This dataset contains samples collected at O'Gorman Rocks and Ellis Fjord near Davis station from December 1997 to March 1998. Depth-stratified zooplankton samples were obtained for determination of zooplankton abundance and biomass. Water samples were collected for the determination of chlorophyll a concentration, protist identification and abundance, and the concentration of particulate and dissolved organic carbon. Sediment trap material was collected for the analysis of faecal pellets (identification and CHN analyses), protist identification and abundance, and the measurement of particulate organic carbon concentration. Zooplankton grazing experiments were performed in the laboratory at Davis station and zooplankton were also collected for CHN analyses. Data from this project arose from projects ASAC 963 and ASAC 2229.

This metadata record covers ASAC projects 113, 191 and 625. (ASAC_113, ASAC_191, ASAC_625). The total lipid, fatty acid, sterol and pigment composition of water column particulates collected near the Australian Antarctic Base, Davis Station, were analysed over five summer seasons (1988-93) using capillary GC, GC-MS, TLC-FID and HPLC. Polar lipids were the dominant lipid class. Maximum lipid concentrations usually occurred in samples collected in December and January and corresponded with increased algal biomass. Both lipid profiles and microscopic observations showed significant variation in algal biomass and community structure in the water column during each season and on an interannual basis. During the period of diatom blooms (predominantly Nitzschia species) the dominant sterol and fatty acid were trans-22-dehydrocholesterol and 20:5w3, accompanied by a high 16:1w7 to 16:0 ratio. Very high polyunsaturated fatty acid and total lipid concentrations were associated with diatom blooms in the area. Bacterial markers increased late in all seasons after the summer algal blooms. Long chain C30 sterols also increased during the latter half of all seasons. Fjord samples collected in the area reflected greater biomass and diversity in algal and bacterial makers than coastal sites. Signature lipids for the alga Phaeocystis pouchetii, thought to be a major alga in Antarctic waters, were identified in field samples over the five summer seasons studied. Methods Study site Davis Base is situated on the Vestfold Hills, Antarctica and incorporates numerous lakes and fjords (Fig. 1). Samples of water column particulate matter were collected during five summer seasons (1988-93), 500 meters off-shore from Magnetic Island, situated 5 km NW of Davis. Three other sampling areas were situated in the fjords of the Vestfold hills and include two sites in Ellis Fjord, one midway along Ellis Fjord and one near Ellis Fjord mouth and one sample midway along Long Fjord (Fig. 1). These fjords are protected from the marine environment, but are both marine fjords. Davis Station and Magnetic Island were used for the weekly sample sites. The mouth of Long Fjord, the mouth of Ellis Fjord, midway down Long Fjord, the deep basin in Ellis Fjord, O'Gorman Rocks and Hawker island (ocean side) were used for monthly samples. Field collection There was an initial pilot season in 1988-89, which was followed by two more detailed studies in the summers of 1989-90 and 1990-91. Four samples was also analysed from the 1991-92 and five from the 1992-93 summer seasons. During the initial pilot study at Magnetic Island in the 1988-89 summer, three water column particle samples were taken for lipid analyses. The 1989-90 and 1990-91 summer field seasons incorporated weekly sampling of the water column particulates at Magnetic Island. The phytoplankton in the fjords were studied during the summers of 1989-90 and 1990-91. The three sites that were chosen were all sampled three times in each season. Samples were also collected during the 1989-90 and 1990-91 seasons from the Magnetic Island and Fjord site s for pigment analyses. Three and five samples were collected respectively in the 1991-92 and 1992-93 seasons. Samples were also taken for microscopic analyses. For lipid analyses 30-40 liter water column particulate samples were collected at a depth of 10 m. A Seastar or INFILTREX water sampler was used in situ to filter the water through a 14.2 cm Schleicher and Schuell glass fibre filter over a three to four hour period. All filters used during sampling were preheated in a muffle furnace at 500 degrees C overnight to minimise contamination. For pigment analyses 2 to 4 litres were filtered through glass fibre filters (4.7 cm GF/F, nominal pore size 0.7 micro meters). The samples were frozen at -20 degrees C until extraction.