bluuebunny/crossref_metadata_2025 huggingface dataset:
The potential carbon benefit in drylands of China
Authors: Tan Zimin , Wang Shuai
Published: March 2024

China’s drylands cover a large area and provide important ecosystem services as carbon sink by storing large amounts through vegetation and soils, so that it can be the key component of China’s terrestrial ecosystems. Due to water limitation and severe carbon-water trade-offs, China’s drylands are highly dynamic, which has an important impact on the trend of carbon sequestration in ecosystems of China and the interannual variability. Many studies have focused on carbon storage in cropland, grassland and forest ecosystems, but few comprehensive analyses focused on carbon storage and potentials in China's drylands. Here, we train a model with multiple influence factors to simulate the carbon storage potential in drylands of China to predict the biomass carbon carrying capacity of China’s drylands. After comparing observed and predicted biomass carbon density of drylands of China, we find that the carbon storage in China’s drylands realised by nearly 70 percent. The carbon actual storage in the drylands of the east of Inner Mongolia, the Northeast China, the northern part of Xinjiang, and the Huang-huai-hai region are the highest, and the potential carbon benefits of these places are highest too. Following by the Qinghai-Tibet Plateau and Jin-Shaan-Gan areas, and the lowest carbon storage and potential carbon benefits were found in the central and western parts of Inner Mongolia. Divided by the aridity gradient, it was found that the semi-arid zone has highest potential for carbon storage. We also identified areas where vegetation has not yet reached its full potential, such as the eastern and southern parts of the Tibetan Plateau and the Xinjiang region. Although the potential carbon storage in these areas is low, the proportion of carbon storage realised is below 40 percent, which has higher potential and conservation priority, indicating that the conservation of carbon in drylands of China needs to pay attention to the proportion of carbon sequestration realised at the same time, in addition to the potential carbon benefits.
Tracking transient changes in the plumbing system at Campi Flegrei Caldera
Authors: Giacomuzzi Genny , Chiarabba Claudio , Bianco Francesca , Piana Agostinetti Nicola , De Gori Pasquale
Published: March 2024

The Campi Flegrei caldera is experiencing a dramatic episode of unrest with a sharp constant increase in seismicity, ground deformation and gas emission. The ongoing escalation of seismicity in such a densely populated area, with the most energetic earthquake of the last 40 years occurring a few months ago, is generating increasing concern in the community. Until now, we never detected the injection of fresh magma in the shallow system, leaving uncertainties on the proximity of an eruption.
We developed a fully non-linear and trans-dimensional approach to 4D tomography (in space and time), with a self-adaptive parametrization, which enables to overcome intrinsic drawbacks of the tomography based on linearized solvers and fixed model parametrization. This novel method enhances the resolution capability of seismic imaging, highlighting the structure of the plumbing system and revealing for the first time the main shallow magma reservoir beneath the caldera. Transient changes in Vp and Vp/Vs depict a progressive accumulation of magmatic fluids beneath the resurging area and the ascent of magma batches at shallow depth.
The existence of a similar signature also during the previous 1982-84 unrest episode suggests that accumulation of magma batches may be a common way of caldera to grow. Anyway, the ability to fast track changes associated with magma ascent is crucial to forecast and model how restless calderas evolve and may become prone to erupt.
iMagine, AI-supported imaging data and services for ocean and marine science
Authors: Fava Ilaria , Lopez Garcia Alvaro , Schaap Dick , Krijer Tjerk , Sipos Gergely , Kozlov Valentin
Published: March 2024

Aquatic ecosystems are vital in regulating climate and providing resources, but they face threats from global change and local stressors. Understanding their dynamics is crucial for sustainable use and conservation. The iMagine AI Platform offers a suite of AI-powered image analysis tools for researchers in aquatic sciences, facilitating a better understanding of scientific phenomena and applying AI and ML for processing image data.The platform supports the entire machine learning cycle, from model development to deployment, leveraging data from underwater platforms, webcams, microscopes, drones, and satellites, and utilising distributed resources across Europe. With a serverless architecture and DevOps approach, it enables easy sharing and deployment of AI models. Four providers within the pan-European EGI federation power the platform, offering substantial computational resources for image processing.Five use cases focus on image analytics services, which will be available to external researchers through Virtual Access. Additionally, three new use cases are developing AI-based image processing services, and two external use cases are kickstarting through recent Open Calls. The iMagine Competence Centre aids use case teams in model development and deployment, resulting in various models hosted on the iMagine AI Platform, including third-party models like YoloV8.Operational best practices derived from the platform providers and use case developers cover data management, quality control, integration, and FAIRness. These best practices aim to harmonise approaches across Research Infrastructures and will be disseminated through various channels, benefitting the broader European and international scientific communities.
Accurate simulation of greenhouse gas emissions across fertilizer scenarios with DNDC
Authors: Thentu Tulasi , Forster Daniel , Virkajärvi Perttu , Harrison Matthew Tom , Shurpali Narasinha
Published: March 2024

