bluuebunny/crossref_metadata_2025 huggingface dataset:
Rooted in the city: Unveiling the hidden world of Quercus cerris enzymatic activity in urban soils 
Authors: Gillini Anna , Bilyera Nataliya , Trupiano Dalila , Loginova Iryna , Dippold Michaela , Scippa Gabriella Stefania
Published: March 2024

 The intricate interaction between human activities and the repercussions of climate change has made urban ecosystem health and biodiversity—both vital to human survival and well-being—particularly vulnerable. Recent research has spotlighted the frequently underestimated but crucial role that interactions between plant roots and several biotic and abiotic components of soil play in affecting urban biodiversity and ecosystem dynamics.We conducted a controlled experiment to investigate this relatively obscure aspect of the urban environment. The experiment has been done with young plantlets of Quercus cerris and three urban soils collected from distinct sites in the city of Campobasso (Italy). We selected three sites in the city to clearly show a specific gradient of urbanization and vegetation fragmentation. Q. cerris young plants were grown in the rhizoboxes packed with three urban soils for two weeks to evaluate the impact of soil-plant interactions on the possible enzymes’ release by the roots and root-harboring microorganisms. The spatial distribution of three enzymes, namely acid phosphatase (P-cycle), β-glucosidase (C-cycle), and leucine aminopeptidase (N-cycle), was mapped and detected in each soil region (i.e., bulk soil and rhizosphere longitudinal surface) using a 2-D soil zymography technique.The zymogram analysis revealed that the enzyme activities in soils differed spatially along the urbanization gradient, with the more urbanized soil having the highest levels of enzymatic activity and hotspot presence.The root activity toward the exudation correlated with the highest enzymatic activity, that futrther lead to more intensive turnover of soil organic matter in soil. This could be linked to the exudation of roots to regulate plant growth in unfavorable conditions or to the rhizodeposition of substrates to change soil composition. Further in-depth analyses of the physical and chemical properties of the soil, along with the profiling and characterization of the microbial community composition, are currently underway in order to obtain a better understanding of the role of root enzymatic activities and their consequences on the biogeochemical processes in urban soils.
Changes in global vegetation distribution and composition under idealized overshoot scenarios
Authors: Nieradzik Lars , Lee Hanna , Miller Paul , Schwinger Jörg , Wårlind David
Published: March 2024

Within the framework of the project IMPOSE (Emit now, mitigate later? IMPlications of temperature OverShoots for the Earth system) six idealized emission-overshoot simulations have been performed with the Earth System Model NorESM2-LM2 and used as forcing for the 2nd generation dynamic global vegetation model LPJ-GUESS to investigate the impact of different CO2 overshoots on global vegetation.The simulations describe a set of scenarios with high, medium, and low cumulative CO2 emissions, each of which has a short (immediate) and a long (100 years) peak of cumulative CO2 emissions before declining towards a baseline simulation where a cumulative 1500 PgC is emitted within the first 100 years. The simulations have been performed in a “World without humans”, i.e. without land-use change, urban areas, fire-suppression, etc. to eliminate the somewhat arbitrary human factor. The results clearly show that the height of the overshoot has a large impact on global vegetation distribution and composition while its duration does not seem to play a significant role. Overall, we can state that any overshoot scenario results in vegetation patterns that are different from (though converging towards) the non-overshoot baseline simulation. The higher the overshoot, the larger the initial deviation. We have observed that there is less savannah after an overshoot and less so, the higher the overshoot, due to a reduced amount of tropical rain-green trees. As a result, there is also significantly less potential for fire. Further, there is more boreal vegetation, partly at the expense of temperate summer-green trees. A convergence towards the baseline simulation seems to be possible but isn’t reached by the end of the simulation window. Furthermore, it can be observed that overshoots are asymmetrical when it comes to succession, i.e. while there are well-known succession patterns when global temperatures rise and vegetation is expanding into previously colder regions, patterns are different when the temperatures on the decline. Finally, we like to state that dynamic vegetation is an important feature in Earth-system models w.r.t. vegetation carbon sequestration. Not only do the biogeophysical feedbacks matter, the total amount of carbon sequestered is about 16% higher than in simulations in which dynamic vegetation was supressed. These, and other feedbacks will be investigated in more detail in the ongoing Horizon Europe projects OptimESM and RESCUE.
Assessment of legal, regulatory, and environmental issues in the commissioning of low head Pumped Hydro Storage technology: a case study in the Greater North Sea
Authors: De Luca Antonio , Peviani Maximo , Scanu Sergio , Miccoli Andrea , Scapigliati Giuseppe , Marcelli Marco
Published: March 2024

