ALBERT

Description: Warming air and sea temperatures, longer open-water seasons and sea-level rise promote the erosion of permafrost coasts in the Arctic, which profoundly impacts organic matter pathways. Although estimates on organic carbon (OC) fluxes from erosion exist for some parts of the Arctic, little is known about how much OC is transformed into greenhouse gases (GHGs). In this study we investigated two different coastal erosion scenarios on Qikiqtaruk – Herschel Island (Canada) and estimate the potential for GHG formation. We distinguished between a delayed release represented by mud debris draining a coastal thermoerosional feature and a direct release represented by cliff debris at a low collapsing bluff. Carbon dioxide (CO2) production was measured during incubations at 4 °C under aerobic conditions for two months and were modelled for four months and a full year. Our incubation results show that mud debris and cliff debris lost a considerable amount of OC as CO2 (2.5 ± 0.2 and 1.6 ± 0.3% of OC, respectively). Although relative OC losses were highest in mineral mud debris, higher initial OC content and fresh organic matter in cliff debris resulted in a ~three times higher cumulative CO2 release (4.0 ± 0.9 compared to 1.4 ± 0.1 mg CO2 gdw-1), which was further increased by the addition of seawater. After four months, modelled OC losses were 4.9 ± 0.1 and 3.2 ± 0.3% in set-ups without seawater and 14.3 ± 0.1 and 7.3 ± 0.8% in set-ups with seawater. The results indicate that a delayed release may support substantial cycling of OC at relatively low CO2 production rates during long transit times onshore during the Arctic warm season. By contrast, direct erosion may result in a single CO2 pulse and less substantial OC cycling onshore as transfer times are short. Once eroded sediments are deposited in the nearshore, highest OC losses can be expected. We conclude that the release of CO2 from eroding permafrost coasts varies considerably between erosion types and residence time onshore. We emphasize the importance of a more comprehensive understanding of OC degradation during the coastal erosion process to improve thawed carbon trajectories and models.

Description: Drilling of a 21.8-m-deep borehole on top of the 10.5-m-high Nori pingo that stands at 32 m asl in Grøndalen Valley (Spitsbergen) revealed a 16.1-m-thick massive ice enclosed by frozen sediments. The hydrochemical compositions of both the massive ice and the sediment extract show a prevalence of Na+ and Cl� ions throughout the core. The upper part of the massive ice (stage A) has low mineralization and shows an isotopically closed-system trend in δ18O and δD isotopes decreasing down-core. Stage B exhibits high mineralization and an isotopically semi-open system. The crystallographic structure of Nori pingo’s massive ice provides evidence of several large groundwater intrusions that support the defined formation stages. Analysis of local aquifers leads to suggest that the pingo was hydraulically sourced through a local fault zone by low mineralized sodium–bicarbonate groundwater of a Paleogene strata aquifer. This groundwater was enriched by sodium and chloride ions while filtering through marine valley sediments with residual salinity. The comparison between the sodium–chloride-dominated massive ice of the Nori pingo and the sodium–bicarbonate-dominated ice of the adjacent Fili pingo that stands higher up the valley may serve as an indicator for groundwater source patterns of other Nordenskiöld Land pingos.

Description: Boreal forests cover over half of the global permafrost area and protect underlying permafrost. Boreal forest development, therefore, has an impact on permafrost evolution, especially under a warming climate. Forest disturbances and changing climate conditions cause vegetation shifts and potentially destabilize the carbon stored within the vegetation and permafrost. Disturbed permafrost-forest ecosystems can develop into a dry or swampy bush- or grasslands, shift toward broadleaf- or evergreen needleleaf-dominated forests, or recover to the pre-disturbance state. An increase in the number and intensity of fires, as well as intensified logging activities, could lead to a partial or complete ecosystem and permafrost degradation. We study the impact of forest disturbances (logging, surface, and canopy fires) on the thermal and hydrological permafrost conditions and ecosystem resilience. We use a dynamic multilayer canopy-permafrost model to simulate different scenarios at a study site in eastern Siberia. We implement expected mortality, defoliation, and ground surface changes and analyze the interplay between forest recovery and permafrost. We find that forest loss induces soil drying of up to 44%, leading to lower active layer thicknesses and abrupt or steady decline of a larch forest, depending on disturbance intensity. Only after surface fires, the most common disturbances, inducing low mortality rates, forests can recover and overpass pre-disturbance leaf area index values. We find that the trajectory of larch forests after surface fires is dependent on the precipitation conditions in the years after the disturbance. Dryer years can drastically change the direction of the larch forest development within the studied period.

Description: Upscaling plant biomass distribution and dynamics is essential for estimating carbon stocks and carbon balance. In this respect, the Russian Far East is among the least investigated sub-Arctic regions despite its known vegetation sensitivity to ongoing warming. We representatively harvested above-ground biomass (AGB; separated by dominant taxa) at 40 sampling plots in central Chukotka. We used ordination to relate field-based taxa projective cover and Landsat-derived vegetation indices. A general additive model was used to link the ordination scores to AGB. We then mapped AGB for paired Landsat-derived time slices (i.e. 2000/2001/2002 and 2016/2017), in four study regions covering a wide vegetation gradient from closed-canopy larch forests to barren alpine tundra. We provide AGB estimates and changes in AGB that were previously lacking for central Chukotka at a high spatial resolution and a detailed description of taxonomical contributions. Generally, AGB in the study region ranges from 0 to 16 kg m−2, with Cajander larch providing the highest contribution. Comparison of changes in AGB within the investigated period shows that the greatest changes (up to 1.25 kg m−2 yr−1) occurred in the northern taiga and in areas where land cover changed to larch closed-canopy forest. As well as the notable changes, increases in AGB also occur within the land-cover classes. Our estimations indicate a general increase in total AGB throughout the investigated tundra–taiga and northern taiga, whereas the tundra showed no evidence of change in AGB.

Description: The aim of the expedition CACOON Sea was to investigate the transition from fresh water to salt water and its impact on fate and quality on dissolved and particulate organic and inorganic carbon and nitrogen. This is in accordance with the main Changing Arctic Carbon cycle in the cOastal Ocean Near-shore (CACOON, https://www.changing-arctic-ocean.ac.uk/project/cacoon/) project goal to investigate the changing freshwater export and impact of terrestrial permafrost thaw into the near-shore zone of the Laptev Sea.

Description: With the CACOON project, we aim to quantify the effect of changing freshwater export and terrestrial permafrost thaw on the type and fate of river-borne organic matter (OM) delivered to Arctic coastal waters, and resultant changes on ecosystem functioning in the coastal Arctic Ocean. The CACOON ice expedition was the first step to set the observational basis for the projects combined observational, experimental and modelling approach. With the gained sample material, we will conduct laboratory experiments to parameterise the susceptibility of terrigenous carbon to abiotic and biotic transformation and losses, and then use the results from these to deliver a marine ecosystem model capable of representing the major biogeochemical cycles of carbon, nutrients and OM cycling in these regions. We will apply this model to assess how future changes to freshwater runoff and terrigenous carbon fluxes alter the biogeochemical structure and function of shelf ecosystems. Our aims for the project are the following: • generate novel seasonally-explicit datasets of OM source and transformation across the Lena River nearshore environments • identify and parameterise key abiotic and biotic processes affecting terrestrial organic matter fluxes from land-to-ocean • deliver projections of how future changes to freshwater runoff and terrestrial organic matter fluxes will alter the biogeochemical structure and function of shelf ecosystems.

Description: Background: Extreme terrestrial, analogue environments are widely used models to study the limits of life and to infer habitability of extraterrestrial settings. In contrast to Earth’s ecosystems, potential extraterrestrial biotopes are usually characterized by a lack of oxygen. Methods: In the MASE project (Mars Analogues for Space Exploration), we selected representative anoxic analogue environments (permafrost, salt-mine, acidic lake and river, sulfur springs) for the comprehensive analysis of their microbial communities. We assessed the microbiome profile of intact cells by propidium monoazide-based amplicon and shotgun metagenome sequencing, supplemented with an extensive cultivation effort. Results: The information retrieved from microbiome analyses on the intact microbial community thriving in the MASE sites, together with the isolation of 31 model microorganisms and successful binning of 15 high-quality genomes allowed us to observe principle pathways, which pinpoint specific microbial functions in the MASE sites compared to moderate environments. The microorganisms were characterized by an impressive machinery to withstand physical and chemical pressures. All levels of our analyses revealed the strong and omnipresent dependency of the microbial communities on complex organic matter. Moreover, we identified an extremotolerant cosmopolitan group of 34 poly-extremophiles thriving in all sites. Conclusions: Our results reveal the presence of a core microbiome and microbial taxonomic similarities between saline and acidic anoxic environments. Our work further emphasizes the importance of the environmental, terrestrial parameters for the functionality of a microbial community, but also reveals a high proportion of living microorganisms in extreme environments with a high adaptation potential within habitability borders.

Description: With the Arctic rapidly changing, the needs to observe, understand, and model the changes are essential. To support these needs, an annual cycle of observations of atmospheric properties, processes, and interactions were made while drifting with the sea ice across the central Arctic during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition from October 2019 to September 2020. An international team designed and implemented the comprehensive program to document and characterize all aspects of the Arctic atmospheric system in unprecedented detail, using a variety of approaches, and across multiple scales. These measurements were coordinated with other observational teams to explore cross- cutting and coupled interactions with the Arctic Ocean, sea ice, and ecosystem through a variety of physical and biogeochemical processes. This overview outlines the breadth and complexity of the atmospheric research program, which was organized into 4 subgroups: atmospheric state, clouds and precipitation, gases and aerosols, and energy budgets. Atmospheric variability over the annual cycle revealed important influences from a persistent large-scale winter circulation pattern, leading to some storms with pressure and winds that were outside the interquartile range of past conditions suggested by long-term reanalysis. Similarly, the MOSAiC location was warmer and wetter in summer than the reanalysis climatology, in part due to its close proximity to the sea ice edge.The comprehensiveness of the observational program for characterizing and analyzing atmospheric phenomena is demonstrated via a winter case study examining air mass transitions and a summer case study examining vertical atmospheric evolution. Overall, the MOSAiC atmospheric program successfully met its objectives and was the most comprehensive atmospheric measurement program to date conducted over the Arctic sea ice. The obtained data will support a broad range of coupled-system scientific research and provide an important foundation for advancing multiscale modeling capabilities in the Arctic.

Description: Climate change is destabilizing permafrost landscapes, affecting infrastructure, ecosystems, and human livelihoods. The rate of permafrost thaw is controlled by surface and subsurface properties and processes, all of which are potentially linked with each other. However, no standardized protocol exists for measuring permafrost thaw and related processes and properties in a linked manner. The permafrost thaw action group of the Terrestrial Multidisciplinary distributed Observatories for the Study of the Arctic Connections (T-MOSAiC) project has developed a protocol, for use by non-specialist scientists and technicians, citizen scientists, and indigenous groups, to collect standardized metadata and data on permafrost thaw. The protocol introduced here addresses the need to jointly measure permafrost thaw and the associated surface and subsurface environmental conditions. The parameters measured along transects include: snow depth, thaw depth, vegetation height, soil texture, and water level. The metadata collection includes data on timing of data collection, geographical coordinates, land surface characteristics (vegetation, ground surface, water conditions), as well as photographs. Our hope is that this openly available dataset will also be highly valuable for validation and parameterization of numerical and conceptual models, and thus to the broad community represented by the T-MOSAiC project.

Description: To explore the potential of urban settings as habitats for testate amoebae, five historical parks in Potsdam (Germany) were sampled at different sites. A total of 32 sampling sites was chosen in proximity to deciduous (Acer, Castanea, Fagus, Tilia, Platanus, Quercus) and coniferous (Fraxinus, Picea, Pinus, Tsuga) trees. Meadows and creeks were also sampled. The overall taxonomic record comprises 76 species and sub-species. High species numbers of 〉20 per sample were found in meadows and below Fagus, Tilia, and Quercus trees. The species richness per park ranges from 33 to 46 taxa. Most species belong to the eurybiontic ecological group, although litter-inhabiting and hygrophilic and hydrophilic species were also present. Common species found in more than 50% of all samples (superdominants) belong to the genera Centropyxis, Cyclopyxis, Euglypha, and Trinema. Interestingly, the rare Frenopyxis stierlitzi which inhabits tree hollows was found as a recently described species in a new genus Frenopyxis BOBROV & MAZEI 2020 in the Babelsberg Park. The studied testate amoebae are characterized by a high degree of morphological and morphometric plasticity. Therefore, the study of testate amoebae in urban settings will reveal new insights into their ecology and enhance the definition of morphometric variability for single species.

