ALBERT

Description: We estimated monthly mean basal melt rates in the Lagrangian frame from autonomous phase-sensitive radar (ApRES) measurements at the center of Ekström Ice Shelf, Antarctica (70.82°S, 8.73°W) between April 2020 and December 2022. The data we recorded with a measurement interval of one hour. Basal melt rates are based on the analysis of firn densification, strain thinning, and the change in ice thickness from the determination of vertical displacements. We calculated the mean basal melt rate as well as the standard deviation, and maximum for each month.

Description: Multibeam data were collected with RV Polarstern along the route of cruise PS139/1 and data acquisition was continuously monitored during the survey. Multibeam sonar system was Teledyne/Atlas Hydrosweep DS3. SVPs were retrieved from CTD data and synthetic profiles from World Ocean Atlas 18. SVPs were processed with HydrOffice SoundSpeedManager (https://www.hydroffice.org/soundspeed/main) and extended with World Ocean Atlas 18 (https://www.ncei.noaa.gov/archive/accession/NCEI-WOA18). SVP data were applied during acquisition. Multibeam data are unprocessed and may contain outliers and blunders and should not be used for grid calculations and charting projects without further editing. The raw multibeam sonar data in Teledyne Reson multibeam processing format (.s7k) were recorded with Teledyne PDS software. Raw data files can be processed using software packages like CARIS HIPS/SIPS. For updated vessel configuration files check further details.

Description: Raw data acquired by position sensors on board RV SONNE during expedition SO298 were processed to receive a validated master track which can be used as reference of further expedition data. During SO298 the motion reference unit Kongsberg SeaTex AS MRU-5 combined with Kongsberg SeaTex AS Seapath 320 and two GPS receivers SAAB MGL-4 were used as navigation sensors. Data were downloaded from DAVIS SHIP data base (https://dship.bsh.de) with a resolution of 1 sec. Processing and evaluation of the data is outlined in the data processing report. Processed data are provided as a master track with 1 sec resolution derived from the position sensors' data selected by priority and a generalized track with a reduced set of the most significant positions of the master track.

Description: Raw data acquired by position sensors on board RV SONNE during expedition SO295 were processed to receive a validated master track which can be used as reference of further expedition data. During SO295 the motion reference unit Kongsberg SeaTex AS MRU-5 combined with Kongsberg SeaTex AS Seapath 320 and two GPS receivers SAAB MGL-4 were used as navigation sensors. Data were downloaded from DAVIS SHIP data base (https://dship.bsh.de) with a resolution of 1 sec. Processing and evaluation of the data is outlined in the data processing report. Processed data are provided as a master track with 1 sec resolution derived from the position sensors' data selected by priority and a generalized track with a reduced set of the most significant positions of the master track.

Description: Multibeam data were collected with RV Polarstern along the route of cruise PS139/2 and data acquisition was continuously monitored during the survey. Multibeam sonar system was Teledyne/Atlas Hydrosweep DS3. SVPs were retrieved from CTD data and synthetic profiles from World Ocean Atlas 18. SVPs were processed with HydrOffice SoundSpeedManager (https://www.hydroffice.org/soundspeed/main) and extended with World Ocean Atlas 18 (https://www.ncei.noaa.gov/archive/accession/NCEI-WOA18). SVP data were applied during acquisition. Multibeam data are unprocessed and may contain outliers and blunders and should not be used for grid calculations and charting projects without further editing. The raw multibeam sonar data in Teledyne Reson multibeam processing format (.s7k) were recorded with Teledyne PDS software. Raw data files can be processed using software packages like CARIS HIPS/SIPS. For updated vessel configuration files check further details.

Description: Raw data acquired by position sensors on board RV SONNE during expedition SO298 were processed to receive a validated master track which can be used as reference of further expedition data. During SO298 the motion reference unit Kongsberg SeaTex AS MRU-5 combined with Kongsberg SeaTex AS Seapath 320 and two GPS receivers SAAB MGL-4 were used as navigation sensors. Data were downloaded from DAVIS SHIP data base (https://dship.bsh.de) with a resolution of 1 sec. Processing and evaluation of the data is outlined in the data processing report. Processed data are provided as a master track with 1 sec resolution derived from the position sensors' data selected by priority and a generalized track with a reduced set of the most significant positions of the master track.

