bluuebunny/crossref_metadata_2025 huggingface dataset:
New U-Pb detrital zircon ages from the Upper Cambrian – Lower Ordovician Cow Head Group in the Humber Arm allochthon, Western Newfoundland: continental-scale drainage, local deformation, and global stratigraphy
Authors: Iturralde Jorge , Lowe David
Published: March 2024

The Cambro-Ordovician Cow Head Group is an allochthonous sedimentary succession situated in the Humber zone of Western Newfoundland, the westernmost outer domain of the Appalachian orogenic belt in North America. It records submarine carbonate and rare siliciclastic deposits on a fault-bounded basin Laurentian margin shelf. It is characterized by interstratified carbonate conglomerate, mudstone, grainstone, packstone, wackestone, and lime mudstone. Mega-conglomerate along the Cambro-Ordovician boundary with anomalously coarse clasts are attributed to slope failure of the adjacent carbonate platform. While most authors agree that the transport and deposition of mega-conglomerate was related to seismicity and slope failure, their sedimentation have also commonly been linked to eustatic regression.To try and better understand the tectonic vs. eustatic forces driving the stratal evolution of the Cow Head Group, detrital zircon U-Pb ages were obtained from the Furongian Tuckers Cove and coeval Martin Point members of the Cow Head Group, and used to better constrain the tectonic, eustatic, and stratal evolution of the Laurentian passive margin. The Tuckers Cove Member is particularly significant due to its record of quartz sand influx into an otherwise carbonate- and mud-dominated basin, and because it underlies megaconglomerate sedimentation linked to terminal Cambrian faulting. Moreover, its sedimentation was coeval with the Furongian Steptoean positive carbon isotope excursion (SPICE), and with shelf regression and the delivery of quartz sand documented in otherwise carbonate-dominated intracratonic basins throughout Laurentia, including in central Iowa, Utah, and coeval shelf carbonates in Western Newfoundland. Such a correlation is supported by preliminary detrital zircon U-Pb results from the Tuckers Cove and Martin Point members, revealing a mixture of typical Laurentian cratonic populations including Archean (ca. 2.73 Ga), Paleoproterozoic (ca. 1.9 Ga), Mesoproterozoic (ca. 1.1 Ga), and Neoproterozoic (ca. 593 Ma) detrital zircons. This implies continental-scale erosion and sediment flux, with sediment sourced from a widespread Laurentian cratonic catchment during the Furongian, including Archean and Proterozoic sources like the Superior, Makkoviak and Grenville provinces, and Ediacaran rift-related strata from the western Newfoundland - Quebec Appalachians. At present these zircon data do not resolve tectonic versus eustatic controls on Cow Head Group sedimentation. Nevertheless, they validate the concept of continental-scale weathering, drainage, and clastic sedimentation across Laurentia during the Furongonian. More work is needed to understand the relationship between such punctuated and widespread sediment generation and Late Cambrian plate tectonics, eustasy, and SPICE.
Reconditioning a North Atlantic Hurricane View of Risk to a Chosen Present-Day
Authors: Webber Chris
Published: March 2024

When evaluating a view of risk for the purposes of pricing insurance business or mitigating potential large losses, one salient question that arises is whether the view is representative of the present-day. What time-period the ‘present-day’ represents is not a trivial decision, as it very much depends on the timeframe of the business you insure. An insurer that specialises in high-frequency transactions may choose to adopt a transient short-term view of risk, whereas insurers involved with real estate (e.g. mortgages) would require a much longer, stable view of the present-day to encapsulate the longevity of their liabilities. This study presents a framework and example of reconditioning a long-term historical modelled baseline, as one might determine from any catastrophe model, for North Atlantic Hurricane towards a 5-year medium-term present-day. This study takes a data-driven compartmentalised approach to reconditioning hurricane risk, by separately adjusting storm frequency, intensity, regionality and the temporal distribution of storms (i.e. storm clustering), such that each component is explicitly accounted for. This study aims to elucidate on the most pertinent sources of uncertainty present when reconditioning a view of risk, with application beyond hurricane risk.The results of this study suggest a coherent poleward shift in hurricane risk along the contiguous US coastline, alongside a general increase in hurricane risk. The explicit representation of clustering supports non-local inter-hurricane dependency and subsequently a change in the relationship between two key insurance metrics, the occurrence loss (max in a given year) and the aggregate loss (sum in a given year).
Use of organic trace substances for water management at a bank filtration site at the Rhine, Germany
Authors: Hellwig Alexandra , Woschick Lydia , Vogt Clara , Droste Björn , Antunovic Dirk , Albrecht Anette , Rohns Hans-Peter , Scheytt Traugott
Published: March 2024

