ALBERT

Description: Core and outcrop analysis from Lena mouth deposits have been used to reconstruct the Late Quaternary sedimentation history of the Lena Delta. Sediment properties (heavy mineral composition, grain size characteristics, organic carbon content) and age determinations (14C AMS and IR-OSL) are applied to discriminate the main sedimentary units of the three major geomorphic terraces, which form the delta. The development of the terraces is controlled by complex interactions among the following four factors: (1) Channel migration. According to the distribution of 14C and IR-OSL age determinations of Lena mouth sediments, the major river runoff direction shifted from the west during marine isotope stages 5-3 (third terrace deposits) towards the northwest during marine isotope stage 2 and transition to stage 1 (second terrace), to the northeast and east during the Holocene (first terrace deposits). (2) Eustasy. Sea level rise from Last Glacial lowstand to the modern sea level position, reached at 6-5 ka BP, resulted in back-filling and flooding of the palaeovalleys. (3) Neotectonics. The extension of the Arctic Mid-Ocean Ridge into the Laptev Sea shelf acted as a halfgraben, showing dilatation movements with different subsidence rates. From the continent side, differential neotectonics with uplift and transpression in the Siberian coast ridges are active. Both likely have influenced river behavior by providing sites for preservation, with uplift, in particular, allowing accumulation of deposits in the second terrace in the western sector. The actual delta setting comprises only the eastern sector of the Lena Delta. (4) Peat formation. Polygenetic formation of ice-rich peaty sand (''Ice Complex'') was most extensive (7-11 m in thickness) in the southern part of the delta area between 43 and 14 ka BP (third terrace deposits). In recent times, alluvial peat (5-6 m in thickness) is accumulated on top of the deltaic sequences in the eastern sector (first terrace).

Description: Natural faults are known to host a wide range of mineral types, with a wide range of fault strength (quantified by the coefficient of friction) and friction velocity-dependence (quantified by the parameter a-b). In particular the velocity-dependence of friction is important because it partially determines the style of fault slip, from stable creep through a family of slow slip or slow earthquakes, to fast earthquakes. We use a chemical approach related to water-rock interactions. We measured the cation exchange capacity (CEC) of 10 different rock and mineral standards, including non-clays and a range of phyllosilicate minerals. We use the CEC as a proxy for the mineral surface charge and the ability to bind water to the mineral surfaces. For these materials, we conducted laboratory shearing experiments measuring the pre-shear cohesion, peak friction coefficient, residual friction coefficient, post-shear cohesion under 10 MPa effective normal stress. The velocity-dependence of friction a-b was determined from 3-fold velocity step increases in the range 0.1-30 µm/s.

Description: This is a compilation of all short-wave and long-wave radiation datasets from Tamanrasset that were and are published in the frame of BSRN. New data will be added regularly. The data are subject to the data release guidelines of BSRN (https://bsrn.awi.de/data/conditions-of-data-release/).

Description: Data presented here were collected between January 2021 to September 2023 within the research unit DynaCom (Spatial community ecology in highly dynamic landscapes: From island biogeography to metaecosystems, https://uol.de/dynacom/ ) of the Universities of Oldenburg, Göttingen, and Münster, the iDiv Leipzig and the Nationalpark Niedersächsisches Wattenmeer. Experimental islands and saltmarsh enclosed plots were created in the back barrier tidal flat and in the saltmarsh zone of the island of Spiekeroog. Temperature in the sediment surface layer (in approximately 0.05m depth) was measured with DEFI-T miniature temperature recorders (JFE Advantech Co., Ltd., Tokyo; DEFI-T). The manufacturer pre-calibrated temperature recorders and were installed on the experimental islands and in salt-marsh enclosed plots at different elevation levels. Recorded data were internally logged until the readout with the DEFI Series software (V1.02). The position was derived from a portable DGPS-system. Date and Time is given in UTC. Data handling was performed according to Zielinski et al. (2018): Post-processing of collected data was done using MATLAB (R2018a). Quality control was performed by (a) erasing data covering maintenance activities, (b) removing outliers, defined as data exhibiting changes of more than two standard deviations within one time step, and (c) visually checks.

