ALBERT

Description: This dataset provides abundance data for macrofaunal taxa determined from sediment samples collected around the Antarctic Peninsula. A minimum of three samples (cores) were taken at each station with a MUC10 multicorer or giant box corer during PS81. The whole sediment cores (top to bottom) were preserved in a in 4%-borax-buffered formaldehyde solution prior to sieving (sieve size 500 µm) and counting (detailed methods in Säring et al. submitted). Only at station 241, cores were sliced into depth layers (0–2 cm, 2–5 cm, 5– bottom) and size fractions distinguished (sieve size 500 µm, 1000 µm). Abundances are presented per whole core as ind./m². Data from different layers and size fractions (station 241) are available upon request. Macrofauna communities included individuals from 13 higher taxa. The macrofauna abundance data are part of a larger ecological study on meio- and macrofauna communities and their relation to environmental conditions and remineralisation at the sediment-water interface (see Related to below). For the larger study, sediment cores from which macrofauna abundance data are deposited here were also used for microcosm incubations: Untreated incubations (Benthic ecosystem Function Experiments BEFEx), and incubations with and without microalgae addition (Algae Feeding Experiment AFEx). Cores from BEFEx and AFEx without algae are labeled with NT (not treated), cores from AFEx with algae are labeled as T (treated).

Description: This dataset contains biotic and abiotic data from water-column samples taken with Niskin bottles mounted on the CTD rosette from 14 sites in the Weddell Sea (mostly South-Eastern). Data are provided for water-column pigments (chlorophyll a and phaeopigment content through fluorometry), total carbon (TC) and nitrogen (TN) and stable isotope values of carbon and nitrogen (δ13C, δ15N) from the chlorophyll maximum (Cmax, defined as the water depth with maximum fluorescence detected during in-situ profiles) and close to the sea bottom. Water was filtered onto glass fiber filters (GF/C for pigments, combusted GF/F for C and N analyses) and stored at -80°C prior to analysis. Detailed methods are described in Säring et al. (submitted) except for stable isotopes: Flash combustion in a Flash 2000 (Thermo) elemental analyser to a Delta V advantage (Thermo) isotope ratio masspectrometer. δ values are reported relative to atmospheric N₂ (δ15N) and Vienna PeeDee Belemnite (δ13C). Reference materials for stable isotope analysis: IAEA-N1, IAEA-N2, IAEA-N3, NBS 22, IAEA-CH-3 and IAEA-CH-6; calibration material: Acetanilide (Merck). The analytical precision for both stable isotope ratios was 〈±0.2‰. Samples were not acidified to avoid loss of material. We assumed low inorganic carbon content in the water column for our analyses. This data table is part of a larger study analysing the role of environmental parameters for meio- and macrofaunal community composition (see Related to below).

Description: A systematic investigation of the extant coccolithophore community around Azores Archipelago was performed during the cruise M150 of FS Meteor between August, 27, and October, 2, 2018, in the scope of the project BIODIAZ - Controls in benthic and pelagic BIODIversity of the AZores. For the description of the spacial and vertical distribution of the extant coccolithophore community sampling was done at 50 stations along 9 transects including 3 islands, a seamount and islets from 5 to 8 water depths between surface and 150 m. A total of 306 samples were obtained, filtered onboard onto polycarbonate membranes and sections of these filters mounted in the laboratory on microscope slides for analysis by cross-polarized light microscopy. At least 400 coccospheres were counted through a randomly selected sequence of fields of view and the absolute abundances (Coccospheres/L) were estimated.

Description: Multibeam bathymetry raw data was recorded in the North Atlantic during cruise SO276 MerMet 17-6 that took place between 2020-06-22 and 2020-07-26. The data was collected using the ship's own Kongsberg EM 122. Sound velocity profiles (SVP) were applied on the data for calibration. Please see environmental data (zip file) and the cruise report for details.