The increasing demand for water in industry, agriculture, and private households as well as climate change are leading to more dynamic river and groundwater levels. This demands a new and improved monitoring approach to groundwater resources. The BMBF-funded research project iMolch (project number: 02WGW1667D) aims to develop sustainable water management concepts for Germany using innovative monitoring strategies. The general purpose of the investigations is to gain a complex understanding of hydrodynamic and hydrochemical processes in order to enable a more sustainable use of water resources on the basis of the indicator concept. This study investigates the spatial and temporal variation of different substances using as one example the urban bank filtration site in Düsseldorf, Germany. This site is used to draw conclusions on groundwater quality and dynamics as well as redox processes using the transport and retention of organic trace substances.Hydraulic and hydrochemical measurements were carried out fortnightly over a period of 1,5 years (31/01/2018–08/05/2019) across a study transect on the Rhine riverbanks with 15 measuring points. The analyses focus on changes in the concentrations of organic trace substances over time and the relationship to flow distance, flow duration and climatic conditions. Based on land use and occurrence, various organic compounds, such as fertilisers and pesticides, but also pharmaceuticals and detergents are monitored. The dependence between substance concentrations and Rhine river level decreases with increasing distance to the Rhine. Following the extreme drought in the summer of 2018, during which only low concentrations of trace substances were detected in the entire study area, there was an abrupt increase in substances entering the Rhine. This coincides with a significant Rhine high stand in the winter of 2018/2019. It is noticeable here that an increased concentration of substances discharged from the Rhine can also be detected at measuring points beyond the well gallery, on the land side of the measuring point transect.In dry periods, such as the summer of 2018, the proportion of bank filtrate in the raw water is significantly lower. In contrast, the Rhine floods the pumping well gallery during high water level periods, such as the winter of 2018/2019. During this time there is no landward flow to the pumping wells. The occurrence of organic trace substances even shows that the flood of the river Rhine pushes the water in the bank filtrate up to the well gallery and far beyond into the hinterland despite ongoing water pumping. These observations are crucial for the subsequent water management during different water levels of the river Rhine. Prediction models will be built up to help as water management tools to improve monitoring systems and for transfer of these results to other sites.
Adsorptive removal of humic acid from water by magnesium oxide
Authors: Sinha Rupal , Ghosal Partha Sarathi
Published: March 2024

Disinfection is a critical drinking water treatment procedure to guarantee water safety in urban water supply systems. However, an inevitable consequence is the generation of secondary pollutants, referred to as disinfection byproducts (DBPs). Toxicological researches have linked the ingestion of DBPs to harmful human health consequences like a higher risk of bladder cancer, reproductive problems, etc. Subsequently, the water authorities face immense challenges due to their existence in the drinking water. The foremost approach to limiting their generation in the drinking water is to eliminate their precursors prior-to disinfection. Humic acid (HA), a significant constituent of the natural organic matter in surface water, has been acknowledged as the primary precursor of DBPs. Thus, the present work aims to reduce humic acid content in water by magnesium oxide (MgO) adsorbent. To ascertain the mechanism of humic acid removal, characterizations of the adsorbents were conducted both before and after. At neutral pH level, the impacts of various process parameters are examined, including contact time, adsorbent dosage, initial humic acid concentration, and temperature. Moreover, studies were performed to assess the effects of different solution pH on the elimination of humic acid. The removal of humic acid was found to be increased at low pH. At pH 3, over 85% elimination was obtained. Furthermore, the role of several anions, including nitrate, sulfate, and chloride, in the adsorption of humic acid has also been evaluated. Overall, the present study would be conducive to proving the applicability of MgO for the reduction of HA and other organic matter from water and, hence, reduce the generation of DBPs.
Comparison of Wind profile models across the Ekman layer
Authors: Ansorge Cedrick
Published: March 2024

Knowledge of the wind profile in the planetary boundary layer is key to many applications from wind power engineering via boundary-layer schemes in the atmosphere to PBL closure in large- and mesoscale models. In this presentation, we will present an account on existing, operational wind profile models against a novel representation of the wind vector across the Ekman layer. Our novel representation of the wind profiles is based on a consistent non-dimensionalization of the entire boundary layer down to the surface and thus takes into account rotational effects in vicinity to the bottom boundary. We compare our theory to both existing wind profile models and to data from direct numerical simulation up to Reτ~4000.*This work is part of the project "trainABL" funded by the European Commission throgh the European Research Council (ERC) under its Starting Grant Scheme (ERC-2019-StG Grant No. 851374)
Timing of deformation in the Moravosilesian Foreland Basin – new insights from detrital zircon U-Pb dating
Authors: Xiao Yao , Rembe Johannes , Čopjaková Renata , Zhou Renjie
Published: March 2024

