RRS "Discovery" cruises 285-286, 3 Nov - 10 Dec 2004; 13 Dec 2004 - 21 Jan 2005. CROZet circulation, iron fertilization and EXport production experiment (CROZEX)

CROZEX (CROZet circulation, iron fertilization and EXport production experiment) is a complex, multidisciplinary project to examine the causes and consequences of the annual bloom that forms north of the Crozet Plateau in the southwest Indian Ocean sector of the Southern Ocean. The CROZEX cruises took place between 3 Nov 2004 and 21 Jan 2005. Much of the cruise was planned around a series of Major Stations every two or three days at each of which a series of CTD casts was made to sample physical parameters, currents, nutrients, phytoplankton, iron and phytoplankton productivity, 234Th and SAPS. Other work at each Major Station included zooplankton nets, radium samples, Pelagra deployment and occasionally other sampling such as LHPR tows, neodynium, mooring deployment, coring, Argo float deployment and water collection for bioassay experiments. Five moorings were deployed, one of which was recovered at the end of the cruise. The other four, with 6 sediment traps in total were deployed for a year. In between Major Stations there were some additional sCTD casts to fill in hydrographic details and SeaSoar tows. Underway measurements included thermosalinograph and fluorimeter, hull-mounted ADCP, surface nutrients, iron from a special TMS (trace metal) fish, CO2, analytical flow cytometry, aerosols and rain.