Description: Recent studies increasingly recognize the importance of critical-zone weathering during mountain building for long-term CO2 drawdown and release. However, the focus on near-surface weathering reactions commonly does not account for CO2 emissions from the crust, which could outstrip CO2 drawdown where carbonates melt and decarbonize during subduction and metamorphism. We analyse water chemistry from streams in Italy’s central Apennines that cross a gradient in heat flow and crustal thickness with relatively constant climatic conditions. We quantify the balance of inorganic carbon fluxes from near-surface weathering processes, metamorphism and the melting of carbonates. We find that, at the regional scale, carbon emissions from crustal sources outpace near-surface fluxes by two orders of magnitude above a tear in the subducting slab characterized by heat flow greater than 150 mW m–2 and crustal thickness of less than 25 km. By contrast, weathering processes dominate the carbon budget where crustal thickness exceeds 40 km and heat flow is lower than 30 mW m–2. The observed variation in metamorphic fluxes is one to two orders of magnitude larger than that of weathering fluxes. We therefore suggest that geodynamic modulations of metamorphic melting and decarbonation reactions are an efficient process by which tectonics can regulate the inorganic carbon cycle.

Description: A newly built versatile device for mode I fracture toughness measurement is presented. To test this apparatus, measurements have been conducted on two crystalline rocks, the Aue Granite and the Äspö Diorite, and two chalks from the Paris basin, Obourg and Ciply chalks. The fracture toughness KIC can be measured with two different testing procedures, the Semi-Circular Bend (SCB) and the Straight Edge Cracked Round Bar Bend (SECRBB) methods, both known for the easiness of the notched sample preparation. For the SCB tests, ultrasonic sensors were mounted at the sample surface to monitor changes in P-wave velocity and record acoustic emission activity. Our results are in reasonably good agreement with published data on the same rocks. The SECRBB test provides values of the fracture toughness 37% higher compared to the SCB test for the Obourg chalk. This discrepancy may be explained by a sample size effect. The fracture toughness of water saturated chalks is strongly reduced compared to that of the dry chalks by almost 50%. This shows that fracture toughness is a valuable parameter to assess the importance of water weakening in porous rocks.

Description: Metamorphosed banded iron formation (BIF) in granulite-amphibolite facies, tonalitic orthogneisses from a series of locations in the Kolli Massif of southern India are described and analysed with regard to their lithologies, whole rock chemistry, mineral reaction textures, and mineral chemistry. On the basis of their mineral reaction textures along magnetite-quartz grain boundaries these BIFs are grouped according to their predominant silicate mineralogy: 1) amphibole; 2) orthopyroxene; 3) orthopyroxene–clinopyroxene; 4) orthopyroxene-clinopyroxene-garnet; 5) clinopyroxene-garnet-plagioclase; and 6) Fe-Mg silicates are absent. Two-pyroxene and garnet-pyroxene Fe-Mg exchange thermometry, coupled with thermodynamic pseudo-section modelling of whole rock data from one of the magnetite-quartz-orthopyroxene-clinopyroxene-bearing lithologies, indicates that the magnetite-quartz-orthopyroxene-clinopyroxene-garnet assemblages formed at ~900 to 1200 MPa and 750 to 900 °C under relatively low H2O activities. Magnetite-quartz-orthopyroxene reaction textures were experimentally replicated at 800 and 900 °C and 1000 MPa in a synthetic BIF using isolated magnetite grains in a quartz matrix to which was added a hypersaline Mg- and Al-bearing fluid (approximately 1% by mass), which permeated along all the grain boundaries. The fact that Fe-Mg silicate reaction textures did not form in one of the BIF samples, which had experienced the same P-T conditions as the other BIF samples, suggests that, unless a BIF initially incorporated Mg, Al, and Ca during formation with or was infiltrated from the surrounding rocks by Mg-, Al-, and Ca-bearing saline fluids, these silicate minerals could not and would not have formed from the inherent magnetite and quartz during granulite-facies and amphibolite-facies metamorphism.

Description: Natural alteration of zircon takes place in melts or fluids either via dissolution coupled with overgrowth or via a coupled dissolution-reprecipitation process. The latter results in the zircon being partially or totally replaced by new, compositionally re-equilibrated zircon or a new mineral phase or both. In this study, fragments (50–300 μm) from a large, inclusion-free, clear, 520–530 Ma euhedral zircon with light radiation damage from a nepheline syenite pegmatite, Seiland Igneous Province, northern Norway, were experimentally reacted in 20 mg batches with 5 mg of ThO2 + ThSiO2 + SiO2 and a series of alkali-bearing fluids in sealed Pt capsules at 900 °C and 1000 MPa for 6–11 days in the piston cylinder press using a CaF2 setup with a cylindrical graphite oven. ThO2 + ThSiO2 + SiO2 was present at the end of the experiment. In experiments involving H2O, H2O + NaCl, H2O + KCl, and 2 N KOH, no reaction textures formed other than a slight dissolution of the zircon grain fragments. Experiments involving 2 N NaOH, Na2Si2O5 + H2O, and NaF + H2O resulted in zircon reaction textures with varying degrees of intensity, which took the form of partial replacement by compositionally modified zircon via a coupled dissolution-reprecipitation process. In the NaF + H2O experiment some overgrowth also occurred. Altered zircon is separated by sharp compositional boundaries from unaltered zircon. Secondary ion mass spectrometry (SIMS) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis indicates that, relative to the unaltered zircon, the altered zircon is strongly enriched in Th, and heavily to moderately depleted in U and (Y + REE). In all the experiments, 206Pb (3–5 ppm in unaltered zircon) is depleted in the altered zircon to below the SIMS detection limit and to at or below the LA-ICP-MS detection limit. Hafnium and Ti concentrations in the altered zircon retained the same approximate value (within error) as the original zircon. The results from these experiments demonstrate that zircon can be compositionally modified by alkali-bearing and alkali-F-bearing fluids via a coupled dissolution-reprecipitation process. Near to total loss of radiogenic Pb via such processes under high-grade conditions resets the internal zircon geochronometer. Although the end result is the same as with zircon overgrowth, i.e. the production of new generation zircon at the time of a metamorphic/metasomatic event, such replacement processes can explain incomplete isotopic ‘resetting’; inclusion production through unmixing of solid solutions in metastable zircon compositions; and ‘ghost’ textures that preserve initial growth features but with isotopic disturbance. Diagnostic replacement features produced in experiments, such as interface geometries between altered and unaltered zircon, provide markers of the mechanism and aid in zircon interpretation. A major implication from this study is that if zircon with low radiation damage can be metasomatically altered under high-grade conditions, this would have important consequences with respect to zircons presumed role as an impregnable container for mineral inclusions. Namely the mineral inclusions contained within zircon could also be altered, reset as a geochronometer, or even replaced by another mineral.

Description: Fluid injection into subsurface reservoirs may cause existing faults/fractures to slip seismically. To study the effect of temperature on injection-induced fault slip, at a constant confining pressure of 10 MPa, we performed a series of injection-induced shear slip experiments on critically stressed sandstone samples containing saw-cut fractures (laboratory-simulated faults) under varying fluid pressurization rates (0.1 and 0.5 MPa/min, respectively) and temperatures (25, 80, and 140 °C, respectively). At 25 °C, slow fault slip events with a peak slip velocity of about 0.13 μm/s were observed on a tested sample in response to a low fluid pressurization rate of 0.1 MPa/min. In contrast, fluid injection with a high pressurization rate of 0.5 MPa/min caused fault slip events with a peak slip rate up to about 0.38 μm/s. In response to a given fluid pressurization rate, several episodes of slip events with a higher slip velocity were induced at an elevated temperature of 140 °C, indicating an appreciable weakening effect at elevated temperatures. We also experimentally constrained the rate-and-state frictional (RSF) parameters at varying effective normal stresses and temperatures by performing velocity-stepping tests. The obtained RSF parameters demonstrate that for a relatively high normal stress, increasing temperature tends to destabilize fault slip. Post-mortem microstructural observations reveal that elevated temperatures promote the generation of abundant fine-grained gouge particles associated with injection-induced shear slip. Our experiments highlight that injection-induced fault slip is affected by temperature-related wear production over the fault surface.

Description: Earlier experiments have shown that cyclic hydraulic fracturing (CHF) systematically reduces the monotonic breakdown pressure (MBP). However, cyclic injection also causes a significantly longer injection time to failure as compared to the monotonic injection tests and complex fracture propagation that is hard to predict. In this study, a different injection scheme employing rock fatigue behavior, named creep injection, was tested on granite cylinders. The creep injection creates continuous pressurization under a constant borehole pressure (CBP) with a pre-defined maximum value below the MBP. Three different pressure ratios (CBP/MBP) of 0.85, 0.9 and 0.95 were tested. We found that both the CHF and hydraulic fracturing with creep injection can reduce the breakdown pressure by ca. 15 ~ 20% without confining pressure. Two mechanisms could explain the reduction: the influence of fluid infiltration within the theory of linear poroelasticity and stress corrosion within the subcritical crack growth theory. The lifetime of the granite cores subjected to creep injection is comparable with previous CHF experiments employing the same pressure ratio. In addition, the lifetime increases logarithmically when the ratio of CBP/MBP is decreased. This relationship has a high regression coefficient of R2 = 0.97, and the lifetime can be well predicted using a stress corrosion index of 70. On the contrary, CHF shows a significantly larger variance in the lifetime with a regression coefficient of R2 = 0.19 and, therefore, is hard to predict. Our results also point out that the injection scheme can modify hydraulic fracture patterns, in terms of fracture aperture, branching, and fracture propagation.

Description: Numerous borehole logging datasets gathered for commercial and scientific purposes are available around the globe. However, studies valorising the chronostratigraphic potential of these datasets through time series analyses remain sparse despite the excellent completeness of downhole logging data retrieved in a fast and high-resolution fashion. The major reason for this is the complexity of such approaches and potential pitfalls that may discourage non-experienced users. Here we provide an overview that summarizes the most relevant properties of borehole logging measurements for time series analysis and cyclostratigraphy. Further, we provide a brief introduction of most relevant time series analyses methods, including several examples of borehole logging cyclostratigraphy. Compared to analyses and interpretations of data from cores or exposures, it is important to be aware of borehole logging data specific pitfalls. These include environmental corrections like the effect of variation in borehole diameter, the effects of drilling fluids, and that presented logs may consist of merged results logged in several depth sections.

Description: Qongjiagang pegmatite-type Li deposit in Tibet is the first discovered pegmatite-type deposit with economic value in the Himalayan region, which confirms that the Himalayan region has the potential to become a strategic base of rare metal in China, and provide indications to find pegmatite-type Li deposit in the Himalayan region. In this study, we use SEM to identify the type, frequency and occurrence (relationship with cracks) of mineral inclusions in the three main accessory minerals, monazite, apatite and zircon from granite and pegmatite of Qongjiagang Li deposit, combining with the EPMA analysis of feldspar inclusions in apatite to comprehensively trace the property and evolution of the melts and fluids. Our study indicates that: (1) the main mineral inclusions in monazite, apatite and zircon from Qongjiagang Li deposit include silicate, oxide, phosphates and a small amount of sulfide, not only the REE-rich monazite and apatite filling or intersecting cracks are formed by hydrothermal alteration, but also the uraninite and thorianite isolated from cracks occur in the self-irradiation region of zircon are related to fluids; (2) the appearances of columbite and pyrochlore inclusions in the apatite from tourmaline-muscovite granite demonstrate that the initial melt is enriched in Nb and Ta, the amount and type of rare metal mineral inclusions can be used as an indicator for rare metal mineralization in highly evolved granite and pegmatite; (3) the plagioclase inclusions with high and a large range of An values in apatite from spodumene pegmatite represent the capture of less-differentiated melt and continuously fractional crystallization. Our results indicate that the types and compositions of mineral inclusions in accessory minerals can be good tracers for the characteristics and evolution of melts and fluids in the highly evolved granite-pegmatite system

Description: This publication provides the codes produced for the article "Temporally dynamic carbon dioxide and methane emission factors for rewetted peatlands. Nature Communications Earth and Environment" by Aram Kalhori, Christian Wille, Pia Gottschalk, Zhan Li, Josh Hashemi, Karl Kemper, and Torsten Sachs (https://doi.org/10.1038/s43247-024-01226-9). In the article, the authors estimate the cumulative GHG emissions of a rewetted peatland in Germany using the long-term ecosystem flux measurements. They observe a source-to-sink transition of annual carbon dioxide (CO2) fluxes and decreasing trend of methane (CH4) emissions. This software is written in R and MATLAB. Running the codes ([R files and .m files](Code)) and loading the data files ([CSV files and .mat files](Data)) requires the pre-installation of [R and RStudio] (https://posit.co/downloads/) and ([MATLAB]. The RStudio 2022.07.2 Build 576 version has been used for the R scripts. The land cover classification work was performed in QGIS, v.3.16.11-Hannover. Data were analyzed in both MATLAB and R and plots created with R (R Core Development Team 2020) in RStudio®.

