bluuebunny/crossref_metadata_2025 huggingface dataset:
Seasonal DMSP production dynamics in temperate waters driven by significant contributions from both eukaryotic and prokaryotic autotrophs
Authors: Hopkins Frances , Airs Ruth , Williams Beth , Ma Qianyao , Zhu Xiaoyu , Todd Jonathan
Published: February 2023

The influence of dimethyl sulfide (DMS) on climate is potentially large but highly uncertain. Some of this uncertainty results from the over-simplification of biological drivers of marine DMS production within predictive models. The available models rely on chlorophyll (chl) as the sole biological parameter and often fail to replicate observations, particularly during highly productive events with elevated seawater DMS concentrations. The major precursor for DMS is dimethylsulfoniopropionate (DMSP), an abundant compatible solute produced by many marine eukaryotes and prokaryotes. Despite its importance, knowledge of how, why and by what DMSP is produced is limited. For example, haptophytes and dinoflagellates typically produce 50-100 times more DMSP per unit chl than diatoms and prochlorophytes - yet the relevant enzymes have until recently been poorly characterised, limiting our understanding. Furthermore, although the DMSP synthesis genes and their transcripts are widespread in surface ocean bacterial communities, the contribution by this group of organisms to total DMSP production is so far unquantified.Here, we explore the diversity and expression of functional DMSP synthesis and lyase genes alongside DMS/P biogeochemical states and rates over a spring-summer time series (March – July 2021) at an established time series station in temperate shelf sea waters, to characterise the biological drivers of DMSP and DMS production.DMSP concentrations ranged from <5 nmol L-1 to 160 nmol L-1, with peaks in mid April and late June. The April peak coincided with significant increases in the transcription of eukaryotic DMSP biosynthesis genes. As the season progressed, the eukaryotic transcripts fell dramatically, whilst an increase in transcription of prokaryotic (cyanobacterial) DMSP biosynthesis genes was observed. DMS concentrations in the spring/summer productive period were characterised by three sharp peaks in early May (27 nmol L‑1), early June (13 nmol L-1) and late June (20 nmol L-1),interspersed with lower concentrations of ~2 - 6nmol L-1. Each peak was associated with distinct prokaryotic community composition. Some relationships were observed between the DMS peaks and the transcription of eukaryotic DMS production genes and prokaryotic DMS degradation genes, demonstrating the fine balance of processes which determine net DMS production in the surface ocean.  Overall, we observed that both eukaryotic and prokaryotic autotrophs significantly contributed to seasonal variation in DMSP production in these temperate waters.
A coupled data assimilation framework with an integrated surface and subsurface hydrological model
Authors: Tang Qi , Delottier Hugo , Schilling Oliver S. , Kurtz Wolfgang , Brunner Philip
Published: February 2023

We developed an ensemble based data assimilation (DA) system for an integrated hydrological model to facilitate real-time operational simulations of water quantity and quality. The integrated surface and subsurface hydrologic model HydroGeoSphere (HGS) (Brunner & Simmons, 2012) which simulates surface water and variably saturated groundwater flow as well as solute transport, was coupled with the Parallel Data Assimilation Framework (PDAF) (Nerger et al., 2005). The developed DA system allows joint assimilation of multiple types of observations such as piezometric heads, streamflow, and tracer concentrations. By explicitly considering tracer and streamflow data we substantially expand the hydrologic information which can be used to constrain the simulations.    Both the model states and the parameters can be separately or jointly updated by the assimilation algorithm.  A synthetic alluvial plain model set up by Delottier et al., (2022) was used as an example to test the performance of our DA system.  For flow simulations, piezometric head observations were assimilated, while for transport simulations, noble gas concentrations (222Rn, 37Ar, and 4He) were assimilated. Both model states (e.g., hydraulic head or noble gas concentrations) and parameters (e.g. hydraulic conductivities and porosity) are jointly updated by the DA. Results were evaluated by comparing the estimated model variables with independent observation data between the assimilation runs and the free run where no data assimilation was conducted. In a further evaluation step, a real-world, field scale model featuring realistic forcing functions and material properties was set up for a site in Switzerland and carried out for numerical simulations with the developed DA system. The synthetic and real-world examples demonstrate the significant potential in combing state of the art numerical models, data assimilation and novel tracer observations such as noble gases or Radon.
The GOLDFINGER Project: Imaging a Late-Variscan gneissic dome. Preliminary results.
Authors: Palomeras Imma , Gomez-Barreiro Juan , Ayarza Puy , Martínez-Catalán José R. , Martí David , Ruiz Mario , Barrios Santos , Dos Santos Kelvin , Sanchez-Sanchez Yolanda , Elez Javier , Yenes Mariano , DeFelipe Irene , Pérez-Cáceres Irene , Crespo Elena , Castiñeiras Pedro
Published: February 2023