Low head Pumped Hydro Storage (PHS) has emerged as a promising solution for energy storage, particularly with the increasing development of off-shore wind power in Northern Europe. The ALPHEUS project (Augmenting Grid Stability Through Low Head Pumped Hydro Energy Utilization and Storage), funded by the European Union’s Horizon 2020 program, places significant emphasis on investigating environmental issues and potential related impacts. By addressing key environmental aspects, the project aims to contribute to the sustainable integration of low head PHS, aligning with the broader goals of promoting renewable energy and grid stability in Europe.The coastal zone, marked by diverse physical and ecological conditions, is susceptible to the exploitation of numerous natural resources. Studying the current status and the intricate relationships between natural ecosystems and PHS structures during installation, operation, and decommissioning involves identifying and analyzing various multidisciplinary components, including, ecology, engineering, and economics aspects. This evaluation is an integral part of the legislative and regulatory framework governing the assessment of suitable places for the deployment of coastal or off-shore energy production facilities.The legal and regulatory framework relating to environmental aspects in two countries bordering the North Sea is also compared. Germany and The Netherlands are selected as examples for pilot sites assessment in this study including an evaluation of potential environmental constraints, the availability of environmental public data, and an assessment of existing infrastructure to be potentially converted. The assessment of sites from the environmental point of view is achieved on the basis of the “Marine Strategy Framework Directive” scheme identifying the potential interactions between the ecological parameters and the potential impacts of a PHS infrastructure. The success of sustainable low head Pumped Hydro Storage technology relies on the management of natural resources and the resolution of conflicts among sea use actors such as local communities and stakeholders.
Geoelectrical monitoring of tree-soil water interactions at urban sites 
Authors: Hoppenbrock Johannes , Gerchow Malkin , Beyer Matthias , Hörmann Vera , Quambusch Mona , Strohbach Michael , Bücker Matthias
Published: March 2024

The impact of climate change is increasingly restricting water availability in the soil, posing a significant challenge in urban areas where plants have to deal with limited space and sealed surfaces hinder rainwater infiltration. However, the amount of plant-available soil moisture plays a crucial role in plant vitality and is therefore important for ecosystem health. In urban environments, obtaining information on soil moisture is challenging. Commonly used methods, such as soil-moisture sensors, are often not applicable or do not provide a spatially resolved picture of soil moisture.Within the context of the interdisciplinary project CliMax, we explore the applicability of geophysical methods to characterize soil moisture in the rhizosphere in urban areas. Over the past year, monthly monitoring Electrical Resistivity Tomography (ERT) measurements were conducted at nine different tree locations in Braunschweig, Germany, characterized by diverse tree species and degrees of sealing of the surface. Additionally, temporally and spatially higher-resolution measurements were selectively taken. Various time-lapse inversion approaches implemented in the open geophysical inversion library pyGIMLi were tested and applied. Furthermore, Time-Domain Reflectometry (TDR) soil-moisture sensor data from different depths are available at each site, allowing calibration of ERT results with respect to soil moisture.The time-lapse inversion reveals well-resolved variation in soil moisture over the observed period, distinguishing between weather fluctuations and the influence of trees on the water balance. The water uptake is evident through increased resistivity values directly beneath the trees. Our study indicates that, depending on tree species and degree of sealing, the investigated urban trees predominantly extract water from the upper 1-4 meters. This finding is substantiated at specific locations by the data from deployed soil-moisture sensors.
Inverting thermal imagery of fumarole plumes to reveal gas fluxes
Authors: Jessop David , Klein Amelie
Published: March 2024

The mass and heat fluxes emitted by fumarole vents form a large portion of the total degassing budgets at volcanoes undergoing unrest, particularly at hydrothermal volcanoes. For example, the fumarole fluxes at la Soufrière represent around 78% of the total heat budget (Jessop et al., 2021). Pitot-tube instruments provide perhaps the most reliable data for fumarole fluxes but require the user to directly contact the hot, acidic, and toxic gases. Flux estimations from MultiGAS traverses still require the user to be in contact with fumarole gases but at a distance from the vent where the plume is much cooler. The errors associated with this method are substantial (c. 40%).Physically, fumarole plumes are similar to volcanic plumes produced by explosive activity in the absence of particles and hence similar models can be used (e.g. Woitischek et al., 2021). In this work, we propose using a wind-bent plume model (e.g. Woodhouse et al., 2013; Aubry et al., 2017) to match thermal images of the fumarole plume. Fumarole plumes typically are not opaque (see image) and so we develop a radiative model to account for this (cf. Cerminara et al., 2015). Our model requires the mass and heat flow rates to be specified at the vent. These parameters are retried by inverting our model with data extracted from thermal images acquired between 2017–2023 using a ground-based camera at the level of the vent. We find a slow but steady increase in vent flux over the period of study which is in keeping with data from MultiGAS and Pitot-tube measurements during the same period. The errors associated with our method are much lower than those of the MultiGAS traverse method and will allow for finer analyses of fumarole degassing data and its implications for understanding volcanic unrest.Aubry, T. J. et al. (2017). “Turbulent entrainment into volcanic plumes: new constraints from laboratory experiments on buoyant jets rising in a stratified crossflow”. Geophys. Res. Lett. 44.20, pp. 10198–10207. DOI: 10.1002/2017GL075069.Jessop, D. E. et al. (2021). “A multi-decadal view of the heat and mass budget of a volcano in unrest: La Soufrière de Guadeloupe (French West Indies)”. Bull. Volcanol. 3, p. 16. DOI: 10.1007/s00445-021-01439-2.Cerminara, M. et al. (2015). “Volcanic plume vent conditions retrieved from infrared images: a forward and inverse modeling approach”. J. Volcanol. Geoth. Res. 300, pp. 129–147. DOI: 10.1016/j.jvolgeores.2014.12.015.Woitischek, J. et al. (2021). “On the use of plume models to estimate the flux in volcanic gas plumes”. Nat. Commun. 12.1, p. 2719. DOI: 10.1038/s41467-021-22159-3.Woodhouse, M. J. et al. (2013). “Interaction between volcanic plumes and wind during the 2010 Eyjafjallajokülleruption, Iceland”. J. Geophys. Res.-Solid Earth 118.1, pp. 92–109. DOI: 10.1029/2012JB009592. 
Characterization, distribution, and evolution of surface fronts in the Amazon Plume region
Authors: Napolitano Dante , Gula Jonathan , Coadou-Chaventon Solange , Carton Xavier , Speich Sabrina
Published: March 2024