Description: Compound weather and climate events have obtained increasing attention in recent years in the context of anthropogenic climate change. Compound pluvial-fluvial flooding (CPFF), usually referring to the superposition of heavy local rainfall in urban areas and riverbank overflow, is however rarely investigated. We perform a systematic literature review on this emerging topic and identify knowledge gaps. Major knowledge gaps concern the dependence between pluvial and fluvial flooding, and thus the co-occurrence probability, and its past and (possible) future changes. Although it is expected that CPFF increases in a warming world, we could not identify a single attempt to understand temporal changes. More systematic and comprehensive data collection and process documentation, particularly for pluvial and flash floods, are required to better understand and assess CPFF. Another major gap is the limitation of CPFF studies to hazard assessments. Implementing damage models would allow, with modest effort, to transfer hazard statements into risk statements. This would allow, in turn, to understand the scale of the problem in terms of societal relevance.

Description: We investigate the crustal and upper mantle structure of the Aysén region of Chile from 44° to 49° S, a place where the diverging oceanic Nazca and Antarctic plates subduct beneath the South American continent. The Seismic Experiment in the Aysén Region of Chile (SEARCH) project operated a network of up to 60 land-based seismometers in this region between 2004 and 2006, centered over a 6 Myr old subducted spreading center. The data are used to examine the wave velocity structure beneath the region using relative-arrival teleseismic travel time tomography, using 2534 wave residuals from 173 teleseismic earthquakes. It is possible to image the velocity structure beneath the seismic network from 30 down to 300 km depth. The model can resolve structures at a spatial scale between 60 and 200 km and shows a large difference between the northern and southern parts of the region. To the north, a 100 km thick fast anomaly exists which dips away from the subduction trench; likely to be related to the subducting Nazca plate. Going to the south, as the age of this plate at the subduction trench decreases and arc volcanism shuts off, the fast anomaly migrates further from the trench, suggesting that the Nazca plate subducts at a reduced angle over a larger distance before the subduction angle steepens. The distinct sections of the fast anomaly suggest that slab tears exist across the fracture zones between subducted plate segments. Where the 6 Myr old subducted ridge segment is predicted to lie, there is a region of low velocity between 100 and 300 km depth, and no fast region associated with a subducting slab is present, indicating the presence of an asthenospheric window between the subducted Nazca and Antarctic plates.

Description: We investigate the crustal and upper mantle structure of the Aysén region of Chile from 44° to 49° S, a place where the diverging oceanic Nazca and Antarctic plates subduct beneath the South American continent. The Seismic Experiment in the Aysén Region of Chile (SEARCH) project operated a network of up to 60 land-based seismometers in this region between 2004 and 2006, centered over a 6 Myr old subducted spreading center. The data are used to examine the wave velocity structure beneath the region using relative-arrival teleseismic travel time tomography, using 2534 wave residuals from 173 teleseismic earthquakes. It is possible to image the velocity structure beneath the seismic network from 30 down to 300 km depth. The model can resolve structures at a spatial scale between 60 and 200 km and shows a large difference between the northern and southern parts of the region. To the north, a 100 km thick fast anomaly exists which dips away from the subduction trench; likely to be related to the subducting Nazca plate. Going to the south, as the age of this plate at the subduction trench decreases and arc volcanism shuts off, the fast anomaly migrates further from the trench, suggesting that the Nazca plate subducts at a reduced angle over a larger distance before the subduction angle steepens. The distinct sections of the fast anomaly suggest that slab tears exist across the fracture zones between subducted plate segments. Where the 6 Myr old subducted ridge segment is predicted to lie, there is a region of low velocity between 100 and 300 km depth, and no fast region associated with a subducting slab is present, indicating the presence of an asthenospheric window between the subducted Nazca and Antarctic plates.

Description: A multisite method of fragments-based rainfall temporal (daily to hourly) disaggregation procedure conditioned on circulation pattern (CP) classification is developed and applied to the German part of the Rhine river basin. The performance of the CP-based disaggregation in representing key rainfall characteristics is evaluated and the influence of different number of CP classes is investigated. Compared with the standard (monthly-based) method of fragments disaggregation, the CP-based procedure including a seasonal stratification improves the disaggregation quality in hourly rainfall extremes, although it shows no improvement in reproducing standard rainfall statistics, such as mean and standard deviation. CP classifications with more classes tend to perform better in representing hourly rainfall statistics in the Rhine basin. The developed procedure opens up the possibility to consider dynamic changes in the atmosphere, such as changes in the frequency, persistence and seasonality of circulation patterns, that may be associated with climate change.

Description: Flood risk models provide important information for disaster planning through estimating flood damage to exposed assets, such as houses. At large scales, computational constraints or data coarseness leads to the common practice of aggregating asset data using a single statistic (e.g., the mean) prior to applying non-linear damage functions. While this simplification has been shown to bias model results in other fields, the influence of aggregation on flood risk models has received little attention. This study provides a first order approximation of such errors in 344 damage functions using synthetically generated depths. We show that errors can be as high as 40 % of the total asset value under the most extreme example considered, but this is highly sensitive to the level of aggregation and the variance of the depth values. These findings identify a potentially significant source of error in large-scale flood risk assessments introduced, not by data quality or model transfers, but by modelling approach.

Description: The data provided here is an exemplary dataset for the flux site Zarnekow from one year (2018). The complete dataset that is needed to run the codes for all the years can be obtained from the European Fluxes Database Cluster under site ID DE-Zrk (Sachs et al., 2016) or provided upon request. This repository is intended to provide the necessary MATLAB and R code to reproduce the results by Kalhori et al. (2024). The data are provided as zip folder containing (1) a csv file with associated definition of variables and units (file: 2023-004_Kalhori-et-al_README_2018_units.txt), (2) a shapefile (file: 2023-004_Kalhori-et-al_2018_LAiV_DOP.shp) and (3) a Geotiff (file: 2023-004_Kalhori-et-al_2018_LAiV_DOP.tiff).

Description: The West Siberian Seaway connected the Tethys to the Arctic Ocean in the Paleogene and played an important role for Eurasian-Arctic biogeography, ocean circulation, and climate. However, the paleogeography and geological mechanisms enabling the seaway are not well constrained, which complicates linking the seaway evolution to paleoenvironmental changes. Here, we investigate the paleogeography of the Peri-Tethys realms for the Cenozoic time (66–0 Ma), including the West Siberian Seaway, and quantify the influence of mantle convection and corresponding dynamic topography. We start by generating continuous digital elevation models for Eurasia, Arabia, and Northern Africa, by digitizing regional paleogeographic maps and additional geological information and incorporate them in a global paleogeography model with nominal million-year resolution. Then we compute time-dependent dynamic topography for the same time interval and find a clear correlation between changes in dynamic topography and the paleogeographic evolution of Central Eurasia and the West Siberian Seaway. Our results suggest that mantle convection played a greater role in Eurasian paleogeography than previously recognized. Mantle flow may have influenced oceanic connections between the Arctic and global ocean providing a link between deep mantle convection, surface evolution, and environmental changes. Our reconstructions also indicate that the Arctic Ocean may have been isolated from the global ocean in the Eocene, even if the West Siberian Seaway was open, as the Peri-Tethys – Tethys connection was limited, and the Greenland-Scotland Ridge was a landbridge.

Description: Lower crustal flow in regions of post-orogenic extension has been inferred to explain the exhumation of metamorphic core complexes and associated low-angle normal (detachment) fault systems. However, the origin of detachment faults, whether initially formed as high-angle or low-angle shear zones, and the extension is symmetric or asymmetric remains enigmatic. Here, we use numerical modeling constrained by geophysical and geological data to show that symmetric extension in the central Menderes Massif of western Anatolia is accommodated by the crustal flow. Our geodynamic model explains how opposite dipping Gediz and Büyük Menderes detachment faults are formed by ∼40° footwall rotation. Model predictions agree with seismic tomography data that suggests updoming of lower crust beneath the exhumed massifs, represented as “twin domes” and a flat Moho. Our work helps to account for the genetic relation between the exhumation of metamorphic core complexes and low-angle normal faulting in both Cordillera and Aegean orogenic regions and has important implications on crustal dynamics in extensional provinces.

Description: The geoid is an equipotential surface that broadly mimics the mean sea level. The difference between the geoid and the reference spheroid at any location is referred to as a geoid anomaly. The geoid ‘highs’ (positive) or ‘lows’ (negative) are primarily associated with mass anomalies, thereby could offer important information about compositional and thermal properties in the Earth's interior. The maximum geoidal surplus (+85 m) is observed to the east of New Guinea whereas the largest deficit (−106 m) is observed in the Indian Ocean south of Sri Lanka – commonly known as the Indian Ocean geoid low (IOGL). On a global geoid map, the IOGL anomaly covers an extensive circular area spanning 〉2000 km in diameter (Fig. 1). Several different hypotheses have been put forth to explain this enigmatic anomaly. These include effects of isostatically uncompensated crust (Ihnen and Whitcomb, 1983), depression in the core-mantle boundary (Negi et al., 1987), slab graveyards in the mantle (Spasojevic et al., 2010), anomalous variations in the mantle transition zone (Reiss et al., 2017; Rao et al., 2020) and presence of a very low-velocity material arising from the African large low shear velocity province (LLSVP) or simply known as the African superplume (Ghosh et al., 2017). Most of these hypotheses rely upon either very sparse seismological observations, numerical modelling or remote sensing data. Global seismic tomographic models provide first-order information about the Earth's interior (Simmons et al., 2010, Simmons et al., 2012, Simmons et al., 2015). However, the uneven distribution of seismological networks has stymied production of high-resolution sub-surface images. In search of concrete causative mechanisms behind the IOGL anomaly, deep seismological observations from the Indian Ocean have been awaited for a long time. Between 2015 and 2020, the Ministry of Earth Sciences (MoES) India deployed a focused linear broadband passive seismological array comprising 17 ocean bottom seismometers (OBS) for two successive seasons comprising 14 months each (Fig. 1). These OBS stations thus continuously recorded local and teleseismic events for 〉28 months (Pandey, 2017). Besides, some recent studies also carried out active OBS deployments in this region to evaluate crustal and upper mantle structures (Pandey et al., 2022; Ningthoujam et al., 2022; Altenbernd-Lang et al., 2022). This special issue was conceived to present a compilation of new field observations as well as numerical modelling studies to infer potential mass anomalies within the crust and mantle beneath the IOGL region. A collection of nine papers presented in this volume explore the role of causative sources at varying depths to explain the IOGL anomaly. In summary, scientific contributions in this special issue suggest minimal crustal contributions towards the spectacular IOGL anomaly. On the other hand, new seismological studies suggest that the IOGL anomaly can be reasonably explained by a combination of positive mass anomalies in the lower mantle and/or negative mass anomalies in the upper mantle. Varied outcomes further stress upon the need to carry out more long-term seismological observations in order to image precise mantle structure beneath the IOGL region.

Description: Volcanism in continental rifts is generally observed to shift over time from the inside of the basin to its flanks and vice versa, but the controls on these switches are still unclear. Here we use numerical simulations of dike propagation to test the hypothesis that the spatio-temporal evolution of rift volcanism is controlled by the crustal stresses produced during the development of the rift basin. We find that the progressive deepening of a rift rotates the direction of the principal stresses under the basin, deflecting ascending dikes. This causes an early shift of volcanism from the inside of the graben to its flanks. The intensification of this stress pattern, due to further deepening of the basin, promotes the formation of lower crustal sill-like intrusions that can stack under the rift, shallowing the depth at which dikes nucleate, eventually causing a late stage of in-rift axial volcanism. Given the agreement between our model results and observations, we conclude that the temporal shifts in the location of rift volcanism are controlled to first order by the elastic stresses developing in the crust as the rift matures. We thereby suggest that geodynamic models should account for elasticity and the redistribution of surface loads in order to effectively reproduce rift-related magmatism.

Description: Peatlands account for a significant fraction of the global carbon stock. However, the complex interplay of abiotic and biotic factors governing anaerobic carbon mineralization in response to warming remains unclear. In this study, peat sediments were collected from a typical northern peatland-Changbai Mountain to investigate the behavior and mechanism of anaerobic carbon mineralization in response to depth (0–200 cm) and temperature (5 °C, 15 °C and 20 °C), by integrating geochemical and microbial analysis. Several indices including humification indexes (HI), aromaticity, and water extractable organic carbon (WEOC) components were applied to evaluate carbon quality, while 16S rRNA sequencing was used to measure microbial composition. Regardless of temperature, degradations of carbon quality and associated reduction in microbial abundance as well as diversity resulted in a decrease in anaerobic carbon mineralization (both CO2 and CH4) towards greater depth. Warming either from 5 °C to 15 °C or 20 °C significantly increased anaerobic carbon mineralization in all depth profiles by improving carbon availability. Enhanced carbon availabilities were mediated by the change in microbial composition (p 〈 0.01) and an increase in metabolic activities, which was particularly evident in the enhanced β-glucosidase activity and microbial collaborations. A remarkable increase of over 10-fold in the relative abundance of the Geothrix genus was observed under warming. Overall, warming resulted in an enhanced contribution of CH4 emission and a higher ratio of hydrogenotrophic methanogenesis, as evidenced by carbon isotope fractionation factors. In addition, deep peat soils (〉100 cm) with recalcitrant carbon demonstrated greater temperature sensitivity (Q10: ∼2.0) than shallow peat soils (Q10:∼1.2) when temperature increased from 15 °C to 20 °C. The findings of this study have significantly deepened our understanding for mechanisms of carbon quality and microbe-driven anaerobic carbon mineralization in peatlands under global warming.

