Intensive sea surface microlayer investigations of open leads in the pack ice during Arctic Ocean 2001 expedition

During the third Icebreaker ODEN expedition to the North Pole, Arctic Ocean 2001, the surface of open leads between the pack ice was investigated for physical parameters. The major purpose was to evaluate the occurrence of a surfactant microlayer in the leads. This was done by estimating sea-surface tension and collecting sea-surface microlayers in open leads (SMOL). Three collection methods used for SMOL were rotating drums covered with hydrophilic Teflon, thin hydrophobic Teflon sheets, and glass plates. Collections were successfully made at 14 stations between 21 July and 21 August 2001, at geo-positions between 86degrees29'N and the geographical North Pole. Surface tensions resembled surfactant-free seawater surfaces during the first 2 weeks of August but were depressed by 6-9 mN m(-1) during the third week of August. Variations in SMOL physical properties were large between stations. Weather conditions and collection equipment functionality are discussed in relation to results.