The Amazon River runoff reigns absolute as the most prominent river discharge to the ocean, with about 0.2 Sv of freshwater entering the Northwest Atlantic. The Amazon River outflow together with the North Brazil Current (NBC), dominates the low sea surface salinity spread into the open ocean. At the edge of the river plume, stirring by the NBC and its eddies generates sharp gradients at scales from Ο(0.1-100) km. These (equatorial to tropical) submesoscale fronts are important, for example, in modulating air-sea interactions and the energy cascade. In the EUREC4A-OA project, we use state-of-the-art Saildrone observations and numerical simulation to assess surface gradients in the northwestern tropical Atlantic. Our objective is to provide a comprehensive picture of surface gradients and associated fronts in the Amazon Plume region. From observations, we find that the plume influences density gradients from scales l < 30 km; sharp gradients skyrocket within the plume at l < 10 km, a scale that has recently been shown to mark a shift from an inverse to a forward energy cascade. Using a Δx ≅1 km CROCO simulation, we assess the spatial distribution of surface fronts and their spatio-temporal variability. Salinity dominates surface gradients even outside the plume due to an almost permanent barrier layer formed by mixing of low salinity water from previous seasons. Near the shelf, the Amazon runoff controls the formation and evolution of fronts. As we move poleward, the NBC dictates the distribution of the surface fronts. The influence of the NBC gradually decreases until the distribution of fronts closely follows the mixed layer dynamics.
Exploring Hydrogen Storage Strategies in Geological Formations to Minimise Gas Mixing
Authors: Williams Harri , Heinemann Niklas , Molnar Ian , Veloso Fernanda , Boardman Carl , Gladding Toni , Rashwan Tarek
Published: March 2024

Large-scale H2 storage within porous geological formations – such as depleted hydrocarbon reservoirs – presents a practical opportunity leveraging existing energy industry infrastructure to address renewable energy intermittency (e.g., from wind and solar). H2 can be generated from excess renewable energy, stored in these reservoirs, and drawn when needed. Depleted gas reservoirs have proven to trap gases (e.g., natural CH4) over geological timescales, and have been used for large-scale CH4 storage. The working gas (i.e., H2) is the fraction that is injected, stored temporarily, and produced from the reservoir. The cushion gas, the share of the injected gas that remains in the reservoir to maintain operational pressures and drive the production, represents an initial investment in the storage operation. Therefore, because H2 is relatively expensive, the use of a cheaper alternative cushion gas – such as CO2 and / or in-situ CH4 – can reduce the investments needed. Furthermore, the use of CO2 storage can simultaneously contribute to Net-Zero goals (as the CO2 will remain fixed in the reservoir).
One of the main challenges associated with the use of alternative cushion gases in these storage systems is the mixing with the working gas. Increased mixing will increase the cost of separation after production. In this study, we explore how the mixing of cushion and working gas can be minimised by using the reservoir geometry of laterally extensive reservoirs such as the Southern North Sea gas fields. Ultimately, the reservoir architecture and the infrastructure will dictate the extend of the contact area between the cushion and working gases, and by reducing this, the risk of mixing will be reduced. This work proposes an alternative operational strategy that investigates the storage of H2 working gas and CO2 cushion gas in a depleted system, where both gases are kept separated by injecting them at opposing ends of a reservoir to reduce the surface area of the mixing gas interface.
A search for dilation in low frequency earthquake waveforms
Authors: Hawthorne Jessica , Thomas Amanda , Papin Lois , Huang Hui , Cavendish Samuel
Published: March 2024