Description: The maturity of sedimentary organic matter is a key parameter for evaluating oil and gas resources. Existing maturity indicators have different evaluation principles and application scopes. This study investigated samples of high to overmature lacustrine source rocks (Ro = 1.33%–4.24%) from the deep Shahezi formation in the Songliao basin, including the zone of catagenesis and metagenesis. Various methods, including vitrinite reflectance, Tmax, laser Raman spectroscopy, and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) were used to evaluate the samples' maturity. Through laser Raman analysis of representative samples from the Shahezi formation, most laser Raman parameters showed an inflection point or reversal when the thermal evolution of deep source rocks in the Shahezi formation reaches a certain stage. The variation trend of some Raman parameters and Ro has strong regularity (1.33% 〈 Ro 〈 3.52%). Based on FT-ICR MS, this research analyzed the relative content and molecular composition of polycyclic and heterocyclic aromatic compounds in soluble organic matter of lake source rock samples and comparison samples (marine shale). Quantitative maturity evaluation of organic matter was performed by converting the signal intensity of each compound. The fitting results of maturity parameter based on FT-ICR MS and Tmax indicated that the maturity parameter of the samples have high coefficient of correlations with maturity in the vitrinite reflectance (Ro) range of 1.33%–2.5% and the Tmax range of 420 °C–600 °C. The maturity parameter values decreased as Ro exceeded 2.5% and Tmax exceeded 600 °C. These findings are attributed to the thermal stability of organic compounds and the formation of pyrobitumen and graphite. The parameters of laser Raman spectroscopy also confirmed the growth of aromatic rings reflected by the maturity parameters of FT-ICR MS. These two methods revealed the structural changes of organic matter in the thermal evolution process from multiple perspectives and provided insights for the maturity evaluation of deep source rocks.

Description: The dynamic Neogene evolution of the Western European Alps included exhumation of the external crystalline massifs, thrust propagation to the foreland, drainage network reorganization, and major climatic variations. To constrain possible interactions between those factors, accurate geomorphological and sedimentological archives are required. However, intra-orogenic areas are subject to erosion, and extensive glacial cover during the Quaternary erased most of the geomorphic markers in the Alps. For these reasons, the genesis of the main features of the modern landscape, such as the major valleys and the drainage network, remains poorly understood. This study highlights how recently discovered karstic archives from the perched paleo-karst of the Obiou peak (Dévoluy massif, SE France) record the tectonic and drainage-network evolution of this part of the Alps during the Neogene. The Obiou caves are located at 2250-2380 m elevation, ∼1600 m above the modern Drac valley; they contain fluvial deposits including sand-clay units and rounded crystalline cobbles derived from the adjacent Ecrins-Pelvoux massif. As the Dévoluy and Ecrins-Pelvoux massifs are currently separated by the axial Drac valley (a major tributary of the Isère River), these cave sediments must have been deposited by a radial drainage system before incision of the modern Drac. We report new multi-method results from these sediments, including cosmogenic-nuclide burial dating (21Ne, 10Be, 26Al in quartz), provenance analysis (clast petrography and heavy-mineral analysis), and detrital thermochronology (apatite fission-track and (U-Th)/He) combined with a paleo-environmental reconstruction from palynology. 21Ne/10Be dating of cobbles and sand constrains the burial age to 11.5 ± 1.5 Ma, providing a maximum age for the modern axial drainage system and a minimum long-term incision rate of ∼140 m/Myr for the Drac valley. Comparison of the combined data to both modern rivers and nearby Oligocene foreland-basin deposits provides evidence for two successive drainage reorganizations. Early Miocene exhumation and development of high topography in the Ecrins-Pelvoux massif, linked to localized thrusting on a crustal-scale ramp, led to initial deflection of the antecedent radial drainage network, beheading its headwaters by establishment of the axial upper Durance valley. Subsequent propagation of thrusting into the subalpine Dévoluy massif and associated uplift during the mid to late Miocene led to establishment of the modern drainage system.

Description: Satellite altimetry has revolutionized river monitoring, particularly for hydrologists working on river flow monitoring in sparsely or ungauged areas. Despite this, there's a lack of a comprehensive evaluation of radar and lidar altimeters with varying sensor specifications for river water level retrieval, seasonal change characterization, and water surface slope (WSS) using gauged long-term water level and global navigation satellite system (GNSS) data. This study addresses this gap by combined evaluation of radar (ENVISAT to Sentinel-3) and lidar (ICESat-1, ICESat-2) altimeters along the Ganga River, from Prayagraj to Varanasi. We found that, all the radar altimetry missions showed better accuracy for water level retrievals (R2 〉 = 0.8; RMSE 0.11 to 1.16 m) and water level change quantification (RMSE 0.59 m). However, Sentinel-3 with SAR acquisition mode outperformed (RMSE 0.11 to 0.14 m) all the radar missions having low resolution mode. Despite lidar missions' high vertical accuracy, they show relatively lower accuracy in water level time series generation due to non-repeating characteristics. In contrary, ICESat-2 demonstrates potential in capturing spatial and seasonal variability of WSS, enhancing the accuracy of SWOT discharge products when combined with SWOT River database (SWORD). This study provides a comprehensive baseline for end-users interested in utilizing radar and lidar missions for various hydrological applications, including river discharge estimation. Moreover, the studied river reach shares the SWOT calibration orbit, allowing the utilization of generated satellite and in-situ databases for the effective evaluation of SWOT measurements.

Description: The TomoSense experiment was funded by the European Space Agency (ESA) to support research on remote sensing of forested areas by means of Synthetic Aperture Radar (SAR) data, with a special focus on the use of tomographic SAR (TomoSAR) to retrieve information about the vertical structure of the vegetation at different frequency bands. The illuminated scene is the temperate forest at the Eifel National Park, North-West Germany. Dominant species are beech and spruce trees. Forest height ranges roughly from 10 to 30 m, with peaks up to over 40 m. Forest Above Ground Biomass (AGB) ranges from 20 to 300 Mg/ha, with peaks up to over 400 Mg/ha. SAR data include P-, L-, and C-band surveys acquired by flying up to 30 trajectories in two headings to provide tomographic imaging capabilities. L- and C-band data were acquired by simultaneously flying two aircraft to gather bistatic data along different trajectories. The SAR dataset is complemented by 3D structural canopy measurements made via terrestrial laser scanning (TLS), Unoccupied Aerial Vehicle lidar (UAV-L) and airborne laser scanning (ALS), and in-situ forest census. This unique combination of SAR tomographic and multi-scale lidar data allows for direct comparison of canopy structural metrics across wavelength and scale, including vertical profiles of canopy wood and foliage density, and per-tree and plot-level above ground biomass (AGB). The resulting TomoSense data-set is free and openly available at ESA for any research purpose. The data-set includes ALS-derived maps of forest height and AGB, forest parameters at the level of single trees, TLS raw data, and plot-average TLS vertical profiles. The provided SAR data are coregistered, phase calibrated, and ground steered, to enable a direct implementation of any kind of interferometric or tomographic processing without having to deal with the subtleties of airborne SAR processing. Moreover, the data-base comprises SAR tomographic cubes representing forest scattering in 3D both in Radar and geographical coordinates, intended for use by non-Radar experts. For its unique features and completeness, the TomoSense data-set is intended to serve as an important basis for future research on microwave scattering from forested areas in the context of future Earth Observation missions.

Description: The detection of geothermal anomalies using Thermal Infrared (TIR) remote sensing data is challenging because of how sensor specifications (such as the infrared wavelength used for the measurement, spectral dependence of the emissivity, angle at which the measurement is made, state of the surface and height of the sensor above the surface) and physical parameters (such as solar radiation, topography, albedo, soil compaction and coherence of rocks) affect Land Surface Temperature (LST) retrieval and analysis. This work tests whether TIR remote sensing measurements with thorough spatial and temporal sampling can improve LST retrievals. Multi-temporal TIR data from 2000 through 2019 from Landsat 7 and 8 TIR instruments and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) were used to detect geothermal areas in the geologically active region of the southern Main Ethiopian Rift. In addition, field-based temperature data from 19 sites were evaluated for comparison to the remotely detected geothermal anomaly areas. We have used the single-channel algorithm and Normalized Difference Vegetation Index (NDVI) method of emissivity retrieval to derive LST for each year. The result shows that the mean LST is highest in 2003 (320.1 K) and lowest in 2019 (303.1 K). The change in mean LST was between −9 K to 13 K. These LST results from ASTER images were validated with MODIS LST products and showed a correlation coefficient 〉0.6. LST of the year 2003 has been much closer to the actual temperature value from field data. Fifteen sites (79%) fit with the identified geothermal anomaly areas. LST values in known geothermal activity sites show no correlation (〈 0.5) with time attesting. That is, even though LST varies with time (e.g., day and night and seasonal changes), the LST of areas with geothermal potential remain more or less constant on yearly basis.

Description: Permian chert successions were geographically extensive, spanning from the palaeoequator to the northern high latitudes. Large-scale chert production was abruptly terminated in the latest Permian, resulting in a multi-million-year “chert gap” in the Early Triassic. In order to constrain the tempo of chert production changes and understand their nature, we combine proxy data with Si box model analyses and focus on the Talung Formation of South China—the most representative Upper Permian siliceous unit in the equatorial Tethys. Two deepwater sections from the northern margin of the Yangtze Platform were investigated, showing that bedded cherts had already become less common in the Clarkina changxingensis conodont zone. The waning of chert production coincided with water column deoxygenation and an increase in carbonate and siliciclastic components in the late Changhsingian. The final collapse of the chert factory in South China predated the negative C excursion and climate warming but coincided with a sharp decrease in primary productivity. Together with Si box model output, we suggest that warming-induced expansion of the oceanic dissolved silica inventory (and decrease in burial efficiency) alone cannot maintain a multi-million-year chert gap. Instead, a loss of siliceous biomass during the end-Permian crisis is the primary cause of the Early Triassic chert demise.

Description: Predicting Earth Orientation Parameters (EOP) is crucial for precise positioning and navigation both on the Earth’s surface and in space. In recent years, many approaches have been developed to forecast EOP, incorporating observed EOP as well as information on the effective angular momentum (EAM) derived from numerical models of the atmosphere, oceans, and land-surface dynamics. The Second Earth Orientation Parameters Prediction Comparison Campaign (2nd EOP PCC) aimed to comprehensively evaluate EOP forecasts from many international participants and identify the most promising prediction methodologies. This paper presents the validation results of predictions for universal time and length-of-day variations submitted during the 2nd EOP PCC, providing an assessment of their accuracy and reliability. We conduct a detailed evaluation of all valid forecasts using the IERS 14 C04 solution provided by the International Earth Rotation and Reference Systems Service (IERS) as a reference and mean absolute error as the quality measure. Our analysis demonstrates that approaches based on machine learning or the combination of least squares and autoregression, with the use of EAM information as an additional input, provide the highest prediction accuracy for both investigated parameters. Utilizing precise EAM data and forecasts emerges as a pivotal factor in enhancing forecasting accuracy. Although several methods show some potential to outperform the IERS forecasts, the current standard predictions disseminated by IERS are highly reliable and can be fully recommended for operational purposes.

Description: Hydrothermal alteration is crucial in the formation of many ore deposits, with potassium (K) mobilization and cycling being prevalent. Potassic metasomatism of wall rocks generally forms K-bearing minerals, such as hydrothermal feldspar and mica. However, determining the source and redistribution of K (and other elements transported by the same fluid) in hydrothermal systems is challenging. K isotopes offer a potential solution to this problem. This study presents new K isotope data from two K-rich alteration assemblages — K-feldspar and sericite-quartz-pyrite — in the Jiaodong gold province of China. The data covers a compositional range from unaltered granites to syn-magmatic potassic alteration (formation of K-feldspar) and post-magmatic syn-mineralization phyllic alteration (formation of sericite). Potassic alteration in granite correlates with significant K addition, whereas phyllic alteration of earlier phases of magmatic and hydrothermal K-feldspar resulted in K loss. K-feldspar altered granites display similar δ41K values (–0.55 to –0.42 ‰ for whole-rocks and –0.56 to –0.48 ‰ for K-feldspar separates) as unaltered granite (–0.52 to –0.47 ‰). The narrow δ41K range suggests that magmatic fluid exsolution and magmatic-hydrothermal alteration have a minor effect on δ41K of the altered rock. Phyllic alteration of K-feldspar altered precursor rock leads to K loss and elevated δ41K values ranging from –0.36 to –0.19 ‰ for whole-rocks and –0.34 to –0.17 ‰ for sericite mineral separates. As sericite preferentially incorporates 41K, sericite will have higher δ41K values than the precursor K-feldspar, whereas the fluids will have lower δ41K values. Our study demonstrates that hydrothermal alteration may affect the K isotope composition of altered rocks in several ways, contingent on the nature of the involved phases, making K isotopes a promising tool for studying hydrothermal alteration and associated mineralization.