The aim of this paper was to compare effects of organic and mineral fertilizers on greenhouse gas (GHG) emissions from legume grasslands in Finland. We invoke DNDC, a process-based model that integrates effects of agricultural practices, soil characteristics, nitrogen mass balance and climate change on GHG emissions from soil-plant ecosystems. Data measured in the field were collected from 2017 to 2020 using an eddy covariance site cultivated with legume grass species (Phleum pratense L., Festuca pratensis Huds, Trifolium pratense L., Hordeum vulgare L.) at Anttila, Maaninka, eastern Finland. The focus of the modelling was to evaluate the performance of DNDC heat exchange version under two distinct management practices: organic input, utilizing digestate residue (slurry), and mineral input (NPK) with chemical fertilizer. The primary emphasis was on understanding the model's accuracy in simulating greenhouse gas emissions and comparing the total annual greenhouse gas exchanges between these two management approaches. The DNDC heat exchange model version was calibrated and validated for key processes, including Gross Primary Productivity (GPP), Net Ecosystem Exchange (NEE), Ecosystem Respiration (Reco), Soil Temperature, and Water-Filled Pore Space (WFPS) at 5 cm and 20 cm depths. The model demonstrated satisfactory performance in estimating the total annual GHG exchanges during validation years under both management practices. For the mineral treatment, the model demonstrated fair performance (Spearman's correlation (ρ) for GPP (0.81), NEE (0.72), and Reco (0.85)). Root Mean Square Error (RMSE) and Mean Absolute Error (MAE) values indicated reasonable agreement between model predictions and measured data. Notably, soil temperature simulations demonstrated an excellent correlation (ρ=0.99) with low RMSE and MAE. Water-Filled Pore Space (WFPS) at both 5 cm and 20 cm depths exhibited good correlations, with acceptable RMSE and MAE values. Similarly, for organic inputs, the DNDC model had fair correlation (ρ) for GPP (0.81), NEE (0.72), and Reco (0.85). Soil temperature and WFPS at 5 cm presented high positive correlations (ρ=0.98 and 0.55), accompanied by low RMSE and MAE. WFPS at 20cm, while exhibiting good correlation (ρ=0.065), displayed a slightly elevated RMSE and MAE. Overall, we conclude that the model offered valuable insights into GHG dynamics associated with organic and mineral fertilization practices. Overestimation of biomass yield for some of the data by DNDC suggests that future work would be well placed targeting physiology determinants of biomass in the model.
Superimposed ice formation reduces meltwater runoff from ice slab areas of the Greenland Ice Sheet 
Authors: Tedstone Andrew , Machguth Horst , Clerx Nicole , Jullien Nicolas , Picton Hannah , Ducrey Julien , van As Dirk , Colosio Paolo , Tedesco Marco , Lhermitte Stef
Published: March 2024

Refreezing is an important component of the Greenland Ice Sheet's surface mass balance. At higher elevations of the ice sheet which are underlain by porous firn, meltwater percolates into the firn pore space where it refreezes in-situ, and therefore does not run off. However, in the last three decades, surface melting has increased at a faster rate than accumulation. In the percolation zone, this has caused anomalous densification of the firn pore space by meltwater percolation and refreezing, leading to metres-thick near-impermeable ice 'slabs' forming and causing the runoff limit to rise.In-situ hydrological observations on ice slabs show that surface meltwater percolates through the seasonal snowpack to flow laterally at metres an hour through a slush matrix atop the ice slab. A saturated slush matrix on top of a cold ice slab therefore has the potential to accrete superimposed ice onto the slab surface.We present the first measurements of superimposed ice formation (SIF) on top of ice slabs in the vicinity of the runoff limit on the K-Transect, south-west Greenland and quantify the impact of SIF on local surface mass balance and runoff. Next, we use vertical heat flow modelling to calculate the ability of an ice slab to refreeze surface melt during a melt season. With synthetic aperture radar observations, we estimate the contribution of residual stored meltwater to autumn-time refreezing. Finally, we assess the importance of SIF across all regions of the ice sheet underlain by ice slabs.Our findings reveal widespread and substantial refreezing in areas that, at a first glance of recent satellite imagery, can appear to be dominated by runoff. Ice slabs undoubtedly enable surface runoff from higher elevations of the ice sheet. However, their cold content and their shallow surface slopes, promoting water retention, can also enable substantial refreezing. In our field area at the 2022-2023 runoff limit, net refreezing corresponded to roughly 50 % of melt. Ice-sheet-wide, ice slabs enable runoff but are also hotspots of refreezing, retaining around 27 Gt of melt as superimposed ice between 2017 and 2022.
Assessing Natural Hydrogen Generation in Serpentinization Environments: A Workflow Based on a Comprehensive Case Study Analysis from the HyAfrica Project
Authors: Christiansen Rodolfo , Sobh Mohamed , Gabriel Gerald
Published: March 2024

Natural hydrogen, emerging as a clean and abundant energy source, holds significant promise for advancing sustainable energy solutions. Its production offers a carbon-neutral alternative to fossil fuels, aligning with global efforts to mitigate climate change. This research focuses on developing a methodology to estimate the rates of natural hydrogen generation in serpentinization areas; in this case a local area in Eastern Morocco. It employs a multilevel approach that encompasses the modeling and analysis of the surface, near-surface, and deep components of the natural hydrogen system. At the surface level, potential hydrogen seeps are identified as semi-circular structures and surface faults are examined using high-resolution geophysical data. For the near-surface component or seal of the potential reservoir, which can extend thousands of meters deep, a full 3D geological model is constructed. The deep component, representing the source rock, is analyzed through the inversion of potential field data. These inversion results allow estimating the degree of serpentinization of the rocks, their volumes, and the affected surfaces. Subsequently, these volumes of rock are compared with temperature estimates to determine which part of the rock is capable of generating hydrogen. Laboratory-based hydrogen generation values from rock samples are then scaled up to the model, facilitating the calculation of hydrogen generation rates from the detected ultramafic rocks.
Robust degradation index and pore water pressure model for cyclically loaded soil materials
Authors: Jagodnik Vedran
Published: March 2024