Description: This file contains data on number of mesopelagic fish collected during the CSIC-SUMMER survey carried out in October 2020 in five zones around the Iberian Peninsula: Balears and Alboran in the western Mediterranean, and Cadiz, Lisboa and Galicia. The scientific midwater trawl Mesopelagos fitted with a Multisampler placed at the end of the net was used to collect specimens at seven layers of the water column. The depth of the net was controlled by a SCANMAR system. In the five zones, hauls were carried out day and night to study vertical migration patterns of mesopelagic fish. A total of 24 deployments were made (between 0 and 700 m), of which 14 discriminated water layers. Additionally, to more accurately sample the epipelagic layers 7 night hauls were restricted to the first 210 m of the water column. Fish were identified and counted on board, or frozen for later processes in the laboratory. These data were obtained within the European Union Project 'Sustainable Management of Mesopelagic Resources' (SUMMER, Grant Agreement 817806) as funded by the Horizon 2020 Research and Innovation Programme.

Description: To determine the effect of the rate of temperature increase (acute vs. gradual) and magnitude as well as the timing of nutrient addition on a natural marine phytoplankton community, a bottle incubation experiment has been conducted at the Institute for Chemistry and Biology of the Marine Environment (ICBM) in Wilhelmshaven, Germany. The community was collected at the Helgoland Roads long-term time series site in the German part of the North Sea (https://deims.org/1e96ef9b-0915-4661-849f-b3a72f5aa9b1) on the 6ᵗʰ of March 2022. The surface water containing the phytoplankton community was collected from the RV HEINCKE with a pipe covered with a 200 µm net attached to a diaphragm pump. In the first experimental run, the community was exposed to either gradual or acute temperature increase (from 6 to either 12 or 18°C) with 25 different N:P supply ratios added as a batch at the beginning of the bottle incubation. Simultaneously, the same community was gradually acclimated to their experimental temperatures under ambient nutrients and was used in a second experimental run in which it received the same 25 different N:P supply ratios after temperature acclimation. The light conditions were set to 175 µmol s-1 m-2 and a day-night cycle of 12h:12h which corresponds to the natural conditions at that time of the year. With this, it was possible to test the effect of a gradual vs. acute temperature increase and the timing of nutrient addition i.e., before or after the temperature change. This experimental set-up summed up to 400 units (8 temperature treatments x 5 nitrogen levels x 5 phosphorus levels x 2 replicates). Each experimental run was ended after 12 days. Fluorescence (395/680 Exc./Em.) was measured every second day using a SYNERGY H1 microplate reader (BioTek®) to determine phototrophic growth over time. At the end of each experiment, one replicate was filtered onto pre-combusted acid-washed glass microfiber filters (WHATMAN® GF/C) for intracellular carbon (POC), nitrogen (PON), and phosphorus (POP) content. The POP filters were pre-combusted and then analysed by molybdate reaction after digestion with a potassium peroxydisulfate solution (Wetzel and Likens 2003). The POC and PON filters were dried at 60°C before they were measured in an elemental analyser (Flash EA 1112, Thermo Scientific, Walthman, MA, USA).

Description: This raster dataset, in Cloud Optimized GeoTIFF format (COG), provides information on land surface changes at the pan-arctic scale. Multispectral Landsat-5 TM, Landsat-7 ETM+, and Landsat-8 OLI imagery (cloud-cover less than 80%, months July and August) was used for detecting disturbance trends (associated with abrupt permafrost degradation) between 2003 and 2022. For each satellite image we calculated the Tasseled Cap multi-spectral index to translate the spectral reflectance signal to the semantic information Brightness, Greenness, and Wetness. In order to characterize change information, we calculated the linear trend of the Brightness, Greenness and Wetness over two decades on the individual pixel level. The final map product therefore contains information on the direction and magnitude of change for all three Tasseled Cap parameters in 30m spatial resolution across the pan-arctic permafrost domain. Features detected include coastal erosion, lake drainage, infrastructure expansion, and fires. The general processing methodology was developed by Fraser et al. 2014 and adapted and expanded by Nitze et al. 2016 and Nitze et al. 2018. Here we upscaled the processing to the circum-arctic permafrost region and the recent 20-year period from 2003 through 2022. The service covers the permafrost region up to 81° North: Alaska (USA), Canada, Greenland, Iceland, Norway, Sweden, Finland, Russia, Mongolia, and China. For Russia and China, regions not containing permafrost were excluded. The data has been processed in Google EarthEngine within the research projects ERC PETA-CARB, ESA CCI+ Permafrost, NSF Permafrost Discovery Gateway, and EU Arctic PASSION. The dataset is a contribution to the 'Panarctic requirements-driven Permafrost Service' of the Arctic PASSION project (see references). Changes in the Tasseled Cap indices Brightness, Greenness, and Wetness are displayed in the image bands red, green, and blue, respectively. Here, coastal erosion (a trend of a land surface transitioning to a water surface) is depicted in dark blue colors, while coastal accretion (a trend of a water surface transitioning to a land surface) is depicted in bright orange colors. Drained lakes appear in bright yellow or orange colors, depending on the soil conditions and vegetation regrowth. Fire scars are a further common feature, which can appear in different colors, depending on the time of the fire and pre-fire land cover. The data can be explored via the Arctic Landscape EXplorer (ALEX, see references) and is available as a public web map service (WMS, see references), both hosted by Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research.