Description: We apply a transdimensional, hierarchical Markov chain Monte Carlo sampling algorithm (McMC) for 2-D cross-hole travel-time tomography in transversely isotropic media with vertical symmetry axis. The McMC approach has several advantages compared to classical inversion approaches: It is a global search, the high number of tested models allows the statistical analysis including the calculation of a reference model as well as uncertainty estimation, no initial models or regularization parameters are needed, the amount of data noise is automatically determined, and the model parametrization is data dependent and self-adjusting. For the forward solution a FD Fast Marching method utilizing second-order Godunov schemes is used. The performance of the approach is first tested on synthetic datasets to evaluate the potential and possible limitation to recover anisotropic models. We have shown that the recovery of models described by 2 anisotropic parameters (Thomsen parameters) and the vertical velocity is possible for observation scenarios with good distribution of sources and receivers. For more realistic observational geometries (i.e. cross-hole experiments), the recovery of the 3 parameters is limited, but still possible for example for the elliptical anisotropic case (ε = δ) or regarding the horizontal velocity. Finally we applied the McMC approach to a well-studied real cross-hole data set from the MALLIK 2002 research program and compared the results with previous conventional inversions.

Description: Significant progress in permafrost carbon science made over the past decades include the identification of vast permafrost carbon stocks, the development of new pan-Arctic permafrost maps, an increase in terrestrial measurement sites for CO2 and methane fluxes, and important factors affecting carbon cycling, including vegetation changes, periods of soil freezing and thawing, wildfire, and other disturbance events. Process-based modeling studies now include key elements of permafrost carbon cycling and advances in statistical modeling and inverse modeling enhance understanding of permafrost region C budgets. By combining existing data syntheses and model outputs, the permafrost region is likely a wetland methane source and small terrestrial ecosystem CO2 sink with lower net CO2 uptake toward higher latitudes, excluding wildfire emissions. For 2002–2014, the strongest CO2 sink was located in western Canada (median: −52 g C m−2 y−1) and smallest sinks in Alaska, Canadian tundra, and Siberian tundra (medians: −5 to −9 g C m−2 y−1). Eurasian regions had the largest median wetland methane fluxes (16–18 g CH4 m−2 y−1). Quantifying the regional scale carbon balance remains challenging because of high spatial and temporal variability and relatively low density of observations. More accurate permafrost region carbon fluxes require: (a) the development of better maps characterizing wetlands and dynamics of vegetation and disturbances, including abrupt permafrost thaw; (b) the establishment of new year-round CO2 and methane flux sites in underrepresented areas; and (c) improved models that better represent important permafrost carbon cycle dynamics, including non-growing season emissions and disturbance effects.

Description: Carbon-13 position-specific isotope analysis of fatty acids from vegetable oils was performed using Nuclear Magnetic Resonance in the present study. The measured 13C patterns are not totally in accordance with the conventional view of the relative 13C-depletion of acetogenic lipids and their alternation of 13C-enriched and 13C-depleted carbon positions. The results presented here provide a new evaluation of the isotopic fractionation associated with fatty acids biosynthesis. Whereas it is commonly acknowledged that the pyruvate dehydrogenase (PDH) is responsible for the 13C distribution within fatty acids, data from the present work demonstrate that the conversion of acetyl-CoA to malonyl-CoA catalyzed by acetyl-CoA carboxylase (ACC) needs to be considered while explaining the measured non-stochastic 13C pattern within fatty acids. These data combined with steady-state calculations give a new description of metabolic steps responsible for the typical 13C intramolecular distribution of acetogenic lipids. In addition, the non-stochastic pattern measured in these plant fatty acids is similar to those previously detected within long-chain n-alkanes suggesting a preservation through geological time and demonstrating the interest of position-specific isotope analysis for studying the evolution of metabolic pathways.

Description: Finding an appropriate satellite image as simultaneous as possible with the sampling time campaigns is challenging. Fusion can be considered as a method of integrating images and obtaining more pixels with higher spatial, spectral and temporal resolutions. This paper investigated the impact of Landsat 8-OLI and Sentinel-2A data fusion on prediction of several toxic elements at a mine waste dump. The 30 m spatial resolution Landsat 8-OLI bands were fused with the 10 m Sentinel-2A bands using various fusion techniques namely hue-saturation-value, Brovey, principal component analysis, Gram-Schmidt, wavelet, and area-to-point regression kriging (ATPRK). ATPRK was the best method preserving both spectral and spatial features of Landsat 8-OLI and Sentinel-2A after fusion. Furthermore, the partial least squares regression (PLSR) model developed on genetic algorithm (GA)-selected laboratory visible-near infrared-shortwave infrared (VNIR–SWIR) spectra yielded more accurate prediction results compared to the PLSR model calibrated on the entire spectra. It was hence, applied to both individual sensors and their ATPRK-fused image. In case of the individual sensors, except for As, Sentinel-2A provided more robust prediction models than Landsat 8-OLI. However, the best performances were obtained using the fused images, highlighting the potential of data fusion to enhance the toxic elements’ prediction models.

Description: The growing production and use of plastics are becoming a serious progressive issue and people pay increasing attention to the effects of plastics on ecosystems and human health. The availability of hyperspectral data from space sensors inspired us to study the feasibility to detect and identify different types of plastics in aircraft -, Goafen-5 (GF-5) and PRISMA satellite data by means of deep -, and machine learning models trained with spectral signatures. In this context, various inhouse and public spectral libraries are used to create a comprehensive database with mixed pixels of different plastic and non-plastic materials. The endmembers of plastic types involved in this study are polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyethylene terephthalate (PET) and polystyrene (PS), covering 95% of the global production. Additionally, some important varieties of industrial plastics types such as acrylonitrile butadiene styrene (ABS), ethylene vinyl acetate (EVA), polyamide (PA), polycarbonate (PC), and polymethyl methacrylate (PMMA) were included in the investigations. Different samples with varying optical properties (color, brightness, transmissivity) have been selected for each plastic type. As non-plastic materials we have chosen spectra of vegetation, rocks, soils and minerals contained in the public US libraries (ECOSTRESS and USGS). The number of spectra for the training of the deep learning and machine learning models was enlarged by a random linear mixing method and the resulting database was separated into a training and a test group for subsequent multi-label classification. Algorithms selected are a convolutional neural network (CNN), random forest (RF) and support vector machine (SVM). To investigate the transferability to any hyperspectral image data obtained by air-, and spacecraft sensors, we opted for a unification of the spectral response functions (SRF) and the spectral sampling intervals of all data. Validation is accomplished based on the test group of the spectral database, and tested by controlled laboratory and aircraft experiments recorded over surfaces with varying background materials. Results are further analyzed for the influence of different noise quantities and abundance levels. The performance of the three models is roughly balanced for the validation of the spectral data with an overall accuracy of 97%, 96%, and 95% for the CNN, RF, and SVM, models respectively. In the controlled lab experiments, various accuracy indicators, such as the recall rates and the comprehensive metrics F1-score, OA, and Kappa suggest the RF classifier as the most robust one, followed by the SVM and CNN models. As for the evaluation of the aircraft data from controlled experiments, the RF further outperforms the other two models, behaving most robustly and reliably against conditions with unknown plastics and unknown background surfaces. Thus, the RF was used to classify the ten types of plastics mentioned above in one GF-5 and two PRISMA satellite recordings of the same area. In comparison of both sensor systems, the RF produced high quality and transferable results for detecting plastic mainly related to greenhouses, sport fields, photovoltaic constructions and industrial sites that are discussed in detail in this paper.

Description: The present work was aimed to identify and quantify the offsets biasing the thermal rock strain as measured with clip-on extensometers at a mechanical testing system (MTS) so as to increase the reliability of such measured strain. We conducted an experiment via cycling the temperature of a sample of aluminum alloy between ambient temperature and 90 °C under the hydrostatic confining pressure as maintained at 2 MPa. Thereby, the readouts of the extensometers appeared to be irreversible subsequent to the temperature cycle mimicking residual deformation in the sample. The numerically simulated temperature in the setup of the testing system was heterogeneous throughout such temperature cycling test showing an irreversible plug-in temperature in particular. These temperatures resulted in the apparent amplification of the circuit as constituted by the extensometer and the amplifiers as well as the relevant reading offset. Such induced offset biased the actual sample strain besides the expansion (contraction) in the metal parts of the extensometers yielding the apparent irreversible strain in the sample. We presented a workflow for quantifying the amplification- and the metal part-related offsets. The validity of the workflow was demonstrated via rectifying the strain in a rock sample that was monitored throughout a temperature cycle between 30 °C and 40 °C. Our present work would be referable for experimental researches on thermal rock strain with similar setup of measurement. The amplification- and the metal part-related offsets could be likewise estimated and excluded from the measurements conducted elsewhere before the strain in a tested sample could be obtained.

Description: Seafloor massive sulfides are modern analogues to ancient volcanogenic massive sulfide deposits, which are particularly enriched in volatile and precious metals (e.g., Te, Au, Ag, Cu, Bi, Se) in subduction-related settings. However, the sources of metals are still poorly constrained, and it remains elusive, whether magmatic volatile influx controls their distribution in submarine hydrothermal systems on the plate tectonic-scale. Here, we demonstrate, for the first time, that Te, As, and Sb contents as well as related Te/As and Te/Sb ratios vary systematically with the δ34S composition of pyrite and native S, as reported by high-resolution coupled SIMS δ34S and trace element LA-ICP-MS micro-analysis. The better correlation of element ratios (Te/As, Te/Sb) opposed to trace element contents (e.g., Te) with δ34S in pyrite demonstrates that element ratios provide a more robust record of magmatic volatile influx than their absolute contents. On this basis, we define a quantitative threshold of high Te/As (〉0.004) and Te/Sb (〉0.6) ratios in pyrite that are indicative of magmatic volatile influx to submarine subduction-related hydrothermal systems. Two-component fluid mixing simulations further revealed that 〈5 % of magmatic volatile influx drastically changes the Te/As (and Te/Sb) ratio of the modelled fluid, but only slightly changes its δ34S composition. This suggests that Te/As and Te/Sb ratios are more sensitive to a magmatic volatile influx into seawater-dominated hydrothermal systems than δ34S signatures if the magmatic volatile influx was low. Beyond this, our results demonstrate that magma-derived fluid mixing with seawater only has a negligible effect on the magmatic volatile record of Te/As and Te/Sb, while the S isotope system is prone for seawater overprinting leading to commonly ambiguous source signatures. Thus, Te/As and Te/Sb systematics in pyrite provide a robust proxy to evaluate the contribution of magmatic volatiles to submarine hydrothermal systems from the grain- to plate tectonic-scale.

Description: A variety of industrial applications of hydrate-based CO2 capture and utilization technologies are hindered by the complex and slow hydrate formation; however, improving CO2 hydrate formation kinetics can be facilitated by adding the accelerators (promoters). In this regard, understanding the promotion mechanisms of these compounds on the hydrate formation at the molecular level would assist in either establishing feasible processes or finding more efficient promoters. In this work, CO2 hydrate growth and formation in the presence of hybrid metal particles (Ag, Cu, and Fe) and urea molecule has been explored through molecular dynamics (MD) simulation at below and above water freezing point. Different criteria were used to characterize and analyse the CO2 hydrate formation kinetics. The outcomes reveal that, although the mixture of Cu, Ag, and Fe metal particles has positive effects on the rate of hydrate formation above the ice point, the mixture of Cu, Fe, and urea (without the inclusion of Ag) in comparison with the other investigated systems, possesses the highest promotion effect on the clathrate hydrate growth rate. This combination of metal particles creates various functions in the solution phase adjacent to the hydrate surface. The metal particles and urea could promote the formation of new cages at the hydrate-solution boundary by decreasing the heat and mass transport resistances of CO2 in water. In addition, the improvement of combined metal particles and urea under water freezing was found to be less substantial. However, the behaviours of combined metal particles without urea at different thermodynamic conditions are quite dissimilar.

