bluuebunny/crossref_metadata_2025 huggingface dataset:
Geometry and mechanics of a complex fault system from deep analysis of seismic sequences within the Irpinia Near Fault Observatory
Authors: Festa Gaetano , Scotto di Uccio Francesco , De Landro Grazia , Elia Luca , Michele Maddalena , Muzellec Titouan , Scala Antonio , Strumia Claudio , Supino Mariano , Beroza Greg , Camanni Giovanni , Chiaraluce Lauro , D'Agostino Nicola , Picozzi Matteo , Zollo Aldo
Published: March 2024

The Irpinia Near Fault Observatory is a dense instrumented infrastructure monitoring the normal fault system of the Irpinia region, in the Southern Apennines (Italy). The area is one of the highest seismic hazard regions in Italy; nevertheless, the background seismicity rate is low, with about 4000 earthquakes detected in the last 15 years of network operation, with a magnitude of completeness of 1.1. Thus, understanding the fault system mechanical state requires high quality data and advanced tools for seismicity location and characterization, along with new monitoring systems, able to catch the earthquake signals at or below the noise level.  

In this study, we investigated the geometrical and mechanical properties that can be inferred from the (micro)seismic sequences occurred during the network operation. The seismic catalogs enhanced through the use of machine learning and similarity-based techniques, and double-difference event relocation show that the events define kilometric-scale structures, sub-parallel to the main faults that generated the M 6.9, 1980 Irpinia earthquake. We estimated the stress release and the rupture area of the events within the sequences, showing that the static stress transfer is the main mechanism of triggering of the events within the sequences. The seismicity delineates slip-driven alignments that can be associated with fault roughness. In the case of the major sequence, the event distribution might also indicate the occurrence of an aseismic deformation episode, too small to be detected by surface GNSS instruments. 

Finally, we also analyzed the seismicity recorded along the 1-year DETECT experiment, during which 200 velocimetric stations were deployed as a constellation of seismic arrays, within Irpinia Near Fault Observatory region. We discovered that deep seismicity mainly occurs in sequences, with most events having a magnitude smaller than the unity. When jointly analyzed with the 3D P-wave tomographic model, these sequences illuminate a SW-dipping, previously unknown, segmented fault with a total length of more than 30 km. This structure could be causative for a future M6+ event, depending on the rupture ability to overcome the geometrical stepover on the fault. 
The Role of Diurnal Hysteresis between Near-surface Temperature and Relative Humidity on Mitigating Near-surface Atmospheric Dryness
Authors: Shih Ching-Hung , Lo Min-Hui
Published: March 2024

Diurnal hysteresis, characterized by a time lag or phase difference between diurnal cycles of two variables, provides valuable insights into land-atmosphere interaction and ecological processes. While it is widely accepted that diurnal surface temperature and relative humidity variations are inversely locked in phase, recent studies have reported diurnal hysteresis between relative humidity and temperature. This phenomenon arises from contributions related to diurnal water vapor variation resulting from local evapotranspiration and water vapor advection from other regions. This study employed a multi-linear regression approach to quantify the phase lag time between temperature and relative humidity by distinguishing linear and non-linear contributions of diurnal temperature variation to relative humidity. Our analysis utilized data from the FLUXNET2015 dataset, which offers ecosystem-scale meteorological measurements worldwide, the HadISD dataset, providing quality-controlled surface weather data globally, and ERA5-Land, offering finer-scale and accurate land reanalysis data on a global scale, to explore the regions exhibiting diurnal hysteresis globally. Our findings reveal the presence of diurnal hysteresis between relative humidity and temperature in coastal, lakeside, and montane regions, notably in New Guinea, southwestern Arabia, the Andes, and the Himalayas. In these regions, the vapor pressure deficit (VPD) is mitigated due to the out-of-phase diurnal relationship between temperature and relative humidity, leading to a smaller underestimation bias in daily VPD when estimated by daily temperature and relative humidity. Even though lower VPD might reduce evapotranspiration in regions showing diurnal hysteresis due to decreased atmospheric demand, the non-local moisture transport provides these regions with additional water vapor. This counters the temperature rise in the morning and aids in sustaining the diurnal hysteretic relationship, maintaining the VPD mitigation in these regions. Furthermore, climate change is likely to change the diurnal hysteretic relationship, posing a threat to VPD mitigation. This study underscores the importance of identifying regions with diurnal hysteresis and highlights the potential implications of changing diurnal hysteretic relationships on local microclimates.
Atmospheric organic matter forms core-shell aerosol particles on mineral surfaces 
Authors: King Martin , McGrory Megan , Ward Andrew
Published: March 2024