The Moravosilesian Foreland Basin preserves information of an important interval of the evolution of the eastern European Variscan Orogen. The basin largely was deposited on the Brunovistulian microplate, which underthrusts east-vergent Moldanubian and Moravosilesian units. It hosts an up to 7.5 km thick suite of siliciclastic marine sediments, recording the unroofing of the adjacent Moldanubian zone and the Moravosilesian nappes. Moreover, the basin records polyphase, late-stage Variscan, foreland-affecting deformation occurring between 330 Ma and 310 Ma. Outcrops of the basin can be found in the Drahany upland, southeast of the Czech town of Olomouc and the Nízký-Jeseník mountains, northeast of Olomouc. We conducted zircon U-Pb dating on four detrital samples of a suite of three marine formations in the Drahany upland (Yao et al., 2024). Maximum depositional ages (MDA) of the allochtonous Protivanov (328.7 ± 1.8 Ma), and the parautochthonous Rozstání (326.1 ± 1.0 Ma) and Myslejovice (335.1 ± 2.4 to 329.8 ± 2.4 Ma) formations are coeval to the depositional age of tuff layers within the shallow marine to continental, synorogenic, coal-rich Ostrava formation of the Nízký-Jeseník mountains, which were deposited between 329.2 ± 0.5 Ma and 324.2 ± 0.5 Ma.This finding challenges the established stratigraphy of the Protivanov, Rozstání and Myslejovice formations, which were previously based on detrital fossiliferous limestone pebbles. The MDAs of all three formations suggest a Serpukhovian rather than Visean depositional age. This has strong implications on the timing of NE-verging basin folding and thrusting. It constraines late-stage Variscan deformation propagation into the foreland to a timespan between
Implementation of quality control in a national soil moisture monitoring system
Authors: Jagersberger Verena , Pelzmann Valentina , Ehrendorfer Johannes , Eybl Jutta , Breinl Korbinian , Strauss Peter , Klammler Gernot , Weninger Thomas
Published: March 2024

The Austrian Hydrographic Service operates an extensive network of hydrographic measuring stations all over the country. The soil water measuring network comprises 62 stations where, among others, water content, matric potential, and soil temperature are measured. Only through the implementation of a consistent quality control system and data harmonization is it possible to provide expedient datasets that can be published or used for further purposes. Although automated quality control procedures for soil moisture are integrated in some national and international networks, there is currently no uniform quality control and harmonization of measurement data implemented in the Austrian network. Thus, the goal of this study was to evaluate existing options for the implementation of a system for the control of data quality with the highest possible degree of automatization.Technical implementation and structure of the stations vary greatly in the monitoring network in terms of measuring depths and installed sensors. Of the 62 measuring stations, 15 were set up as so-called type-2 measuring stations with a lower number of sensors and an IOT data transmitter. The aim of this type of station being reduced installation and maintenance effort as well as lower costs. On the other end of the complexity range, weighing lysimeters with field reference are maintained since decades.To establish the most appropriate procedure, established systems from international literature, like ISMN and SaQC or NASMD, were compiled and tested for their applicability in the Austrian monitoring network. For evaluation, the results of the automated quality check routines were compared to those of a visual expert check via an error matrix. The aim was to determine which quality control procedures are most effective and lead to the best results in terms of flagging different quality levels or likely errors. Leaning on the findings of the quality control procedures for soil moisture, a procedure for the matric potential shall be developed and implemented in the network, since this state variable of soils is crucial for understanding soil water processes.
The Growing Influence of Transportation Sector on PM10 Pollution in Warsaw metropolitan area (2019-2021)
Authors: Starzomska Aleksandra , Kamiński Jacek W. , Jeleniewicz Grzegorz , Strużewska Joanna , Norowski Aleksander
Published: March 2024

Air quality in urban areas is currently one of the most severe problems. High exposure to air pollution is due to high population density and higher pollutant concentrations than outside urban areas. A pollutant that exceeds limit concentrations in urban areas in Poland is PM10. The transport sector's contribution to air pollution throughout Warsaw (the capital of Poland) for PM10 particulate matter is 19%.A modelling study carried out in Warsaw shows that the transportation sector is one of the important sources of pollution. We will present PM10 concentrations in Warsaw metropolitan area from 2019-2021. Based on the scenarios calculated with the "brute-force" approach, the contributions of line sources from transport, automobiles, railroads and airports were assessed.The transportation sector's share in total emissions of PM10 is increasing annually. Over 3 years, the transportation sector's share in the Warsaw district increased by 5%. The largest share occurred in the two districts located in the centre and north of the city, an increase of 6 and 7%. Invariably, the lowest share of the territory of districts on the outskirts of the town is about 4%. In the 2019-2021 period, the transport sector's share increased in the Warsaw district by 4% and in districts adjacent to the city border by 3 %. In the districts located farther from the city centre, the increase in the share of emissions from the transport sector ranged from 1.5% to 0.5%.
On the generation of a meteotsunami, the case study of supercell storm, over Adriatic Sea.
Authors: Ferretti Rossella , Memmola Francesco , Coluccelli Alessandro , Brocchini Maurizio , Corvaro Sara , Penna Pierluigi , Falco Pierpaolo
Published: March 2024