The fault zone process that creates slow earthquakes remains unclear, but one proposed mechanism to limit slip speeds depends on shear-induced dilatancy and the resulting pore pressure changes.  This process would imply that the fault zone dilates during slow earthquakes.  So in this study, we search for the signature of dilation in the focal mechanisms of tremor’s low frequency earthquakes (LFEs).It is, however, difficult to directly observe dilation in LFE waveforms.  The paths travelled by LFEs’ 1-10 Hz seismic waves are complex, and Earth structure is poorly known at the short wavelengths of interest.   This complexity makes it difficult to disentangle path effects from source properties.  Thus we look for differences in the seismic waves created by two groups of LFEs: groups of events that are in the same location but occur at different times.  The earlier events are smaller and thought to rupture through more solid, low-permeability fault rock and thus may have large dilation, while the later events rupture areas that have recently slipped and thus may have smaller dilation.In our initial analysis, we stack and analyse waveforms of LFEs identified in Cascadia by Bostock et al (2015).  However, we identify no significant difference in the waveforms or any significant trends in the polarisation of the difference.  Preliminary results suggest that the early and late LFEs have waveforms that differ by less than 1-2%.  That zero to minimal difference could indicate that there is no dilation.  Perhaps early and late LFEs are exclusively shear slip, and shear-induced dilatancy does not limit LFE slip speeds.  However, it is also possible that dilation is simply small.  The early, potentially large-dilation LFEs could have a dilation-to-shear slip moment ratio of 0.05, and the later, potentially small-dilation LFEs have a dilation-to-shear ratio of 0.04.   Such dilation would be large enough to significantly affect LFE slip rates but would not be visible with our current data and techniques.In our continuing work, then, we seek to decrease the uncertainty in our observations by identifying and stacking more LFEs and by extracting more information from seismograms including many LFEs.
Gravity wave model validation using nightglow emission observations for lower ionosphere disturbance modelling
Authors: Jaffré Ewen , Bellisario Christophe , Keckhut Philippe , Froissart Pierre-Yves , Trémoulu Samuel , Chane-Ming Fabrice , Simoneau Pierre , Hauchecorne Alain , Saillant Stéphane
Published: March 2024

Lower ionosphere is the theater of interactions between the ionized atmosphere and homogeneous atmosphere. Some phenomena such as gravity and acoustic waves which originate from the homogeneous atmosphere also impact the ionosphere and are suspected to be the source of sporadic disturbances in the E-region. Our goal is to correlate these disturbances to acoustic and gravity waves through modelling and ionosphere sounding. We first present the first steps towards this goal, a bi-dimensionnal, inviscid and compressible acoustic-gravity wave model coupled to a nightglow emission model (NEMO).  Then subsequent cross-comparisons with acoustic and gravity waves seen in the OH nightglow emission layer using an infrared sensor and MRA (Multi-Resolution Analysis) are discussed. These comparisons will help to improve the model’s rendering of wave impacts on their transportation medium, before extending the model’s range to ionospheric heights and properties.
Planar dynamics of non-spherical close tidally locked binaries asteroids 
Authors: Caritá Gabriel , Hussmann Hauke , Prado Antonio Fernando Bertachini de Almeida , Callegari Nelson , Morais Maria Helena Moreira , de Carvalho Ricardo Egydio
Published: March 2024

Asteroids are originated by the evolution of the disk in the Solar System and, in general, do not have spherical and symmetrical shapes. The reason for those irregular shapes is the small mass of the bodies, such that gravity is not sufficient to make them reach a spherical shape. Those irregular shapes make the study of spacecraft orbits to investigate those objects  complex. Adding this to the fact that their weak gravitational field allows forces that are usually negligible or of second order  for spacecraft near a massive body (e.g.,  solar radiation pressure) to be comparable to the gravitational forces, provides an interesting and important problem to be studied in terms of astrodynamics. The study of asteroids is important because they carry essential scientific information about the origin and evolution of the Solar System. For all these points, it is important to understand their motion and investigate the motion of a spacecraft close to the asteroid. Asteroids may exist alone or in groups of two or three. Recent observations show that binary asteroids could be even more common than we think. In that sense, the present research focused on studying the orbital evolution of a binary asteroid system with almost equal masses composed of two non-spherical asteroids tidally locked that are close to each other, and the dynamical evolution of spacecraft orbiting the system. Since Keplerian orbital elements are not always a good approach for spacecraft in high mass ratio binary systems, to study this problem, we consider the mathematical models of the planar full two-body-problem for the binary asteroid, and the circular restricted three-body problem for the spacecraft, adding ellipsoidal geometry to represent the non-spherical shapes of the binary in order to find natural stable solutions. We also analyzed the structure of the phase space and the importance of the effect of solar radiation pressure on this dynamics. We studied the dynamics and the effect of the gravitational shape of close binary systems in their mutual orbits, as well as the existence of spacecraft circular and resonant orbits. As an application of this research, we studied the binary system Antiope 90. We found stable, close direct and retrograde orbits for the jacobi constants between -1.1 and -0.5; and internal resonant retrograde orbits within the primary and the secondary for the energy -0.7. The majority of the dynamical structure has survived over 90 days assuming the effects of solar pressure radiation.
From erratic boulders to sacramental emblems - the geocultural significance of millstones embedded in the walls of Gothic churches in the Southern Baltic Lowlands
Authors: Brykała Dariusz , Czubla Piotr , Dąbski Maciej , Gierszewski Piotr , Piotrowski Robert , Mosakowski Zachariasz , Bartz Wojciech , Juschus Olaf , Witek Waldemar , Piotrowska Joanna , Tylmann Karol , Prarat Maciej , Pogodziński Paweł
Published: March 2024