Core-shell particles have been created in an optical trap by placing thin films (∼ 10−40 nm) of atmospheric matter collected and extracted from urban aerosol and wood-burning smoke samples onto mineral silica particles (diameter ∼2 μm). The structures formed by these samples were a symmetrical core-shell and not an engulfing structure or asymmetric structure. Mie scattering of light from the optically trapped particles demonstrated that the experimental and calculated Mie spectra were consistent with the scattering of light by core-shell aerosol, and not with the scattering of homogeneous or partially-engulfed aerosol. The work presented may be the first experimental demonstration of organic materials extracted from the atmosphere favouring a symmetrical core-shell morphology on solid particles. Furthermore oxidation of these core-shell particles with ozone demonstrated a thinning shell of organic film and no change in morphology . Figure 1 demonstrates our initial results with an increasing thicker core-shell film of woodsmoke extract on a silica core particle and Figure 2 demonstrates the ability to follow refractive index and film thickness during oxidation of this thin film. The Mie scattering allows calculation of the refractive indices as a function of wavelength and film thicknesses. The refractive index of ∼40nm thick shells were determined to a precision of ∼0.01 and ∼0.006, and the thickness of the shell was determined to a precision of 0.2nm and 0.1nm for the aged urban and wood-smoke samples respectively.  The core-shell morphology, significantly reduces the complexity of atmospheric modelling of the radiative properties of these aerosol.

 
Carbonation experiment of basaltic crystals and glasses using supercritical CO2 under different PT conditions
Authors: Pierozzi Andrea , Rateau Remi , Orlando Andrea , Borrini Daniele , Rodriguez Blanco Juan Diego
Published: March 2024

Greenhouse gases, especially CO2, have been increasing worldwide. To address this issue, carbon capture and storage (CCS) technology has been researched and developed to decrease atmospheric CO2 concentrations. Among the various methods studied, mineral carbonation is an emerging technique that involves the reaction between Ca-Mg-Fe bearing basaltic rocks and CO2 to store it in the rocks through the formation of carbonate minerals. The CarbFix project in Iceland is an example of this method. However, there is still much to learn about the physicochemical relationships between water, dissolved ions, and growing crystals in complex multicomponent systems at the atomic and nanoscale, which are essential for the successful implementation of CCS in basaltic reservoirs.One of the methods being explored in this study involves the utilization of supercritical CO2, which is achieved above the critical temperature and pressure of 30.97 °C and 73.773 bar, respectively. Under these conditions, CO2 exhibits both liquid and gaseous properties. This work shows the results of an experiment conducted in basaltic crystals and basaltic glasses at the temperature and pressure range of 100 and 200 ºC, and 64 to 79 bar, to investigate the reaction between CO2(sc), water, natural forsterite and basaltic glass, which have demonstrated that under these conditions we have the partial dissolution of the previous mineralogical phases, and the subsequent formation of new alteration phases, but also the precipitation of carbonates with Ca, Mg and Fe. We will compare our results with studies of carbonation of synthetic forsterite.  
Combination of Multiple Investigation Methods to Reveal the Recharge Area of a Karst Aquifer
Authors: Calli Suleyman Selim , Celik Mehmet , Karakas Zehra Semra
Published: March 2024

Karst aquifers are heterogeneous groundwater systems having both diffuse and concentrated recharge mechanisms. Since their complex recharge, storage, and discharge characteristics, the groundwater divide is generally different from the topographical catchment borders. As a result, karst hydrogeologists are using different methods to obtain more certain recharge areas. Tracer tests are very important and preferred tools to obtain the groundwater recharge areas. An ideal tracer must be detectable in very low concentrations, conservative along the pathways, and cost-effective. In this manner, mineralogical analysis of the suspended particles would be a very good alternative to the isotopic, biochemical, and dye tracers due to the easy collection and cost-efficient analysis methods. In the present study, we collected rock samples from approximately 10 locations surrounding the potential recharge area of the karst aquifer covering all lithological units surrounding the study area. Then, we collected sediment samples at the discharge outlet of the karst spring and suspended particles by filtering the water samples. We analyzed both the sediments and rock samples by the petrographic thin-sections, XRD whole rock, and XRD-clay fraction analysis to compare the minerals between the rock and sediment samples. We obtained Eocene-aged Planktonic Foraminiferal fossils in the spring sediments (in the thin sections), which perfectly fit the Eocene-aged limestone formation in the study area. By overlapping the lithological outcrop of the formation with the isotope-derived recharge elevation, we obtained the locations of two major dolines in the study area. As the final step, we validated our results by conducting dye-tracer tests from these points, and we recovered the tracer dye from the karst springs.
Investigation on Flood Resistance Characteristics of Waterfront Plants: A Case Study of Baxi Stream in Fujian Province, China
Authors: Chen Jinn-Chyi , Li Feng-Bin , Fan Jian-Qiang , Lai Xi-Zhu , Li Gui-Liang , Huang Wen-Sun
Published: March 2024