The late Variscan gravitational collapse and coeval magmatism are getting the attention of the community due to their role in the generation of strategic mineral resources. In this regard, the GOLDFINGER project’s main scope is to study how the Variscan orogenic architecture controls the generation of strategic ore deposits (i.e. Sn, W, Nb, Ta, Sc, Au, Sb). With this goal, a 3D model of a gneissic dome with several mineral deposits will be constructed based on high-resolution geophysics (Seismic/Gravity/Magnetism), and regional geology. The study area encompasses the Martinamor gneiss dome which represents a Late-Variscan syn-collisional extensional system with a well-preserved architecture. This gneiss dome structure presents low topography, relatively flat structural geometry in-depth, and contrasting lithotypes regarding seismic, gravity, and magnetic properties. As part of the project, in spring 2022 the area was covered by 30 low-period seismic recorders with 2Hz sensors in a regular grid. The 35x40 km grid consisted of 60 nodes, separated by approximately 4.5 km. To achieve the final node number, the stations were deployed twice, first in a regular grid with nodes each 6 km, and then the grid was moved 3 km to the west and to the south for a second deployment. The seismic stations were continuously recording in the field for up to 40 days in each deployment. We are using a state-of-the-art technique to retrieve high-resolution seismic images of the Martinamor gneiss dome using seismic interferometry applied to seismic background noise (SBN). The preliminary results show that SBN interferometry allows us to 1) detect and track discontinuities that can be related to the structures that control the ore deposits, and 2) identify the location of deep intrusions that are inferred as sources of metallogenic fluids. In this contribution, we present the GOLDFINGER geophysical experiment and the preliminary results.Funding: grant PID2020-117332GB-C21 funded by MCIN/ AEI /10.13039/501100011033; EIT-Raw Materials project 17024 (SIT4ME: Seismic Imaging Techniques for Mineral Exploration); SA085P20 from the JCYL government, and TED2021-130440B-I00 by MCIN. IP is funded by MCIU and USal (BEAGAL18/00090).
Differences in the Formation and Evolution of the Inner Rainbands during the Rapid Intensification of Typhoon Cempaka (2021)
Authors: Fan Xueqi
Published: February 2023

The organization and propagation of inner rainbands of landfalling Typhoon Cempaka (2021) during rapid intensification (RI) are investigated from two ground-based Doppler radars. Dual-Doppler analysis based on ground-based radars provide long-lasting high temporal and spatial three dimensional wind fields to examine the possible mechanisms for the organization of inner rainbands. In the early period when the convections were preferentially located inside the RMW, deformation plays an important role in the formation of inner rainbands. Convective cells were advected by the cyclonically rotating tropical cyclone swirling flow while being deformed into spiral shapes. In the later period when the convections were preferentially located outside the RMW, positive part of wavenumber-2 reflectivity associated with the rainband is collocated with the positive component of wavenumber-2 vorticity. The wavenumber-2 reflectivity moved at an azimuthal phase speed of 64.5% of the local tangential wind and very close to the theoretically predicted speed. It is evident that vortex Rossby wave is associated with the organization of rainband in the later stage.
Water preparation methods of dissolved organic fraction determination for C-14 AMS measurements
Authors: Molnár Anita , Janovics Róbert , Veres Mihály , Molnár Mihály
Published: February 2023

The determination of 14C in dissolved inorganic carbon (DIC) fraction has important task in nuclear environmental monitoring and water base protection. The aim of my research is to develop a preparation method for the 14C determination of dissolved organic carbon (DOC) and to develop sample preparation of total carbon containing both organic and inorganic fractions. In practice, the measurement of dissolved inorganic carbon (DIC) 14C is of essencial importance for example in environmental studies, as the amount of DIC is usually more than 100 times the amount of DOC and there is an easy, rapid preparation method. However, it is often difficult to interpret water dating and water residence time by measurement of dissolved inorganic fraction, because DIC dissolved in water can come from several sources: deep CO2 uptake and bedrock dissolution, not only from the surface biogenic environment at the time of seepage. Therefore, the measurement of dissolved organic carbon (DOC) component gets more importance around nuclear facilities because of its efficiency in detection of anthropogenic effect. To this aim, preparation methods have been developed that are suitable to determine the specific 14C activity concentration of the total dissolved carbon (TD14C) as well as of the dissolved organic form (non-purgeable organic fraction). The measurement of 14C in organic form is a difficult task, the amount of material is usually very small (only a few µg) and samples are difficult to handle furthermore the necessary sample volume usually is more than 500 mL. One of the solutions for DO14C sample preparation is an application of wet oxidation method. In this case the organic components are oxidized by acid and CO2 is extracted. This type of sample preparation technique is basically very sensitive about modern and fossil carbon contamination. However, the method has the additional disadvantage of high chemical demand (hence the contamination introduced) and a complicated and long sample preparation process. These disadvantages can be overcome by testing the total dissolved fraction 14C, which contains both fraction: inorganic and organic forms. Sample preparation can be performed in a significantly shorter time and at lower cost and can be used effectively alongside DI14C for the detection and monitoring of organic forms, for example in environmental monitoring of nuclear facilities. By determining DI14C and TD14C and carbon concentrations, DO14C can be estimated with a good approximation (±10% rel. error). ,,Prepared with the professional support of the Doctoral Student Scholarship Program of the Co-operative Doctoral Program of the Ministry of Innovation and Technology financed from the National Research, Development and Innovation Fund.” The research was supported by the European Union and the State of Hungary, co-financed by the European Regional Development Fund in the project of GINOP-2.3.4-15-2020-00007 “INTERACT”.
Metallogenetic potencial of the Paleoproterozoic mafic-ultramafic Hamutenha intrusion (SW Angola). New data from PLANAGEO project
Authors: Morais Igor , Batista Maria João , Represas Patricia , Albardeiro Luis , Prazeres Cátia , Plastov José Manuel , Sousa João Carlo , Bravo Paulo , Sousa Pedro , Carvalho João , Rodrigues José Feliciano , Oliveira Daniel , Cordeiro Domingos
Published: February 2023