In the afternoon of July 22, 2023, a very intense thunderstorm developed over the central Po Valley. It  quickly cross the Adriatic sea traveling from the center of the Po Valley to the Croatian coast, moving in the direction northwest-southeast. The thunderstorm  speed ranged between 50 and 80km/h, with  a downdraft exceeding 100 km/h, wind gust up to 120 km/h, which led to the formation of intense hailstorms with hail larger than 8 cm. The pressure difference between the front and central regions of storm,  reaced  6 hPa, with peaks up to 10 hPa. As the supercell moved towards the coast, the combined effects of the downdraft and the pressure variation, along with the storm's speed, likely triggered a meteotsunami. Both amateur evidences and instrumental observations showed the propagation of a  wave along the Adriatic coast, from North to South, with an amplitude of about 40 cm and a period of approximately 20 minutes. This phenomenon was observed from Ravenna (where the stormcell moves from land to sea) to Ancona, San Benedetto del Tronto, and Ortona with a propagation speed comparable with the storm  speed thus, in good agreement with a possible Proudman resonance. Physical analysis and numerical simulations of the atmosphere and ocean were performed  using numerical models: WRF (Weather Research and Forecasting System), ICON (Icosahedral Numerical Model), and ROMS (Regional Oceanographic Modeling System), coupled with SWAN (Simulating Waves in Nearshore) at 1 km horizontal resolution. The atmospheric results accurately reproduced  the storm's structure and evolution. The coupled ROMS and SWAN model was performed to assess the individual impacts of the downdraft, the vertical component of the downdraft, the pressure surge, and the overall storm surge. This work presents the outcomes and key factors contributing to the generation and amplification of this phenomenon. 
Differential influence of solution pH on the adsorption of fluoride in Icelandic volcanic soils varying in weathering degree and organic matter content
Authors: Denis Arnaud , Saldi Giuseppe , Delmelle Pierre
Published: March 2024

Fluorine, in the form of fluoride, is a minor but ubiquitous element found in magmas. It is released into the environment during volcanic degassing and exists as various salts on the surfaces of ash particles. Fluoride is also liberated during the weathering of magmatic rocks. The presence of fluoride in surface/ground waters and soils can pose a health hazard to humans and livestock. Additionally, fluoride enhances the dissolution of aluminosilicates during water-rock interaction. However, fluoride interacts strongly with iron (oxy)hydroxides (notably, ferrihydrite) and allophanes, secondary poorly crystallised minerals commonly found in volcanic soils. In volcanic regions, these reactions limit the mobility of fluoride significantly while causing its accumulation in the soil. We lack a quantitative description of the factors that control fluoride adsorption in volcanic soils, which hinders a comprehensive assessment of the geochemical behaviour of fluoride in these environments. Here we measured the fluoride adsorption envelopes (pH 2.8–7) of Icelandic volcanic soils with different weathering degrees and organic matter contents. The experiments were performed with a 1.3 mmol l-1 NaF solution and using pH-stat titration. The minimum and maximum fluoride adsorption typically occurs at pH of 2.8 and ≥6, respectively, reflecting the combined influence of pH and soil anion exchange capacity (AEC). At pH
Earthworms transport microplastic fibres in soils
Authors: Heinze Wiebke Mareile , Mitrano Denise M. , Cornelis Geert
Published: March 2024

Microplastic (MP) contamination of agricultural soils is a growing concern. Synthetic textiles shed MP fibres throughout their lifecycle, which can end up in agricultural soils through the application of urban by-products as soil amendment. MP fibres can affect soil structure and have potentially adverse effects on soil organisms in high concentrations. Polyesters, such as polyethylene terephthalate (PET), are highly resistant to biodegradation and thus very persistent in soils. Understanding the fate and transport behaviour of MP fibres in soils is therefore essential for estimating long-term exposure levels and the potential effects of MP fibres on soil health. Fibres are considered less mobile in soil porewater compared to other particle shapes, but earthworms potentially displace or ingest and excrete fibres, even those within the millimetre size range. Hence, MP fibres may be prone to biologically driven transport despite their relatively large length.We therefore investigated whether earthworm burrowing causes vertical transport of relatively large MP fibres in soil. We measured the redistribution of MP fibres in laboratory-based process-studies introducing anecic earthworms (Lumbricus terrestris) to soil columns (30 cm depth) spiked with PET MP fibres of 1.3±0.7 mm length. The MP fibres were spiked to an upper surface layer of soil and doped with a metal tracer to facilitate detection with inductively-coupled plasma mass-spectrometry after acid extraction. MP fibre transport was monitored over a total of 4 weeks in different depth segments of the soil columns. We further analyzed the size distribution of MP fibres for the different depths using a visual microscope. At the end of the experiment, MP fibres were detectable in all depth segments, highlighting the transport potential of MP fibres by larger earthworms, such as L. terrestris. We also observed that the depth-dependent decline for MP fibres was stronger in comparison to previous studies with smaller particles proposedly because these are ingested more easily. Accordingly, we expect a relative enrichment of smaller MP fibres in the deeper soil layers. We conclude that biologically driven transport may overall be influenced, but less dependent, on particle length than other transport processes such as advective transport in soil pores. In the field, MP fibres will be exposed to bioturbation processes for much longer times than in this current study, likely resulting in a successive downward transport of even larger fibres depending on the local soil conditions and earthworm activity.
Building Response Operators Using Koopman Formalism: the Link between Free and Forced Variability
Authors: Moroney John , Lucarini Valerio , Zagli Niccolo'
Published: March 2024