Urban waterfront green spaces are pivotal in maintaining urban-rural landscape patterns, enhancing habitats and biodiversity, modulating temperature and humidity, purifying air, mitigating noise, and improving the urban microclimate. They play a crucial role in regulating the urban ecological environment and enhancing natural environmental capacity. Several waterfront plants demonstrate a high adaptability to local hydrological and climatic conditions, and are resilient to drastic water level changes. Their roots can stabilize riverbanks or riverbeds during abnormal floods. However, there is a dearth of empirical research data on these native plants. This study focuses on the flood that occurred on June 13, 2022, in Baxi Stream, Yong'an City, Fujian Province, China, causing damage to revetments, sidewalks, plants, roads, and disrupting urban traffic. Utilizing this flood event as a case study, we collected terrain data via real-time kinematic (RTK) surveying and unmanned aerial vehicles (UAV). We examined flood traces on structures, buildings, and trees to determine the water level, water surface slope, and inundation depth of waterfront green space during the flood event. We also investigated several common invasive natural plants, including Gramineae, Cyperaceae, and Polygonaceae families, and artificially cultivated plants like Cannaceae. Using the plant type survey data, we calculated the shear stress and flow velocity during the flood event to comprehend the anti-flow characteristics of waterfront plants in the study area. Our findings revealed that naturally invasive Gramineous plants, such as Saccharum spontaneum L. and Phragmites australis, possess a high flood resilience, withstanding  mean flow velocity exceeding 5m/s. This study can provide a valuable reference for the selection of greening plants for waterfronts or plant engineering methods to safeguard waterfronts or riverbeds.
Keeping the PACE with the NASA Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission
Authors: Cetinic Ivona , Werdell Jeremy
Published: March 2024

The PACE mission, scheduled to launch in Feb 2024, represents NASA’s next great investment in ocean biology, clouds, and aerosol data records to enable advanced insight into ocean and atmospheric responses to Earth’s changing climate. A key aspect of PACE is its inclusion of an advanced satellite radiometer known as the Ocean Color Instrument (OCI) to measure the “colors” of the ocean, land, and atmosphere. Whereas heritage instruments observe roughly six visible wavelengths from blue to red, OCI will collect a continuum of colors that span the visible rainbow from the ultraviolet to near infrared and beyond. In doing so, OCI will be the first of its kind to collect such “hyper”spectral radiometry on daily global scales, which will allow unique and highly advanced continuous identification of aquatic phytoplankton communities, as well as atmospheric aerosol, cloud, and terrestrial data products. PACE will also include two small multi-angle polarimeters that also measure “color”, but with additional capabilities to do so in multiple directions and with consideration of polarized light. Both polarimeters will substantially improve how we view our atmosphere and the interaction of airborne particles and clouds.  Overall, This PACE instrument suite will revolutionize studies of global biogeochemistry, carbon cycles, and hydrosols / aerosols in the ocean-atmosphere system.
Fitting, Filling, and Filtering of Salt Dilution Breakthrough Curves for Reduced Field Time, Increased Accuracy, and Optimized Happiness
Authors: Sentlinger Gabriel , Anderson Zachary
Published: March 2024

The Salt Dilution Tracer method has been used in some form for >100 years (Allen and Taylor, 1923, Østrem, G. 1964, Moore, D 2004).  Recently, the method has undergone a renaissance as techniques and equipment have been improved, facilitating lower dosing (
Revisiting the ‘East African Paradox’: CMIP6 models also fail to simulate observed drying trends in the Horn of Africa Long Rains
Authors: Schwarzwald Kevin , Seager Richard
Published: March 2024

The recent 5-season drought in the Horn of Africa, which contributed to food security issues that nearly resulted in a declaration of famine by the UN, has renewed interest in the “East African Paradox” (cf. Rowell et al., 2015): despite observed drying trends in the March-April-May “long” rains, global coupled climate models—whose output is increasingly used to drive hydrological models and inform projections of the socioeconomic risks of climate change in East Africa—project increases in seasonal rainfall totals over both the historical period and throughout future projections in the region. This ‘Paradox’ could arise from low-frequency internal variability causing drying even if long-term trends are wetting or from structural biases in climate models (e.g. simulation of the equatorial Pacific Ocean) that cause spurious trends in model simulations. Large Ensembles, including for SST-forced runs, make differentiating between internal variability and biases in model mean behavior more feasible, and another decade of observational data since the emergence of the ‘Paradox’ helps improve our understanding of historic internal variability.We use a large multi-model ensemble of opportunity of coupled and SST-forced runs from the latest model generation (CMIP6), spanning the observational record, to revisit the magnitude and causes of the ‘Paradox’. We find that drying trends in the long rains are timescale-dependent and weaker than they were during the peak ‘Paradox’ period. This is mostly well modeled by the SST-forced ensemble, though coupled models continue to have erroneously strong wetting trends. The ‘Paradox’ therefore is reduced to what are the causes of low frequency SST trends and why coupled models cannot reproduce them.  We will discuss if these changes are the result of natural variability temporally masking the forced trend and what the sign of that trend might be.  These results have implications for projections of future climate impacts with a potentially quantifiable range of internal variability providing more actionable information than the deep uncertainty on forced trends introduced by structural model errors.
Granger causality in tail
Authors: Bodik Juraj
Published: March 2024