In the SW sector of the Angolan shield occur the Kunene Anorthositic Complex (KAC), one of the most remarkable magmatic anorthositic suites worldwide. The KAC is considered a long-lived magmatic system that operated in the area intermittently during the Mesoproterozoic (1450 ± 2 Ma to 1371 ± 2.5 Ma). Smaller mafic-ultramafic intrusive bodies ranging in composition from dunite to harzbugite, pyroxenite, troctolite and gabbro are located in the KAC periphery (e.g. Epupa, Ombuku, Hamutenha, Oncócua). The Hamutenha body is a 3 km long oriented NW-SE, banded intrusion with internal zonation hosted in the Paleoproterozoic granitic rocks (1970 ± 2 Ma). The internal zone is composed by rocks with ultramafic nature, mostly harzburgites and dunites with diorites in the external zone.The Hamutenha outcrop has been identified as having great potential to host Cr, Ni and PGE mineralizations. Previous soil geochemistry work, carried on dunitic outcrops (3000 samples) identified high anomalies in Cr (12 500 mg/kg-1), Ni (3100 mg/kg-1) and Co (375 mg/kg-1). The Hamutenha dunites are depleted in platinum-group elements (PGE) although the high Ti content in spinels (15.66 % of TiO2) indicate a parental magma relatively rich in Ti, similar to another intrusions of same type with mineralizations of Fe-Ti-Cr and Pt-Pd sulfides.In the PLANAGEO project (National Geology Plan of Angola), the National Laboratory of Energy and Geology (Portugal) (LNEG) carried out detailed geochemical and geophysical surveys in the Hamutenha outcrop in order to evaluate the metallogenetic potential. Soil geochemistry showed high contents in Cr (618 mg/kg-1), Co (76 mg/kg-1), Ni (100 mg/kg-1) and 1.15% of TiO2 over ultramafic rocks. The Hamutenha rocks project in the MORB-OIB field, very close to E-MORB composition, indicating that the enriched mantle (EMORB) was the source of the magma that generated ultramafic rocks. This samples show high content in Cr (1555 mg/kg-1), Ni (1855 mg/kg-1) and Co (145 mg/kg-1). The PGE show low values, except in one sample with 21 μg/kg-1) of Pd. The mineralogical analysis using SEM showed that the opaques paragenesis of Hamutenha dunitic rocks are composed by Cr, Mg and Ti spinels, chromite, magnetite, titanomagnetite, pentlandite and Ni-Fe metallic alloys. The pentlandite shows appreciable values of Ni (30.46 – 32.40 wt.% of Ni) and the chromiferous spinels 10.43 – 22.47 wt.% of Cr.
A new clumped isotope-temperature calibration of cultured coccoliths under different pCO2 and temperature conditions
Authors: Clark Alexander J. , Torres Romero Ismael , Jaggi Madalina , Bernasconi Stefano M. , Stoll Heather
Published: February 2023

Carbonate clumped isotope thermometry, based on the temperature-dependence of clumping of 13C and 18O in the carbonate molecule (Δ47) is a promising tool for paleoclimate reconstruction. In the last few years many discrepancies among Δ47-temperature calibrations have been resolved across the range of relevant paleoclimate temperatures (Meinicke et al., 2020; Anderson et al., 2021). However, there might be other environmental effects on biogenic carbonates from parameters such as the pCO2 and growth rates of the organisms that are still unresolved. We provide a new assessment of the temperature dependence of clumped isotopes in laboratory grown biogenic carbonate at well-constrained experimental conditions, with results from three species of coccolithophores across a growth temperature range of 6-27°C. The three cultured species cover a range of growth rates, growth conditions and species-specific carbon and oxygen vital effects. Because variations in pCO2 and media carbon chemistry are known to trigger vital effects in carbon and oxygen isotopes in coccoliths, we decoupled the temperature solubility effect on CO2 by manipulating culture CO2 independently. Three pCO2 levels at reduced, present day and elevated levels; 200, 400 and 1000 ppm respectively, were kept constant for at least two different temperatures through a continuous culturing set-up. Our new multi-parameter comparison, using updated standardization approaches, provides a critical test of previous conclusions (Katz et al., 2017) that coccolithophore clumped isotopes show little to no vital effects and are close to abiotic equilibrium. Thus, we have performed the first calibration of coccolith calcite and clumped isotopes combining different temperature and pCO2 conditions.References:Anderson, N. T., J. R. Kelson, S. Kele, M. Daëron, M. Bonifacie, J. Horita, T. J. Mackey, et al. 2021. "A Unified Clumped Isotope Thermometer Calibration (0.5–1,100°C) Using Carbonate‐Based Standardization." Geophysical Research Letters 48 (7).Katz, A., M. Bonifacie, M. Hermoso, P. Cartigny, D. Calmels. 2017. “Laboratory-grown coccoliths exhibit no vital effect in clumped isotope (Δ47) composition on a range of geologically relevant temperatures.” Geochimica et Cosmochimica Acta 208: 335-353.Meinicke, N., S.L. Ho, B. Hannisdal, D. Nürnberg, A. Tripati, R. Schiebel, and A.N. Meckler. 2020. "A robust calibration of the clumped isotopes to temperature relationship for foraminifers." Geochimica et Cosmochimica Acta 270: 160-183.
Methods of weather forecasting and navigation in the N-Atlantic in the Middle Ages tested with a modern NWP tool
Authors: Ólafsson Haraldur , Weitzel Philipp , Rousta Iman , Soula Benoît , Jacopin Léo
Published: February 2023

