°S, 18°E. This eddy was surveyed during a period of 7 days between 25th January and 1st February 2004 by CTD/Rosette casts along five equally spaced meridional sections. Along the westernmost section, 17°E, the station spacing was 5 mi (9 km), and along the other 4 (17°40', 18°20', 19°00' and 19°40' E), it was 12 mi (22 km); the sections were completed systematically working from west to east. Investigation revealed that the initial chlorophyll concentration was too low for the fertilisation experiment and so this eddy was rejected, but not before a useful set of physical data had been obtained. Instead, a second eddy (Eddy 2), at about 49°S, 2°E was selected for the experiment and was ultimately occupied for a period of 40 days. Altogether, this eddy was investigated during the period 8th February to 20th March 2004; however, the data for the initial CTD/Rosette survey were collected during a period of 6 days between 14th and 20th February. The stations were evenly spaced 12 mi (22 km) apart meridionally and zonally, or 12' latitude and about 18.6' of longitude, with ten stations along each of eight equally spaced meridional sections between 1°19' and 3°29' E. The sections were collected systematically from west to east.

Supplement to: Leach, Harry; Strass, Volker H (2019): Cyclonic eddies and upper thermocline fine-scale structures in the Antarctic Circumpolar Current. Ocean Dynamics, 69(2), 157-173