Description: Kelps (Phaeophyceae, Laminariales) function as ecosystem engineers along many Arctic rocky shores. With ongoing climate change, the frequency and intensity of marine heatwaves are increasing. Further, extensive meltwater plumes darken Arctic fjords. It was the aim of this study to analyse the future development of Arctic kelp forest ecosystems. We conducted a laboratory experiment, in which we determined physiological and biochemical responses of Agarum clathratum and Saccharina latissima to a marine heatwave scenario (4, 7, and 10°C) being acclimated to either low-light (3 µmol photons m²/s) or in-situ-light (120 µmol photons m²/s) conditions. Grown sporophytes were sampled in Nuup Kangerlua, Greenland from a sampling depth between 7-10 m. Meristematic discs were cut (diameter 2 cm) and distributed equally between treatments and replicates. The discs acclimated to the light conditions for two days, before the 12 days heatwave scenario started, followed by a five-day recovery period. Maximum quantum yield of photosystem II (Fv/Fm) measurements were measured every second day, using a pulse amplitude modulated fluorometer (Portable Chlorophyll Fluorometer PAM-2100, Heinz Walz GmbH, Effeltrich, Germany). The following kelp response parameters were measured before (day 6), at the peak (day 18) and after (day 23) the experimental heatwave. Growth was analysed by measuring the discs dry weight (g). Rapid light curves were measured with a pulse amplitude modulated fluorometer (Portable Chlorophyll Fluorometer PAM-2100, Heinz Walz GmbH, Effeltrich, Germany), using irradiance steps between 0-611 µmol photons m²/s to derive photosynthesis vs. irradiance curve parameters (Pmax, alpha, EK). Dark respiration and net photosynthetic rates were measured with a 4-channel optode set-up (FireStingO2 Fibre-Optic Oxygen Meter FSO2-C4, PyroScience Sensor technology, Aachen, Germany) by analysing the oxygen evolution in response to different light intensities within a 25 ml Schott bottle, each containing meristematic discs. Pigment content was analysed with a High-Performance Liquid Chromatograph (HPLC, LaChromElite® system, L-2200 autosampler (chilled), DA-detetctor L-2450; VWR-Hitachi International GmbH, Darmstadt, Germany). Total phlorotannin concentration was analysed with the Folin-Ciocalteau assay, using a phloroglucinol dilution series (C6H6O3, Sigma-Aldrich: 0–1000 µg/ml).

Description: The TRIAXUS ROTV (Remotely Operated Towed Vehicle, MacArtney) is a towed and undulating system which is equipped with a SEABIRD FASTCAT, SBE 49, AANDERAA OXYGEN OPTODE 4330 F, a SEASCAN SUNADeep Nitrate Sensor, a Turner Chl a sensor and a Seascan Video Plankton Recorder (VPR). It measures: seawater temperatures, salinity, dissolved oxygen, nitrate concentrations, Chlorophyll a in the water column. The Videoplanktonrecorder detects particles and organisms in the water column. Trichodesmium colonies were identified using a deep learning software.

Description: Multibeam data were collected during RV Polarstern cruise PS139/1 (2023-10-22 to 2023-11-03). Multibeam sonar system was Atlas Hydrographic Hydrosweep DS 3 multibeam echo sounder. Data are processed with Caris HIPS, with SV data from CTDs and World Ocean Atlas 18 (https://www.ncei.noaa.gov/archive/accession/NCEI-WOA18), tidal correction with TPXO9_atlas_v5 (https://www.tpxo.net/global/tpxo9-atlas), and manual cleaning. The soundings are combined in daily files, the format is XYZ ASCII (〈Lon〉 〈Lat〉 〈Depth in meters, positive up, relative to mean sea level〉). Additional blockmedian grids have been computed with depth dependent cell size to visualize the data. These grids are not meant for scientific analysis or navigation, but for overview purposes only.

Description: Snow height was measured by the Snow Buoy 2022S110, an autonomous platform, installed in the Atka Bay, Antarctic during Antarctic Fast Ice Network 2022 (AFIN 2022). The resulting time series describes the evolution of snow height as a function of place and time between 29 Jun 2022 and 29 Jan 2023 in sample intervals of 1 hour. The Snow Buoy consists of four independent sonar measurements representing the area (approx. 10 m**2) around the buoy. The buoy was installed on fast ice. In addition to snow height, geographic position (GPS), barometric pressure, air temperature, and an internal ice temperature were measured. Negative values of snow height occur if surface ablation continues into the sea ice. Thus, these measurements describe the position of the sea ice surface relative to the original snow-ice interface. Differences between single sensors indicate small-scale variability of the snow pack around the buoy. The data set has been processed and contains quality flags for different kinds for erroneous data. Flag values are the sum of individual error codes. The value of 0 refers to no error. Quality flag, position: The geographic position is flagged +1 if the drift velocity, as derived from the GPS longitude and latitude, exceeds a threshold of 10 deg latitude or 50 deg longitude per time step; +2 if the position exceeds extreme values, such as longitude 〉 360 deg; +4 if the position is exactly 0.0. Quality flag, snow: The snow height is flagged for each sensor +1 for manual corrections during processing (e.g. sensor issues); +2 if the snow accumulation exceeds 0.1 m per hour; +4 if the difference in snow height is larger than 0.03 m compared to values within the last and next 2 hours; +32 if the value exceeds the height of sensor on the platform at 1.5 m. Quality flag, temperature: The air temperature is flagged +1 for manual corrections during processing (e.g. sensor issues); + 32 if the value is below – 50 °C. Quality flag, pressure: The barometric pressure is flagged +1 for manual corrections during processing (e.g. sensor issues).