Northern Poland and North-Eastern Germany are unique in the World regions with such a large number of Gothic churches, in which walls old querns and millstones were embedded and exposed. Already the very idea of sacralising such stones, which were commonly used in hand mills, water mills and wind mills, is fascinating. There are several concepts as to why they were inserted into the walls of churches. One of them refers to the idea of the so-called Eucharistic Mill, popular in German-speaking area during the Middle Ages. An object used to make bread could not simply be thrown away after being used up.  Thanks to the fact that these stones were set into the walls of churches as early as the Middle Ages, we have an exceptional opportunity to learn about the degree of advancement in the technique of their production, use and conservation in the 13th to 15th centuries. At the same time, we were able to identify several examples of erratic boulders (in situ) with traces of production for millstones.We identified more than 70 querns and millstones. Almost all of the examples were made from local erratic boulders (transported to the Southern Baltic Lowlands during the Pleistocene glaciations from Fennoscandia), as there were no quarries in this area. Their size varies from several centimetres to over 1 metre in diameter. Based on the millstone-eye we are able to determine whether it was runner-stone or bedstone. There have also been surviving examples with furrows still visible. Many of the millstones are semi-finished pieces, unfinished for some reason at various stages of production.This work was supported by the National Science Centre, Poland (Grant No. 2019/35/B/HS3/03933).
The concomitance of water use regulations and loss in soil-plant hydraulic conductivities
Authors: Abdalla Mohanned , Carminati Andrea , Ahmed Mutez
Published: March 2024

Stomatal regulation, which governs water loss and hence plant water use, is a key feature facilitating plant adaptation to water-limited environments. Nevertheless, the underlying mechanisms governing stomatal closure remain disputed. Recent studies proposed that the loss in hydraulic conductivities within the soil-plant system is the main driver of stomatal closure. However, the primary hydraulic constraint along the system, being in the soil and/or within the plant, remains without consensus. Furthermore, simultaneous measurements of the hydraulic limitation and stomatal regulation, especially in intact plants, is challenging. Here, we reviewed the recent literature on the relationship between stomatal closure and the loss of hydraulic conductance of key elements across the soil-plant-atmosphere continuum: soil, root, root-soil interface, xylem and leaf. We observed higher correlation between stomatal closure and declining below-ground hydraulics rather than leaf and/or xylem hydraulics. This analysis confirms the notion that stomatal closure is triggered by the decline of the soil-plant hydraulic conductance, and that this decline has often a below-ground origin. Understanding the key regulatory role of below-ground hydraulics is critical for forecasting and managing plant behavior under drought. 
The automated mineralogy: an important tool for geometallurgy studies of battery recycling
Authors: Dadé Mickaël
Published: March 2024

Since few years, a lot of companies and industries are developing battery recycling processes for the recovery of critical elements such as Li, Ni and Co. Before hydrometallurgical processing, mechanical and/or thermal treatment are applied in order to produce a black powder, also called blackmass. This high-value powder contains these above mentioned critical elements as well as graphite, rare earth metals and impurities such as solvents, plastics, aluminium and copper. The only data currently used to determine the quality of blackmass are chemical analyses of the major elements. However, micro-textures, liberation of elements and phases, as well as the amount of impurities in various phases are important parameters for the efficiency and performance of a hydrometallurgical process.In order to evaluate the suitability for hydrometallurgical recycling process, it is essential to analyse the blackmass not only chemically but also with respect to size, shape and composition of particles. This presentation shows how these data can be acquired by using a refined QEMSCAN database. This database was created based on billions of point analyses on a total of some million particles. The results show that:Particles can be micro-texturally characterized and classified with respect to chemical element contents.
Important textural and chemical particle variations exist in the blackmass of different origins showing different qualities.
Elements deleterious to hydrometallurgical processing (i.g. Si, Mg, K, Ca, Fe, Al, Cu and others) can be present in specific and well liberated particles.
Cathode active material compositions (different types of NMC as well as LCO, NCA, LFP, NiMH, etc) that are specific for each battery type can be distinguished.
Digital simulation of additional physical mineral processing can optimize blackmass quality with respect to valuable elements.
Special attention must be given to potential health risks during recycling and the processing of blackmass as elements like Cd and Co can be present in ultrafine particles.
Assessment and Comparison of Sapwood Diameter Measurement Techniques in Scots pine: A Multi-Method Analysis
Authors: Hammerle Albin , Nußbaumer Daniel , Wohlfahrt Georg , Mayr Stefan
Published: March 2024