Rail traffic, the process of dynamic compaction or even seismic activities such as earthquakes can lead to multiple loading cycles of the soil material. When a fully saturated soil is loaded by these various factors, a build-up of pore water pressure can occur, leading to degradation of strength and, if the sand material is uniform, liquefaction. The degree of strength reduction is usually represented by the degradation index δi, and is often compared with the increase in normalized pore water pressure ru.
The degradation index is a function of the plasticity index PI, and the variation of the index with the number of cycles and the pore water pressure ratio goes from a strongly nonlinear behavior for sand to an almost linear behavior for highly plastic clays.
In this study, a simple and robust model is formulated for the prediction of the degradation index and pore water pressure build-up considering three different material types: (i) pure sand, (ii) a mixture of sand and clay with low plasticity, and (iii) kaolin clay.
Strain-controlled tests were performed in a triaxial apparatus with a frequency of 0.1 Hz at three different confining stresses.
Which willows for Soil and Water Bioengineering structures on high-elevation streambank? Ex situ study of cutting capacity of three shrub species
Authors: Rousset Juliette , Menoli Sarah , François Adeline , Evette André
Published: March 2024

Soil and Water Bioengineering techniques are a sustainable alternative to civil engineering to prevent erosion processes that threaten streambank stability. These techniques are still poorly developed and documented in subalpine streams, where climatic and hydrological conditions are particularly challenging. It is well known that the success and integration of a SWBE technique is best achieved when it is possible to use indigenous plants and plant material. At the subalpine belt, shrub and tree willows are among the dominant woody species on streambanks. Even if a few past studies claimed that they could play a full role in stabilising the banks of high-elevation streams, their biotechnical characteristics are nearly unknown. The unique information available comes from empirical and not detailed results showing a low resprouting rate of cuttings. Still, no data or information on these capacities are known in the subalpine environment. We conducted an in situ experimental study to assess the cutting capacity of willow species at high elevations to improve SWBE on these streambanks.Three species of subalpine shrub willow were chosen: S.caesia, S.foetida and S.hastata. These willows have no protected status in the French Alps, making them ideal for soil and water bioengineering. S.purpurea, known for its high resprouting ability in foothill streambanks, was used as a control species. The cuttings were placed in culture chambers for 4 months under controlled conditions of light, humidity, and temperature. We tested the effect of a growth hormone (indole-3-butyric acid), with the assumption that it would stimulate willow growth. 25 cuttings from each species were treated with the hormone while another 25 were not treated. At the end, we measured root diameter, primary root number, root biomass, cumulated stem length, stem number and, stem and leaves biomass. The recovery rate was high for all four species (>95%). No significant differences were found between the hormonal treatments. For each trait measured, there were significant differences for at least one of the species, reflecting significant differences in root and aerial morphology between species. S.hastata was distinguished by its very high biomass and S. purpurea by its very long structure. The results revealed significant differences between these species, in terms of morphology, resource allocation and therefore properties for soil and water bioengineering structures. All of the four species appeared to be suitable in SWBE structures. These findings have important implications for the effective installation of cuttings in SWBE structures in subalpine environments.
Multi-scale hydraulic-based graph neural networks: generalizing spatial flood mapping to irregular meshes and time-varying boundary condition
Authors: Bentivoglio Roberto , Isufi Elvin , Jonkman Sebastian Nicolaas , Taormina Riccardo
Published: March 2024

Deep learning models emerged as viable alternatives to rapid and accurate flood mapping, overcoming the computational burden of numerical methods. In particular, hydraulic-based graph neural networks present a promising avenue, offering enhanced transferability to domains not used for the model training. These models exploit the analogy between finite-volume methods and graph neural networks to describe how water moves in space and time across neighbouring cells. However, existing models face limitations, having been exclusively tested on regular meshes and necessitating initial conditions from numerical solvers. This study proposes an extension of hydraulic-based graph neural networks to accommodate time-varying boundary conditions, showcasing its efficacy on irregular meshes. For this, we employ multi-scale methods that jointly model the flood at different scales. To remove the necessity of initial conditions, we leverage ghost cells that enforce the solutions at the boundaries. Our approach is validated on a dataset featuring irregular meshes, diverse topographies, and varying input hydrograph discharges. Results highlight the model's capacity to replicate flood dynamics across unseen scenarios, without any input from the numerical model, emphasizing its potential for realistic case studies.
Potential field signature of a late-Variscan extended realm. Implications for western Iberia Sn-W mineralization
Authors: Ayarza Puy , Rivero Montero Mercedes , Gómez Barreiro Juan , Martínez Catalán José Ramón , Calvín Pablo , Sánchez Sánches Yolanda , Palomeras Immaculada
Published: March 2024