Description: This study focuses on the origin of fluorite ore deposits that are associated with the Eocene alkaline igneous suite of the Tamazert complex in the Moroccan High Atlas. Based on field observations and mineralogy, two major ore styles were identified: 1) a disseminated purple fluorite in aegirine-rich nepheline syenites (stage 1) and 2) a banded purple-white fluorite ore in karstic cavities and veins hosted in the Jurassic carbonate (stage 2). Both fluorite mineralization stages are commonly accompanied by calcite. The distribution of fluorite deposits at the peripheries of syenite and the surrounding Jurassic carbonates suggests the development of long-lived hydrologic systems around the shallow intrusion. Based on fluid inclusion, Rare Earth Elements and Yttrium (REY), and C–O isotopic constraints, this study reveals that different fluid systems were responsible for the deposition of fluorite ores in and around the Tamazert alkaline igneous complex. The disseminated interstitial fluorite precipitated from a F-rich magmatic-hydrothermal fluid, which exsolved from the highly evolved alkaline-silicate melt and was subsequently altered by Na–Ca metasomatic brines. Vein-type fluorite deposits hosted in the Jurassic carbonates precipitated from low salinity (1.6–8.5 wt% NaCl equiv.) and heated (Th = 118–157 °C) meteoric fluids, which migrated in response to the heat flow around the shallow intrusion. Fluid cooling, fluid interaction with Jurassic carbonates, and pressure fluctuations were the most important fluorite deposition mechanisms. The evolved melt provided F and REY for the interstitial fluorites, whereas meteoric fluids leached F− from syenites and other F-bearing igneous rocks. Based on the fractionation pattern, the REY inventory of the vein fluorites was acquired by interaction of meteoric fluids with Jurassic carbonates.

Description: In recent years, there has been a substantial increase in the induced seismicity associated with geothermal systems. However, understanding and modeling of injection-induced seismicity have still remained as a challenge. This paper presents a two-dimensional fully thermo-hydro-mechanical (THM) coupled boundary element approach to characterize the fault response to forced fluid injection and assess the effect of different injection protocols on seismic risk mitigation as well as permeability enhancement. The laboratory-derived rate-and-state friction law was used to capture the frictional paradigm observed in mature faults produced in granite rocks. All phases of stick-slip cycles, including aseismic slip, propagation of dynamic rupture, and interseismic periods, were simulated. The modeling results showed that the residual values of effective normal stress and static shear stress after a particular event completely dominate the constitutive behavior of fault friction during the next seismic event. The seismic energy analyses indicated that there is a negative correlation between the seismic magnitude and the total injected volume, such that a prolonged monotonic injection eventually results in the steady slip, rather than the seismic slip. Several fluid injection protocols were designed based on a volume-controlled (VC) approach and traffic light systems (TLS) to explore their effectiveness on the seismic risk mitigation and permeability enhancement. The results showed that cyclic injection based on TLS is the most effective approach for irreversible permeability enhancement of faults through promoting slow and steady slips. Our numerical simulations also revealed that fluid extraction (backflow-fixing bottom hole pressure at atmospheric pressure), regardless of the injection style, can considerably reduce the seismicity-related risks by preventing the fast-accelerated fracture slip during the post-injection stage. This study presents novel insights into modeling the rate-and-state governed faults exposed to forced fluid injection, and provides useful approaches for shear stimulation of faults with reduced seismic risks.

Description: Andean broken foreland zones, located to the east of the highest Andes, are associated with populated areas and sedimentary basins with relative economic importance. Understanding their seismogenic potential is crucial for urban development and infrastructure planning. In particular, the San Rafael Block is part of the broken foreland developed to the south of the Chilean-Pampean flat subduction zone. A local seismic network allows analyzing the seismogenic potential of the San Rafael Block. Earthquake distribution suggests a northeast-dipping ramp rooting at the lower crust, cropping out at the western topographic front of the basement uplift. Gravity data confirm the asymmetry of the San Rafael block with a western topographic front associated with the main structure that exhumes the basement. Seismological and gravity data allow proposing a west-verging structure, contrary to previous interpretations based on surficial structural data. The results presented here identify the highest shallow seismogenic potential on the western side of the block, near the El Nihuil dam, and only deep events at the eastern neotectonic front which allegedly hosted historical earthquake occurrences such as the Villa Atuel-Las Malvinas earthquake in 1929.

Description: A stationary mantle plume heats the overlying lithosphere from below, generating melts and causing lithospheric erosion. When the lithosphere moves away from the plume, it can be re-established by melt residues that have been since attached, partly due to cooling, at the base of the lithosphere. The Etendeka flood basalt region in northwest Namibia used to overlie the Tristan da Cunha mantle plume in the Early Cretaceous and thus provides an ideal place to examine plume-lithosphere interaction. Here we determine the upper mantle shear wave velocity structure of southern Africa down to 400 km depth by waveform inversion of multi-mode Rayleigh waves in order to find the imprints left by the Tristan da Cunha mantle plume. Thick lithosphere with high shear wave velocities is observed beneath the Congo and Kalahari Cratons, extending down to 200 km depth with the largest thickness beneath the Limpopo Belt. Along the landfall of the Walvis Ridge and Damara Belt, our model reveals a thick lithosphere down to 100–200 km depths. The thick lithosphere seems to constitute the Congo Craton, but the thick Congo cratonic lithosphere is extended farther south than observed in most of the previous models. We propose that the lithosphere along the landward extension of the Walvis Ridge was affected by magmatic processes related to the plume, but has been partially reconstructed since then by melt depletion and successive cooling. A high velocity anomaly beneath the northwest coast of Namibia down to a depth of ∼80 km coincides with distribution of the Etendeka basalt at the surface and the seaward-dipping reflectors at the continental margin. At sub-lithospheric depths, a low-velocity anomaly (at 100–200 km depth) and a high-velocity anomaly (at 250–350 km depth) can be detected. The origin of these anomalies could be related to an ongoing edge-driven convection process.

Description: The Campi Flegrei (CF) caldera, in southern Italy, is the source of some of the most powerful Late Pleistocene eruptions of the European sub-continent (e.g., Campanian Ignimbrite, Neapolitan Yellow Tuff eruptions). Although the CF caldera has been continuously and intensively investigated for decades, relatively little is known regarding its earliest volcanic activity. In this work, integrating existing and new tephrostratigraphic data, we provide a comprehensive and updated framework for the CF volcanic activity which has occurred at ∼160 ka and between ∼110 ka and ∼90 ka. The new tephrostratigraphic, geochemical (EMPA + LA-ICP-MS), chronological (40Ar/39Ar dating) and grain-size distribution data relate to CF tephra deposits preserved in mid-proximal (Campanian Plain), distal (Tyrrhenian Sea) and ultra-distal (Lower Danube area) sedimentary archives. Our results allowed us to recognize the presence of at least 13 CF eruptions covering the investigated time frame, with 12 eruptions occurring between 110 and 90 ka. Our high-resolution stratigraphic and chronological investigation also allowed us to recognize that the Triflisco/C-22 tephra, previously considered as a single marker layer, can be actually separated into three different events, sourced from within the CF area in the short time interval of ∼93-90 ka, suggesting a more complex and intense volcanic history than previously thought. Moreover, a Bayesian age-depth model, constrained by previous and new high precision 40Ar/39Ar ages, has led to a reliable estimate of the ages of those undated CF eruptions. Overall, the updated framework on the stratigraphy, chronology, dispersion, and geochemistry of the CF tephra of ∼160 ka and between 110 ka and 90 ka consolidates the notion that the Middle-Late Pleistocene activity in theCF area represents a significant stage of its volcanic evolution, characterised by intense and frequent explosive eruptions.

Description: Clathrate hydrates or gas hydrates have received worldwide attention due to their potential to be utilized in various sustainable technologies. The hydrate-based industrial applications as well as developing green technologies or safely extracting natural gases stored in the nature require profound comprehension of the phenomena associated with gas hydrates. On the flip side, identifying the characteristics of different hydrate formers and the effects of a wide range of introduced additives to these technologies is the critical objective, so that needs to be deeply investigated at both macroscopic and microscopic scales. The expensive experiments and limited availability of facilities at the nanoscale encourage researchers to apply novel computational methods and simulation approaches. For three decades, molecular dynamics (MD) simulations in the field of gas hydrates have been widely used to mathematically analyse the physical movements of molecules and the evolution of atomic positions in time. In this work, the mechanisms involved in the pure, binary, and mixed gas hydrates, and the impressions of promoters/inhibitors/minerals on gas hydrates were briefly reviewed. Also, the phenomena and properties associated with gas hydrates such as nucleation, growth, stability, dissociation, cage occupancy, storage capacity, morphology analysis, guest role, thermo-physical and mechanical properties, dynamical and vibrational behaviours of gas hydrates were reviewed. This work aims to provide readers with an extensive overview of MD simulations of gas hydrates to stimulate further research on this riveting field.

Description: Leaf area is a key structural characteristic of forest canopies because of the role of leaves in controlling many biological and physical processes occurring at the biosphere-atmosphere transition. High pulse density Airborne Laser Scanning (ALS) holds promise to provide spatially resolved and accurate estimates of plant area density (PAD) in forested landscapes, a key step in understanding forest functioning: phenology, carbon uptake, transpiration, radiative balance etc. Inconsistencies between different ALS sensors is a barrier to generating globally harmonised PAD estimates. The basic assumption on which PAD estimation is based is that light attenuation is proportional to vegetation area density. This study shows that the recorded extinction strongly depends on target detectability which is influenced by laser characteristics (power, sensitivity, wavelength). Three different airborne laser scanners were flown over a wet tropical forest at the Paracou research station in French Guiana. Different sensors, flight heights and transmitted power levels were compared. Light attenuation was retrieved with an open source ray-tracing code (http://amapvox.org). Direct comparison revealed marked differences (up-to 25% difference in profile-averaged light attenuation rate and 50% difference at particular heights) that could only be explained by differences in scanner characteristics. We show how bias which may occur under various acquisition conditions can generally be mitigated by a sensor intercalibration. Alignment of light weight lidar attenuation profiles to ALS reference attenuation profiles is not always satisfactory and we discuss what are the likely sources of discrepancies. Neglecting the dependency of apparent light attenuation on scanner properties may lead to biases in estimated vegetation density commensurate to those affecting light attenuation estimates. Applying intercalibration procedures supports estimation of plant area density independent of acquisition characteristics.

Description: The majority of geochemical and cosmochemical research is based upon observations and, in particular, upon the acquisition, processing and interpretation of analytical data from physical samples. The exponential increase in volumes and rates of data acquisition over the last century, combined with advances in instruments, analytical methods and an increasing variety of data types analysed, has necessitated the development of new ways of data curation, access and sharing. Together with novel data processing methods, these changes have enabled new scientific insights and are driving innovation in Earth and Planetary Science research. Yet, as approaches to data-intensive research develop and evolve, new challenges emerge. As large and often global data compilations increasingly form the basis for new research studies, institutional and methodological differences in data reporting are proving to be significant hurdles in synthesising data from multiple sources. Consistent data formats and data acquisition descriptions are becoming crucial to enable quality assessment, reusability and integration of results fostering confidence in available data for reuse. Here, we explore the key challenges faced by the geo- and cosmochemistry community and, by drawing comparisons from other communities, recommend possible approaches to overcome them. The first challenge is bringing together the numerous sub-disciplines within our community under a common international initiative. One key factor for this convergence is gaining endorsement from the international geochemical, cosmochemical and analytical societies and associations, journals and institutions. Increased education and outreach, spearheaded by ambassadors recruited from leading scientists across disciplines, will further contribute to raising awareness, and to uniting and mobilising the community. Appropriate incentives, recognition and credit for good data management as well as an improved, user-oriented technical infrastructure will be essential for achieving a cultural change towards an environment in which the effective use and real-time interchange of large datasets is common-place. Finally, the development of best practices for standardised data reporting and exchange, driven by expert committees, will be a crucial step towards making geo- and cosmochemical data more Findable, Accessible, Interoperable and Reusable by both humans and machines (FAIR).

Description: Forests account for nearly 90 % of the world's terrestrial biomass in the form of carbon and they support 80 % of the global biodiversity. To understand the underlying forest dynamics, we need a long-term but also relatively high-frequency, networked monitoring system, as traditionally used in meteorology or hydrology. While there are numerous existing forest monitoring sites, particularly in temperate regions, the resulting data streams are rarely connected and do not provide information promptly, which hampers real-time assessments of forest responses to extreme climate events. The technology to build a better global forest monitoring network now exists. This white paper addresses the key structural components needed to achieve a novel meta-network. We propose to complement - rather than replace or unify - the existing heterogeneous infrastructure with standardized, quality-assured linking methods and interacting data processing centers to create an integrated forest monitoring network. These automated (research topic-dependent) linking methods in atmosphere, biosphere, and pedosphere play a key role in scaling site-specific results and processing them in a timely manner. To ensure broad participation from existing monitoring sites and to establish new sites, these linking methods must be as informative, reliable, affordable, and maintainable as possible, and should be supplemented by near real-time remote sensing data. The proposed novel meta-network will enable the detection of emergent patterns that would not be visible from isolated analyses of individual sites. In addition, the near real-time availability of data will facilitate predictions of current forest conditions (nowcasts), which are urgently needed for research and decision making in the face of rapid climate change. We call for international and interdisciplinary efforts in this direction.

