Surface spectral albedo complementary to ROV transmittance measurements at 6 ice stations during POLARSTERN cruise ARK-XXVII/3 (IceArc) in 2012

The dataset consists of spectra and photogrpahs of the surface (sea ice and melt ponds) obtained in the Central Arctic during the Polarstern cruise ARK-XXVII/3 at 6 ice stations. The spectra were measured with a portable spectroradiometer ASD FieldSpecPro 3. The photographs were taken with a digital camera Olympus C765 in the "Auto" mode. The measurements have been performed every 10 meters along 100 m ROV transects (transects used for underice ROV flights) where available. Otherwise the albedo measurements have been done at the selected cites complementary to point transmitance measurements or at cites featuring characteristic sea ice surface.

The Austrian Glacier Inventories GI 1 (1969), GI 2 (1998), GI 3 (2006), and GI LIA in ArcGIS (shapefile) format

Glacier inventories provide the basis for further studies on mass balance and volume change, relevant for local hydrological issues as well as for global calculation of sea level rise. In this study, a new Austrian glacier inventory has been compiled, updating data from 1969 (GI 1) and 1998 (GI 2) based on high-resolution lidar digital elevation models (DEMs) and orthophotos dating from 2004 to 2012 (GI 3). To expand the time series of digital glacier inventories in the past, the glacier outlines of the Little Ice Age maximum state (LIA) have been digitalized based on the lidar DEM and orthophotos. The resulting glacier area for GI 3 of 415.11 ± 11.18 km**2 is 44% of the LIA area. The annual relative area losses are 0.3%/yr for the ~119-year period GI LIA to GI 1 with one period with major glacier advances in the 1920s. From GI 1 to GI 2 (29 years, one advance period of variable length in the 1980s) glacier area decreased by 0.6% yr?1 and from GI 2 to GI 3 (10 years, no advance period) by 1.2%/yr. Regional variability of the annual relative area loss is highest in the latest period, ranging from 0.3 to 6.19%/yr. The mean glacier size decreased from 0.69 km**2 (GI 1) to 0.46 km**2 (GI 3), with 47% of the glaciers being smaller than 0.1 km**2 in GI 3 (22%).

Phytoplankton composition and biomass during leg 7 of Galathea 3 cruise across the southern Indian Ocean

Phytoplankton composition and biomass was investigated across the southern Indian Ocean. Phytoplankton composition was determined from pigment analysis with subsequent calculations of group contributions to total chlorophyll a (Chl a) using CHEMTAX and, in addition, by examination in the microscope. The different plankton communities detected reflected the different water masses along a transect from Cape Town, South Africa, to Broome, Australia. The first station was influenced by the Agulhas Current with a very deep mixed surface layer. Based on pigment analysis this station was dominated by haptophytes, pelagophytes, cyanobacteria, and prasinophytes. Sub-Antarctic waters of the Southern Ocean were encountered at the next station, where new nutrients were intruded to the surface layer and the total Chl a concentration reached high concentrations of 1.7 µg Chl a/L with increased proportions of diatoms and dinoflagellates. The third station was also influenced by Southern Ocean waters, but located in a transition area on the boundary to subtropical water. Prochlorophytes appeared in the samples and Chl a was low, i.e., 0.3 µg/L in the surface with prevalence of haptophytes, pelagophytes, and cyanobacteria. The next two stations were located in the subtropical gyre with little mixing and general oligotrophic conditions where prochlorophytes, haptophytes and pelagophytes dominated. The last two stations were located in tropical waters influenced by down-welling of the Leeuwin Current and particularly prochlorophytes dominated at these two stations, but also pelagophytes, haptophytes and cyanobacteria were abundant. Haptophytes Type 6 (sensu Zapata et al., 2004), most likely Emiliania huxleyi, and pelagophytes were the dominating eucaryotes in the southern Indian Ocean. Prochlorophytes dominated in the subtrophic and oligotrophic eastern Indian Ocean where Chl a was low, i.e., 0.043-0.086 µg total Chl a/L in the surface, and up to 0.4 µg Chl a/L at deep Chl a maximum. From the pigment analyses it was found that the dinoflagellates of unknown trophy enumerated in the microscope at the oligotrophic stations were possibly heterotrophic or mixotrophic. Presence of zeaxanthin containing heterotrophic bacteria may have increased the abundance of cyanobacteria determined by CHEMTAX.