Weather forecasting in the Middle Ages was most likely mostly based on persistence, and there are indications that persistence and correlation between elements of the sensible weather, in particular fog, helped in navigation in the N-Atlantic during the Viking age.Investigation of the weather in the CARRA dataset, produced by dynamic downscaling, reveals that the connection between wind directions and fog is different on the leg between Iceland and Greenland from what it is between Iceland and Norway.  Consequently, the same navigational rules could not be applied on both these legs, making navigation from Iceland to Greenland even more difficult than navigation from Norway to Iceland.  This, in addition to very high frequency of fog and of strong winds in the vicinity of Greenland, made sailing and navigation between Iceland and the Medieval Nordic settlements in Greenland exceptionally difficult.    
Lake water level modeling using a Long-Short-Term-Memory (LSTM) neural network
Authors: Jankowfsky Sonja , Li Shuangcai , Salinas Jose , Nicotina Ludovico , Hilberts Arno
Published: February 2023

High lake water level-induced flooding could cause catastrophic property damage and loss of life. The frequency and severity of lake flooding has been increasing in recent years, likely due to climate change . To quantify the lake flooding risk, accurate modeling of lake water level is critical. However, simulation of lake water level is a challenging problem in the field of hydrology, due to the various hydrological and morphological characteristics of river-lake systems. To solve this challenge, Moody's RMS has developed a coupled physical based – Machine Learning model, using a Long-Short-Term-Memory (LSTM) neural network which incorporates both dynamical variables and static variables . This model is tested and validated with representative lakes in the Southeastern US, and compared with other models including linear, dense, decision tree regression, random forest, and convolution neural network, which demonstrates the reliability and superiority of LSTM in lake water level modeling
Biogeochemistry and Peat Properties of Restored Wetlands
Authors: Smeds Jacob , Nilsson Mats , Skyllberg Ulf , Björn Erik , Bertilsson Stefan , Bishop Kevin , Öquist Mats
Published: February 2023

The major objective behind peatland restoration is to improve ecosystem services, such as increased biodiversity, increased carbon sequestration, increased groundwater storage, and improved surface water quality. However, a century or more of drained conditions has drastically changed the soil properties in relation to natural wetlands and this is likely to profoundly influence the potential for various biogeochemical peat processes. Thus, peatland restoration may result in undesired impacts and potential environmental threats. Two such undesired effects are increased methane production and increased mercury methylation.In this study, we investigated how nine boreal peatlands across a latitudinal gradient in Sweden have been affected by rewetting after up to a century of drained conditions. Each peatland was sampled for three 50 cm deep peat cores that were analyzed for carbon, nitrogen, δ13C, δ15N, bulk density, and organic matter proportion. Adjacent to each restored peatland, we sampled a corresponding pristine (natural) peatland to facilitate a comparison of how the peat properties have been affected by drainage and subsequent rewetting of the peatlands. Groundwater depth was monitored at all peatland locations to confirm restored conditions at the rewetted peatlands.The results indicate that a long period of drained conditions and subsequent rewetting have changed the peat properties, with differences shown in C/N ratio, dry bulk density, and organic matter content. Rewetting will thus not regenerate a pristine environment. Instead, it creates new conditions to which various biogeochemical processes will respond and these do not necessarily represent conditions prior to disturbance. Our study will provide background information to understand the biogeochemical dynamics in peatlands after restoration, especially since the study covers a large span of nutrient conditions and catchment settings. This understanding will be fundamental for the development of strategies to minimize undesired biogeochemical responses following peatland restoration. Presentation preference: Oral, virtuallyBilling address:SLU FakturamottagningBox 7090750 07 UppsalaReferens: 241MOT  
Thermokarst processes as triggers of debris flows: A case study at Hüttekar Rock Glacier (Austrian Alps)
Authors: Seelig Simon , Wagner Thomas , Krainer Karl , Avian Michael , Olefs Marc , Haslinger Klaus , Winkler Gerfried
Published: February 2023