The internal part of the Central Iberian Arc (CIA) features a number of long-wavelength, high amplitude aeromagnetic anomalies that overlap gneiss domes developed during late Variscan extension. Some of the largest anomalies are located at the core of the CIA and coincide with the western Iberia Sn-W belt, e.g., the Porto-Veira-Guarda Magnetic Anomaly (PVGMA) and the Central System Magnetic Anomaly (CSMA). Despite both of them lying on top of the products of crustal extension and melting (granites and migmatites), outcropping rocks do not feature high magnetic susceptibilities, raising the question about the origin of the anomalies.In the last two years, ground high-resolution magnetic and gravity surveying has been carried out in the northern part of the CSMA, in the boundary between igneous rocks and their metamorphic host rocks. The latter are part of thermal domes developed in the latest stages of Variscan extension. Results show that magnetic highs coincide with gravity highs, thus indicating that the source of the anomalies is probably basic rocks. Indeed, scarce outcropping gabbros have magnetite, and feature a moderate magnetic susceptibility, but a very high magnetic remanence (Qn
Glacial history of the King Haakon Trough System, sub-Antarctic South Georgia
Authors: Streuff Katharina , Lešić Nina-Marie , Kuhn Gerhard , Römer Miriam , Kasten Sabine , Bohrmann Gerhard
Published: March 2024

In an effort to elucidate an important part of the Quaternary evolution of sub-Antarctic South Georgia, hydroacoustic data from its southern continental shelf are presented. The island with its surrounding shelf is of key interest for climate reconstructions, because it is located within the core belt of the Southern Westerlies and between the main fronts of the Antarctic Circumpolar Current in the Southern Ocean. This makes it particularly susceptible to changes in climate conditions on a local, regional, but also Southern Hemisphere-wide scale.The data provide new insights into the glacial evolution of the King Haakon Trough, one of several cross-shelf trough systems around the island. Numerous landforms, identified from high-resolution bathymetry data, document phases of ice advance and retreat. They are interpreted to be related to the confluence of two major trunk glaciers fed by an extended, possibly warm-based, South Georgia Ice Cap. Linear bedforms become progressively elongated towards the shelf and imply accelerated ice flow and/or softer sediment substrate towards the shelf edge. In contrast, recessional moraines and large morainal banks not only evidence shelf-wide ice extent during a peak glaciation, but also attest to staggered retreat, at least during the initial phase of deglaciation. The establishment of a complex bottom-current system around the onset of the last deglaciation is implied by the presence of moats and contourite drifts, which are mainly recorded in sub-bottom profiler data from the trough system. These data also show an acoustically semi-transparent facies of variable thickness present on the mid- and outer shelf as basal trough fill, which, on the basis of its acoustic appearance and the presence of several strong internal reflectors, is interpreted as a sequence of stacked glacial tills. These are similar to stacked tills previously documented from the Antarctic Peninsula and probably document a minimum of three extensive ice advances around South Georgia. Because the tills in the King Haakon Trough occur over a distance of ~26 km across the shelf, it is postulated that they derive from a minimum of three separate glaciations, rather than from re-advances within one glaciation period. Accordingly, the new findings from the combined bathymetry and sub-bottom profiler data show that the marine-geological archives around South Georgia offer unique potential to constrain how ice masses in the Southern Ocean responded to Quaternary climate change.
Centennial observed snowfall trends and variability in the European Alps
Authors: Bozzoli Michele , Crespi Alice , Matiu Michael , Majone Bruno , Giovannini Lorenzo , Zardi Dino , Brugnara Yuri , Bozzo Alessio , Cat Berro Daniele , Mercalli Luca , Bertoldi Giacomo
Published: March 2024

Climate change significantly affects snow, emphasizing the urgency to comprehend the temporal and spatial variations in snowfall trends. Analysing historical snowfall data across large areas is often impeded by the lack of continuous long-term time series. This study investigates snowfall trends (HN) by examining observed time series from 46 Alpine sites at various elevations spanning the period 1920-2020. In addition to HN, the analysis focuses on key parameters such as precipitation (P), mean temperature (TMEAN), and large-scale synoptic descriptors — the North Atlantic Oscillation (NAO), Arctic Oscillation (AO), and Atlantic Multidecadal Oscillation (AMO) indices — to discern patterns and variations in HN over the years.The study reveals that over the past century, below 2000 m a.s.l., there has been a decline in HN across the Alps, particularly in southern and low-elevation sites, despite a slight increase in winter precipitation. The South-West and South-East regions experienced average losses of 4.9% and 3.8% per decade, respectively, while the Northern region showed a smaller relative loss of -2.3% per decade. The negative HN trends are primarily attributed to a TMEAN increase of 0.15 °C per decade. The majority of the HN decrease occurred between 1980 and 2020, as a result of a more pronounced increase in TMEAN. This is reinforced by changes in the running correlation between HN and TMEAN, NAO, AO over time; before 1980, there was no correlation, while in later years, the correlation increased. This suggests that in recent times, the right combination of temperature, precipitation, and atmospheric patterns has become crucial for snowfall. On the other hand, no correlation was found with the AMO index.
How biochar suspension influences soil microbial activity and phosphorus availability
Authors: Loginova Iryna , Bilyera Nataliya , Banfield Callum , Kutoley Denis , Kuzyakov Yakov , Dippold Michaela A.
Published: March 2024