Description: Understanding permafrost processes and changes requires long-term observational datasets of ground and climate variables. Despite the fact that the Arctic climate changes more rapidly than the rest of the globe, observational data density in the region is low and most time series are short. Long term observations are available from the Bayelva Site at Ny-Ålesund, Svalbard, where meteorology, energy balance components and subsurface observations have been made since 1998 and are still continued today. The climate observations include snow depth, snow dielectric number, snow temperature, liquid precipitation, air temperature, relative humidity, wind speed and direction, and radiation fluxes. The below-ground observations cover active layer and permafrost temperature, soil volumetric water content and soil bulk electrical conductivity. Since the data provide observations of temporally variable parameters that mitigate energy fluxes between permafrost and atmosphere, such as snow depth and soil moisture content, they are suitable for use in integrating, calibrating and testing permafrost as a component in Earth System Models. The resulting quality-controlled dataset is unique in the Arctic and serves as a baseline for future studies.

Description: An updated version of this dataset is available here: https://doi.pangaea.de/10.1594/PANGAEA.929749.

Description: To test the potential of meteoric 10Be (10Bem) as a river sediment transit time proxy, we measured 10Bem concentrations in river suspended sediment of the Rio Bermejo (northern Argentina), which is a river with a ~1300 km lowland flowpath void of tributaries. We collected fluvial suspended sediment in vertical depth profiles at five sampling locations along the length of the Rio Bermejo (northern Argentina) during near-bankfull conditions, when discharge varied between 675 and 1080 m**3/s and banks were actively eroding. Additionally, we collected one depth profile from Rio San Francisco (RSF) and one from the Rio Bermejo 10 km upstream of the RSF confluence. Combining these profiles and weighting them by the relative proportions of their total sediment load input to the mainstem Bermejo serves as an integrated headwater depth profile. In the thalweg, we collected water and suspended sediment from a boat using a weighted 8-liter horizontal sampling bottle (Wildco Beta Plus bottle) with an attached pressure transducer to measure sampling depth. We separated sediment from the water using a custom-built 5-liter pressurized filtration unit with a 293 mm diameter, 0.2 µm polyethersulfone filter. In the laboratory, we rinsed sediment off the filters directly into an evaporating dish with ultrapure 18.2 MΩ water (pH~7; when needed, we added NH3 solution to the water to maintain pH~7). Samples were dried in an oven at 40ºC, and subsequently homogenized. Sediment particle size distributions were measured on ~10 mg aliquots using a laser diffraction particle size analyzer (Horiba LA-950). Specific surface area (SSA) of bulk sediment samples was measured on ~4 g aliquots using a Quantachrome NOVAtouch LX gas sorption analyzer and the Brunauer, Emmett, and Teller (BET) theory (Brunauer et al., 1938). The total reactive phase, including amorphous oxyhydroxides and crystalline oxide grain coatings, was extracted from the sediment samples using a procedure adapted from Wittmann et al. (2012, doi:10.1016/j.chemgeo.2012.04.031). 10Bem was purified from the extracted material, spiked with a 9Be carrier solution containing 150 µg of 9Be, and packed into targets for AMS measurement at the University of Cologne Centre for Accelerator Mass Spectrometry (Cologne, Germany). 10Be /9Be measurements were normalized to the KN01-6-2 and KN01-5-3 standards (Dewald et al., 2013, doi:10.1016/j.nimb.2012.04.030) that are consistent with a 10Be half-life of 1.36 ± 0.07 x10^6 yrˉ¹ (Nishiizumi et al., 2007, doi:10.1016/j.nimb.2007.01.297). [10Be]m was calculated from the normalized and blank-corrected 10Be/9Be ratios. The reported 1σ uncertainties include counting statistics and the uncertainties of both standard normalization and blank correction. Stable 9Be concentrations were measured on a separate aliquot of the sample solution using inductively coupled plasma optical emission spectroscopy (ICP-OES). Uncertainty of ICP-OES measurements was 5%.

Description: The lack of consistent and reliable estimates of the bathymetry beneath the ice shelves of western Dronning Maud Land is addressed by inverting airborne gravity data to model the underlying bathymetry. The gravity inversion is supported by known depth reference points from seismic data, multibeam and ice thickness radar data across grounded ice sheets. The dataset comprises seabed and ice base depths of Ekström, Atka, Jelbart, Fimbul and Vigrid ice shelves relative to WGS84.