Linking free and forced variability is one of the key challenges in climate science. As the climate system is an out of equilibrium one, the standard application of the fluctuation-dissipation theorem is out of scope. It has been shown in the past that it is possible to construct response operators that can be used to perform climate change projections using a more general formulation of response theory for nonequilibrium systems. Nonetheless, such operators lack the key property of interpretability: one cannot separate the contribution to the total response coming from different modes of natural variability of the system. We show here in a few low-dimensional models how this issue can be taken care of by taking advantage of the Koopman formalism. One can then write the response operator as a sum of terms each associated with a specific mode of variability. The obtained results also shed light on previous findings by Hasselmann and colleagues and on recently proposed data-driven methods aimed at deriving response operators from data.
Model Tree and Regularization Approaches for Estimation of Missing precipitation Records
Authors: Nguyen Thu , Azad Anika , Teegavarapu Ramesh
Published: March 2024

Missing precipitation records occur for several reasons, and their estimation is a significant challenge due to the spatial-temporal variability of precipitation. In this study, model tree (MT), regression tree (RT) approaches, and different variations of optimization formulations combined with three regularization schemes (i.e., ridge regression and Elastic net) are proposed and used to estimate missing precipitation data. Concepts of objective selection of sites for estimating missing data using correlations and distributional similarity are also used. The MT and RT models based on optimization and regularization approaches were developed and tested to estimate missing daily precipitation data from 1971 to 2016 at twenty-two rain gauges in Kentucky, U.S.A. The models were analyzed and evaluated using multiple performance and error measures. Results indicate that MT-based and regularization models provided the best estimates considering the performance measures. Regularization models provided better estimates of missing data than the optimization models while reducing the complexity of the model and improving performance. Objective selection of the sites for estimation also improved missing data estimation.
Linking energy efficiency of surface runoff, logistic growth and landform changes
Authors: Zehe Erwin , Schroers Samuel , Kleidon Axel , Eiff Olivier , Savenije Hubert
Published: March 2024

This study proposes a free energy centred approach to surface runoff and morphological development of hillslopes and rivers. The starting point is the strong analogy between the functioning of engines on the one hand and watersheds on the other hand. Like an engine converts energy input into motion/kinetic energy, watersheds and hillslopes convert potential energy inputs by rainfall into potential energy and kinetic energy of surface runoff. The latter determines the maximum work water can perform on the sediments. Similar to the energy efficiency of an engine, relating the free energy/work output to the energy input, we define energy efficiencies for each process in the aforementioned cascade of rainfall-runoff formation and sediment transport. The efficiency in generating potential energy of surface runoff depends on precipitation, the runoff coefficient, topography and landforms. While the vast amount of the runoffs potential energy is dissipated, a minute amount sustains the kinetic energy of surface runoff and stream flow, driving erosive changes in watersheds. Here the efficiency depends on the controls of driving and frictional forces: the geo-potential gradient, material roughness and hydraulic radius of the river. We applied this framework to surface runoff at the hillslope scale and the Amazon basin. At the hillslope scale we found that typical morphological stages of hillslope forms and related transitions of dominant erosion processes (from soil creep, rain splash, to soil wash) evolve towards a declining energy efficiency in surface runoff. This implies a reduction in power to trigger future landform changes. However, rill and river networks do essentially the opposite. By reducing the specific dissipation, they increase the efficiency in the conversion of potential into kinetic energy of overland and streamflow. In several cases, rill networks were found to even maximize total power of surface runoff in the sheet and rill domains. For the Amazon and its tributaries, we found distinct self-similar patterns of stream flow potential energy along each river course. Starting from the source, potential energy in stream flow was growing with downstream distance, up to a maximum value, and exhibited from there an almost linear decline to the river mouth. This implies that the maximum work the river can perform is growing from its source to this maximum, as the rapid growth in the stream flow mass over-weights the steep downstream decline in geopotential. We found the same behavior at the hillslope scale. In a third step, we found that for the largest terrestrial river networks on the world that Horton’s laws of stream area and length were close the Feigenbaum constants characterising bifurcations of logistic growth at related deterministic chaos. This suggest parallels between the interplay of growth and mortality of populations, and the interplay of stream power generation and its turbulent dissipation.
Isotope fingerprinting of organically complexed chromium – the natural story of a pollutant
Authors: Wang Wenhao , Chrastný Vladislav , Hettler Johannes , Kumar Naresh , Kraemer Stephan
Published: March 2024