Biochar (BC) application to soil is a method of long-term carbon (C) sequestration in croplands. Along with contribution to climate change mitigation, agronomic benefits of biochar are widely accepted. Amelioration and nutritive benefits of biochar are mainly attributed to high applications rates, which may not be viable for farmers. We suggest a new approach: band application, which implements biochar in modern intensive crop rotations and optimizes both C and nutrients cycles (i.e. phosphorus (P)).As maize is globally one of the most widely planted crops, corncobs (CC) may be utilized for BC production. Corncob biochar (CC BC) may be implemented into the farming practice as suspension with liquid phosphorus solution jointly applied in band in the close proximity to seeds.We conducted an incubation experiment to evaluate the short-term effects (within 32 days) of corncob biochar and inorganic P application on P availability and microbial activity in a loamy Luvisol.Corncobs were pyrolyzed to biochar (350oC; 0.2-0.3oC s-1), grinded (
MIS 8 to MIS 7 sub-orbital-scale climate variability along the northern Mediterranean borderland recorded in a Macedonian mammillary speleothem
Authors: Temovski Marjan , Molnár Kata , Vargas Danny , Rinyu László , Palcsu László
Published: March 2024

The central parts of Southeastern Europe, located along the northern boundary of the Mediterranean region, represent a transient zone affected by both Mediterranean and continental atmospheric influences. An impressive record of past climate variations in this region has been obtained mainly from lacustrine sediments in the southern parts and loess deposits in the northern parts. Although radiometrically dated speleothems provide higher resolution records with superior chronological constrains, not many published speleothem records are available from this region, with none covering Marine Isotope Stage (MIS) 7.We present here a record of MIS 8 – MIS 7 sub-orbital-scale climate variations obtained from a U-Th dated Macedonian subaqueous speleothem composed of mammillary calcite that deposited between 246.0±6.2 ka and 225.8±5.4 ka, covering Termination III (T-III), MIS 7e and MIS 7d. Proxy records were obtained from conventional and clumped isotopes, with an additional insight from uranium isotopes and petrography. The stable isotope data has relatively high resolution (60-310 yr) allowing identification of millennial-, and at sections centennial-scale climate variations.The speleothem record reflects an increased Mediterranean influence, as suggested also by other proxy records from the region, especially during MIS 7e. However, periodically increased continental influences are also identified, especially during T-III and MIS 7d. The calcite δ18O values seem to reflect mainly temperature-controlled precipitation δ18O, with changes between Mediterranean and Atlantic moisture source also noticeable. The δ13C values mainly reflect the alternating influence of continental and Mediterranean climates, expressed by summer moisture availability, partly overprinted by temperatures. Increased winter precipitation during MIS 7e is identified, corresponding to Sapropel 9. The abrupt climate change during T-III is represented in the stable isotope record with an event that corresponds to the S8.1 stadial event, as identified in a speleothem from Ejulve Cave (NW Spain), and the Younger Dryas-III weak monsoon interval, as identified by Chinese speleothem records, considered analogous to either Heinrich 1 or Younger Dryas in Termination I, respectively.
Hydrogeological and Hydrochemical Investigations for Coastal Saline Aquifer Management: A Field-Based Managed Aquifer Recharge Study
Authors: Tripathi Deepak , Verma Apoorv , Yadav Brijesh Kumar
Published: March 2024

Amid intensifying water scarcity and heightened vulnerability of coastal aquifers to saltwater intrusion, the prudent adoption of Managed Aquifer Recharge (MAR) surfaces as a promising approach for effective water management in coastal zones. This study aimed to evaluate the applicability of MAR in the coastal aquifer to better understand the dynamic freshwater-saline water interactions. For this, a series of field experiments were conducted on the coastline of the Arabian Sea located in Kerala State of India. A comprehensive Hydrogeological and Hydrochemical approach is employed to discern salinity patterns within coastal aquifers, with the aim of facilitating sustainable water resource management through MAR. Initially, four vertical electrical soundings (VES) were conducted to get the resistivity variation along the coastline. The results unveiled distinct subsurface conditions. Towards the north, a narrow freshwater zone was identified overlying saline water. Conversely, in the southernmost region, signs of saltwater intrusion were observed, with highly saline groundwater present at shallow depths. Subsequently, groundwater characterization within a 5-kilometre stretch revealed total dissolved solids (TDS) concentration ranging from 80 to 18810 ppm with an average of 4244.74 ppm. While electrical conductivity (EC) ranged from 0.17 to 38.37 mS/cm, with an average value of 8.66 mS/cm. These findings reflect the non-uniform distribution of salinity due to saltwater intrusion in the region, posing significant challenges to the utilization of freshwater resources. Based on these observations, three piezometer wells were drilled in proximity to the high-salinity zone within the unconfined aquifer. These comprised one injection well and two observation wells.  Three different volumes viz. 2500L, 5000L and 7500L were injected in the injection well at a similar recharge rate. The results indicated that higher injection volumes led to significantly increased freshwater storage duration: 178% for 5000L and 500% for 7500L compared to 2500L. Results also indicate that MAR has the potential to customize the groundwater gradient, mitigating saltwater intrusion in freshwater zones to some extent in the short term. However, concerns arise about the long-term viability of MAR in highly saline coastal areas, particularly due to higher diffusion, buoyancy effects, and mixing of freshwater and saltwater observed in the sandy aquifer.
The oxygen and carbon isotope records of East Asian climate variations during the Eocene warm periods from Weihe Basin, central China
Authors: Wang Kexin , Lu Huayu , Sun Wenfeng , Liang Chenghong , Zhang Hongyan , Wang Yichao , Lv Hengzhi , Wang Jingjing , Zhang Hanzhi , Lai Wen
Published: March 2024

