The field work is done during 1-2 months long expeditions aboard icebreaker research vessels of several nations. Ships of Canada and the US Coast Guard vessel Healy will work in the Canadian and central Arctic. Polarstern (Germany) and Hesperides (Spain will work in both the Arctic basin and the Antarctic Ocean. Ships of Australia and Japan will work in the Pacific sector of the Southern Ocean. The BONUS program of France is focusing on the Indian-Atlantic connection south off Africa. Each expedition often has experts onboard of several of the 18 nations involved in IPY-GEOTRACES. Ultraclean devices for collecting and filtering seawater are required to avoid contamination of pristine natural seawater with abundant iron (steel ships !), lead, mercury, and other metals of the ship itself. Clean air laboratories and techniques are similar as those used in the semi-conductor industry. Detection of trace levels of dissolved metals and isotopes is done both by direct shipboard techniques, often miniaturized (e.g. flow injection chemoluminescence) as well as afterwards with large instruments in the home institutes (e.g. inductively coupled plasma ionization mass spectrometry with multiple isotopes collectors).