Chromium (Cr) is a redox sensitive element and Cr isotope composition (δ53Cr) has been widely utilised to reflect the extent of Cr(VI) reduction during Cr pollution mitigation, as well as changes in past atmospheric/oceanic oxygenation. Whilst redox transformations are thought to primarily drive the Cr isotopic variability in modern aquatic environments, other processes, such as ligand promoted dissolution, can occur, potentially overprinting the intrinsic δ53Cr signal.In this study, laboratory-controlled batch and flow-through column experiments on two distinct soil materials were conducted to understand the leaching behaviour of Cr and Cr isotopes, under both oxygenated and O2-free conditions. Significant dissolution of Cr(III), together with Fe and Mn, from the solid phase in the presence of low-molecular-weight organic acids was observed over the time course of all experiments. Initial isotope analyses on Cr(III)-citrate complexes show that δ53Cr values are ~ −0.60 to −0.09‰, reflecting the pristine Cr isotopic signature of the two soil materials. In addition, whilst formation of authigenic Fe particles means that a fraction of dissolved Cr is scavenged, such that solid phase Cr may be associated with Fe, Cr does not seem to be remobilised during reductive dissolution of Fe (and Mn) oxides in these experiments.Results from this study have several implications. Firstly, as Cr is a known carcinogen, increased levels of organic ligands, e.g., in paddy field systems, can cause increased environmental and health risks. Secondly, organic ligands may play an overlooked role in modulating the input and removal processes of dissolved Cr to/from various environments. Finally, ligand-bound Cr(III) likely has a ‘stabilised’ isotopic signature that is distinct from Cr(VI), making it possible to trace this ‘additional’ Cr in aquatic systems; it is difficult to characterise or quantify these Cr-organic complexes using conventional analytical methods.This work is part of the CHROMA project funded by H2020-MSCA-IF (101031974).
Navigating the first years of flood regulation in the Venice Lagoon - a delicate balance between humans and nature
Authors: Michielotto Alessandro , Tognin Davide , Mel Riccardo Alvise , Finotello Alvise , Carniello Luca , D'Alpaos Andrea
Published: March 2024

Coastal areas, such as deltas estuaries and lagoons, are highly dynamic environments shaped by the interplay of depositional and erosional forces. While providing a multitude of valuable ecosystem services, spanning from wave-energy dissipation to habitat provision and carbon sequestration, they also serve as important hubs, supporting large populations. However, communities living along low-lying coastal environments are currently threatened by rapidly rising sea levels and the intensification of the extreme events, which increase the flooding risk.To reduce the risk of floods, different engineered structures (e.g., flood-gate barriers) have been adopted worldwide. Here, we present a study delving into the first years of operation of the Mo.S.E. system, the mobile storm-surge barrier system activated in the Venice Lagoon starting from October 2020. The research aims to investigate the impacts of the flood regulations, exploring the potential counter-effects of water level reductions on the lagoonal ecosystems.During storm surges, floodgte barriers at the three lagoon inlets are raised to temporarily disconnect the lagoon from the open sea, keeping water levels below a prescribed safety threshold to avoid the flooding of the city of Venice. However, the intertwined action of wind waves and reduced water levels may generate an intensification of the eorional processes across the tidal flats. The reduced water levels negatively affect also salt-marsh sedimentation. Although erosion processed can increase the suspended sediment volume within the tidal basin, lower water levels reduce salt-marsh flooding depths and duration, and the sediment deposition over marsh surfaces.We also explore a hypothetical scenario considering an optimized flood regulation procedure, aimed at reducing the duration of flood-gate closures. Slightly higher water levels, prescribed by the optimized regulation, would allow sediment deposition over salt-marsh surfaces without compromising the preservation of urban areas from flooding.Our findings offer valuable insights, underscoring the paramount importance of promoting effective defensive intervention policies. Our results might help to identify feasible solutions that better balance the preservation of  coastal urban areas with the protection of natural coastal ecosystems
Are the physical barriers sustainable to saltwater intrusion under changing climatic conditions?
Authors: Sadhasivam Rajagopal , Srinivasan Venkatraman , Nambi Indumathi
Published: March 2024

Physical barriers such as subsurface dams (SSD) and cutoff walls (COW) and hydraulic barriers such as freshwater recharge and saltwater pumping are some of the widely studied control measures to mitigate saltwater intrusion (SWI) in coastal aquifers. Past studies have focused on optimizing the design of these control measures, including installation location, depth, pumping, and injection rates under the specified hydraulic and boundary conditions of the aquifer. On the other hand, sea-level rise (SLR) and freshwater flux reduction (FFR) (caused by groundwater pumping and/or reduced aquifer recharge) alter the hydraulic conditions and can potentially change the optimum design of these control measures as well as their performances. Unlike hydraulic barriers with some potential to adapt to these altered hydraulic conditions (by modifying pumping and injection rates), physical barriers are fixed and not easily modifiable. Hence, the performances of physical barriers are highly subjected to changing climate conditions (SLR and FFR), and systematic vulnerability assessment of physical barriers is lacking. Here, we use a widely studied field-scale problem to assess the vulnerability of SSD and COW under SLR and FFR scenarios using constant flux inland boundary conditions. Our results indicate that SSD and COW are resilient to SLR, with SSD being more effective compared to COW. Furthermore, SSD and COW are highly vulnerable to FFR. While SSD is more effective than COW under small declines in FFR, COW outperforms SSD under large FFR. Using sensitivity simulations, we show that our results are valid across a range of aquifer and barrier parameters. These results add insights to the design of physical barriers, taking into account future climatic conditions. Also, our analysis aids in selecting appropriate mitigation measures to address the changing climatic conditions.
An expert-based framework for susceptibility analysis for tsunamigenic landslides in Indonesia
Authors: Braun Anika , Dohmen Katrin , Fernandez-Steeger Tomas Manuel
Published: March 2024