Description: To determine the depositional age and the long-term delivery of meteoric 10Be (10Bem) to the Rio Bermejo floodplain (northern Argentina), we collected floodplain sediment samples at four locations identified as point bars of abandoned Rio Bermejo channels. We used a stainless-steel hand auger to collect sediment down to a maximum depth of ~5 m, or until refusal. For 10Bem and 9Bereac analysis, we extracted samples that integrated material from 0-20 cm below the surface, 20-50 cm, and regularly spaced 40 cm intervals for lower depths. We homogenized the material prior to packing into clean plastic bags. Sediment particle size distributions were measured on ~10 mg aliquots using a laser diffraction particle size analyzer (Horiba LA-950). The total reactive phase, including amorphous oxyhydroxides and crystalline oxide grain coatings, was extracted from the sediment samples using a procedure adapted from Wittmann et al. (2012, doi:10.1016/j.chemgeo.2012.04.031). 10Be was purified from the extracted material, spiked with a 9Be carrier solution containing 150 µg of 9Be, and packed into targets for AMS measurement at the University of Cologne Centre for Accelerator Mass Spectrometry (Cologne, Germany). 10Be/9Be measurements were normalized to the KN01-6-2 and KN01-5-3 standards (Dewald et al., 2013, doi:10.1016/j.nimb.2012.04.030) that are consistent with a 10Be half-life of 1.36 ± 0.07 x10 yrˉ¹ (Nishiizumi et al., 2007, doi:10.1016/j.nimb.2007.01.297). 10Bem was calculated from the normalized and blank-corrected 10Be/9Be ratios. The reported 1σ uncertainties include counting statistics and the uncertainties of both standard normalization and blank correction. Stable 9Be concentrations were measured on a separate aliquot of the sample solution using inductively coupled plasma optical emission spectroscopy (ICP-OES). Uncertainty of ICP-OES measurements was 5%. We used coarse quartz grain OSL analysis to determine depositional ages for each floodplain core. For OSL analysis, we collected light-sealed samples by driving an opaque tube into our floodplain cores at two select depths in each core. OSL measurements were performed using a Risø DA 15 OSL/TL reader equipped with a 90Sr beta irradiator (4.9 Gy/min). OSL signals were stimulated with blue LEDs (470 nm, 50 s, 125 ºC) and detected through an optical filter (U 340 Hoya). For each sample, 40 aliquots were measured using the single-aliquot regenerative dose (SAR) protocol (Murray and Wintle, 2000, doi:10.1016/S1350-4487(03)00053-2) for equivalent dose determination.

Description: Coastlines globally are increasingly being illuminated with Artificial Light At Night (ALAN) from various urban infrastructures such as houses, offices, piers, roads, ports and dockyards. Artificial sky glow can now be detected above 22% of the world's coasts nightly and will dramatically increase as coastal human populations more than double by the year 2060. One of the clearest demonstrations that we have entered another epoch, the urbanocene, is the prevalence of ALAN visible from space. Photobiological life history adaptations to the moon and sun are near ubiquitous in the surface ocean (0-200m), such that cycles and gradients of light intensity and spectra are major structuring factors in marine ecosystems. The potential for ALAN to reshape the ecology of coastal habitats by interfering with natural light cycles and the biological processes they inform is increasingly recognized and is an emergent focus for research. This dataset is derived from two primary satellite data sources: an artificial night sky brightness world atlas (Falchi et al., 2016) and an in-water Inherent Optical Property (Lee et al., 2002) dataset derived from ESA's Ocean Colour Climate Change Initiative (OC-CCI https://www.oceancolour.org/). These primary datasets are both used in conjunction with in-situ derived measurements and radiative transfer modelling in order to quantify the critical depth (Zc) to which biologically relevant ALAN penetrates throughout the global ocean's estuarine, coastal and near shore regions, in particular the area defined by an individual country's Exclusive Economic Zone. The critical depth is defined as the depth at which the modelled light level in the water column, illuminated by ALAN, drops below 0.102 µWm-2, the minimum irradiance of white light that elicits diel vertical migration in adult female Calanus copepods (Batnes et al., 2015). This is function of incident ALAN irradiance at the surface as well as the in-water transparency (governed by in-water optically active constituents). This dataset is an updated version of https://doi.pangaea.de/10.1594/PANGAEA.922885.