Granger causality plays a pivotal role in uncovering directional relationships among time-varying variables and enhancing decision-making in complex systems. While this notion gains heightened importance during extreme events in highly volatile periods,state-of-the-art methods primarily focus on causality within the body of the distribution. We introduce a new rigorous mathematical framework for “Granger causality in tail,” designed to evaluate whether an extreme event in one time series causes a corresponding extreme event in another. Moreover, we describe how we can quantify the magnitude of the causal impact of an extreme event on other variables. 
We establish equivalences between our Granger causality in tail and other causal concepts, including “classical Granger causality,” “Sims causality,” and “structural causality.” By proving the key properties of Granger causality in tail, we assert its usefulness in high-dimensional complex systems with potential hidden confounders. Here, to model the tails of the variables, we utilize the “extreme value theory” framework. We also propose an inference method for detecting the presence of Granger causality in tail and provide insights into the asymptotic properties of our estimator within the framework of a stochastic recurrence equation (SRE) model.
Household Chemicals Amplifying Urban Pollution
Authors: Gkatzelis Georgios ,   AEROMMA Team
Published: March 2024

Urban aerosol particles are one of the largest human health hazards globally. A significant fraction of urban aerosol is secondary, .i.e., formed via atmospheric chemical reactions of emitted trace gases, with secondary organic aerosol (SOA) driving health impacts in urban air. Decades of air quality regulations have substantially reduced the motor vehicle emissions of organic compounds that act as precursors to SOA and ozone pollution. In this presentation we show that volatile chemical products from household chemicals are becoming one of the largest sources of organic vapors in US and European cities. We highlight the potential of such emission sources to form ozone and SOA using data collected during mobile measurements conducted in 2018 and aircraft measurements conducted in the summer of 2023 on NASA's DC-8 aircraft as part of the AEROMMA mission. Moreover, we will emphasize upcoming measurements in Germany utilizing a Zeppelin as an aerial platform, which will allow us to probe the urban “breath” of European cities and quantify the chemical evolution and SOA production from volatile chemical products downwind of urban centers. These measurements will be complemented by controlled atmospheric simulation chamber experiments to oxidize urban emissions and retrieve their SOA yields as a parametrization to be used by chemical transport models.
Large CO2 and CH4 emissions from drainage ditches in oil palm plantations on peat soil
Authors: Kasak Kuno , Soosaar Kaido , Dronova Iryna , Melling Lulie , Wong Gx , Sangok Faustina , Ranniku Reti , Villa Jorge , Mander Ülo
Published: March 2024

Tropical peatlands contain approximately 17% of the total global peat carbon and are under pressure for deforestation and the formation of oil palm plantations. The conversion of large peatland forests in Malaysia and Indonesia has resulted in these plantations becoming substantial sources of greenhouse gases. While previous research has focused on estimating the C loss from the soil, the impact of drainage ditches on the overall C budget remains largely unexplored. However, on average, drainage ditches with free surface water cover roughly one-third of the total drained land. Hence, these ditches could be significant CO2 and CH4 sources and while not considered for C budget calculation it could lead to significant underestimation of total C loss from these ecosystems. Here we represent the CO2 and CH4 emissions from drainage ditches in an oil palm plantation located in Sarawak, Malaysia. CO2 and CH4 samples (n=107) were collected from a recently created plantation (~5 y.o.) and from the plantation, which is under second rotation using a floating chamber and LI7810 analyzer (LICOR Biosciences). Additional parameters such as water pH, electrical conductivity, dissolved oxygen concentration, temperature, turbidity, salinity, water level, and dissolved gas concentration (dCO2 and dCH4; analyzed in the lab with GC-2014, Shimadzu) were measured from each sampling spot. After measurements, we collected sediment samples for soil TN, TOC, TIC, DOC, DIC, and DN analyses. The results revealed that the average net CH4 flux (combining both diffusive and ebullitive emissions) from drainage ditches in the first and second rotations was 0.31 ± 0.65 g m-2 d-1 and 0.29 ± 0.54 g CH4-C m-2 d-1, respectively. The average CO2 flux from the first and second rotations was 4.27 ± 2.1 g CO2-C m-2 d-1 and 4.4 ± 2.5 g CO2-C m-2 d-1, respectively. To estimate surface water coverage at the whole site, green vegetation, open water, and bare soil were mapped from the site drone imagery collected in Spring 2023 using object-based supervised classification and spectral indicators computed from red, green, and blue image bands. The total surface water coverage will give us an understanding of the total CO2 and CH4 flux in the entire region that originates from drainage ditches. Our results strongly underscore the significant role of drainage ditches in contributing to the overall carbon loss from oil palm plantations on organic soils. Proper consideration of these emissions is essential for accurate carbon budget calculations and for devising effective strategies to mitigate greenhouse gas emissions in these ecosystems.
Morphology and Composition of Murtoos and Meltwater Corridors Associated with the Cordilleran Ice Sheet in South-Central British Columbia
Authors: Sodeman Alexander , Brennand Tracy
Published: March 2024