Landslides can induce extremely high tsunami waves, reaching several tens of meters. These tsunamis typically impact only localized areas within about 100 km of the landslide. The most significant impact is generated in the immediate proximity to the landslide. Due to the short time between wave initiation and reaching the coast, early warning systems for these events have not yet been developed. This study aims to assess the exposure of particular regions to this specific form of tsunami with a focus on the Indonesian coastline. The approach not only evaluates the potential for the occurrence of landslides but also assesses whether there is a potential for the formation of particularly high tsunami waves, e.g. due to reflection or superposition of waves.The limited number of known landslides that have triggered tsunamis in the past is not sufficient to enable a data-driven analysis. Hence, a heuristic approach is adopted in this study. It consists of the following 4 steps.(1) Orientation workshop: A group of international scientists working on landslides and tsunamis discusses and selects parameters that might be relevant for the analysis.(2) Online survey: The parameters selected in step (1) are ranked by a larger group of scientists.(3) Result workshop: The survey results are discussed in another workshop.(4) Susceptibility analysis: The parameter ratings from the online survey are transformed into a model for tsunamigenic landslide susceptibility evaluation and a susceptibility analysis for a pilot area in Indonesia is conducted.During the orientation workshop, 37 parameters were selected to be considered for the susceptibility analysis. As part of the online survey, these were evaluated by a total of 25 scientists working on landslides and tsunamis. For landslide susceptibility in Indonesia, subaerial and submarine slope angle, presence of oversteeped slopes, landform, lithology, presence of lowly consolidated sediments, distance to active tectonic faults, depth and magnitude of historic earthquakes, precipitation, and pore water pressures were voted as crucial parameters. The work on this study is still ongoing and step (4) is planned to be conducted in the future.The results of tsunamigenic landslide susceptibility mapping can aid local officials in elaborating mitigation measures for this type of tsunami. Even minor earthquakes in these areas could trigger landslides, creating waves despite not typically causing seismic tsunamis. Hence, it might be necessary to adapt land-use and evacuation plans in at-risk regions to account for both seismic and landslide-induced tsunamis. The limited availability of high-resolution data representing the submarine environment is the main obstacle, which hampers a deeper analysis of submarine landslide susceptibility and the potential for tsunami wave generation. Future efforts must be made to close this data gap and enable effective protection of coastal populations from landslide-induced tsunamis.
Advancing regional to local climate knowledge: Insights from German NUKLEUS and UDAG Consortium Projects
Authors: Cusinato Eleonora , Braun Christoph , Feldmann Hendrik , Geyer Beate , Keuler Klaus , Ludwig Patrick , Moemken Julia , Sieck Kevin , Trachte Katjia , Frühe Barbara , Steger Christian , Pinto Joaquim G.
Published: March 2024

According to the latest assessment of the IPCC report, regional climate changes in mean climate and extremes are expected to become more widespread and pronounced. As a consequence, climate hazards are projected to increase in every region of the world leading to the necessity of developing climate adaptation and mitigation plans.  In this context, the German Federal Ministry of Education and Research (BMBF) funded several projects whose primary goal is to provide up-to-date regional and local climate projections that will subsequently form the bases for climate German adaptation strategies.This contribution aims at illustrating ongoing research within the framework of two of these consortium projects, namely NUKLEUS (Usable Locale Climate Information for Germany) and UDAG (Updating the data basis for adaptation to climate change in Germany) to the EURO-CORDEX community. The innovative aspect of both projects lies in the creation of an unprecedented ensemble of convection permitting climate projections for “hydrological Germany" at high temporal and spatial resolution, which allows to provide information on climate change at regional and local scales.For this purpose, NUKLEUS downscaled three global coupled models (GCMs) within the CMIP6 framework using three regional climate models (namely REMO, COSMO-CLM6 and ICON-CLM) first to the EURO-CORDEX Eur-11 domain (12 km) and subsequently to the km-scale at approximately 3 km resolution over Germany for the scenario SSP3-7.0. However, the resulting ensemble is not sufficient to provide actionable climate change information. UDAG project aims at overcoming this limitation by downscaling a wide range of CMIP6-GCMs (6-8) using ICON-CLM first to 12 km resolution providing regional climate simulations for Europe for the scenarios SSP3-7.0 and SSP1-2.6 and then to approximately 3 km to generate climate projections specifically targeted for "hydrological Germany."Given the shared use of common CMIP6-GCMs in the downscaling process for both projects, and considering the early stage of the UDAG project, this contribution presents initial insights from the NUKLEUS project. Biases evaluation analysis is conducted, revealing noteworthy distinctions in the RCMs at 12 km and 3 km compared to the CMIP6-GCMs. Subsequently, key metrics for extreme values statistics related to temperature and precipitation are discussed. In summary, these methods and findings serve as a preliminary groundwork for the forthcoming UDAG analysis. 
Glacier meltwater, a potential source of methane in West Antarctica Peninsula
Authors: Brusselman Axelle , Crabeck Odile , Muller Sofia , Araujo Pablo Alejandro , Dogniez Martin , Lepoint Gilles , Michel Loïc , Danis Bruno , Dall'Osto Manuel , Fripiat François , Delille Bruno
Published: March 2024