Eocene warmth has been used as one of the best analogues for future anthropogenic warming. How East Asian hydroclimate responds to the increased temperature during the Eocene is still elusive. Here, we present a combined element and isotopic geochemistry study of an Eocene lacustrine sequence covering the period 46-33 Ma from Weihe Basin, central China. Based on the formation process of lake carbonate and the paleosol CO2 barometer equation, a calculation model of lake carbonate carbon isotope (δ13Ccarb) that is suitable for open lake basins with low productivity is proposed. The sensitivity analysis of the Eocene lacustrine carbonate δ13Ccarb  show that the SRF is the main influencing factor of the carbon isotope fractionation. The reconstructed SRF of the Eocene is generally high, with an average value of ~215 g C/m2/yr, revealing a relatively warm and humid environment in the Weihe Basin. After ~41 Ma, the SRF gradually decreased, indicating that the climate in the Weihe Basin gradually became colder and drier. This trend is consistent with the global cooling, especially at ~36 Ma, ~33 Ma (the Eocene-Oligocene transition EOT) showing the most significant reduction. The reconstructed precipitation oxygen isotope (δ18Op) in the Eocene warmth is characterized by a positive value (~-6 ‰) in the northwest inland region, and relatively negative  values in the central region such as the Weihe Basin and Lanzhou Basin (~-10 ‰), and the Qinghai-Tibetan Plateau area (~-11 ‰). This kind of distribution is similar to modern precipitation δ18Op, indicating that a prototype of the East Asian summer monsoon circulation has probably formed in the Middle Eocene.
Non-stationarity in the NAO–Gulf Stream SST front interaction
Authors: Bellucci Alessio , Famooss Paolini Luca , Omrani Nour-Eddine , Athanasiadis Panos , Ruggieri Paolo , Patrizio Casey , Keenlyside Noel
Published: March 2024

The interaction between the North Atlantic Oscillation (NAO) and the latitudinal shifts of the Gulf Stream sea surface temperature front (GSF) has been the subject of extensive investigations. There are indications of non-stationarity in this interaction, but differences in the methodologies used in previous studies make it difficult to draw consistent conclusions. Furthermore, there is a lack of consensus on the key mechanisms underlying the response of the GSF to the NAO. This study assesses the possible non-stationarity in the NAO–GSF interaction and the mechanisms underlying this interaction during 1950–2020, using reanalysis data. Results show that the NAO and GSF indices covary on the decadal timescale but only during 1972–2018. A secondary peak in the NAO–GSF covariability emerges on multi-annual timescales but only during 2005–2015. The non-stationarity in the decadal NAO–GSF co-variability is also manifested in variations in their lead–lag relationship. Indeed, the NAO tends to lead the GSF shifts by 3 years during 1972–1990 and by 2 years during 1990–2018. The response of the GSF to the NAO at the decadal timescale can be interpreted as the joint effect of the fast response of wind-driven oceanic circulation, the response of deep oceanic circulation, and the propagation of Rossby waves. However, there is evidence of Rossby wave propagation only during 1972–1990. Here it is suggested that the non-stationarity of Rossby wave propagation caused the time lag between the NAO and the GSF shifts on the decadal timescale to differ between the two time periods.
Submarine landslides unravel the dynamics of the past East Antarctic Ice Sheet 
Authors: Huang Xiaoxia , De Santis Laura , Leitchenkov German , Escutia Carlota
Published: March 2024

A giant submarine landslide in front of the Wilkes subglacial basin along the Cook continental margin—one of the least explored areas on Earth—has been documented for the first time. This area is critical to understanding the stability of one among the most vulnerable sectors of the Antarctic Ice sheet to climate and ocean warming. It is named as Cook mega-slide complex (CMSC), which occurred in the early Pliocene according to the seismic interpretation correlated to the IODP Exp 318 sites. The giant submarine landslide is well imaged on the seismic profiles and exhibits various kinematic indicators with the basal glide planes and original headwall scarps. It affected the area of c. 22, 686.5 km2, approximately 3399 km3 of sediments evacuated from the continental margin. With a scale similar to Storegga Slide on the Norway margin, the size of the CMSC is mostly likely the largest submarine landslide ever discovered around the Antarctic margin. We propose that glacial isostatic adjustment and glacial outburst floods caused by the East Antarctic Ice Sheet (EAIS) retreat lead to the formation of the large slides and create the condition for slope instability and erosion. The development and collapse of peripheral bulge has been firstly observed from Antarctic margin, associated with the glaciation and subsequent deglaciation of the EAIS, led to a distinct spatial variation in sea level changes and further affected the deposition on the slope. Our results yield intriguing insights into the relationship of stratigraphic evolution, submarine landslides, and past EAIS instabilities throughout the warm periods of the late Miocene-Pliocene, and thereby provide important constraints for ice sheet modeling and sea level prediction.
Reutilising hydrocarbon wells as deep heat exchangers to decarbonise heating in the Northern Netherlands 
Authors: Miocic Johannes , Drenth Jan , van Benthem Pieter
Published: March 2024