Subglacial hydrology has been shown to significantly influence ice sheet dynamics in both Greenland and Antarctica.  Though direct observation and study of the subglacial hydrological network is limited by the presence of thick overlying ice, insights into subglacial hydraulics can be gained by studying landforms derived from meltwater in deglaciated landscapes.  Murtoos and meltwater corridors are examples of meltwater derived landforms, the former being triangular-shaped hills flanked by shallow troughs, and the latter being broad, shallow landforms with clear erosional boundaries and distinct internal morphologies.  While meltwater corridors have been previously identified in British Columbia, this study represents the first identification and study of murtoos associated with the Cordilleran Ice Sheet.  We identified a large network of murtoos and meltwater corridors in south-central British Columbia and studied both the morphology and internal composition of both landform groups using high resolution elevation data and near surface geophysical surveys. Electrical resistivity tomography (ERT) and ground-penetrating radar (GPR) surveys on different murtoos reveal a homogeneous internal composition of sandy diamicton, while the troughs lateral to murtoos contain sorted sediment.  We interpret the murtoos as subglacial meltwater erosional remnants, their morphology determined by meltwater erosion of the lateral troughs.  The meltwater corridors studied contain two distinct morpho-stratigraphic relationships: channelized reaches exhibiting shallow intersecting and/or parallel troughs floored by sandy diamicton, the residuals resembling glacial curvilineations; and flat bed reaches with narrow eskers composed of fine sand and gravel.  We interpret the channelized and flat bed reaches as being formed by subglacial meltwater erosion and deposition, respectively, with the switch in process and form being determined by bed topography.  Together, these landforms suggest extremely wet-bed conditions during deglaciation of the Cordilleran Ice Sheet, with widespread subglacial meltwater erosion and deposition.  These observations provide insight into the likely conditions beneath portions of the Greenland and/or Antarctic ice sheets where widespread meltwater production has been reported, such as the western land terminating portion of the Greenland Ice Sheet.
How does nitrogen control soil organic matter composition? – A theory and model
Authors: Yeung Chun Chung , Bugmann Harald , Hagedorn Frank , Díaz-Yáñez Olalla
Published: March 2024

Current soil biogeochemical models have difficulties matching the observed composition of soil organic matter (i.e., the relative proportions of deadwood, raw litter, organic horizon, particulate organic carbon, and mineral-associated organic carbon). In reality, nitrogen (N) controls microbial decomposition and physiological processes, whereas in most models it is merely considered a plant nutrient. In addition, many N fertilization studies have shown that N exerts different effects on different C pools via changing exoenzyme activities, microbial growth, and necromass production via microbial turnover. These divergent effects control SOM composition and have C-cycle consequences.We expanded the CENTURY model by incorporating multiple hypothesized microbial responses to nitrogen availability, including 1) decomposition reduction of recalcitrant substrates when N is in excess; 2) decomposition stimulation of high C:N substrates when N limitation is alleviated; 3) microbial adaptation of turnover rate; 4) microbial adaptation of CUE; and 5) secondary feedback to decomposition via changes in microbial biomass in response to N. We systematically tested multiple model variants using two sets of simulations, one along a natural N gradient in Swiss forests, and another one with artificially increased N input (i.e., simulating an N-fertilization experiment). We evaluated the simulated outputs using data on soil organic matter fraction stocks, their relative proportions, and temporal responses under N addition.From the simulation results, we identified the necessary processes to explain the temporal response pattern of different C pools to N addition, in accordance with findings from meta-analyses. In addition, we identified patterns of SOM composition over a natural gradient of N supply (no artificial N addition), which can again be explained by the N-driven processes we implemented. We conclude that considering the direct effects of nitrogen as a key additional constraint on microbial processes is essential to improve the realism and accuracy of soil biogeochemistry models.
Kinetic signatures, asymmetries, and FTEs associated with Mercury’s dayside magnetopause reconnection as revealed by 3D MHD-AEPIC simulations
Authors: Jia Xianzhe , Li Changkun , Chen Yuxi , Toth Gabor
Published: March 2024

Mercury possesses a dynamic magnetosphere driven primarily by magnetic reconnection occurring regularly at the magnetopause and in the magnetotail. Using the Magnetohydrodynamics with Adaptively Embedded Particle-in-Cell (MHD-AEPIC) model, we have performed a series of global simulations with different upstream conditions to study in detail the kinetic signatures, asymmetries, and flux transfer events (FTEs) associated with Mercury’s dayside magnetopause reconnection. By treating both ions and electrons kinetically, the embedded PIC model reveals crescent-shaped phase-space distributions near reconnection sites, counter-streaming ion populations in the cusp region, and strong temperature anisotropies within FTEs. A novel algorithm has been developed to automatically identify reconnection sites in our 3D simulations. The spatial distribution of reconnection sites as modeled by the PIC code exhibits notable dawn-dusk asymmetries, likely due to such kinetic effects as X-line spreading and Hall effects. Across all simulations, simulated FTEs occur quasi-periodically every few seconds with their key properties showing clear dependencies on the upstream solar wind Alfvénic Mach number and the IMF orientation, consistent with MESSENGER observations and previous Hall-MHD simulations. FTEs formed in our MHD-AEPIC model are found to contribute a significant amount (~ 3% - 36%) of the total open flux generated at the dayside magnetopause. Taken together, the results from our MHD-AEPIC simulations provide new insights into the kinetic processes associated with Mercury’s magnetopause reconnection that should prove useful for interpreting in situ observations from MESSENGER and BepiColombo.
Modelled asymmetric Antarctic glaciation during the Eocene-Oligocene Transition
Authors: Knahl Hanna , Lohmann Gerrit , Klages Johann Philipp , Niu Lu , Gierz Paul
Published: March 2024