During the late Austral summer of 2023, we carried out three surveys in the West Antarctic Peninsula (WAP) from Horseshoe Island (67° 514 south) to the Northern tip of the Peninsula to document the distribution of CH4 in surface waters. We observed a striking feature in Dodman Island in the Grand Didier Channel with a marked supersaturation of methane (up to 400%) in the bay of the island, whereas saturation (maximum of 260%) was observed elsewhere. Our main hypothesis is that this supersaturation is linked to meltwater from the glacier on the island, which acts as a source of methane in the water column. This hypothesis is supported by vertical profiles of CH4 concentration, field observations of sub-glacial water flowing to the surface of the water column, as well as by variations in salinity showing a freshwater inflow. This phenomenon has already been suggested in the Arctic (Lamarche-Gagnon et al., 2019) but does not yet seem to have been demonstrated in the Antarctic. These data show that it would be worthwhile investigating areas with active glaciers to determine whether melting glaciers can be a source of methane for the Antarctic water column.
Why climate models underestimate the exacerbated summer warming in Western Europe
Authors: Schumacher Dominik L. , Singh Jitendra , Hauser Mathias , Fischer Erich M. , Wild Martin , Seneviratne Sonia I.
Published: March 2024

Since 1980, mean summer temperatures in Western Europe have warmed three times faster than global mean temperatures. This strong warming of about 2.3 °C tends to be underestimated in model simulations, affecting both global and in particular regional climate models (RCMs). We demonstrate that the majority of global and regional climate model simulations exhibit weaker circulation-related warming contributions than observed, partly accounting for the discrepancy between observations and models. Crucially, most RCMs from the Coordinated Regional Downscaling Experiment (CORDEX) additionally underestimate the thermodynamic contribution to warming that occurs primarily in response to anthropogenic forcings. Because the driving global climate models of the CORDEX RCM simulations all provide at least sufficient, and typically even excessive global background warming, this partly compensates for the frequent lack of regional thermodynamic warming. We find that the main cause of the latter is the widespread use of constant aerosol concentrations in RCM simulations, such that the regional brightening and associated warming in Europe due to aerosol reductions in the past decades is not captured. We infer a summer warming underestimation of about 0.5 °C since 1980 when relying on RCMs with constant rather than evolving aerosols over Western Europe, although this depends on the GCM–RCM ensemble subset. Locally, in parts of Eastern Europe with stronger aerosol reductions than further west, the discrepancies can exceed 1 °C. The use of constant aerosol representations not only contributes to the summer warming discrepancy in Europe but also impacts other seasons except winter. At the timescales of heat extremes, the aerosol representation-inflicted mismatch manifests even more clearly: heatwave intensity changes since 1980 are already underestimated by RCMs with constant aerosols by about 1°C in western Europe, and the warming discrepancies grow even larger in projections, exceeding 2 °C in large parts of Europe and at the end of the ongoing century. Our work highlights the importance of representing all relevant external forcings and associated responses in RCM simulations, as the added value of high-resolution climate projections is questionable when the strong regional brightening and warming in Europe and other regions is by design omitted.
Dynamic shifts in eastern boundary upwelling systems: climate-change driven impacts on frequency, intensity and spatial patterns of upwelling.
Authors: Panthakka Anjaneyan , Kuttippurath Jayanarayanan
Published: March 2024

Global temperatures and atmospheric carbon dioxide (CO2) have been rising since the industrial period due to increased anthropogenic activities. The adverse impact of this warming and changing climate systems significantly reflects on Eastern Boundary Upwelling Systems (EBUS) in the global ocean. Here, we investigate the influence of climate change on EBUS by analysing the long-term changes in upwelling and productivity within these ecologically crucial regions. Based on the Bakun's (1990) hypothesis, which suggests that modifications in land-sea thermal gradients affect atmospheric pressure cells and subsequently influence upwelling patterns in EBUS, we analyse the daily time series data of wind and sea surface temperature (SST). Furthermore, we assess the impact of changes in these upwelling patterns on productivity.We employ a set of matrices to objectively characterise upwelling dynamics, focusing on frequency, intensity and duration across four EBUS. Our findings reveal a compelling relationship between SST changes and upwelling events, demonstrating a decrease in SST associated with increased upwelling frequency and reduced intensity. Interestingly, variations emerge among EBUS and regions within them, notably an intensification of upwelling in the Humboldt Current systems. Despite this observed response, clear evidence supporting the associated changes in wind dynamics that drive upwelling remains elusive.This study enhances our understanding of how shifts in global temperatures impact EBUS, which are crucial systems in regulating fisheries and marine ecosystems. Consistent changes in the timing, intensity and spatial heterogeneity of coastal upwelling are evident in most EBUS. The spatially variable yet subtle changes are observed in accordance with climate change patterns. These findings provide valuable insights into the complex interplay between climate-driven shifts and the dynamic nature of EBUS, suggesting implications for marine ecosystems and coastal communities.