During passage from Stanley (Falklands Islands) to South Georgia, Stanley to Rothera and within the Western Core Box, 14 depth profiles, 70 surface seawater samples and 60 air samples were analysed for trace gas concentrations. In the Western Core Box, 6 CTD casts (3 off-shelf and 3 on-shelf) were carried out. Seawater and air samples were analysed for selected alkyl nitrates and organohalogens using a gas chromatograph - mass selective detector (GC-MSD). Data collected on biological and physical processes occurring within these regions was also used to compare alkyl nitrate and organo-halogen dynamics in these two geographically-close but hydrodynamically different ocean regions.
During 2005-2006 season, water samples were collected from Ryder Bay at the Rothera Time Series (RaTS) site. A biogeochemical profile of water samples was conducted at 5 depths: 0m (surface), 5m, 10m, 15m and 25m In addition to this, primary productivity measurements using 14C-sodium bicarbonate in conjunction with water-cooled light gradient (photosynthetron) and also nutrient uptake measurements using 15N labelled stable isotopes, were performed on the water samples.
Conductivity-Temperature-Depth casts were conducted at Ryder Bay and Marguerite Bay from the James Clark Ross (cruise numbers: JR112/113, JR136/137, JR155 and JR174). The CTD casts at each site were made at a range of depths from the bottom to the surface waters with samples collected for macronutrients, particulate biogenic silica,carbon and nitrogen for later analysis.
The 2005-2006 field campaign was to determine alkyl nitrate and organo-halogen concentrations in the upper 100m of the water column at the Rothera Time Series (RaTS) site. Water samples were collected using a Niskin bottle hand winched to depths of 0, 5, 10, 15, 25, 50 and 100m. In total 12 depth profiles were obtained between 4 January and 4 March 2006. All trace gas seawater samples were extracted by purging and the resulting samples were analysed for selected alkyl nitrates and organohalogens using a gas chromatograph - mass selective detector (GC-MSD). The instrument was set up in the Bonner Laboratory at Rothera between November 2005 and April 2006. Sampling was not possible between mid-October and late December 2005 as the sea-ice remaining in the bay was not safe enough to traverse but was too abundant to launch a boat.
Water samples were collected from Ryder Bay at the Rothera Time-Series (RaTS) site, using a small boat. A biogeochemical profile was performed at the following 5 depths: 0m (surface), 5m, 10m, 15m and 25m, for four RaTS events on: 7 January, 13 January, 19 January and 1 February 2005. Samples were taken for: phytoplankton nitrate, ammonium and urea uptake measurements, using stable isotope incubations and also primary production PvE curves were produced using 14C radioisotope incubations; Dissolved macronutrients (nitrate, silicate, phosphate, and urea); Surface dissolved iron. A scaled-down sampling RaTS event was performed by the Rothera Marine Assistants involving sampling for all above measurements once every 3 weeks at the 5m depth only at the RaTS site.