Description: The Holocene delta deposit (1st terrace) exposure SOB14-A-21 (72.53671°N, 127.98945°E) was sampled on 17 August 2014 North of Sobo-Sise Island in the Lena Delta during the framework of the joint Russian-German Expedition LENA 2014. The surface (top) of the exposure was characterized by mosses and sedges. The exposure itself was predominately sandy with few organic remnants. The top organic layer is thin (1.5 cm) and the active layer depth could not be determined exactly. However, the top 170 cm of the exposure were unfrozen although the thaw front might not only be from the top down but also horizontally due to the nature of the exposure. The exposure was first cleaned with a spade and then sampled with a knife and a hole saw from top to bottom. The entire exposure had a depth of 605 cm whereof the bottom 35 cm consisted of ice. Every 25 cm a sample was collected resulting in 22 samples (20 sediment samples and 2 ice samples). The samples were kept cool during the transport and later analyzed in the laboratory for bulk density, total organic carbon, and total nitrogen with a Vario EL III Elemental Analyzer. Prior to analysis, samples were freeze-dried, homogenized, and ground before measuring the samples with the elemental analyzer. The ice samples were not analyzed.

Description: Foraminiferal shells of the species M. allisonensis from the PETM section of ODP Site 865, Central Pacific, were cast with 3 grains of UWC-3 calcite standard (Kozdon et al., 2009) in the center of a 25 mm round epoxy mount, ground to the level of best exposure, polished, cleaned, and Au-coated. Prior to geochemical analysis, shells were examined by Scanning Electron Microscopy (SEM) to identify subdomains suitable for in-situ d13C and Mg/Ca ratio measurements and to avoid diagenetically altered zones within each shell. In-situ d13C measurements were performed with ~7 µm beam spot size in the WiscSIMS Laboratory at UW-Madison by a CAMECA ims-1280 large radius multicollector ion microprobe) using the protocols described in a previous study (Kozdon et al., 2018). The in-situ d13C microanalyses primarily targeted subdomains located at the base of pustular outgrowths (muricae) along the chamber walls of each shell. Previous studies have shown that these subdomains are less susceptible to post-depositional alteration than the rest of the shell (Kozdon et al., 2011; Kozdon et al., 2013). Between one and five SIMS d13C microanalyses were performed for each shell. Reproducibility of the individual spot analysis of UWC-3 standard (d13C = -0.91‰ V-PDB, Kozdon et al., 2011) bracketing samples is on average 0.7‰ (± 2 SD).

Description: Tree canopies are considered to effectively buffer climate extremes and to mitigate climate change effects. Droughts, which are predicted to become more frequent in the course of climate change, might alter the microclimatic cooling potential of trees. However, our understanding of how microclimate at the tree canopy level is modulated by environmental and tree characteristics and their interactions is still limited. Here, we investigated canopy temperature regulation for five mature co-occurring tree species for two contrasting hydrological situations during the severe drought in 2018.