A cascading process including thermokarst lake outburst, debris flow initiation, and river blockage, hit a high mountain valley in the Austrian Alps during summer 2019. The rapid development of thermokarst features on an active rock glacier, including a lake with a water volume of approximately 166,000 m³ as well as a 350 m long drainage channel, most likely triggered the failure of ice-cemented debris within its front, with subsequent mobilization of roughly 50,000 m³ of sediment. This study explores the drivers of thermokarst evolution by tracking the lake development using satellite imagery and modeling its energy budget. We employ a simple balance model, assuming that the atmospheric energy input was efficiently transferred to the frozen rock glacier core through convection of lake water. This process provided sufficient melting energy to establish the thermokarst channel draining the lake within several hours. Our results highlight the need to account for thermokarst processes in hazard assessment studies involving permafrost-affected terrain.
Rotational sensor on Etna volcano: What can we learn about volcano-seismic events?
Authors: Eibl Eva P. S. , Rosskopf Martina , Sciotto Mariangela , Di Grazia Giuseppe , Currenti Gilda , Jousset Philippe
Published: February 2023

Rotational sensors have been deployed on several volcanoes worldwide including Kilauea, Stromboli, Etna and a few volcanoes in Iceland. Within this presentation we focus on our first experiment using a rotational sensor on Etna in Italy. We recorded the volcanic activity including degassing and vigorous strombolian activity in August to September 2019. We compare our results using a rotational sensor with a normal Trillium Compact seismometer and the seismic network maintained by the INGV. We detect LP events, VT events and volcanic tremor, study the wavefield and back azimuths of the events and derive phase velocities of the ground. Luckily, we were able to assess the quality of our results using the detailed earthquake catalogues and locations derived at the INGV. We can easily detect changes in the wavefield e. g. when strong strombolian activity kicks in and are looking forward to applications on other volcanoes where details of the volcanic activity or changes might go unnoticed if no rotational sensor is present.
Magnetic carbon-based biomaterials for the recovery of pollutants from contaminated water
Authors: Pulcher Roberta , Greggio Nicolas , Marazza Diego , Dinelli Enrico , Buscaroli Alessandro
Published: February 2023

Magnetic biochars (MB) have been widely studied for the removal of pollutants from wastewater (Hassan et al., 2020; Li et al., 2020). In fact, they can significantly lower the costs of wastewater treatment due to easy separation of the adsorbent and high reusability. Moreover, MB increase the physico-chemical properties of the carbon (Hassan et al., 2020; Wurzer & Mašek, 2021). Generally, carbon-based adsorbent, or biochar are functionalized with iron (Fe-) containing precursor, specifically chloride or sulfate salts of Fe2+ and Fe3+ ions (Sewu et al., 2020). However, these salts may have toxic properties, so their use raises environmental concerns.Iron-rich waste represents a more sustainable alternative to iron salts to introduce magnetic characteristics to biochar (Wang et al., 2015; Sewu et al., 2020; Wurzer & Mašek, 2021). In this research, Fe-rich sludges produced during the clari-flocculation and filtration phases of potabilization process of drinkable water, is used for the production of MB from vine pruning, a local, highly available, organic waste.The potabilization plant of Ridracoli dam, located in Emilia-Romagna region (Northeast Italy), treats around 55.000.000 m3y-1 of water and produces 1.400 - 1.800 m3y-1 of sludge (30% solid residue) (Toller et al., 2020).Fe-rich sludges were characterized with XRD, XRF, TGA analysis and employed to functionalize the vine pruning biomass either via wet impregnation and dry mixing, in easy and low cost pyrolysis route.The resulting MB were characterized with CHNS analyzer, BET analyzer, XRD and XRF. MB have been tested for the adsorption of inorganic contaminants, such as boron and arsenic, from aqueous solution. Different adsorbent dosages, contact time, and initial feedstocks (pristine or pyrolyzed biomass) were investigated in the adsorption tests. Preliminary results show that functionalization of pristine biomass produces a more efficient adsorbent compared to functionalization of pyrolyzed biomass. Also, MB produced with wet impregnation methods present better adsorption capacity than dry mixing MB.This study shows that functionalization of organic biomass with Fe-rich sludge, an abundant and environmentally sustainable Fe rich source, is a viable way to produce a magnetic biochar applicable for pollutants removal from wastewater.
Reynolds stresses in gravity currents approaching an obstacle
Authors: Di Lollo Giovanni , Adduce Claudia , Brito Moisés , Ferreira Rui M.L. , Ricardo Ana
Published: February 2023