The evolution from greenhouse to icehouse climate during the Eocene-Oligocene Transition (EOT) (~34.4–33.7 Ma) is associated with a drastic cooling of global climate and significant ice sheet build-up. However, extent and location of the such early permanent ice masses are still largely unknown. Here, we coupled the AWI-Earth System Model with the Parallel Ice Sheet Model to draw a bigger picture of the relationship between Antarctic ice sheet presence and global climate dynamics during the EOT and the Early Oligocene Glacial Maximum (EOGM) just afterwards.Our model results reveal an asymmetric ice sheet cover, and notably, identify a CO2-threshold necessary for initiating marine-terminating ice sheet advance onto West Antarctic continental shelves—one major component in Earth's paleoclimatic puzzle. We identify the Southern Ocean dynamics as a direct result of Southern gateway configurations to be a key driver of East Antarctic ice sheet growth. Our Antarctic climate and vegetation simulations match available proxy data well for this period of fundamental change. Therefore, our new simulations significantly contribute to a much deeper understanding of Antarctic ice sheet growth during the EOT and subsequent EOGM, thereby highlighting the importance of Southern high latitude environmental change for controlling Earth’s climate dynamics.
Hydrogeochemical And Isotopic Assesment of The Open Mine Pit Lakes Near Kesikköprü Dam Area, Türkiye
Authors: Arslan Şebnem , Yurttaş Olgu
Published: March 2024

In cases where the excavation depth reaches the groundwater level as a result of open-pit surface mining operations, open mine pit lakes (MPL) form by the discharge of groundwater to the surface. Processes known to affect the MPL chemistry include groundwater inflow, direct precipitation, pit wall-precipitation contact, groundwater-wall rock interaction, evaporation, and other geochemical and limnological processes taking place within the MPL. While changing the hydrogeological system, mining activities might also affect the groundwater chemistry. Degradation of groundwater quality might occur as a result of the interaction between wall-rock and groundwater within the MPL. For this reason, the chemical characteristics of these mine lakes should be revealed in order to protect the groundwater systems and also before using the water inside MPL’s for different purposes like irrigation. Kesikköprü Dam is a dam located in Bala district of Ankara province, the capital of Türkiye, and has been providing drinking water to Ankara in recent years. Although mining activities have been carried out around this dam since the 1950s, where one of Turkey's richest iron deposits is located, no hydrogeological or hydrogeochemical studies have been carried out prior to this study. Therefore, the aim of this study is to evaluate the hydrogeochemical and stable isotopic characteristics of the mine lakes formed as a result of iron mining activities around Kesikköprü Dam. Within this study, three MPL’s were evaluated whose surface areas range from 0.27 ha to 0.92 ha. The pH and Electrical Conductivity values of these three lakes vary between 8.47-8.58 and 883-2500 µS/cm, respectively. According to the major ion chemistry analyses results, Na, Ca and Mg are the dominant major cations and SO4 and HCO3 are the dominant major anions. The major ion chemistry of these lakes have been influenced by reverse ion exchange processes. The MPL waters are oversaturated with respect to certain minerals like dolomite, aragonite, calcite and magnesite. There is dissolved arsenic in concentrations up to 16 µg/l. Dissolved arsenic is found in the form of pentavalent arsenic (As5+). The stable isotopes of hydrogen and oxygen suggest that there is evaporation from the lake surfaces and the isotopic signatures of MPL water samples prior to evaporation unveiled that there is contribution of groundwater inflow from a shallow groundwater system in the area. The abandoned MPLS’s should be rehabilitated so as to prevent exposure of the groundwater systems which become vulnerable to contaminatation.Keywords: Open Mine Pit Lakes; Hydrogeochemistry; Stable Isotopes; Dissolved arsenic; Kesikköprü Dam, Ankara; Türkiye
Permafrost thermal response to improved soil hydro-thermodynamics in historical and scenario simulations with a modified version of the MPI-ESM 
Authors: García-Pereira Félix , González-Rouco Jesús Fidel , Meabe-Yanguas Nagore , Steinert Norman Julius , Jungclaus Johann , de Vrese Philip , Lorenz Stephan
Published: March 2024