Accurate determination of the sapwood area in trees is crucial for understanding stem hydraulic capacities and sap to heartwood transitions. Hence it is essential to analyse sap flow data.This study investigates the efficacy of various methods - electric resistivity tomography (ERT), visual inspection, thermography and staining - in measuring sapwood widths in Scots pine (Pinus sylvestris) growing in a mountainous pine forest in Mieming, Austria (AT-Mmg). Twenty trees were probed at breast height utilizing these techniques, and comparative analyses were conducted to assess their accuracy and efficiency.ERT was performed with a PICUS system (Argus electronic, Germany). Low resistivities indicated high water content, and values along west and east oriented radii were extracted to determine sap wood borders. For the remaining measurements, wood cores (diameter 5mm, west and east oriented) were taken with an increment borer. Visual determination of the sapwood width was carried out immediately after coring, right before thermal images of the cores were taken. Thermography relied on temperature variation along the core, due to evaporative cooling of the sapwood. Finally, cores were sealed in a chamber which enabled axial flow of safranin solution and thus staining of sap wood areas.All methods allowed identifying the transition zone between sap and heartwood. Remarkably, the comparative analysis among these methods unveiled close alignment and consistency in sapwood width measurements. Compared with staining, serving as the benchmark as based on the xylem hydraulic function, visual inspection, thermography, and ERT yielded results congruent with the stained cores.The results demonstrate that all techniques under study enabled reliable measurements of sap wood widths in Scots pine. Analyses based on wood cores were easy and less time consuming than ERT, though the latter enabled insights into the entire cross-sectional sapwood. The capability and agreement of these methods for use with other conifers and/or angiosperms remains to be tested.
Is climate change responsible for recent retreat of the Pine Island Glacier in West Antarctica?
Authors: Bradley Alex , Bett David , Holland Paul , Williams C. Rosie , Arthern Robert
Published: March 2024

Pine Island Glacier is a fast flowing ice stream in West Antarctica. At present, it is rapidly thinning and retreating, and has been since at least the 1970s, when satellite records began. Sediment records indicate that this retreat was initiated in the 1940s, but the influence of climate change on key forcing components only became significant in the 1960s, i.e. the trigger for retreat occurred naturally. However, current ice loss remains responsive to fluctuations in forcing, indicating that Pine Island Glacier is not undergoing a purely unstable retreat after this trigger. This begs the question: to what extent is climate change responsible for the recent retreat of the Pine Island Glacier?Adopting a recently published framework, we assess this question. One major challenge is the computational expense associated with the large ensemble of simulations required to account for significant uncertainties in ice sheet model parameters; to overcome this, we use a two stage Ensemble Kalman Inversion and Model Emulation approach. Ultimately, this procedure yields posterior distributions of parameters, including the trend in forcing resulting from climate change; essentially, this allows us to address the question: given the observed Pine Island Glacier retreat, how large does the trend in forcing have to have been?
Opportunistic Model Intercomparison of the Miocene Ocean Circulation – MioMIP
Authors: Naik Trusha , de Boer Agatha , Coxall Helen , Burls Natalie , Bradshaw Catherine , Donnadieu Yannick , Farnsworth Alexander , Frigola Amanda , Herold Nicholas , Huber Matthew , Karami Pasha , Knorr Gregor , LeGrande Allegra , Lunt Daniel , Prange Matthias , Zhang Yurui
Published: March 2024

During the Miocene epoch (~23-5 Ma), the Earth experienced a notably warmer climate, with global surface temperatures ranging approximately 4°C to 8°C higher than pre-industrial levels, accompanied by atmospheric CO2 concentrations in the range of 400-800 ppm. Throughout this period, tropical ocean gateways underwent constriction or closure, while high-latitude gateways expanded. These developments likely played a pivotal role in shaping the modern ocean circulation structure, with strong bipolar hemispheric overturning in the Atlantic, although the precise mechanisms remain poorly understood. This study explores Miocene ocean circulation through an opportunistic climate model intercomparison (MioMIP1), encompassing 14 simulations that use different paleogeographies, CO2 levels, and vegetation distributions. A consistent feature across all models is the fresher-than-modern Arctic and a resulting increased freshwater export to the North Atlantic. Consequently, the Atlantic Meridional Overturning Circulation (AMOC) appears markedly weaker than its modern counterpart in all simulations, ranging from approximately 1 to 16 Sv. However, there is no discernible correlation between the transport of Arctic freshwater to the Atlantic and the strength of the AMOC across the simulations. Similarly, contrary to earlier suggestions, our analysis reveals that neither Panama nor the Tethys gateway exerts a consistent impact on circulation across the simulations. This implies that the influence of these three straits on circulation dynamics also depends on other factors such as background palaeogeography, CO2 levels, vegetation, or model physics and requires further study. In three out of the 13 simulations, deep overturning in the North Pacific (PMOC) is observed, ranging from approximately 5 to 10 Sv. Notably, in the North Atlantic, the simulations with a higher salinity have a stronger AMOC, and although this is not observed as distinctly in the North Pacific, the simulations with a PMOC exhibit a reduced salinity contrast between the North Pacific and North Atlantic and highlight the salinity feedback in play. A proto-AMOC appears to be developing in most of the simulations, albeit weak. This indicates that while the AMOC began to take shape during the Miocene, it likely attained its modern strength during the late Miocene.
Quartz amorphization to produce porosity in crustal shear zones
Authors: Précigout Jacques , Prigent Cécile , McGill Gina , Arbaret Laurent , Airaghi Laura , Wallis David
Published: March 2024