To meet the climate targets outlined in the Paris Agreement, European Green Deal, and the goal of reducing dependence on fossil fuel imports per the REPower EU Action, decarbonizing and reducing energy consumption in the heating and cooling sector is imperative. This sector, a major contributor to household energy use, plays a pivotal role in achieving sustainable energy goals.Geothermal energy, particularly through geothermal doublets, stands out as an ideal solution for supplying energy for space heating and cooling. However, the inherent risks associated with fluid exchange with the subsurface make it scientifically or politically challenging in certain areas. Addressing this concern, deep borehole heat exchangers function as closed-loop systems, eliminating fluid exchange with the subsurface.In this study, we explore the feasibility of repurposing existing oil and gas wells in the Northern Netherlands as deep coaxial borehole heat exchangers to provide heat to local communities. Utilizing analytical solutions, we calculate the thermal power output of 365 gas wells suitable for retrofitting. These wells exhibit bottom hole temperatures exceeding 80°C, capable of delivering temperatures above 60°C or thermal powers exceeding 800 kW, depending on flow rate and inflow temperature.Our analysis includes assessing the proximity of well locations to high-density heat demand neighborhoods within a 6 km radius, facilitating the provision of supply temperatures for future local heat district networks. Notably, heat loss from well to neighborhood generally remains below 2°C, ensuring sufficient heating power supply to nearby residential areas. Several well clusters demonstrate significant heat over-supply, suggesting the potential for transporting excess heat to more distant locations. In cases where heat supply from wells is too low, in particularly in neighbourhoods with very low building efficiency rating (
Possible interactions of hazardous elements with pharmaceuticals in soils of a Mediterranean wetland (L’Albufera, Valencia, Spain)
Authors: Andreu Vicente , Gimeno-Garcia Eugenia , Sadutto Danielle , Picó Yolanda
Published: March 2024

There is scarce information about toxic effects, environmental dynamics and even toxic levels or regulations, mainly in soils, of several elements widely used in agriculture and industry. These so called elements “of emerging concern” have not been studied, mainly regarding their environmental effects or relationships. By the other hand, tons of pharmaceuticals are liberated by effluents of the wastewater treatment plants to the environment and agricultural fields daily. As study case, we have selected an important area in Spain that is affected by high anthropogenic pressures.The target area of study the alluvial plain between the rivers Turia and Jucar (Valencia, SPAIN), with an extension of 486 km2, which is characterized by its dense network of channels and ravines for irrigation one of the most productive agricultural areas of Spain. This area includes a wide zone of rice farming and a Natural Park (L’Albufera). In this study area, 33 sampling zones were selected covering the different water sources and agricultural types, to monitor the distribution of the levels of 15 hazardous metals.Total concentrations of the selected metals (Al, As, B, Be, Bi, Co, Fe, Li, Mo, Se, Rb, Sr, Ti, Tl and V) were determined. Standard analytical methods were used to measure soil physical and chemical properties. Total content of the twelve heavy metals, in soil samples, were extracted by microwave acid digestion and determined by ICP-OES. In the same zones, 32 pharmaceuticals were also studied. soil samples were extracted by pressurized liquid extraction (SPE). and determined by liquid-chromatography tandem mass spectrometry (LC-MS/MS).Maximum average values were determined for Ti, Sr and Rb with 466.36, 263.16 and 63.62 mg/kg, respectively. Highest values for B, Li and Tl were 76.05, 70.91 and 56.37 mg/kg, respectively. The Northern part of the Albufera lake, devoted to rice farming, concentrated the highest values of almost all the selected elements. From the 32 studied pharmaceuticals, 29 were detected being the most frequents Bisphenol A, Caffeine and Tramadol. Maximum values were observed for Alprazolam (67.28 ng/g), Ibuprofen (76.11 ng/g) and Lorazepam (62.02 ng/g).The interactions between metals and pharmaceuticals, and from both with soil characteristics and the influence of environmental factors were also studied.More research is needed to stablish their toxic levels and effects, or even their average concentrations in soils of these elements, very scarcely studied in the majority of them.AcknowledgementsThis work has been supported by the Generalitat Valenciana (Regional Autonomous Government) through the project CIPROM/2021/032.
Garnet and zircon petrochronological study of the garnet clinopyroxenite from Eastern Hebei terrane，North China Craton——no evidence for Archean eclogite-facies metamorphism？
Authors: Yang Ruyi , Cheng Hao
Published: March 2024