Soil warming is particularly sensitive in Arctic regions, underlain by permafrost. Permafrost degradation with warming enhances the release of substantial amounts of carbon into the atmosphere, which acts as a positive radiative feedback. However, the increasing temperature is not the only factor affecting permafrost degradation. Water availability changes affecting the Arctic, induced by changes in the atmospheric general circulation considerably affect the soil moisture and ice presence and subsequently thermal structure in permafrost regions. The interaction between soil hydrology and thermodynamics is still poorly represented by most of the CMIP6 land surface models (LSMs), mainly in terms of the soil depth, vertical resolution, and coupling between hydrology and thermodynamics.This work explores the response of the Max Planck Institute Earth System Model (MPI-ESM) in historical and scenario simulations to changes in the hydrological and thermodynamic features of its LSM, JSBACH, in permafrost-affected regions. An ensemble of experiments was performed with varying soil depth and vertical resolution under two configurations of the hydro-thermodynamical coupling, which generate comparatively drier or wetter conditions over permafrost areas. Results show that deepening JSBACH reduces the intensity of near-surface warming, reducing the deep permafrost degradation area by ca. 2 million km2 and constraining the active layer thickness deepening by the end of the 21st century in high radiative forcing scenarios. Nevertheless, the largest impacts on permafrost extent and active layer thickness are produced by the dry and wet settings, which yield diverging soil moisture and warming conditions during the 21st century. These two configurations show differences in near-surface and deep permafrost extent of up to 5 million km2 by the end of the 21st century.
Temporal growth of epitaxial layers in the CaCO3-REECO3OH system during mineral replacement processes
Authors: Rodriguez-Blanco Juan , Szucs Adrienn Maria , Rateau Remi , Maddin Melanie , Terribili Luca
Published: March 2024

Mineral replacement reactions are essential for the understanding of the genesis and chemistry of REE-bearing carbonatite deposits. Many of these reactions involve interaction of Ca-Mg and REE carbonate phases, leading to the formation of minerals with complex compositions and structures.This study explores the oriented surface precipitation of REE carbonates during the interaction of individual and multiple REE-bearing aqueous solutions with calcite and aragonite (CaCO3) at low hydrothermal conditions (25-220 °C). This mineral-fluid interaction is translated into a temperature-dependent solvent-mediated surface precipitation and subsequent pseudomorphic mineral replacement of the CaCO3 seeds by newly formed REE carbonates. This complex replacement sequence includes the crystallisation of metastable kozoite (orthorhombic REECO3OH) via the formation of individual spindle-shaped crystals following a transient non-random orientation on the surface of the host grains, gradually covering their full surfaces.Our experiments show that the likelihood of formation of the oriented overgrowth and its stability are controlled by structural constraints which in turn depend on four factors: temperature, ionic radii and ionic potential of the REE in the system, and dissolution rate of the host CaCO3 minerals. Also, we demonstrate that REE elements can be rapidly immobilized as REE hydroxicarbonates, even at low hydrothermal conditions. An explanation of the epitaxial overgrowth’s configuration and the atomic arrangement of the structures of the CaCO3 polymorphs and REE-kozoite will be discussed. [1] Szucs AM et al. Reaction Pathways toward the Formation of Bastnäsite: Replacement of Calcite by Rare Earth Carbonates. Crystal Growth & Design, 2021;21(1):512–527.[2] Szucs AM et al. Targeted Crystallization of Rare Earth Carbonate Polymorphs at Hydrothermal Conditions via Mineral Replacement Reactions. Global Challenges. 2022;2200085.
Climate, culture and population size
Authors: Timmermann Axel , Wasay Abdul , Raia Pasquale , Ruan Jiaoyang
Published: March 2024

Human history is full of examples documenting that cultural innovations played a key role in reducing the impact of environmental stress on early populations. Over the past 1 million years this type of adaptation (e.g., clothing, shelter, hunting techniques, social behaviour) likely also increased human population size. Humans are cumulative cultural learners, who can integrate knowledge and culture from one generation to the next. The larger the number of interacting people, the faster the rate of innovation.  Here we introduce a stochastic consumer-resource modeling framework, that simulates the dynamics of cultural transmission, learning, and innovation, population size, and resource depletion in a changing environment. Culture is introduced as a booster to carrying capacity. A zero-dimensional version of the model simulates nonlinear phase-synchronization between culture, population and external climate forcings. We will also present the first results of the model in 2 dimensions with full global resolution and 3 interacting hominin species to assess which role differences in cultural innovation played in the extinction of Neanderthals and Denisovans.  
Changes in the residence time of a spring in a tectonic active zone of central Mexico
Authors: Sierra Garcia Betsabe Atalia , Olea-Olea Selene , Medina Ortega Priscila
Published: March 2024

The residence time of a spring located in central Mexico has been affected by seismic activity. The region is influenced by the interaction of five tectonic plates - Cocos, North American, Pacific, Rivera, and Caribbean - with convergent, divergent, and transform boundaries, leading to frequent earthquakes.The spring, known as the name “Agua Hedionda”, has therapeutic properties due to sulfate concentrations exceeding 1 g/L that contributes significantly to the local economy. However, the earthquake of magnitude 7.1 in 2017 had a substantial impact, particularly on the flow quantity and sulfate concentrations, evidencing the vulnerability of the spring and, consequently, the community's economy.To comprehend the vulnerability and changes in the spring, data of tracers (O-18, H-2, H-3, C-14), major ions and flow measurements were collected in 2022.Then, these data were compared with pre- and post-earthquake information.Tracers facilitated the estimation of residence time for water reaching the spring, indicating a regional flow after the earthquake and an intermediate flow before and currently. The chemical and isotopic data suggest a mixing of flows.Tectonic movements imply that the spring received water with a longer residence time compared to its original state. The combined analysis of these data in tectonically active areas offers valuable insights into changes in residence times, thereby understanding variations and the vulnerability of groundwater resources.
Modeling the Mercury Cycle in the Sea Ice Environment: A Buffer between the Polar Atmosphere and Ocean
Authors: Huang Shaojian , Wang Feiyue , Yuan Tengfei , Song Zhengcheng , Wu Peipei , Zhang Yanxu
Published: March 2024