Micropores are commonly observed in quartz-rich rocks that deformed at depths of the viscous, metamorphic continental crust. Although the presence of such porosity – often occurring with angular, pyramidal shapes – has major implications for fluid circulations and rock strength, whether or not they are produced by deformation remains unclear. Here we provide detailed documentations of pure quartz aggregates decorated by micropores in granitic shear bands from Naxos (Greece). Through estimations of geometrically necessary dislocation densities, we first document very high values (>> 1015 m-2) along intragranular boundaries, several of them containing micropores. We then performed focused ion beam (FIB) cross-sectioning and transmission electron microscopy to image pore shapes along all types of quartz boundaries. Pores do not necessarily arise with angular shapes, but they are systematically embedded within amorphous SiO2, i.e., silica glass, along both grain and intragranular boundaries. FIB volume reconstruction also revealed pyramid-like pits occurring with round-shape faceted pores, the shape of which challenges long-lasting hypotheses for pores to originate. Together with recent studies[1,2], our findings support deformation to produce porosity through (1) mechanical amorphization where dislocations accumulate and (2) fluid exsolution from the resulting glass because of a pressure/stress drop, here attributed to grain boundary sliding. [1] Idrissi, H., Carrez, P. & Cordier, P. On amorphization as a deformation mechanism under high stresses. Current Opinion in Solid State and Materials Science 26: 100976 (2022)[2]Li, B. Y., Li, A. C., Zhao, S. & Meyers, M. A. Amorphization by mechanical deformation. Materials Science & Engineering R 149: 100673 (2022)
Quantifying crustal thickening and surface uplift in the northernmost Central Andes
Authors: Marulanda Sebastián , Parra Mauricio , Leon Santiago , Sobel Edward , Glodny Johannes
Published: March 2024

Since its onset in the Late Cretaceous, episodic mountain building in the Central Andes has shaped the landscape, climate, and biota of western South America through a series of synchronous regional pulses of intensified deformation and surface uplift acting at the scale of the entire orogen. However, despite this common Late Mesozoic through Cenozoic tectonic history, the ~4000 km long Central Andes exhibit remarkable latitudinal differences in both height and width, pointing to the potential importance of local heterogeneities in controlling the magnitude of topographic growth associated with each of the regional mountain building episodes. A thorough understanding of the driving mechanisms behind these latitudinal differences requires first determining the times, rates, magnitudes and spatiotemporal patterns of crustal thickening and surface uplift along the orogen. While this has been done extensively in recent years for the southern and central portions of the Central Andes, such processes are still insufficiently constrained in its northernmost part.In this work, we use new and published whole-rock geochemistry data from the Late Cretaceous to Late Miocene arc-related magmatism recorded in northernmost Peru to quantitatively estimate crustal thickening and surface uplift using empirically calibrated “chemical mohometers” based on the ratios of key trace elements. We compare our results with the tectonostratigraphic evolution and tectonic subsidence history of the adjacent foreland and hinterland basins. Finally, we present new apatite U-Th-Sm/He and apatite fission-track thermochronological data from a transect across the northernmost Central Andes. These data, integrated with structural observations and the reconstructed crustal thickening and surface uplift history, unravel the relative contribution of magmatism and shortening to the observed crustal thickening.
An analysis of strong velocity pulses from the empirical data and dynamic rupture simulations of the 2023 Kahramanmaras earthquake doublets
Authors: Yen Ming-Hsuan , Türker Elif , Cotton Fabrice
Published: March 2024