Description: The tectonic structure of the Eastern Alps is heavily debated with successive geophysical studies that are unable to resolve areas of ambiguity (e.g., the presence of a switch in subduction polarity and differing crustal models). In order to better understand this area, we produce a high resolution Moho map of the Eastern Alps based on a dense seismic broadband array deployment. Moho depths were derived from joint analysis of receiver function images of direct conversions and multiple reflections for both the SV (radial) and SH (transverse) components, which enables us to map overlapping and inclined discontinuities. We observe the European Moho to be underlying the Adriatic Moho from the west up to the eastern edge of the Tauern Window. East of the Tauern Window, a sharp transition from underthrusting European to a flat and thinned crust associated with Pannonian extension tectonics occurs, which is underthrust by both European crust in the north and by Adriatic crust in the south. The Adriatic lithosphere underthrusts northward below the Southern Alps and becomes steeper and deeper towards the Dinarides where it dips towards the north-east. Our results suggest that the steep high velocity region in the mantle below the Eastern Alps, observed in tomographic studies, is likely to be of European origin.

Description: Net catches of cephalopods were obtained during the cruises POS320/2 (March 2005), MSM49 (November/December 2015) and WH383 (March/April 2015) off Cabo Verde at a total of 18 stations at depths between 0 and 1000 m. Cephalopods were caught during POS320/2 with either a Isaacs-Kidd midwater trawl (IKMT) with a 6 m2 net opening, 4 mm mesh size equipped with a flowmeter, a Hydro-Bios Multinet Maxi with a 0.5 m2 net opening and 500 µm mesh size between the surface and 250 m water depth, or an 80 feet bottom trawl. Net sampling during MSM49 was conducted with two types of multiple opening/closing nets (MOCNESS) and an IKMT. The smaller MOCNESS had a net opening of 1 m2 opening (three nets with a mesh size of 2 mm and six nets with a mesh size of 335 μm) and the larger MOCNESS a net opening of 10 m2 opening (five nets, mesh size: 1.5 mm) and were deployed between the surface to 1000 m. The IKMT had a net opening of 7 m2 and ended in a cod end of 500 µm mesh size. It was deployed to a maximum depth of 500 m. During WH383 a pelagic trawl ('Aalnetz', Engel Netze, Bremerhaven, Germany) with a mouth opening of 16 x 30 m, length of 150 m including multiple opening-closing device, 260 meshes by 180 cm stretched mesh size at the front, a cod end 20 mm stretched mesh-opening and a 1.8 mm inlet sewn into last 1 m of cod end was used with a multisampler (Construction Services AS, Bergen, Norway) allowing depth-stratified sampling. During WH383 three strata (mean vertical extension of ca. 40 m) were trawled mostly during night and one time during daytime at depths between 30 and 700 m in horizontal tows for 30 minutes per stratum with a mean speed of three knots (2.8-3.3 kn). During this cruise, night trawls took place at 22:00 local time, and the day-time trawl at 12:00 local time. Onboard, cephalopods were identified morphologically to the lowest taxonomic level possible (species, genus or family), and whole specimens were preserved in formalin as voucher.

Description: Time-series data of physical oceanography and carbon/particle export were obtained from mooring HG-N-FEVI-37 in the Fram Strait in July 2018 - August 2019 as part of the Helmholtz infrastructure program Frontiers in Arctic Marine Monitoring (FRAM) and the long-term monitoring program at AWI HAUSGARTEN. The mooring was deployed during RV POLARSTERN expedition PS114, and recovered during PS121. The attached archive contains raw data files of two Seabird SBE37 microcats (nominal depths: 48m, 2626m; sampling interval 1h), two AADI RCM11 current meters (nominal depths: 2448m, 2624m; sampling interval 1h) and one AADI Seaguard current meter (nominal depth: 210m; sampling interval 1h). The mooring also included two sediment traps (nominal depths: 203m, 2441m). Auxiliary information such as sensor calibration sheets, mooring diagrams and schedule files are also provided, if applicable.

Description: Time-series data of physical & biological oceanography, nutrient biogeochemistry and molecular biology were obtained from mooring HG-IV-S-3 in the Fram Strait in July 2018 - August 2019 as part of the Helmholtz infrastructure program Frontiers in Arctic Marine Monitoring (FRAM) and the long-term monitoring program at AWI HAUSGARTEN. The mooring was deployed during RV POLARSTERN expedition PS114, and recovered during PS121. The attached archive contains raw data files of two Seabird SBE37 microcats (nominal depths: 26m, 52m; sampling interval 1h) and one Wetlabs ECO Triplet fluorometer (nominal depth: 24m; sampling interval 2h). The Wetlabs ECO PAR sensor (nominal depth: 24m; sampling interval 1h) was flooded and all data was lost. The mooring also included a McLane RAS water sampler (nominal depth: 24m) and a McLane PPS phytoplankton sampler (nominal depth: 26m). Auxiliary information such as sensor calibration sheets, mooring diagrams and schedule files are also provided, if applicable. The processed data of all sensors will be made available in separate entries.

Description: Time-series data of physical & biological oceanography, nutrient biogeochemistry, molecular biology and carbon/particle export were obtained from mooring HG-EGC-5 in the Fram Strait in July 2018 - August 2019 as part of the Helmholtz infrastructure program Frontiers in Arctic Marine Monitoring (FRAM) and the long-term monitoring program at AWI HAUSGARTEN. The mooring was deployed during RV POLARSTERN expedition PS114, and recovered during PS121. The attached archive contains raw data files of three Seabird SBE37 microcats (nominal depths: 72m, 241m, 508m; sampling interval 1h), three AADI RCM11 current meters (nominal depths: 79m, 248m, 511m; sampling interval 1h), one AADI Seaguard current meter (nominal depth: 987m, sampling interval 1h), one Wetlabs ECO PAR sensor (nominal depth: 72m; sampling interval 1h), one Wetlabs ECO Triplet fluorometer (nominal depth: 72m; sampling interval 2h), two Satlantics SUNA nitrate sensors (nominal depths: 72m, 241m; sampling interval 4h), one Sunburst SAMI-pCO2 sensor (nominal depth: 241m; sampling interval 1h) and two Sunburst SAMI-pH sensors (nominal depths: 72m, 241m; sampling interval 3h). One Sunburst SAMI-pCO2 sensor (72m) was flooded and all data was lost. The mooring also included two McLane RAS water samplers (nominal depths: 72m, 241m) and one sediment trap (nominal depth: 504m). Auxiliary information such as sensor calibration sheets, mooring diagrams and schedule files are also provided, if applicable.

Description: Time-series data of physical & biological oceanography, nutrient biogeochemistry and molecular biology were obtained from mooring F4-W-2 in the Fram Strait in August 2019 - June 2021 as part of the Helmholtz infrastructure program Frontiers in Arctic Marine Monitoring (FRAM) and the long-term monitoring program at AWI HAUSGARTEN. The mooring was deployed during RV POLARSTERN expedition PS121, and recovered during PS126. The attached archive contains raw data files of one Seabird SBE37 microcat (nominal depths: 249m; sampling interval 1h), one Satlantics SUNA nitrate sensor (nominal depth: 249m; sampling interval 6h), one Sunburst SAMI-pCO2 sensor (nominal depth: 249m; sampling interval 2h) and one Sunburst SAMI-pH sensor (nominal depth: 249m; sampling interval 3h). The mooring also included a McLane RAS water sampler (nominal depth: 249m). The profiling SBE19plus system that was operated on the NGK winch (nominal depth: 153m) was lost. Additionally, the available data could not be downloaded from the main controller due to a corrupt SD card. Auxiliary information such as sensor calibration sheets, mooring diagrams and schedule files are also provided, if applicable.

Description: Time-series data of physical & biological oceanography, nutrient biogeochemistry and molecular biology were obtained from mooring HG-IV-S-4 in the Fram Strait in August 2019 - June 2021 as part of the Helmholtz infrastructure program Frontiers in Arctic Marine Monitoring (FRAM) and the long-term monitoring program at AWI HAUSGARTEN. The mooring was deployed during RV POLARSTERN expedition PS121, and recovered during PS126. The attached archive contains raw data files of three Seabird SBE37 microcats (nominal depths: 18m, 23m, 47m; sampling interval 1h), two Seabird SBE56 temperature loggers (nominal depths: 28m, 38m; sampling interval 30s), one Wetlabs ECO Triplet fluorometer (nominal depth: 23m; sampling interval 2h) and one Wetlabs ECO PAR sensor (nominal depth: 23m; sampling interval 2h). One ISUS nitrate sensor (nominal depth: 23m) was flooded and no data is available. The mooring also included a McLane RAS water sampler (nominal depth: 23m) and a McLane PPS phytoplankton sampler (nominal depth: 25m). Auxiliary information such as sensor calibration sheets, mooring diagrams and schedule files are also provided, if applicable.

Description: Time-series data of physical oceanography and ocean current velocities were obtained from mooring HG-N-S-1 in the Fram Strait in September 2019 - June 2021 as part of the Helmholtz infrastructure program Frontiers in Arctic Marine Monitoring (FRAM) and the long-term monitoring program at AWI HAUSGARTEN. The mooring was deployed during RV POLARSTERN expedition PS121, and recovered during PS126. The attached archive contains raw data files of five Seabird SBE37 microcats (nominal depths: 29m, 45m, 72m, 244m, 394m; sampling interval 1h), five Seabird SBE56 temperature loggers (nominal depths: 39m, 94m, 144m, 315m; sampling interval 30s), one upward-looking RDI Workhorse 300kHz ADCP (nominal depth: 44m; sampling interval 1h) and one upward-looking RDI Workhorse Longranger ADCP (nominal depth: 394m; sampling interval 1h). The top float and attached SBE37 were lost a few months after deployment. Consequently, the upper 50 m of line, including one SBE37, two SBE56s and the 300kHz ADCP fell below the second set of floats at 50 m, which makes the ADCP data basically unusable. One SBE56 (nominal depth: 194m) was also lost due to a failure of the plastic attachment. Auxiliary information such as sensor calibration sheets, mooring diagrams and schedule files are also provided, if applicable.

Description: Time-series data of physical oceanography, nutrient biogeochemistry, molecular biology and carbon/particle export were obtained from mooring F4-S-3 in the Fram Strait in July 2018 - August 2019 as part of the Helmholtz infrastructure program Frontiers in Arctic Marine Monitoring (FRAM) and the long-term monitoring program at AWI HAUSGARTEN. The mooring was deployed during RV POLARSTERN expedition PS121, and recovered during PS126. The attached archive contains raw data files of two Seabird SBE37 microcats (nominal depths: 16m, 21m, 47m; sampling interval 1h), one Seabird SBE56 temperature logger (nominal depth: 38m; sampling interval: 30s), one Wetlabs ECO PAR sensor (nominal depth: 21m; sampling interval 2h), one Wetlabs ECO Triplet fluorometer (nominal depth: 21m; sampling interval 2h), one Satlantics SUNA nitrate sensor (nominal depth: 21m; sampling interval 6h), one Sunburst SAMI-pCO2 sensor (nominal depth: 21m; sampling interval 2h) and one Sunburst SAMI-pH sensor (nominal depth: 21m; sampling interval 3h). The mooring also included a McLane RAS water sampler (nominal depth: 21m), a McLane PPS phytoplankton sampler (nominal depth: 23m) and two sediment traps (nominal depths: 204m, 613m). Auxiliary information such as sensor calibration sheets, mooring diagrams and schedule files are also provided, if applicable.

Description: Time-series data of physical oceanography, ocean current velocities and bio-optical seawater properties were obtained from mooring HG-IV-SWIPS-2019 (alternative name: HG-IV-W-4) in the Fram Strait in August 2019 - June 2021 as part of the Helmholtz infrastructure program Frontiers in Arctic Marine Monitoring (FRAM) and the long-term monitoring program at AWI HAUSGARTEN. The mooring was deployed during RV POLARSTERN expedition PS121, and recovered during PS126. The attached archive contains raw data files of an integrated profiling SBE52plus system (nominal depth: 125m) and a single AADI Seaguard current meter (nominal depth: 154m; sampling interval: 1h). Due to technical issues with the SWIPS winch, the associated sensors only delivered useful profiling data during the first 2 months, albeit at a higher frequency than originally planned. Auxiliary information such as sensor calibration sheets, mooring diagrams and schedule files are also provided, if applicable.