ABSTRACT: Gravity currents are flows generated by density differences within two contacting fluids. In this work the interaction between lock-release gravity currents propagating over a horizontal rectangular channel and an emergent cylinder is analyzed through velocity measurements obtained through PIV. Two-dimensional instantaneous velocity fields are measured in a plane perpendicular to the bottom along the center axis of the channel upstream of the obstacle. The experiments were also conducted without the cylinder for comparison purposes and ten repetitions were carried out for each configuration. The analyses focus on the effects that the presence of an adverse pressure gradient has on both the mean velocity field and the turbulence of the leading part of the current, the head, before the impact. The mean velocity field is not affected by the presence of the obstacle and since no differences were found in the spatial distribution of the mean velocity components, the necessary cylinder-induced deceleration occurs uniformly. Turbulence is studied through the components of the Reynolds stress tensor and their fluxes within the head. In the configuration with the cylinder, there are no fluxes of Reynolds stresses in the inner part of the section. Consequently, the Reynolds stress intensity decreases inside the head compared to the configuration without the obstacle. In conclusion, the presence of an adverse pressure gradient stops the mechanism of Reynolds stress distribution from the main source of production, i.e. the front region, to the inner region of the flow. This leads to a decrease in Reynolds stresses in the inner part of the head and an increase in the frontal region.Acknowledgements: This work was partially supported by Foundation for Science and Technology's through funding UIDB/04625/2020 (CERIS research unit).Keywords: Gravity currents, lock release, Particle Image Velocimetry, adverse pressure gradient, Reynolds stress.
Characterisation of the regional groundwater flow system in the South German Molasse Basin using apparent groundwater age distributions with 14CDOC and 81Kr
Authors: Winter Theis , Einsiedl Florian
Published: February 2023

The Upper Jurassic aquifer (UJA) within the South German Molasse Basin (SGMB) is the most important exploration horizon for geothermal energy supply in Bavaria. The UJA shows a heterogeneous geology with karstic features and deep fault-zones. The result is a complex hydrogeology consisting of different groundwater types which differ significantly in their hydrochemical and isotopic composition.Despite the great interest in the Upper Jurassic aquifer for geothermal energy supply, leading to numerous scientific studies, the exact apparent groundwater age, the infiltration area and the regional flow system remain yet unknown.In this study we are using a multi parameter approach for the determination of apparent groundwater age distributions with the innovative 14CDOC and 81Kr methods and combine them with hydrochemistry data and stable water isotopes (δ18O/δ2H).Our results indicate that the UJA system consists of at least two groundwater components: an up to now unknown young meteoric water component from the Pleistocene/Holocene transition and an older Pleistocene component. The apparent 14CDOC ages increase from south to north and show some evidence that the infiltration area of the UJA is located in the southern part of the SGMB and a groundwater flow directed to the north.
Forest Monitoring: Fires and Recovery in Alta Murgia: the MOIRA Project
Authors: Maggi Sabino , Adamo Maria Patrizia , Fuina Silvana , Tarantino Cristina , Vicario Saverio
Published: February 2023

The risk of wildfires has risen significantly in recent years, not just in Europe but around the world. In Italy alone, hundreds of thousands of hectares are burned each year, resulting in deaths, the destruction of forests and loss of biodiversity, and damage to infrastructure and farms. One way to address this issue is through satellite remote sensing, which is a valuable tool for monitoring and managing fires, assessing risks, surveying and evaluating the damage caused by fires and preparing recovery actions.The objective that the Alta Murgia National Park is pursuing with this project is to gather information on fires that have occurred within the Park area, in order to quickly identify affected areas and aid in their perimeter, characterization and control, and to support the preliminary and timely design of forest restoration efforts, as well as the updating of AIB plans according to legal requirements.The project aims to develop automated satellite monitoring procedures using Landsat and Sentinel2 imagery to assess the health of forested areas and identify and characterize degradation caused by negative events such as forest fires, illegal logging, conversion of forest land to agriculture, and improper use of areas historically affected by fire. A module based on difference in the Normalized Burn Ratio (NBR) index would allow to define the effective perimeter of damage caused by a fire within the larger perimeter defined by firefighting crews. Additionally, a module using various vegetation indices, such as those related to chlorophyll and carotenoids, will be employed to compare vegetation changes across the landscape and over time.The project also involves using a time series analysis to retrospectively monitor the recovery of vegetation following a critical event, and a Bayesian approach previously developed by the group will be used to estimate expected phenological statistics with associated error. To further understand the recovery process, a single forested site burned in 2020 will be closely monitored with an eddy covariance tower and through repeated floristic surveys.Lastly, the project aims to establish a pilot low-cost ground-based monitoring and video surveillance system to supplement the existing video surveillance network. This system will focus on monitoring remote or less frequented areas of the park, where installing high-end monitoring stations would not be cost-effective. The system proposed is self-sufficient in terms of power and is capable of performing real-time image analysis over the study area. In the event of a fire or the emission of harmful gases, the system will immediately alert relevant law enforcement agencies.The current work summarizes the current state of the project and the scientific results obtained so far.
The effect of in-situ linear stress gradient on the frictional shear rupture growth in 2D.
Authors: Fakhretdinova Regina , Sáez Alexis , Lecampion Brice
Published: February 2023