The Mw 7.8 and Mw 7.5 doublets of the 2023 Turkey seismic sequence show strong velocity pulses that may have caused extensive damage to buildings and structures. We analyze the velocity pulses from the empirical data (both raw and processed) to understand the causes of these for these doublets. The analysis includes a comparison with the velocity pulses from the synthetic data of the Jia et al. (2023) dynamic rupture simulation available for the first Mw 7.8 event and an analysis of the variability of large instrumented earthquakes of the last 30 years. We characterize the properties of the ground motion pulses (e.g., period, velocity, and orientation) using the algorithm proposed by Shahi and Baker (2014). The identified pulses in the synthetic data show the main characteristics of the pulses (periods, PGV). However, the pulse properties in the synthetic data show less variability than the natural variability found in the empirical data, particularly a random behavior in the pulse orientation. The results then indicate that the pulse characteristics in the near-fault regions of large-magnitude earthquakes exhibit a significant variability and that this variability is similar to the one observed in past large earthquakes. This pronounced variability can be attributed to various factors, including directivity effects and site effects. This suggests that the full complexity of earthquake rupture processes and site configurations should be taken into account to be able to capture the high variability in pulse properties.
Identifying modern Neogloboquadrina pachyderma morphotypes from the Central Arctic Ocean through supervised machine learning – a comparison between water column and seafloor sediment populations
Authors: Weitkamp Tirza , Hsiang Allison , Bird Clare , Vermassen Flor , Darling Kate , Coxall Helen
Published: March 2024

Planktonic foraminifera tests are commonly used in geochronology and palaeoceanographic reconstructions as micropaleontological and geochemical proxies. In the high latitude North Atlantic and Arctic, the polar specialist Neogloboquadrina pachyderma is the most common planktonic foraminifera and is known for its morphological plasticity, resulting in the identification of at least 5 morphotypes within a single genotype. The significance of its morphological variability remains uncertain, with hypotheses linking it to ecological/environmental differences, and/or life history stages. However, N. pachyderma morphotype analysis has been largely limited to sediment studies, lacking a systematic exploration of water column populations. Here, we explore this question using a novel supervised machine learning (SML) and automated image processing (AutoMorph software) approach to acquire large morphometric data sets on populations of Central Arctic N. pachyderma from 8 paired plankton net and sediment (box-core) sample sets. This study addresses the ability of SML to discern the established morphotypes and whether alternative morphological models can better represent the morphological diversity. Additionally, this study explores how morphologic variability in living N. pachyderma populations compare with their sedimented counterpart.The results, based on approximately 15.000 N. pachyderma morphotypes, represents the largest data set for a single planktonic foraminifer species and the largest study of this kind based on water column populations in the Arctic Ocean. The highest specimen abundance was found in the upper 100m. Preliminary findings indicate a dominance of small (55-120µm) N. pachyderma specimens, assumed to be juveniles, whereas the sediment assemblage is dominated by heavily encrusted, larger morphotypes. The water column and sediment assemblages are mismatched, potentially due to the much narrower time window recorded in the water column compared to the annual-millennial timescale in the sediments. This study provides new insights into how ecology and life history of N. pachyderma translates to test morphology – a crucial aspect for taxonomy and geological studies.
Soil-crop long-term feedback matters to assess climate change impact on maize yield in Sub-Saharan Africa
Authors: Couëdel Antoine , Falconnier Gatien N. , Adam Myriam , Cardinael Rémi , Boote Kenneth , Justes Eric , Ruane Alex , Smith Ward , Whitbread Anthony , Corbeels Marc ,   co-authors
Published: March 2024

Sub-Saharan Africa (SSA) faces significant food security risks, primarily due to low soil fertility leading to low crop yields. Climate change is expected to worsen food security issues in SSA due to a combined negative impact on crop yield and soil fertility. A common omission from climate change impact studies in SSA is the interaction between change in soil fertility and crop yield. Integrated soil fertility management (ISFM), which includes the combined use of mineral and organic fertilizers, is expected to increase crop yield but it is uncertain how this advantage is maintained with climate change.   We explored the impact of scenarios of change in soil fertility and climate variables (temperature, rainfall, and CO2) on rainfed maize yield in four representative sites in SSA with no input and ISFM management. To do so, we used an ensemble of 15 calibrated soil-crop models. Reset and continuous simulations were performed to assess the impact of soil fertility vs climate change on crop yield. In reset simulations, SOC, soil N and soil water were reinitialized each year with the same initial conditions. In continuous simulations, SOC, soil N and soil water values of a given year were obtained from the simulation of the previous year, allowing cumulative effects on SOC and crop yields.Most models agreed that with current baseline (no input) management, yield changed by a much larger order of magnitude when considering declining soil fertility with baseline climate (-39%), compared with considering constant soil fertility but changes in temperature, rainfall and CO2 (from -12% to +5% depending on the climate variable considered). The interaction between change in soil fertility and climate variables only marginally influenced maize yield (high agreement between models). The model ensemble indicated that when accounting for soil fertility change, the benefits of ISFM systems over no-input systems increased over time (+190%). This increase in ISFM benefits was greater in sites with low initial soil fertility. We advocate for the urgent need to account for soil-crop long-term feedback in climate change studies to avoid large underestimations of climate change and ISFM impact on food production in SSA.