Sea ice (including overlying snow) is a dynamic interface between the atmosphere and the ocean, influencing the mercury (Hg) cycling in polar oceans. However, a large-scale and process-based model for the Hg cycle in the sea ice environment is lacking, hampering our understanding of regional Hg budget and critical processes. Here, we develop a comprehensive model for the Hg cycle at the ocean–sea ice–atmosphere interface with constraints from observational polar cryospheric data. We find that seasonal patterns of average total Hg (THg) in snow are governed by snow thermodynamics and deposition, peaking in springtime (Arctic: 5.9 ng/L; Antarctic: 5.3 ng/L) and minimizing during ice formation (Arctic: 1.0 ng/L, Antarctic: 0.5 ng/L). Arctic and Antarctic sea ice exhibited THg concentration peaks in summer (0.25 ng/L) and spring (0.28 ng/L), respectively, governed by different snow Hg transmission pathways. Antarctic snow-ice formation facilitates Hg transfer to sea ice during spring, while in the Arctic, snow Hg is primarily moved through snowmelt. Overall, first-year sea ice acts as a buffer, receiving atmospheric Hg during ice growth and releasing it to the ocean in summer, influencing polar atmospheric and seawater Hg concentrations. Our model can assess climate change effects on polar Hg cycles and evaluate the Minamata Convention’s effectiveness for Arctic populations.
Probabilistic optimal transport-driven inversion of the 2012 Palisades rockfall seismic source
Authors: Ursu Rebeca , Naylor Mark , Tang Hui , Turowski Jens M.
Published: March 2024

During rockfall events, the seismic waves are generated in response to the time-varying normal and tangential forces between the Earth and colliding and sliding mass. These forces carry information about the nature of the generative seismic source; hence, the source dynamics can be estimated. Several studies have used forward modeling to determine the amplitude and duration of these forces and, implicitly, the source process that could generate the observed seismic waves. Through running multiple forward models, the force history inversion involves adjusting the force amplitude and duration to minimize the misfit between the proposed source model, convoluted with the force-impulse Green’s functions, and the observations. In the Bayesian framework, the normal likelihood function is traditionally used to measure the misfit between the observed and predicted waveforms with respect to amplitude. However, the normal likelihood function is insensitive to the potential misalignment of the waveforms in time. Moreover, the relevant parameter space often exhibits multiple local minima, which may lead to a convergence to a minimum that does not present the global optimum. Optimal transport distances-driven exponential likelihoods were recently proposed as alternatives thanks to their ability to capture the time structure of the signals. We employed a Metropolis-Hastings sampling strategy in the probabilistic framework to reconstruct the 2012 Palisades rockfall seismic source using two implementations of the Wasserstein distance-based exponential likelihood function. The first implementation transforms between density functions, which are always positive and integrate to one. Therefore, it requires the transformation of the signals into probability density functions, which is done here via a modified graph-space transform scheme. The second method is applied directly to the signals. We evaluated the robustness of the two implementations of the Wasserstein distance-based exponential likelihood function in simulating the source characteristics with respect to the normal likelihood. Preliminary results show that contrary to the expectations, using optimal transport distances-driven exponential likelihoods leads to negligible improvement in the fit to the observed waveform.
Multiple-approaching to architectures and micro-structures of the Siliurian chain corals Halysites from the Shiniulan Formation, Guizhou, South China
Authors: Ren Xinyi , Zhang Zhifei
Published: March 2024

In Guizhou province, Silurian reefs are mostly composed of Tabulate corals, Stromatoporoids, Rugose. As the main reef-building organism, coral reefs have always attracted the attention of researchers. In previous study, predecessors mainly focus on the morphology and taxonomy of coral fossils, using traditional thin slices and hand specimen analysis methods, but the thin slices cause irreversible damage to the fossil, and this method leads to loss of useful information, hand specimens can only provide surface information, can not observe the three-dimensional information of fossils from multiple angles. Therefore, non-traditional micro-XRF, Micro-CT, SEM and Raman were applied in Halysites researches that 2D compositional analysis and 3D microscopic nondestructive morphology reconstruction were established. Chain corals and fillers in the marl are preserved as Calcium Carbonate, however, the fossils are significantly more enriched in C, and Ca elements, coral polyps Coral worms secrete Calcium Carbonate to create hard housing, and provide protection for soft bodies. Coral individuals are linked by connecting Tabule, and no structure such as connecting pore and connecting plate are observed. Tabulate coral is the primary teaching specimen, providing a model for understanding coral reef building. Combined with the thin section and CT, It allows for a simple and intuitive way of teaching paleontology. Meanwhile, This paper is an endeavor to provide comparable examples of skeletal Ca-Carbonate of post-Cambrian colony animals as to understand the diversity of structural patterns and growth modes in earliest skeletal metazoans across the Ediacaran-Cambrian boundary.