Deep heat mining requires activation of slip on pre-existing geological discontinuities and the creation of hydraulically conductive fracture networks. Fluid injection or diffusion of ground waters can rise the fluid pressure near pre-existing fractures and faults, which may induce frictional slip. The fracturing process depends strongly on the initial stress conditions and rupture planes orientation. It is known that vertical stress is varying linearly with depth whereas horizontal stresses are likely not to exhibit linear dependence. Nevertheless, within certain length scales, one may assume linear relations for all stress tensor components.In the previous study [1], it was shown that for a planar rupture which is propagating due to fluid injection under a constant overpressure in the absence of stress gradient, the solution is self-similar and depends only on one dimensionless parameter which determines two limiting regimes. The first so-called "critically-stressed limit” designates that the fault is initially close to failure, whereas the “marginally pressurized limit” represents the case when the fluid pressure is “just sufficient” to activate the fault. One of the main features of the solution in the uniform stress case is that the rupture tips are propagating symmetrically.In our work, we investigate how linear stress gradient acting initially on the fault affects the shear rupture growth, namely, how it breaks the symmetry of the rupture propagation. The problem couples quasi-static elastic equilibrium and fluid flow on the fault plane via a Coulomb shear failure criterion with a constant friction coefficient. From a scaling analysis, it is shown that the problem is governed by two dimensionless parameters, To (similar to the one found in [1]) and dimensionless time. Parameter To is the ratio between the initial distance to failure and the strength of injection [1] calculated at the injection point. To determines two propagation regimes similar to those found in [1] (critically stressed and marginally pressurized limits). Dimensionless time parameter determines symmetric and asymmetric propagation periods and encapsulates the information about stress-gradient values. At early times, the solution is similar to the homogeneous stress case and the rupture stays symmetrical. At times near the characteristic time of each regime, the non-uniform in-situ stress distribution makes the rupture to propagate asymmetrically. We investigate the transition time for each limiting regime and compare it with real field observations. Our solution can also provide a benchmark for numerical solvers. REFERENCES[1] Viesca, R., 2021 Self-similar fault slip in response to fluid injection, Journal of Fluid Mechanics, vol. 928
Investigating the compressibility of the Jovian magnetosphere
Authors: Millas Dimitrios , Achilleos Nicholas , Guio Patrick , Arridge Christopher S.
Published: February 2023

The Jovian magnetosphere can undergo significant changes in its size due to varying external (e.g. solar activity) or internal (e.g. hot plasma pressure) conditions. Simulations have shown that the difference in the dayside stand-off distance between a compressed and an expanded state can be around 30 Jovian radii.In this work, we study the compressibility of the Jovian magnetosphere using a large ensemble of axisymmetric models, obtained from the recently updated UCL/AGA magnetodisc code. Each model is defined by its size (via the stand-off distance) and hot plasma content (via the hot plasma index). Using these models as virtual magnetopause crossings we estimate the compressibility index, calculated via changes in the dayside stand-off distance as a function of the external pressure, which characterises the overall response of the magnetosphere.We find that the system size plays an important role in the Jovian case, as we observe a change in the compressibility index as a function of the stand-off distance. This has also been noted in existing studies on Saturn, using a linear relation between changes in the stand-off distance and the external pressure.As a complementary study, we also estimate the compressibility index using magnetopause crossings from recently published catalogues based on JUNO data.
Exploring the influence of heat waves on wildfire occurrence in Mediterranean countries of southern Europe
Authors: Costa-Saura José Maria , Bacciu Valentina , Spano Donatella , Duce Pierpaolo , Sanesi Giovanni , Elia Mario
Published: February 2023

Heat waves (HWs) and wildfires are potentially considered highly correlated hazards with dramatic impacts on ecosystems and society. However, previous studies focused only on one single hazard leaving out potential compounding and cascading effects. The aim of this work is thus to investigate spatio-temporal patterns for both hazards in Mediterranean Europe and assess the potential influence of HWs on fire regime.The historical wildfire dataset was derived from the Global Wildfire Information System (GWIS). This dataset corresponds to georeferenced polygons detected between 2000 and 2021 by MODIS. To understand the relationship between fires and HWs, we extracted several fire regime metrics accounting for density, seasonality and severity. All the metrics were computed at the scale of 12 km square grid.Then, we characterised the HWs in terms of frequency, duration, seasonality and intensity for the same period based on a high resolution meteorological dataset (ERA5-land from Copernicus Climate Data Store). A HW was defined as a period of at least 6 days with temperatures greater than the 90th percentile whereas intensity was calculated as the total amount of degrees exceeding that percentile during the HW. Finally, we compared HWs occurrence with information about fire events. Compound and cascading events were analysed through hazard maps to identify simultaneous occurrences of the two hazards and look at different combinations of hazard sequences. Finally, multiple linear regression models were applied to explore the complex influence of HWs characteristics on fire metrics.The results highlighted the hotspot areas in Mediterranean countries where the common hazard occurrences were identified, and the role of HWs in the compound and cascading fire hazard events. The findings of this study could support the assessment of hazard patterns and, in turn, prevention and monitoring activities to support disaster risk reduction.
Geohazard assessment of submarine canyon headwalls activity along the Ionian Calabrian and Apulian margin (Ionian Sea)
Authors: Markezic Nora , Coste Marianne , Zecchin Massimo , Forte Emanuele , Ceramicola Silvia
Published: February 2023