Plate tectonics represents a forefront of research in earth sciences, with the establishment of modern-style plate tectonics remaining one of the key unresolved issues. Debates continue about its initiation, with estimates ranging from the Hadean to the Neoproterozoic or Cambrian periods, spanning nearly Earth's entire history. The North China Craton (NCC), as one of the world's oldest cratons, encapsulates a geological history from 3.8 to 1.8 billion years ago, offering valuable insights into early Earth's evolution. Recent work by Ning et al. (2022) highlighted eclogite-facies garnet clinopyroxenite in the Eastern Hebei terrane of the NCC, dated at over 2.47 billion years, suggesting the presence of modern-style plate tectonics by the end of the Archean era.To further investigate the timing and metamorphic processes of the garnet clinopyroxenite, we conducted a comprehensive garnet and zircon petrochronological study. The garnet clinopyroxenite is primarily composed of clinopyroxene and garnet, with accessory minerals including plagioclase, quartz, titanite, magnetite, and ilmenite. Garnet compositional profiles show minimal chemical zonation, with a gradual decrease in XPrp (0.27–0.23) from core to rim, indicative of diffusional resorption driven by retrogression. Conventional thermobarometric calculations suggest peak metamorphic conditions between 761–833°C and 1.0–1.1 GPa, not reaching eclogite-facies. Zircon analysis revealed depleted LREE, positive Ce, and negative Eu anomalies, with most zircons indicating a metamorphic age of 2478 ± 12 Ma. A subset of zircons provided a weighted mean 207Pb/206Pb age of 1770 ± 11 Ma, displaying flat HREE patterns potentially coexisting with garnet. U–Pb data suggest the Eastern Hebei terrane's garnet clinopyroxenite records Neoarchean (ca. 2.50 Ga) and Paleoproterozoic (ca. 1.8 Ga) metamorphic ages. However, the diverse range of zircon U–Pb ages and their ambiguous textural associations complicate the correlation of P–T conditions with specific timeframes. Thus, the peak metamorphic conditions of garnet clinopyroxenite, as estimated by conventional thermobarometry, cannot be conclusively dated to either ca. 2.50 Ga or ca. 1.8 Ga. This ambiguity limits the evidence for Archean eclogite-facies metamorphism. Future garnet-whole rock Sm–Nd/Lu–Hf isochron analysis may offer more definitive dating of metamorphic events and enhance understanding of the garnet clinopyroxenite's thermal history.
What modulates eruptive styles and timescales at Villarrica and Osorno volcanoes (Chile)?
Authors: Utami Sri Budhi , Vander Auwera Jacqueline , Bechon Tonin , Fugmann Paul , Namur Olivier
Published: March 2024

Villarrica and Osorno are two active stratovolcanoes in the Central Southern Volcanic Zone (CSVZ) of the Chilean Andes that share several geochemical characteristics: near-primary, tholeiitic parent magmas (50-53 wt. % SiO2), overlapping major/trace element differentiation trends, and comparable storage conditions [1-4]. Yet, their current or recent eruptive styles diverge significantly. Villarrica is a steady-state, open-vent volcano with a lava lake that produced ~100 moderate-intensity, Strombolian eruptions since 1579; Osorno is a closed-vent volcano with 10x less eruptions for the same period. Our initial hypothesis proposed that differences in eruptive style and frequency could be due to a relatively higher degree of crustal permeability under Villarrica than Osorno [5]. Although preliminary data shows that some differences exist in olivine chemistry and textures between Villarrica (Fo72-87) and Osorno (Fo66-82) [4,5,6], both volcanoes have broadly similar compositional ranges and multimodal distributions, with comparable diffusion timescales. This suggests the degree of crustal permeability underneath both volcanoes are likely comparable, prompting us to consider other parameters, such as magma supply rate. In this contribution, we discuss and evaluate the role of magma supply rate and other parameters in modulating eruptive styles at Osorno and Villarrica, based on an updated dataset of magma storage conditions, diffusion timescales, and inferences drawn from published literature. We aim to further current understanding of subduction zone magmatism and geodynamics, with implications on volcanic hazard reduction.1. Vergara et al. (2004). J. S. Am. Earth Sci. 17: 227-238. 2. Morgado et al. (2015). JVGR, 306: 1-16. 3. Pizarro et al. (2019). JVGR. 384: 48-63. 4. Bechon et al. (2022). Lithos. 106777. 5. Utami et al. (2023) Goldschmidt 2023 Abstract 6. Romero et al. (2022). Bull. Volc. 85 (2).
The impact of increasing atmosphere CO2 concentration on hydrological trends in France over the 21st century
Authors: Huang Peng , Ducharne Agnès
Published: March 2024

The elevated CO2 concentration in the atmosphere has warmed the planet and modified the global precipitation pattern. Typical impact studies that investigate the regional hydrological response to climate change is based on the hydrological models forced by climate model projections. However, the physiological CO2 effects of plants that manifests as reduced transpiration via partially closed leaf stomata and enhanced photosynthesis is often overlooked in these impact studies.  
Here, the potential impact of the physiological CO2 effects on hydrological trends in France over the 21st century is assesed using the validated high-resolution Organising Carbon and Hydrology in Dynamic Ecosystems (ORCHIDEE) land surface model (Huang et al., 2023). The ORCHIDEE land surface model is forced with 4 regionalized climate projections narrowed from the CMIP5 ensemble projection under the RCP 8.5 scenario, with which we test the effect of two atmospheric CO2 conditions: a constant CO2 level of year 2005 and an increasing CO2 concentration of the RCP 8.5. 
 
We find that the physiological CO2 effects result in a decrease of evapotranspiration and an increase of total runoff over France for the 4 projections. Therefore, the physiological CO2 effects enhance the increasing trend of river discharges in wet projections and alleviate the decreasing trend of river discharges in dry projections over the 21st century. Despite the model uncertainties, our study confirms the important physiological CO2 effects on French water availaibility in the future, and this result likely holds at a broader scale.