Description: Time-series data of physical oceanography, ocean current velocities and hydroacoustics were obtained from mooring F4-19 in the Fram Strait in August 2019 - June 2021 as part of the Helmholtz infrastructure program Frontiers in Arctic Marine Monitoring (FRAM) and the long-term monitoring program at AWI HAUSGARTEN. The mooring was deployed during RV POLARSTERN expedition PS121, and recovered during PS126. The attached archive contains raw data files of 7 Seabird SBE37 microcats (nominal depths: 76m, 153m, 253m, 402m, 502m,731m, 1204m; sampling interval 1h), four Seabird SBE56 temperature loggers (nominal depths: 53m, 102m, 203m, 323m; sampling interval 30s), one upward-looking RDI Workhorse 300kHz ADCP (nominal depth: 53m; sampling interval 1h), one upward-looking RDI Workhorse Longranger ADCP (depth: 382m; sampling interval 1h) and two Nortek Aquadopp current meters (nominal depths: 730m, 1205m; sampling interval 20min). The 300 kHz ADCP stopped recording after 3 months due to a battery failure. The mooring also included an ASL Acoustic Zooplankton Fish Profiler (nominal depth: 103m; data archived elsewhere) and a Develogic Sonovault (nominal depth: 800m; data archived elsewhere). Auxiliary information such as sensor calibration sheets, mooring diagrams and schedule files are also provided, if applicable.

Description: Time-series data of physical oceanography, ocean current velocities and carbon/particle export were obtained from mooring HG-N-FEVI-39 in the Fram Strait in September 2019 - June 2021 as part of the Helmholtz infrastructure program Frontiers in Arctic Marine Monitoring (FRAM) and the long-term monitoring program at AWI HAUSGARTEN. The mooring was deployed during RV POLARSTERN expedition PS121, and recovered during PS126. The attached archive contains raw data files of two Seabird SBE37 microcats (nominal depths: 57m, 2646m; sampling interval 1h), two AADI RCM11 current meters (nominal depths: 2468m, 2644m; sampling interval 1h/2h) and one AADI Seaguard current meter (nominal depth: 230m; sampling interval 1h). The mooring also included two sediment traps (nominal depths: 223m, 2461m). Auxiliary information such as sensor calibration sheets, mooring diagrams and schedule files are also provided, if applicable.

Description: Time-series data of physical oceanography, ocean current velocities and carbon/particle export were obtained from mooring HG-IV-FEVI-40 in the Fram Strait in August 2019 - June 2021 as part of the Helmholtz infrastructure program Frontiers in Arctic Marine Monitoring (FRAM) and the long-term monitoring program at AWI HAUSGARTEN. The mooring was deployed during RV POLARSTERN expedition PS121, and recovered during PS126. The attached archive contains raw data files of five Seabird SBE37 microcats (nominal depths: 79m, 257m, 404m, 1204m, 2530m; sampling interval 1h), four Seabird SBE56 temperature loggers (nominal depths: 104m, 154m, 204m, 329m; sampling interval 30s), one Nortek Aquadopp current meter (nominal depth: 754m; sampling interval 20 min), one RDI Longranger ADCP (nominal depth: 413m; sampling interval 1h) and four AADI Seaguard current meters (nominal depths: 207m, 1234m, 2352m, 2528m; sampling interval 1h). The mooring also included three sediment traps (nominal depths: 200m, 1227m, 2345m) and one BioOptical Platform (nominal depth: 569m). Auxiliary information such as sensor calibration sheets, mooring diagrams and schedule files are also provided, if applicable.

Description: Time-series data of physical & biological oceanography, ocean current velocities, nutrient biogeochemistry, molecular biology and carbon/particle export were obtained from mooring HG-EGC-6 in the Fram Strait in August 2019 - June 2021 as part of the Helmholtz infrastructure program Frontiers in Arctic Marine Monitoring (FRAM) and the long-term monitoring program at AWI HAUSGARTEN. The mooring was deployed during RV POLARSTERN expedition PS121, and recovered during PS126. The attached archive contains raw data files of three Seabird SBE37 microcats (nominal depths: 67m, 236m, 453m; sampling interval 1h), three AADI RCM11 current meters (nominal depths: 74m, 243m, 456m; sampling interval 1h), one AADI Seaguard current meter (nominal depth: 981m, sampling interval 1h), one Wetlabs ECO PAR sensor (nominal depth: 67m; sampling interval 2h), one Wetlabs ECO Triplet fluorometer (nominal depth: 67m; sampling interval 2h), two Satlantic SUNA nitrate sensors (nominal depths: 67m, 236m; sampling interval 6h), two Sunburst SAMI-pCO2 sensors (nominal depths: 67m, 236m; sampling interval 2h) and two Sunburst SAMI-pH sensors (nominal depths: 67m, 236m; sampling interval 3h). The mooring also included two McLane RAS water samplers (nominal depths: 67m, 236m) and two sediment traps (nominal depths: 449m, 522m). Auxiliary information such as sensor calibration sheets, mooring diagrams and schedule files are also provided, if applicable.

Description: This dataset contains gas concentrations (CH4, CO2) in high spatial resolution from surface waters in September 2021 in a lake in the Mackenzie Delta ("Swiss Cheese Lake"). We measured surface water gas concentrations from small boats using a Microportable Greenhouse Gas Analyzer connected to a Dissolved Gas Extraction Unit (Los Gatos Research). The measurements were part of the "Mackenzie Delta Permafrost Field Campaign" (mCan2021) within the "Modular Observation solutions for Earth Systems" (MOSES) program.

Description: This dataset contains gas concentrations (CH4, CO2) in high spatial resolution from surface waters in September 2021 in a lake in the Mackenzie Delta ("Lake 3"). We measured surface water gas concentrations from small boats using a Microportable Greenhouse Gas Analyzer connected to a Dissolved Gas Extraction Unit (Los Gatos Research). The measurements were part of the "Mackenzie Delta Permafrost Field Campaign" (mCan2021) within the "Modular Observation solutions for Earth Systems" (MOSES) program.

Description: Despite the importance of surface energy budgets (SEBs) for land-climate interactions in the Arctic, uncertainties in their prediction persist. In situ observational data of SEB components - useful for research and model validation - are collected at relatively few sites across the terrestrial Arctic, and not all available datasets are readily interoperable. Furthermore, the terrestrial Arctic consists of a diversity of vegetation types, which are generally not well represented in land surface schemes of current Earth system models. This dataset describes the environmental conditions for 64 tundra and glacier sites (〉=60°N latitude) across the Arctic, for which in situ measurements of surface energy budget components were harmonized (see Oehri et al. 2022). These environmental conditions are (proxies of) potential drivers of SEB-components and could therefore be called SEB-drivers. The associated environmental conditions, include the vegetation types graminoid tundra, prostrate dwarf-shrub tundra, erect-shrub tundra, wetland complexes, barren complexes (≤ 40% horizontal plant cover), boreal peat bogs and glacier. These land surface types (apart from boreal peat bogs) correspond to the main classification units of the Circumpolar Arctic Vegetation Map (CAVM, Raynolds et al. 2019). For each site, additional climatic and biophysical variables are available, including cloud cover, snow cover duration, permafrost characteristics, climatic conditions and topographic conditions.

Description: At the end of the two year incubation of a subantarctic E. huxleyi culture (2015-11-20 to 2017-12-01), a temperature response experiment was performed using the Now (Day 747) and Future (Day 725) populations. Now and Future populations were grown in triplicate 28 ml Nalgene Oak Ridge-style centrifuge tubes (Sigma) in Now or Future medium, respectively. The tubes were held in an aluminium temperature gradient block similar to Thomas et al. (1963), that was heated at one end and cooled at the other using water maintained at constant temperature by refrigerated circulators (Julabo GmbH). The temperature regime resulted in a range of 10 temperatures along the length of the block from 6.2°C at one end to 16.5°C at the other, with a range within replicates at each temperature of 0.1 – 0.2°C. The block was lit from below which achieved a light level of 62 +/- 7 μmol m⁻² s⁻¹ at the bottom of the tubes in a 12 hour: 12 hour light: dark cycle. To ensure uniform light each replicate was manually rotated through the row holes at the set temperature during the incubation period. Measurements of in vivo chl-a were made daily and growth rates calculated from the least squares regression of the natural logarithm of in vivo fluorescence, versus time.

Description: Time-series data of physical oceanography and ocean current velocities were obtained from mooring SCO1-1 in the Fram Strait from Aug 2018 to Aug 2022. The mooring was deployed during RV MARIA S. MERIAN expedition MSM76 and recovered during RV POLARSTERN expedition PS131. The attached archive contains raw data files of four Seabird SBE16 SeaCATs (nominal depths: 410m, 472m, 538m, 609m; sampling interval 1h), three SBE56 temperature logger (nominal depths: 442m, 502m, 630m; sampling interval 20s) and two AADI RCM11 current meter (nominal depths: 411m, 610m; sampling interval 2h). Auxiliary information such as sensor calibration sheets, mooring diagrams, and schedule files are also provided, if applicable. The data of one SBE16 (472m) could not be obtained because the instrument did not connect.

Description: Time-series data of physical & biological oceanography, ocean current velocities, nutrient biogeochemistry, molecular biology and carbon/particle export were obtained from mooring HG-EGC-7 in the Fram Strait from June 2021 to July 2022 as part of the Helmholtz infrastructure program Frontiers in Arctic Marine Monitoring (FRAM) and the long-term monitoring program at AWI HAUSGARTEN. The mooring was deployed during RV POLARSTERN expedition PS126 and recovered during PS131. The attached archive contains raw data files of three Seabird SBE37 MicroCATs (nominal depths: 38m, 232m, 484m; sampling interval 1h), three AADI RCM11 current meters (nominal depths: 45m, 239m, 487m; sampling interval 1h), one AADI Seaguard current meter (nominal depth: 993m, sampling interval 1h), one Wetlabs ECO PAR sensor (nominal depth: 38m; sampling interval 1h), one Wetlabs ECO Triplet fluorometer (nominal depth: 38m; sampling interval 2h), two Satlantics SUNA nitrate sensors (nominal depths: 38m, 232m; sampling interval 4h), two Sunburst SAMI-pCO2 sensors (nominal depths: 38m, 232m; sampling interval 1h) and two Sunburst SAMI-pH sensors (nominal depths: 38m, 232m; sampling interval 3h). The mooring also included two McLane RAS water samplers (nominal depths: 38m, 232m; data archived elsewhere), one sediment trap (nominal depth: 480m; data archived elsewhere), and four PE samplers (nominal depths: 51m, 239m, 482m, 893m; data archived elsewhere). Auxiliary information such as sensor calibration sheets, mooring diagrams, and schedule files are also provided, if applicable. The pH sensor at 38 m, the ECO Triplet at 38 m and the SUNA at 232m had issues and did not record any valid data.

Description: Time-series data of physical oceanography, ocean current velocities and ocean acoustics were obtained from mooring F4-20 in the Fram Strait from June 2021 to July 2022 as part of the Helmholtz infrastructure program Frontiers in Arctic Marine Monitoring (FRAM) and the long-term monitoring program at AWI HAUSGARTEN. The mooring was deployed during RV POLARSTERN expedition PS126 and recovered during PS131. The attached archive contains raw data files of seven Seabird SBE37 MicroCATs (nominal depths: 76m, 153m, 253m, 402m, 502m, 727m, 1204m; sampling interval 15m/1h), four Seabird SBE56 temperature loggers (nominal depths: 53m, 103m, 203m, 323m; sampling interval 60s), one RDI Workhorse 300kHz ADCP (nominal depth: 53m; sampling interval 60s), one RDI Longranger ADCP (nominal depth: 382m; sampling interval 1h) and two AADI RCM11 current meter (nominal depths: 726m, 1205m; sampling interval 1h). The mooring also included an ASL Acoustic Zooplankton Fish Profiler (nominal depth: 103m, data archived elsewhere) and a Develogic Sonovault (nominal depth: 805m, data archived elsewhere). Auxiliary information such as sensor calibration sheets, mooring diagrams, and schedule files are also provided, if applicable. The SBE37 at 253m had power issues and stopped recording after ~5 months.

Description: Time-series data of physical oceanography and ocean current velocities were obtained from mooring SCO3-1 in the Fram Strait from Aug 2018 to Aug 2022. The mooring was deployed during RV MARIA S. MERIAN expedition MSM76 and recovered during RV POLARSTERN expedition PS131. The attached archive contains raw data files of two Seabird SBE16 SeaCATs (nominal depths: 246m, 405m; sampling interval 1h), one SBE37 MicroCAT (nominal depths: 296m; sampling interval 10m), two SBE56 temperature logger (nominal depths: 326m, 366m; sampling interval 20s) and one RDI Longranger ADCP (nominal depth: 404m; sampling interval 2h). Auxiliary information such as sensor calibration sheets, mooring diagrams, and schedule files are also provided, if applicable. One SBE56 (366m), the ADCP (404m) and one SBE16 (405m) were lost during recovery.