The Ionian Calabrian and Apulian margins are severely incised by a dense network of submarine canyon systems, that have formed in response to ongoing km-scale uplift of Calabria over the last ca. 1Ma. Despite their young age (Pleistocene) they incise the continental shelf and slope over lengths of tens of kilometres, with thalwegs up to 2 km wide, walls higher than 200m and headwalls, that can extend over more than 50 km.Some of the canyon headwalls are very close to the coastline and in some cases, retrogressive features are observed from morphology and sub-bottom observations, representing a potential hazard for population and coastal infrastructures. Some of the canyons are isolated, others form hierarchic systems with five or more canyons merging into dendritic (cauliflower) systems that may or may not be connected to onshore drainage networks. They exhibit different characteristics in terms of headwall geometry, profile concavity and sinuosity.We present new information on their geomorphic attributes to gain new understanding about the dynamic and evolution of the different canyon systems in the last 1Ma. In addition, we aim at extracting information regarding the grain size and sediment type from vintage backscatter geophysical data and subbottom data, to analyse canyon headwall enlargement and their erosive activity. The overall purpose of my study is to bring new insights about the inception and evolution of the different canyon systems in relation to tectonic and sea level changes and thus be able to assess the potential geohazards that retrogressive canyon headwalls may represent today for coastal areas and infrastructures.
Short-term drought effect on biochemical processes and microbial growth in the rhizosphere of two maize genotypes.
Authors: Martín Roldán María , Hartwig Roman , Wimmer Monika , Blagodatskaya Evgenia
Published: February 2023

The rhizosphere is a highly dynamic biological interface where most decomposition processes of soil organics are performed by actively growing microorganisms producing extracellular enzymes. As the rate of enzymatic reactions and affinity of enzymes to the substrate are influenced by plant genotype and water content in soil, we hypothesized to boost genotype effect of wild and root hair deficient maize plants after a short-term drought due to resources limitation. We further hypothesized that (1) maximum enzymatic rates (Vmax) for ß-glucosidase, leucine-aminopeptidase, acid phosphatase, and N-acetylglucosaminidase will decrease due to low accessibility to substrates; and (2) microbial growth will be retarded due to limited nutrients availability. We tested these hypotheses on the Zea mays L. (WT) and a root hair deficient mutant (rth3) grown in soil columns. Drought effect was compared between the brushed soil from roots called root-affected soil, and the rhizosphere soil obtained after the subsequent washing of roots. Microbial growth induced by glucose and nutrients application was determined by microcalorimetry.Only two of four enzymes tested were sensitive to drought: ß-glucosidase and phosphatase. Maximum enzymatic rates of ß-glucosidase and phosphatase in the rhizosphere were, respectively, 73 and 47 % slower under drought treatment, compared to the well-watered plants. In the rhizosphere of rth3, only ß-glucosidase activity was reduced by 32 % under drought treatment compared to well-watered plants In root-affected soil, drought decreased ß-glucosidase activity by 72 and 57% for WT and rth3 plants, respectively. In the rhizosphere of WT plants, higher affinity for substrates was revealed for ß-glucosidase and phosphatase, respectively, as 31 and 42% lower Michaelis-Menten affinity constant (Km) under drought versus optimal watering. In the root-affected soil of rth3 mutant, only ß-glucosidase showed a 39 % lower Km under drought compared to well-watered plants. Higher enzymatic affinity under drought versus optimal moisture indicated a different set of enzymes either of microbial or plant origin. On the other hand, plant genotype effect was visible under drought for ß-glucosidase activity in rhizosphere soil, when maximum rate was 54 % lower for WT plants compared to rth3, suggesting that ß-glucosidase activity hotspots were not associated to root-hairs.Glucose-induced microbial growth was retarded for 12 to 14 hours under drought compared to well-watered treatment. A prolonged lag phase could be due to the smaller fraction of active microorganisms, which is driven by a non-optimal moisture of the soil. Moisture appeared to be a more determinant factor for microbial growth and enzymatic activity compared to plant genotype, whose effect was reinforced under drought.
An underwater "wind-gap" in the Ionian offshore of northern Calabria
Authors: Argnani Andrea , Pellegrini Claudio , Rivere Marzia
Published: February 2023

Orographic reliefs are continuously created and modified in active continental tectonic settings, influencing the drainage pattern and interacting with it. It is not uncommon that stream capture occurs in these settings, causing major rearrangement of river courses. This process often produces a geomorphological feature known as wind gap, i.e. a gap through which a stream once flowed but that is now abandoned and dry as a result of the capture. Analizing a high resolution 3D seismic data set, kindly made available by ENI S.p.A., we discovered a similar feature in the Ionian offshore of the Crotone peninsula, northern Calabria. This underwater region is characterized by intense tectonic activity that is partly controlled by the occurrence of a mobile substrate, possibly overpressured shales. The relevant uplift affecting the nearby Calabria onshore can also contribute to promote gravitational instability. In this setting the "wind gap" is represented by a stretch of a downslope weakly incised channel that has soon been abandoned as a result of the growth of a tectonic structure. The course of the new submarine channel runs sub-parallel to the coast for a long strecth, before taking a downslope trajectory. The present-day submarine channel is deeply incised, showing at least two main phases: a deep valley incision containing an axial valley with a much lower relief, which likely represents the current route of turbidite flows. The main channel valley results from the major erosional episode that affected the continental slope offshore northern Calabria. The limited incision in the abandoned channel strecth suggests that drainage rearrangement occurred in the very early stage of channel incision. Therefore, the estimated age of the tectonic deformation that is responbile for originating the "wind gap" can offer a useful hint on the timing of onset of erosion in this area.